package js_parser

import (
	"fmt"
	"math"
	"reflect"
	"sort"
	"strings"
	"unsafe"

	"github.com/evanw/esbuild/internal/ast"
	"github.com/evanw/esbuild/internal/compat"
	"github.com/evanw/esbuild/internal/config"
	"github.com/evanw/esbuild/internal/js_ast"
	"github.com/evanw/esbuild/internal/js_lexer"
	"github.com/evanw/esbuild/internal/logger"
	"github.com/evanw/esbuild/internal/renamer"
	"github.com/evanw/esbuild/internal/runtime"
)

// This parser does two passes:
//
// 1. Parse the source into an AST, create the scope tree, and declare symbols.
//
// 2. Visit each node in the AST, bind identifiers to declared symbols, do
//    constant folding, substitute compile-time variable definitions, and
//    lower certain syntactic constructs as appropriate given the language
//    target.
//
// So many things have been put in so few passes because we want to minimize
// the number of full-tree passes to improve performance. However, we need
// to have at least two separate passes to handle variable hoisting. See the
// comment about scopesInOrder below for more information.
type parser struct {
	options                  Options
	log                      logger.Log
	source                   logger.Source
	lexer                    js_lexer.Lexer
	allowIn                  bool
	allowPrivateIdentifiers  bool
	hasTopLevelReturn        bool
	fnOrArrowDataParse       fnOrArrowDataParse
	fnOrArrowDataVisit       fnOrArrowDataVisit
	fnOnlyDataVisit          fnOnlyDataVisit
	latestReturnHadSemicolon bool
	hasImportMeta            bool
	allocatedNames           []string
	latestArrowArgLoc        logger.Loc
	forbidSuffixAfterAsLoc   logger.Loc
	currentScope             *js_ast.Scope
	scopesForCurrentPart     []*js_ast.Scope
	symbols                  []js_ast.Symbol
	tsUseCounts              []uint32
	exportsRef               js_ast.Ref
	requireRef               js_ast.Ref
	moduleRef                js_ast.Ref
	importMetaRef            js_ast.Ref
	promiseRef               js_ast.Ref
	findSymbolHelper         config.FindSymbol
	symbolUses               map[js_ast.Ref]js_ast.SymbolUse
	declaredSymbols          []js_ast.DeclaredSymbol
	runtimeImports           map[string]js_ast.Ref
	duplicateCaseChecker     duplicateCaseChecker
	nonBMPIdentifiers        map[string]bool
	lackOfDefineWarnings     map[string]bool

	// For lowering private methods
	weakMapRef     js_ast.Ref
	weakSetRef     js_ast.Ref
	privateGetters map[js_ast.Ref]js_ast.Ref
	privateSetters map[js_ast.Ref]js_ast.Ref

	// These are for TypeScript
	shouldFoldNumericConstants bool
	emittedNamespaceVars       map[js_ast.Ref]bool
	isExportedInsideNamespace  map[js_ast.Ref]js_ast.Ref
	knownEnumValues            map[js_ast.Ref]map[string]float64
	localTypeNames             map[string]bool

	// This is the reference to the generated function argument for the namespace,
	// which is different than the reference to the namespace itself:
	//
	//   namespace ns {
	//   }
	//
	// The code above is transformed into something like this:
	//
	//   var ns1;
	//   (function(ns2) {
	//   })(ns1 || (ns1 = {}));
	//
	// This variable is "ns2" not "ns1". It is only used during the second
	// "visit" pass.
	enclosingNamespaceArgRef *js_ast.Ref

	// Imports (both ES6 and CommonJS) are tracked at the top level
	importRecords               []ast.ImportRecord
	importRecordsForCurrentPart []uint32
	exportStarImportRecords     []uint32

	// These are for handling ES6 imports and exports
	hasES6ImportSyntax      bool
	hasES6ExportSyntax      bool
	importItemsForNamespace map[js_ast.Ref]map[string]js_ast.LocRef
	isImportItem            map[js_ast.Ref]bool
	namedImports            map[js_ast.Ref]js_ast.NamedImport
	namedExports            map[string]js_ast.NamedExport
	topLevelSymbolToParts   map[js_ast.Ref][]uint32

	// The parser does two passes and we need to pass the scope tree information
	// from the first pass to the second pass. That's done by tracking the calls
	// to pushScopeForParsePass() and popScope() during the first pass in
	// scopesInOrder.
	//
	// Then, when the second pass calls pushScopeForVisitPass() and popScope(),
	// we consume entries from scopesInOrder and make sure they are in the same
	// order. This way the second pass can efficiently use the same scope tree
	// as the first pass without having to attach the scope tree to the AST.
	//
	// We need to split this into two passes because the pass that declares the
	// symbols must be separate from the pass that binds identifiers to declared
	// symbols to handle declaring a hoisted "var" symbol in a nested scope and
	// binding a name to it in a parent or sibling scope.
	scopesInOrder []scopeOrder

	// These properties are for the visit pass, which runs after the parse pass.
	// The visit pass binds identifiers to declared symbols, does constant
	// folding, substitutes compile-time variable definitions, and lowers certain
	// syntactic constructs as appropriate.
	callTarget        js_ast.E
	deleteTarget      js_ast.E
	moduleScope       *js_ast.Scope
	isControlFlowDead bool

	// These are for recognizing "typeof require == 'function' && require". This
	// is a workaround for code that browserify generates that looks like this:
	//
	//   (function e(t, n, r) {
	//     function s(o2, u) {
	//       if (!n[o2]) {
	//         if (!t[o2]) {
	//           var a = typeof require == "function" && require;
	//           if (!u && a)
	//             return a(o2, true);
	//           if (i)
	//             return i(o2, true);
	//           throw new Error("Cannot find module '" + o2 + "'");
	//         }
	//         var f = n[o2] = {exports: {}};
	//         t[o2][0].call(f.exports, function(e2) {
	//           var n2 = t[o2][1][e2];
	//           return s(n2 ? n2 : e2);
	//         }, f, f.exports, e, t, n, r);
	//       }
	//       return n[o2].exports;
	//     }
	//     var i = typeof require == "function" && require;
	//     for (var o = 0; o < r.length; o++)
	//       s(r[o]);
	//     return s;
	//   });
	//
	// It's checking to see if the environment it's running in has a "require"
	// function before calling it. However, esbuild's bundling environment has a
	// bundle-time require function because it's a bundler. So in this case
	// "typeof require == 'function'" is true and the "&&" expression just
	// becomes a single "require" identifier, which will then crash at run time.
	//
	// The workaround is to explicitly pattern-match for the exact expression
	// "typeof require == 'function' && require" and replace it with "false" if
	// we're targeting the browser.
	//
	// Note that we can't just leave "typeof require == 'function'" alone because
	// there is other code in the wild that legitimately does need it to become
	// "true" when bundling. Specifically, the package "@dagrejs/graphlib" has
	// code that looks like this:
	//
	//   if (typeof require === "function") {
	//     try {
	//       lodash = {
	//         clone: require("lodash/clone"),
	//         constant: require("lodash/constant"),
	//         each: require("lodash/each"),
	//         // ... more calls to require() here ...
	//       };
	//     } catch (e) {
	//       // continue regardless of error
	//     }
	//   }
	//
	// That library will crash later on during startup if that branch isn't
	// taken because "typeof require === 'function'" is false at run time.
	typeofTarget                js_ast.E
	typeofRequire               js_ast.E
	typeofRequireEqualsFn       js_ast.E
	typeofRequireEqualsFnTarget js_ast.E

	// This helps recognize the "require.main" pattern. If this pattern is
	// present and the output format is CommonJS, we avoid generating a warning
	// about an unbundled use of "require".
	cjsDotMainTarget js_ast.E

	// This helps recognize calls to "require.resolve()" which may become
	// ERequireResolve expressions.
	resolveCallTarget js_ast.E

	// Temporary variables used for lowering
	tempRefsToDeclare []tempRef
	tempRefCount      int

	// When bundling, hoisted top-level local variables declared with "var" in
	// nested scopes are moved up to be declared in the top-level scope instead.
	// The old "var" statements are turned into regular assignments instead. This
	// makes it easier to quickly scan the top-level statements for "var" locals
	// with the guarantee that all will be found.
	relocatedTopLevelVars []js_ast.LocRef
}

// This is used as part of an incremental build cache key. Some of these values
// can potentially change between builds if they are derived from nearby
// "package.json" or "tsconfig.json" files that were changed since the last
// build.
type Options struct {
	injectedFiles []config.InjectedFile
	jsx           config.JSXOptions

	// This pointer will always be different for each build but the contents
	// shouldn't ever behave different semantically. We ignore this field for the
	// equality comparison.
	defines *config.ProcessedDefines

	// This is an embedded struct. Always access these directly instead of off
	// the name "optionsThatSupportStructuralEquality". This is only grouped like
	// this to make the equality comparison easier and safer (and hopefully faster).
	optionsThatSupportStructuralEquality
}

type optionsThatSupportStructuralEquality struct {
	unsupportedJSFeatures compat.JSFeature

	// Byte-sized values go here (gathered together here to keep this object compact)
	ts                             config.TSOptions
	mode                           config.Mode
	platform                       config.Platform
	outputFormat                   config.Format
	asciiOnly                      bool
	keepNames                      bool
	mangleSyntax                   bool
	minifyIdentifiers              bool
	omitRuntimeForTests            bool
	ignoreDCEAnnotations           bool
	preserveUnusedImportsTS        bool
	useDefineForClassFields        bool
	suppressWarningsAboutWeirdCode bool
}

func OptionsFromConfig(options *config.Options) Options {
	return Options{
		injectedFiles: options.InjectedFiles,
		jsx:           options.JSX,
		defines:       options.Defines,
		optionsThatSupportStructuralEquality: optionsThatSupportStructuralEquality{
			unsupportedJSFeatures:          options.UnsupportedJSFeatures,
			ts:                             options.TS,
			mode:                           options.Mode,
			platform:                       options.Platform,
			outputFormat:                   options.OutputFormat,
			asciiOnly:                      options.ASCIIOnly,
			keepNames:                      options.KeepNames,
			mangleSyntax:                   options.MangleSyntax,
			minifyIdentifiers:              options.MinifyIdentifiers,
			omitRuntimeForTests:            options.OmitRuntimeForTests,
			ignoreDCEAnnotations:           options.IgnoreDCEAnnotations,
			preserveUnusedImportsTS:        options.PreserveUnusedImportsTS,
			useDefineForClassFields:        options.UseDefineForClassFields,
			suppressWarningsAboutWeirdCode: options.SuppressWarningsAboutWeirdCode,
		},
	}
}

func (a *Options) Equal(b *Options) bool {
	// Compare "optionsThatSupportStructuralEquality"
	if a.optionsThatSupportStructuralEquality != b.optionsThatSupportStructuralEquality {
		return false
	}

	// Compare "InjectedFiles"
	if len(a.injectedFiles) != len(b.injectedFiles) {
		return false
	}
	for i, x := range a.injectedFiles {
		y := b.injectedFiles[i]
		if x.SourceIndex != y.SourceIndex || x.Path != y.Path || !stringArraysEqual(x.Exports, y.Exports) {
			return false
		}
	}

	// Compare "JSX"
	if a.jsx.Parse != b.jsx.Parse || !stringArraysEqual(a.jsx.Factory, b.jsx.Factory) || !stringArraysEqual(a.jsx.Fragment, b.jsx.Fragment) {
		return false
	}

	// Do a cheap assert that the defines object hasn't changed
	if (a.defines != nil || b.defines != nil) && (a.defines == nil || b.defines == nil ||
		len(a.defines.IdentifierDefines) != len(b.defines.IdentifierDefines) ||
		len(a.defines.DotDefines) != len(b.defines.DotDefines)) {
		panic("Internal error")
	}

	return true
}

func stringArraysEqual(a []string, b []string) bool {
	if len(a) != len(b) {
		return false
	}
	for i, x := range a {
		if x != b[i] {
			return false
		}
	}
	return true
}

type tempRef struct {
	ref   js_ast.Ref
	value *js_ast.Expr
}

const (
	locModuleScope = -1
)

type scopeOrder struct {
	loc   logger.Loc
	scope *js_ast.Scope
}

// This is function-specific information used during parsing. It is saved and
// restored on the call stack around code that parses nested functions and
// arrow expressions.
type fnOrArrowDataParse struct {
	asyncRange          logger.Range
	arrowArgErrors      *deferredArrowArgErrors
	isOutsideFn         bool
	allowAwait          bool
	allowYield          bool
	allowSuperCall      bool
	isTopLevel          bool
	isConstructor       bool
	isTypeScriptDeclare bool

	// In TypeScript, forward declarations of functions have no bodies
	allowMissingBodyForTypeScript bool

	// Allow TypeScript decorators in function arguments
	allowTSDecorators bool
}

// This is function-specific information used during visiting. It is saved and
// restored on the call stack around code that parses nested functions and
// arrow expressions.
type fnOrArrowDataVisit struct {
	superIndexRef *js_ast.Ref

	isArrow        bool
	isAsync        bool
	isInsideLoop   bool
	isInsideSwitch bool

	// This is used to silence references to "require" inside a try/catch
	// statement. The assumption is that the try/catch statement is there to
	// handle the case where the reference to "require" crashes. Specifically,
	// the workaround handles the "moment" library which contains code that
	// looks like this:
	//
	//   try {
	//     oldLocale = globalLocale._abbr;
	//     var aliasedRequire = require;
	//     aliasedRequire('./locale/' + name);
	//     getSetGlobalLocale(oldLocale);
	//   } catch (e) {}
	//
	tryBodyCount int
}

// This is function-specific information used during visiting. It is saved and
// restored on the call stack around code that parses nested functions (but not
// nested arrow functions).
type fnOnlyDataVisit struct {
	// This is a reference to the magic "arguments" variable that exists inside
	// functions in JavaScript. It will be non-nil inside functions and nil
	// otherwise.
	argumentsRef *js_ast.Ref

	// Arrow functions don't capture the value of "this" and "arguments". Instead,
	// the values are inherited from the surrounding context. If arrow functions
	// are turned into regular functions due to lowering, we will need to generate
	// local variables to capture these values so they are preserved correctly.
	thisCaptureRef      *js_ast.Ref
	argumentsCaptureRef *js_ast.Ref

	// If we're inside an async arrow function and async functions are not
	// supported, then we will have to convert that arrow function to a generator
	// function. That means references to "arguments" inside the arrow function
	// will have to reference a captured variable instead of the real variable.
	isInsideAsyncArrowFn bool

	// If false, the value for "this" is the top-level module scope "this" value.
	// That means it's "undefined" for ECMAScript modules and "exports" for
	// CommonJS modules. We track this information so that we can substitute the
	// correct value for these top-level "this" references at compile time instead
	// of passing the "this" expression through to the output and leaving the
	// interpretation up to the run-time behavior of the generated code.
	//
	// If true, the value for "this" is nested inside something (either a function
	// or a class declaration). That means the top-level module scope "this" value
	// has been shadowed and is now inaccessible.
	isThisNested bool
}

const bloomFilterSize = 251

type duplicateCaseValue struct {
	hash  uint32
	value js_ast.Expr
}

type duplicateCaseChecker struct {
	bloomFilter [(bloomFilterSize + 7) / 8]byte
	cases       []duplicateCaseValue
}

func (dc *duplicateCaseChecker) reset() {
	// Preserve capacity
	dc.cases = dc.cases[:0]

	// This should be optimized by the compiler. See this for more information:
	// https://github.com/golang/go/issues/5373
	bytes := dc.bloomFilter
	for i := range bytes {
		bytes[i] = 0
	}
}

func (dc *duplicateCaseChecker) check(p *parser, expr js_ast.Expr) {
	if p.options.suppressWarningsAboutWeirdCode {
		return
	}

	if hash, ok := duplicateCaseHash(expr); ok {
		bucket := hash % bloomFilterSize
		entry := &dc.bloomFilter[bucket/8]
		mask := byte(1) << (bucket % 8)

		// Check for collisions
		if (*entry & mask) != 0 {
			for _, c := range dc.cases {
				if c.hash == hash {
					if equals, couldBeIncorrect := duplicateCaseEquals(c.value, expr); equals {
						r := p.source.RangeOfOperatorBefore(expr.Loc, "case")
						if couldBeIncorrect {
							p.log.AddRangeWarning(&p.source, r,
								"This case clause may never be evaluated because it likely duplicates an earlier case clause")
						} else {
							p.log.AddRangeWarning(&p.source, r,
								"This case clause will never be evaluated because it duplicates an earlier case clause")
						}
					}
					return
				}
			}
		}

		*entry |= mask
		dc.cases = append(dc.cases, duplicateCaseValue{hash: hash, value: expr})
	}
}

func hashCombine(seed uint32, hash uint32) uint32 {
	return seed ^ (hash + 0x9e3779b9 + (seed << 6) + (seed >> 2))
}

func duplicateCaseHash(expr js_ast.Expr) (uint32, bool) {
	switch e := expr.Data.(type) {
	case *js_ast.ENull:
		return 0, true

	case *js_ast.EUndefined:
		return 1, true

	case *js_ast.EBoolean:
		if e.Value {
			return hashCombine(2, 1), true
		}
		return hashCombine(2, 0), true

	case *js_ast.ENumber:
		bits := math.Float64bits(e.Value)
		return hashCombine(hashCombine(3, uint32(bits)), uint32(bits>>32)), true

	case *js_ast.EString:
		hash := uint32(4)
		for _, c := range e.Value {
			hash = hashCombine(hash, uint32(c))
		}
		return hash, true

	case *js_ast.EBigInt:
		hash := uint32(5)
		for _, c := range e.Value {
			hash = hashCombine(hash, uint32(c))
		}
		return hash, true

	case *js_ast.EIdentifier:
		return hashCombine(6, e.Ref.InnerIndex), true

	case *js_ast.EDot:
		if target, ok := duplicateCaseHash(e.Target); ok {
			hash := hashCombine(7, target)
			for _, c := range e.Name {
				hash = hashCombine(hash, uint32(c))
			}
			return hash, true
		}

	case *js_ast.EIndex:
		if target, ok := duplicateCaseHash(e.Target); ok {
			if index, ok := duplicateCaseHash(e.Index); ok {
				return hashCombine(hashCombine(8, target), index), true
			}
		}
	}

	return 0, false
}

func duplicateCaseEquals(left js_ast.Expr, right js_ast.Expr) (equals bool, couldBeIncorrect bool) {
	switch a := left.Data.(type) {
	case *js_ast.ENull:
		_, ok := right.Data.(*js_ast.ENull)
		return ok, false

	case *js_ast.EUndefined:
		_, ok := right.Data.(*js_ast.EUndefined)
		return ok, false

	case *js_ast.EBoolean:
		b, ok := right.Data.(*js_ast.EBoolean)
		return ok && a.Value == b.Value, false

	case *js_ast.ENumber:
		b, ok := right.Data.(*js_ast.ENumber)
		return ok && a.Value == b.Value, false

	case *js_ast.EString:
		b, ok := right.Data.(*js_ast.EString)
		return ok && js_lexer.UTF16EqualsUTF16(a.Value, b.Value), false

	case *js_ast.EBigInt:
		b, ok := right.Data.(*js_ast.EBigInt)
		return ok && a.Value == b.Value, false

	case *js_ast.EIdentifier:
		b, ok := right.Data.(*js_ast.EIdentifier)
		return ok && a.Ref == b.Ref, false

	case *js_ast.EDot:
		if b, ok := right.Data.(*js_ast.EDot); ok && a.OptionalChain == b.OptionalChain && a.Name == b.Name {
			equals, _ := duplicateCaseEquals(a.Target, b.Target)
			return equals, true
		}

	case *js_ast.EIndex:
		if b, ok := right.Data.(*js_ast.EIndex); ok && a.OptionalChain == b.OptionalChain {
			if equals, _ := duplicateCaseEquals(a.Index, b.Index); equals {
				equals, _ := duplicateCaseEquals(a.Target, b.Target)
				return equals, true
			}
		}
	}

	return false, false
}

func isJumpStatement(data js_ast.S) bool {
	switch data.(type) {
	case *js_ast.SBreak, *js_ast.SContinue, *js_ast.SReturn, *js_ast.SThrow:
		return true
	}

	return false
}

func isPrimitiveToReorder(e js_ast.E) bool {
	switch e.(type) {
	case *js_ast.ENull, *js_ast.EUndefined, *js_ast.EString, *js_ast.EBoolean, *js_ast.ENumber, *js_ast.EBigInt:
		return true
	}
	return false
}

func toNullOrUndefinedWithoutSideEffects(data js_ast.E) (bool, bool) {
	switch data.(type) {
	case *js_ast.EBoolean, *js_ast.ENumber, *js_ast.EString, *js_ast.ERegExp,
		*js_ast.EObject, *js_ast.EArray, *js_ast.EFunction, *js_ast.EArrow, *js_ast.EClass:
		return false, true

	case *js_ast.ENull, *js_ast.EUndefined:
		return true, true

	default:
		return false, false
	}
}

func toBooleanWithoutSideEffects(data js_ast.E) (bool, bool) {
	switch e := data.(type) {
	case *js_ast.ENull, *js_ast.EUndefined:
		return false, true

	case *js_ast.EBoolean:
		return e.Value, true

	case *js_ast.ENumber:
		return e.Value != 0 && !math.IsNaN(e.Value), true

	case *js_ast.EBigInt:
		return e.Value != "0", true

	case *js_ast.EString:
		return len(e.Value) > 0, true

	case *js_ast.EFunction, *js_ast.EArrow:
		return true, true
	}

	return false, false
}

func toNumberWithoutSideEffects(data js_ast.E) (float64, bool) {
	switch e := data.(type) {
	case *js_ast.ENull:
		return 0, true

	case *js_ast.EUndefined:
		return math.NaN(), true

	case *js_ast.EBoolean:
		if e.Value {
			return 1, true
		} else {
			return 0, true
		}

	case *js_ast.ENumber:
		return e.Value, true
	}

	return 0, false
}

func typeofWithoutSideEffects(data js_ast.E) (string, bool) {
	switch data.(type) {
	case *js_ast.ENull:
		return "object", true

	case *js_ast.EUndefined:
		return "undefined", true

	case *js_ast.EBoolean:
		return "boolean", true

	case *js_ast.ENumber:
		return "number", true

	case *js_ast.EBigInt:
		return "bigint", true

	case *js_ast.EString:
		return "string", true

	case *js_ast.EFunction, *js_ast.EArrow:
		return "function", true
	}

	return "", false
}

// Returns "equal, ok". If "ok" is false, then nothing is known about the two
// values. If "ok" is true, the equality or inequality of the two values is
// stored in "equal".
func checkEqualityIfNoSideEffects(left js_ast.E, right js_ast.E) (bool, bool) {
	switch l := left.(type) {
	case *js_ast.ENull:
		_, ok := right.(*js_ast.ENull)
		return ok, ok

	case *js_ast.EUndefined:
		_, ok := right.(*js_ast.EUndefined)
		return ok, ok

	case *js_ast.EBoolean:
		r, ok := right.(*js_ast.EBoolean)
		return ok && l.Value == r.Value, ok

	case *js_ast.ENumber:
		r, ok := right.(*js_ast.ENumber)
		return ok && l.Value == r.Value, ok

	case *js_ast.EBigInt:
		r, ok := right.(*js_ast.EBigInt)
		return ok && l.Value == r.Value, ok

	case *js_ast.EString:
		r, ok := right.(*js_ast.EString)
		return ok && js_lexer.UTF16EqualsUTF16(l.Value, r.Value), ok
	}

	return false, false
}

func valuesLookTheSame(left js_ast.E, right js_ast.E) bool {
	switch a := left.(type) {
	case *js_ast.EIdentifier:
		if b, ok := right.(*js_ast.EIdentifier); ok && a.Ref == b.Ref {
			return true
		}

	case *js_ast.EDot:
		if b, ok := right.(*js_ast.EDot); ok && a.HasSameFlagsAs(b) &&
			a.Name == b.Name && valuesLookTheSame(a.Target.Data, b.Target.Data) {
			return true
		}

	case *js_ast.EIndex:
		if b, ok := right.(*js_ast.EIndex); ok && a.HasSameFlagsAs(b) &&
			valuesLookTheSame(a.Target.Data, b.Target.Data) && valuesLookTheSame(a.Index.Data, b.Index.Data) {
			return true
		}

	case *js_ast.EIf:
		if b, ok := right.(*js_ast.EIf); ok && valuesLookTheSame(a.Test.Data, b.Test.Data) &&
			valuesLookTheSame(a.Yes.Data, b.Yes.Data) && valuesLookTheSame(a.No.Data, b.No.Data) {
			return true
		}

	case *js_ast.EUnary:
		if b, ok := right.(*js_ast.EUnary); ok && a.Op == b.Op && valuesLookTheSame(a.Value.Data, b.Value.Data) {
			return true
		}

	case *js_ast.EBinary:
		if b, ok := right.(*js_ast.EBinary); ok && a.Op == b.Op && valuesLookTheSame(a.Left.Data, b.Left.Data) &&
			valuesLookTheSame(a.Right.Data, b.Right.Data) {
			return true
		}

	case *js_ast.ECall:
		if b, ok := right.(*js_ast.ECall); ok && a.HasSameFlagsAs(b) &&
			len(a.Args) == len(b.Args) && valuesLookTheSame(a.Target.Data, b.Target.Data) {
			for i := range a.Args {
				if !valuesLookTheSame(a.Args[i].Data, b.Args[i].Data) {
					return false
				}
			}
			return true
		}
	}

	equal, ok := checkEqualityIfNoSideEffects(left, right)
	return ok && equal
}

func hasValueForThisInCall(expr js_ast.Expr) bool {
	switch expr.Data.(type) {
	case *js_ast.EDot, *js_ast.EIndex:
		return true

	default:
		return false
	}
}

func (p *parser) selectLocalKind(kind js_ast.LocalKind) js_ast.LocalKind {
	// Safari workaround: Automatically avoid TDZ issues when bundling
	if p.options.mode == config.ModeBundle && p.currentScope.Parent == nil {
		return js_ast.LocalVar
	}

	// Optimization: use "let" instead of "const" because it's shorter. This is
	// only done when bundling because assigning to "const" is only an error when
	// bundling.
	if p.options.mode == config.ModeBundle && kind == js_ast.LocalConst && p.options.mangleSyntax {
		return js_ast.LocalLet
	}

	return kind
}

func (p *parser) pushScopeForParsePass(kind js_ast.ScopeKind, loc logger.Loc) int {
	parent := p.currentScope
	scope := &js_ast.Scope{
		Kind:     kind,
		Parent:   parent,
		Members:  make(map[string]js_ast.ScopeMember),
		LabelRef: js_ast.InvalidRef,
	}
	if parent != nil {
		parent.Children = append(parent.Children, scope)
	}
	p.currentScope = scope

	// Enforce that scope locations are strictly increasing to help catch bugs
	// where the pushed scopes are mistmatched between the first and second passes
	if len(p.scopesInOrder) > 0 {
		prevStart := p.scopesInOrder[len(p.scopesInOrder)-1].loc.Start
		if prevStart >= loc.Start {
			panic(fmt.Sprintf("Scope location %d must be greater than %d", loc.Start, prevStart))
		}
	}

	// Copy down function arguments into the function body scope. That way we get
	// errors if a statement in the function body tries to re-declare any of the
	// arguments.
	if kind == js_ast.ScopeFunctionBody {
		if scope.Parent.Kind != js_ast.ScopeFunctionArgs {
			panic("Internal error")
		}
		for name, member := range scope.Parent.Members {
			// Don't copy down the optional function expression name. Re-declaring
			// the name of a function expression is allowed.
			kind := p.symbols[member.Ref.InnerIndex].Kind
			if kind != js_ast.SymbolHoistedFunction {
				scope.Members[name] = member
			}
		}
	}

	// Remember the length in case we call popAndDiscardScope() later
	scopeIndex := len(p.scopesInOrder)
	p.scopesInOrder = append(p.scopesInOrder, scopeOrder{loc, scope})
	return scopeIndex
}

func (p *parser) popScope() {
	// We cannot rename anything inside a scope containing a direct eval() call
	if p.currentScope.ContainsDirectEval {
		for _, member := range p.currentScope.Members {
			p.symbols[member.Ref.InnerIndex].MustNotBeRenamed = true
		}
	}

	p.currentScope = p.currentScope.Parent
}

func (p *parser) popAndDiscardScope(scopeIndex int) {
	// Move up to the parent scope
	toDiscard := p.currentScope
	parent := toDiscard.Parent
	p.currentScope = parent

	// Truncate the scope order where we started to pretend we never saw this scope
	p.scopesInOrder = p.scopesInOrder[:scopeIndex]

	// Remove the last child from the parent scope
	last := len(parent.Children) - 1
	if parent.Children[last] != toDiscard {
		panic("Internal error")
	}
	parent.Children = parent.Children[:last]
}

func (p *parser) popAndFlattenScope(scopeIndex int) {
	// Move up to the parent scope
	toFlatten := p.currentScope
	parent := toFlatten.Parent
	p.currentScope = parent

	// Erase this scope from the order. This will shift over the indices of all
	// the scopes that were created after us. However, we shouldn't have to
	// worry about other code with outstanding scope indices for these scopes.
	// These scopes were all created in between this scope's push and pop
	// operations, so they should all be child scopes and should all be popped
	// by the time we get here.
	copy(p.scopesInOrder[scopeIndex:], p.scopesInOrder[scopeIndex+1:])
	p.scopesInOrder = p.scopesInOrder[:len(p.scopesInOrder)-1]

	// Remove the last child from the parent scope
	last := len(parent.Children) - 1
	if parent.Children[last] != toFlatten {
		panic("Internal error")
	}
	parent.Children = parent.Children[:last]

	// Reparent our child scopes into our parent
	for _, scope := range toFlatten.Children {
		scope.Parent = parent
		parent.Children = append(parent.Children, scope)
	}
}

// Undo all scopes pushed and popped after this scope index. This assumes that
// the scope stack is at the same level now as it was at the given scope index.
func (p *parser) discardScopesUpTo(scopeIndex int) {
	// Remove any direct children from their parent
	children := p.currentScope.Children
	for _, child := range p.scopesInOrder[scopeIndex:] {
		if child.scope.Parent == p.currentScope {
			for i := len(children) - 1; i >= 0; i-- {
				if children[i] == child.scope {
					children = append(children[:i], children[i+1:]...)
					break
				}
			}
		}
	}
	p.currentScope.Children = children

	// Truncate the scope order where we started to pretend we never saw this scope
	p.scopesInOrder = p.scopesInOrder[:scopeIndex]
}

func (p *parser) newSymbol(kind js_ast.SymbolKind, name string) js_ast.Ref {
	ref := js_ast.Ref{OuterIndex: p.source.Index, InnerIndex: uint32(len(p.symbols))}
	p.symbols = append(p.symbols, js_ast.Symbol{
		Kind:         kind,
		OriginalName: name,
		Link:         js_ast.InvalidRef,
	})
	if p.options.ts.Parse {
		p.tsUseCounts = append(p.tsUseCounts, 0)
	}
	return ref
}

// This is similar to "js_ast.MergeSymbols" but it works with this parser's
// one-level symbol map instead of the linker's two-level symbol map. It also
// doesn't handle cycles since they shouldn't come up due to the way this
// function is used.
func (p *parser) mergeSymbols(old js_ast.Ref, new js_ast.Ref) {
	oldSymbol := &p.symbols[old.InnerIndex]
	newSymbol := &p.symbols[new.InnerIndex]
	oldSymbol.Link = new
	newSymbol.UseCountEstimate += oldSymbol.UseCountEstimate
	if oldSymbol.MustNotBeRenamed {
		newSymbol.MustNotBeRenamed = true
	}
}

type mergeResult int

const (
	mergeForbidden = iota
	mergeReplaceWithNew
	mergeOverwriteWithNew
	mergeKeepExisting
	mergeBecomePrivateGetSetPair
	mergeBecomePrivateStaticGetSetPair
)

func (p *parser) canMergeSymbols(existing js_ast.SymbolKind, new js_ast.SymbolKind) mergeResult {
	if existing == js_ast.SymbolUnbound {
		return mergeReplaceWithNew
	}

	// In TypeScript, imports are allowed to silently collide with symbols within
	// the module. Presumably this is because the imports may be type-only:
	//
	//   import {Foo} from 'bar'
	//   class Foo {}
	//
	if p.options.ts.Parse && existing == js_ast.SymbolImport {
		return mergeReplaceWithNew
	}

	// "enum Foo {} enum Foo {}"
	// "namespace Foo { ... } enum Foo {}"
	if new == js_ast.SymbolTSEnum && (existing == js_ast.SymbolTSEnum || existing == js_ast.SymbolTSNamespace) {
		return mergeReplaceWithNew
	}

	// "namespace Foo { ... } namespace Foo { ... }"
	// "function Foo() {} namespace Foo { ... }"
	// "enum Foo {} namespace Foo { ... }"
	if new == js_ast.SymbolTSNamespace {
		switch existing {
		case js_ast.SymbolTSNamespace, js_ast.SymbolHoistedFunction, js_ast.SymbolGeneratorOrAsyncFunction, js_ast.SymbolTSEnum, js_ast.SymbolClass:
			return mergeKeepExisting
		}
	}

	// "var foo; var foo;"
	// "var foo; function foo() {}"
	// "function foo() {} var foo;"
	if new.IsHoistedOrFunction() && existing.IsHoistedOrFunction() {
		return mergeKeepExisting
	}

	// "get #foo() {} set #foo() {}"
	// "set #foo() {} get #foo() {}"
	if (existing == js_ast.SymbolPrivateGet && new == js_ast.SymbolPrivateSet) ||
		(existing == js_ast.SymbolPrivateSet && new == js_ast.SymbolPrivateGet) {
		return mergeBecomePrivateGetSetPair
	}
	if (existing == js_ast.SymbolPrivateStaticGet && new == js_ast.SymbolPrivateStaticSet) ||
		(existing == js_ast.SymbolPrivateStaticSet && new == js_ast.SymbolPrivateStaticGet) {
		return mergeBecomePrivateStaticGetSetPair
	}

	// "try {} catch (e) { var e }"
	if existing == js_ast.SymbolCatchIdentifier && new == js_ast.SymbolHoisted {
		return mergeReplaceWithNew
	}

	// "function() { var arguments }"
	if existing == js_ast.SymbolArguments && new == js_ast.SymbolHoisted {
		return mergeKeepExisting
	}

	// "function() { let arguments }"
	if existing == js_ast.SymbolArguments && new != js_ast.SymbolHoisted {
		return mergeOverwriteWithNew
	}

	return mergeForbidden
}

func (p *parser) declareSymbol(kind js_ast.SymbolKind, loc logger.Loc, name string) js_ast.Ref {
	p.checkForNonBMPCodePoint(loc, name)

	// Allocate a new symbol
	ref := p.newSymbol(kind, name)

	// Check for a collision in the declaring scope
	if existing, ok := p.currentScope.Members[name]; ok {
		symbol := &p.symbols[existing.Ref.InnerIndex]

		switch p.canMergeSymbols(symbol.Kind, kind) {
		case mergeForbidden:
			r := js_lexer.RangeOfIdentifier(p.source, loc)
			p.log.AddRangeErrorWithNotes(&p.source, r, fmt.Sprintf("%q has already been declared", name),
				[]logger.MsgData{logger.RangeData(&p.source, js_lexer.RangeOfIdentifier(p.source, existing.Loc),
					fmt.Sprintf("%q was originally declared here", name))})
			return existing.Ref

		case mergeKeepExisting:
			ref = existing.Ref

		case mergeReplaceWithNew:
			symbol.Link = ref

		case mergeBecomePrivateGetSetPair:
			ref = existing.Ref
			symbol.Kind = js_ast.SymbolPrivateGetSetPair

		case mergeBecomePrivateStaticGetSetPair:
			ref = existing.Ref
			symbol.Kind = js_ast.SymbolPrivateStaticGetSetPair

		case mergeOverwriteWithNew:
		}
	}

	// Overwrite this name in the declaring scope
	p.currentScope.Members[name] = js_ast.ScopeMember{Ref: ref, Loc: loc}
	return ref
}

func (p *parser) hoistSymbols(scope *js_ast.Scope) {
nextMember:
	for _, member := range scope.Members {
		symbol := &p.symbols[member.Ref.InnerIndex]

		// Check for collisions that would prevent to hoisting "var" symbols up to the enclosing function scope
		if symbol.Kind.IsHoisted() && !scope.Kind.StopsHoisting() {
			s := scope.Parent
			for {
				// Variable declarations hoisted past a "with" statement may actually end
				// up overwriting a property on the target of the "with" statement instead
				// of initializing the variable. We must not rename them or we risk
				// causing a behavior change.
				//
				//   var obj = { foo: 1 }
				//   with (obj) { var foo = 2 }
				//   assert(foo === undefined)
				//   assert(obj.foo === 2)
				//
				if s.Kind == js_ast.ScopeWith {
					symbol.MustNotBeRenamed = true
				}

				if existingMember, ok := s.Members[symbol.OriginalName]; ok {
					existingSymbol := &p.symbols[existingMember.Ref.InnerIndex]
					switch existingSymbol.Kind {
					case js_ast.SymbolUnbound, js_ast.SymbolHoisted, js_ast.SymbolHoistedFunction:
						// Silently merge this symbol into the existing symbol
						symbol.Link = existingMember.Ref
						s.Members[symbol.OriginalName] = existingMember
						continue nextMember

					case js_ast.SymbolCatchIdentifier:
						// Silently merge the existing symbol into this symbol
						existingSymbol.Link = member.Ref
						s.Members[symbol.OriginalName] = member

					default:
						// An identifier binding from a catch statement and a function
						// declaration can both silently shadow another hoisted symbol
						if symbol.Kind != js_ast.SymbolCatchIdentifier && symbol.Kind != js_ast.SymbolHoistedFunction {
							r := js_lexer.RangeOfIdentifier(p.source, member.Loc)
							p.log.AddRangeErrorWithNotes(&p.source, r, fmt.Sprintf("%q has already been declared", symbol.OriginalName),
								[]logger.MsgData{logger.RangeData(&p.source, js_lexer.RangeOfIdentifier(p.source, existingMember.Loc),
									fmt.Sprintf("%q was originally declared here", symbol.OriginalName))})
						}
						continue nextMember
					}
				}

				if s.Kind.StopsHoisting() {
					// Declare the member in the scope that stopped the hoisting
					s.Members[symbol.OriginalName] = member
					break
				}
				s = s.Parent
			}
		}
	}

	for _, child := range scope.Children {
		p.hoistSymbols(child)
	}
}

func (p *parser) declareBinding(kind js_ast.SymbolKind, binding js_ast.Binding, opts parseStmtOpts) {
	switch b := binding.Data.(type) {
	case *js_ast.BMissing:

	case *js_ast.BIdentifier:
		name := p.loadNameFromRef(b.Ref)
		if !opts.isTypeScriptDeclare || (opts.isNamespaceScope && opts.isExport) {
			b.Ref = p.declareSymbol(kind, binding.Loc, name)
		}

	case *js_ast.BArray:
		for _, i := range b.Items {
			p.declareBinding(kind, i.Binding, opts)
		}

	case *js_ast.BObject:
		for _, property := range b.Properties {
			p.declareBinding(kind, property.Value, opts)
		}

	default:
		panic("Internal error")
	}
}

func (p *parser) recordUsage(ref js_ast.Ref) {
	// The use count stored in the symbol is used for generating symbol names
	// during minification. These counts shouldn't include references inside dead
	// code regions since those will be culled.
	if !p.isControlFlowDead {
		p.symbols[ref.InnerIndex].UseCountEstimate++
		use := p.symbolUses[ref]
		use.CountEstimate++
		p.symbolUses[ref] = use
	}

	// The correctness of TypeScript-to-JavaScript conversion relies on accurate
	// symbol use counts for the whole file, including dead code regions. This is
	// tracked separately in a parser-only data structure.
	if p.options.ts.Parse {
		p.tsUseCounts[ref.InnerIndex]++
	}
}

func (p *parser) ignoreUsage(ref js_ast.Ref) {
	// Roll back the use count increment in recordUsage()
	if !p.isControlFlowDead {
		p.symbols[ref.InnerIndex].UseCountEstimate--
		use := p.symbolUses[ref]
		use.CountEstimate--
		if use.CountEstimate == 0 {
			delete(p.symbolUses, ref)
		} else {
			p.symbolUses[ref] = use
		}
	}

	// Don't roll back the "tsUseCounts" increment. This must be counted even if
	// the value is ignored because that's what the TypeScript compiler does.
}

func (p *parser) callRuntime(loc logger.Loc, name string, args []js_ast.Expr) js_ast.Expr {
	ref, ok := p.runtimeImports[name]
	if !ok {
		ref = p.newSymbol(js_ast.SymbolOther, name)
		p.moduleScope.Generated = append(p.moduleScope.Generated, ref)
		p.runtimeImports[name] = ref
	}
	p.recordUsage(ref)
	return js_ast.Expr{Loc: loc, Data: &js_ast.ECall{
		Target: js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: ref}},
		Args:   args,
	}}
}

func (p *parser) makePromiseRef() js_ast.Ref {
	if p.promiseRef == js_ast.InvalidRef {
		p.promiseRef = p.newSymbol(js_ast.SymbolUnbound, "Promise")
	}
	return p.promiseRef
}

// The name is temporarily stored in the ref until the scope traversal pass
// happens, at which point a symbol will be generated and the ref will point
// to the symbol instead.
//
// The scope traversal pass will reconstruct the name using one of two methods.
// In the common case, the name is a slice of the file itself. In that case we
// can just store the slice and not need to allocate any extra memory. In the
// rare case, the name is an externally-allocated string. In that case we store
// an index to the string and use that index during the scope traversal pass.
func (p *parser) storeNameInRef(name string) js_ast.Ref {
	c := (*reflect.StringHeader)(unsafe.Pointer(&p.source.Contents))
	n := (*reflect.StringHeader)(unsafe.Pointer(&name))

	// Is the data in "name" a subset of the data in "p.source.Contents"?
	if n.Data >= c.Data && n.Data+uintptr(n.Len) < c.Data+uintptr(c.Len) {
		// The name is a slice of the file contents, so we can just reference it by
		// length and don't have to allocate anything. This is the common case.
		//
		// It's stored as a negative value so we'll crash if we try to use it. That
		// way we'll catch cases where we've forgetten to call loadNameFromRef().
		// The length is the negative part because we know it's non-zero.
		return js_ast.Ref{OuterIndex: -uint32(n.Len), InnerIndex: uint32(n.Data - c.Data)}
	} else {
		// The name is some memory allocated elsewhere. This is either an inline
		// string constant in the parser or an identifier with escape sequences
		// in the source code, which is very unusual. Stash it away for later.
		// This uses allocations but it should hopefully be very uncommon.
		ref := js_ast.Ref{OuterIndex: 0x80000000, InnerIndex: uint32(len(p.allocatedNames))}
		p.allocatedNames = append(p.allocatedNames, name)
		return ref
	}
}

// This is the inverse of storeNameInRef() above
func (p *parser) loadNameFromRef(ref js_ast.Ref) string {
	if ref.OuterIndex == 0x80000000 {
		return p.allocatedNames[ref.InnerIndex]
	} else {
		if (ref.OuterIndex & 0x80000000) == 0 {
			panic("Internal error: invalid symbol reference")
		}
		return p.source.Contents[ref.InnerIndex : int32(ref.InnerIndex)-int32(ref.OuterIndex)]
	}
}

// Due to ES6 destructuring patterns, there are many cases where it's
// impossible to distinguish between an array or object literal and a
// destructuring assignment until we hit the "=" operator later on.
// This object defers errors about being in one state or the other
// until we discover which state we're in.
type deferredErrors struct {
	// These are errors for expressions
	invalidExprDefaultValue  logger.Range
	invalidExprAfterQuestion logger.Range
	arraySpreadFeature       logger.Range

	// These are errors for destructuring patterns
	invalidBindingCommaAfterSpread logger.Range
}

func (from *deferredErrors) mergeInto(to *deferredErrors) {
	if from.invalidExprDefaultValue.Len > 0 {
		to.invalidExprDefaultValue = from.invalidExprDefaultValue
	}
	if from.invalidExprAfterQuestion.Len > 0 {
		to.invalidExprAfterQuestion = from.invalidExprAfterQuestion
	}
	if from.arraySpreadFeature.Len > 0 {
		to.arraySpreadFeature = from.arraySpreadFeature
	}
	if from.invalidBindingCommaAfterSpread.Len > 0 {
		to.invalidBindingCommaAfterSpread = from.invalidBindingCommaAfterSpread
	}
}

func (p *parser) logExprErrors(errors *deferredErrors) {
	if errors.invalidExprDefaultValue.Len > 0 {
		p.log.AddRangeError(&p.source, errors.invalidExprDefaultValue, "Unexpected \"=\"")
	}

	if errors.invalidExprAfterQuestion.Len > 0 {
		r := errors.invalidExprAfterQuestion
		p.log.AddRangeError(&p.source, r, fmt.Sprintf("Unexpected %q", p.source.Contents[r.Loc.Start:r.Loc.Start+r.Len]))
	}

	if errors.arraySpreadFeature.Len > 0 {
		p.markSyntaxFeature(compat.ArraySpread, errors.arraySpreadFeature)
	}
}

func (p *parser) logBindingErrors(errors *deferredErrors) {
	if errors.invalidBindingCommaAfterSpread.Len > 0 {
		p.log.AddRangeError(&p.source, errors.invalidBindingCommaAfterSpread, "Unexpected \",\" after rest pattern")
	}
}

// The "await" and "yield" expressions are never allowed in argument lists but
// may or may not be allowed otherwise depending on the details of the enclosing
// function or module. This needs to be handled when parsing an arrow function
// argument list because we don't know if these expressions are not allowed until
// we reach the "=>" token (or discover the absence of one).
//
// Specifically, for await:
//
//   // This is ok
//   async function foo() { (x = await y) }
//
//   // This is an error
//   async function foo() { (x = await y) => {} }
//
// And for yield:
//
//   // This is ok
//   function* foo() { (x = yield y) }
//
//   // This is an error
//   function* foo() { (x = yield y) => {} }
//
type deferredArrowArgErrors struct {
	invalidExprAwait logger.Range
	invalidExprYield logger.Range
}

func (p *parser) logArrowArgErrors(errors *deferredArrowArgErrors) {
	if errors.invalidExprAwait.Len > 0 {
		r := errors.invalidExprAwait
		p.log.AddRangeError(&p.source, r, "Cannot use an \"await\" expression here")
	}

	if errors.invalidExprYield.Len > 0 {
		r := errors.invalidExprYield
		p.log.AddRangeError(&p.source, r, "Cannot use a \"yield\" expression here")
	}
}

func (p *parser) keyNameForError(key js_ast.Expr) string {
	switch k := key.Data.(type) {
	case *js_ast.EString:
		return fmt.Sprintf("%q", js_lexer.UTF16ToString(k.Value))
	case *js_ast.EPrivateIdentifier:
		return fmt.Sprintf("%q", p.loadNameFromRef(k.Ref))
	}
	return "property"
}

type propertyOpts struct {
	asyncRange  logger.Range
	isAsync     bool
	isGenerator bool

	// Class-related options
	isStatic          bool
	isClass           bool
	classHasExtends   bool
	allowTSDecorators bool
	tsDecorators      []js_ast.Expr
}

func (p *parser) parseProperty(kind js_ast.PropertyKind, opts propertyOpts, errors *deferredErrors) (js_ast.Property, bool) {
	var key js_ast.Expr
	keyRange := p.lexer.Range()
	isComputed := false

	switch p.lexer.Token {
	case js_lexer.TNumericLiteral:
		key = js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.ENumber{Value: p.lexer.Number}}
		p.lexer.Next()

	case js_lexer.TStringLiteral:
		key = js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.EString{Value: p.lexer.StringLiteral}}
		p.lexer.Next()

	case js_lexer.TBigIntegerLiteral:
		key = js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.EBigInt{Value: p.lexer.Identifier}}
		p.markSyntaxFeature(compat.BigInt, p.lexer.Range())
		p.lexer.Next()

	case js_lexer.TPrivateIdentifier:
		if !opts.isClass || len(opts.tsDecorators) > 0 {
			p.lexer.Expected(js_lexer.TIdentifier)
		}
		key = js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.EPrivateIdentifier{Ref: p.storeNameInRef(p.lexer.Identifier)}}
		p.lexer.Next()

	case js_lexer.TOpenBracket:
		isComputed = true
		p.markSyntaxFeature(compat.ObjectExtensions, p.lexer.Range())
		p.lexer.Next()
		wasIdentifier := p.lexer.Token == js_lexer.TIdentifier
		expr := p.parseExpr(js_ast.LComma)

		// Handle index signatures
		if p.options.ts.Parse && p.lexer.Token == js_lexer.TColon && wasIdentifier && opts.isClass {
			if _, ok := expr.Data.(*js_ast.EIdentifier); ok {
				// "[key: string]: any;"
				p.lexer.Next()
				p.skipTypeScriptType(js_ast.LLowest)
				p.lexer.Expect(js_lexer.TCloseBracket)
				p.lexer.Expect(js_lexer.TColon)
				p.skipTypeScriptType(js_ast.LLowest)
				p.lexer.ExpectOrInsertSemicolon()

				// Skip this property entirely
				return js_ast.Property{}, false
			}
		}

		p.lexer.Expect(js_lexer.TCloseBracket)
		key = expr

	case js_lexer.TAsterisk:
		if kind != js_ast.PropertyNormal || opts.isGenerator {
			p.lexer.Unexpected()
		}
		p.lexer.Next()
		opts.isGenerator = true
		return p.parseProperty(js_ast.PropertyNormal, opts, errors)

	default:
		name := p.lexer.Identifier
		raw := p.lexer.Raw()
		nameRange := p.lexer.Range()
		if !p.lexer.IsIdentifierOrKeyword() {
			p.lexer.Expect(js_lexer.TIdentifier)
		}
		p.lexer.Next()

		// Support contextual keywords
		if kind == js_ast.PropertyNormal && !opts.isGenerator {
			// Does the following token look like a key?
			couldBeModifierKeyword := p.lexer.IsIdentifierOrKeyword()
			if !couldBeModifierKeyword {
				switch p.lexer.Token {
				case js_lexer.TOpenBracket, js_lexer.TNumericLiteral, js_lexer.TStringLiteral,
					js_lexer.TAsterisk, js_lexer.TPrivateIdentifier:
					couldBeModifierKeyword = true
				}
			}

			// If so, check for a modifier keyword
			if couldBeModifierKeyword {
				switch name {
				case "get":
					if !opts.isAsync && raw == name {
						p.markSyntaxFeature(compat.ObjectAccessors, nameRange)
						return p.parseProperty(js_ast.PropertyGet, opts, nil)
					}

				case "set":
					if !opts.isAsync && raw == name {
						p.markSyntaxFeature(compat.ObjectAccessors, nameRange)
						return p.parseProperty(js_ast.PropertySet, opts, nil)
					}

				case "async":
					if !opts.isAsync && raw == name {
						opts.isAsync = true
						opts.asyncRange = nameRange
						p.markLoweredSyntaxFeature(compat.AsyncAwait, nameRange, compat.Generator)
						return p.parseProperty(kind, opts, nil)
					}

				case "static":
					if !opts.isStatic && !opts.isAsync && opts.isClass && raw == name {
						opts.isStatic = true
						return p.parseProperty(kind, opts, nil)
					}

				case "private", "protected", "public", "readonly", "abstract", "declare":
					// Skip over TypeScript keywords
					if opts.isClass && p.options.ts.Parse && raw == name {
						return p.parseProperty(kind, opts, nil)
					}
				}
			}
		}

		key = js_ast.Expr{Loc: nameRange.Loc, Data: &js_ast.EString{Value: js_lexer.StringToUTF16(name)}}

		// Parse a shorthand property
		if !opts.isClass && kind == js_ast.PropertyNormal && p.lexer.Token != js_lexer.TColon &&
			p.lexer.Token != js_lexer.TOpenParen && p.lexer.Token != js_lexer.TLessThan && !opts.isGenerator &&
			js_lexer.Keywords[name] == js_lexer.T(0) {
			ref := p.storeNameInRef(name)
			value := js_ast.Expr{Loc: key.Loc, Data: &js_ast.EIdentifier{Ref: ref}}

			// Destructuring patterns have an optional default value
			var initializer *js_ast.Expr = nil
			if errors != nil && p.lexer.Token == js_lexer.TEquals {
				errors.invalidExprDefaultValue = p.lexer.Range()
				p.lexer.Next()
				value := p.parseExpr(js_ast.LComma)
				initializer = &value
			}

			return js_ast.Property{
				Kind:         kind,
				Key:          key,
				Value:        &value,
				Initializer:  initializer,
				WasShorthand: true,
			}, true
		}
	}

	if p.options.ts.Parse {
		// "class X { foo?: number }"
		// "class X { foo!: number }"
		if opts.isClass && (p.lexer.Token == js_lexer.TQuestion || p.lexer.Token == js_lexer.TExclamation) {
			p.lexer.Next()
		}

		// "class X { foo?<T>(): T }"
		// "const x = { foo<T>(): T {} }"
		p.skipTypeScriptTypeParameters()
	}

	// Parse a class field with an optional initial value
	if opts.isClass && kind == js_ast.PropertyNormal && !opts.isAsync &&
		!opts.isGenerator && p.lexer.Token != js_lexer.TOpenParen {
		var initializer *js_ast.Expr

		// Forbid the names "constructor" and "prototype" in some cases
		if !isComputed {
			if str, ok := key.Data.(*js_ast.EString); ok && (js_lexer.UTF16EqualsString(str.Value, "constructor") ||
				(opts.isStatic && js_lexer.UTF16EqualsString(str.Value, "prototype"))) {
				p.log.AddRangeError(&p.source, keyRange, fmt.Sprintf("Invalid field name %q", js_lexer.UTF16ToString(str.Value)))
			}
		}

		// Skip over types
		if p.options.ts.Parse && p.lexer.Token == js_lexer.TColon {
			p.lexer.Next()
			p.skipTypeScriptType(js_ast.LLowest)
		}

		if p.lexer.Token == js_lexer.TEquals {
			p.lexer.Next()
			value := p.parseExpr(js_ast.LComma)
			initializer = &value
		}

		// Special-case private identifiers
		if private, ok := key.Data.(*js_ast.EPrivateIdentifier); ok {
			name := p.loadNameFromRef(private.Ref)
			if name == "#constructor" {
				p.log.AddRangeError(&p.source, keyRange, fmt.Sprintf("Invalid field name %q", name))
			}
			var declare js_ast.SymbolKind
			if opts.isStatic {
				declare = js_ast.SymbolPrivateStaticField
			} else {
				declare = js_ast.SymbolPrivateField
			}
			private.Ref = p.declareSymbol(declare, key.Loc, name)
		}

		p.lexer.ExpectOrInsertSemicolon()
		return js_ast.Property{
			TSDecorators: opts.tsDecorators,
			Kind:         kind,
			IsComputed:   isComputed,
			IsStatic:     opts.isStatic,
			Key:          key,
			Initializer:  initializer,
		}, true
	}

	// Parse a method expression
	if p.lexer.Token == js_lexer.TOpenParen || kind != js_ast.PropertyNormal ||
		opts.isClass || opts.isAsync || opts.isGenerator {
		if p.lexer.Token == js_lexer.TOpenParen && kind != js_ast.PropertyGet && kind != js_ast.PropertySet {
			p.markSyntaxFeature(compat.ObjectExtensions, p.lexer.Range())
		}
		loc := p.lexer.Loc()
		scopeIndex := p.pushScopeForParsePass(js_ast.ScopeFunctionArgs, loc)
		isConstructor := false

		// Forbid the names "constructor" and "prototype" in some cases
		if opts.isClass && !isComputed {
			if str, ok := key.Data.(*js_ast.EString); ok {
				if !opts.isStatic && js_lexer.UTF16EqualsString(str.Value, "constructor") {
					switch {
					case kind == js_ast.PropertyGet:
						p.log.AddRangeError(&p.source, keyRange, "Class constructor cannot be a getter")
					case kind == js_ast.PropertySet:
						p.log.AddRangeError(&p.source, keyRange, "Class constructor cannot be a setter")
					case opts.isAsync:
						p.log.AddRangeError(&p.source, keyRange, "Class constructor cannot be an async function")
					case opts.isGenerator:
						p.log.AddRangeError(&p.source, keyRange, "Class constructor cannot be a generator")
					default:
						isConstructor = true
					}
				} else if opts.isStatic && js_lexer.UTF16EqualsString(str.Value, "prototype") {
					p.log.AddRangeError(&p.source, keyRange, "Invalid static method name \"prototype\"")
				}
			}
		}

		fn, hadBody := p.parseFn(nil, fnOrArrowDataParse{
			asyncRange:        opts.asyncRange,
			allowAwait:        opts.isAsync,
			allowYield:        opts.isGenerator,
			allowSuperCall:    opts.classHasExtends && isConstructor,
			allowTSDecorators: opts.allowTSDecorators,
			isConstructor:     isConstructor,

			// Only allow omitting the body if we're parsing TypeScript class
			allowMissingBodyForTypeScript: p.options.ts.Parse && opts.isClass,
		})

		// "class Foo { foo(): void; foo(): void {} }"
		if !hadBody {
			// Skip this property entirely
			p.popAndDiscardScope(scopeIndex)
			return js_ast.Property{}, false
		}

		p.popScope()
		value := js_ast.Expr{Loc: loc, Data: &js_ast.EFunction{Fn: fn}}

		// Enforce argument rules for accessors
		switch kind {
		case js_ast.PropertyGet:
			if len(fn.Args) > 0 {
				r := js_lexer.RangeOfIdentifier(p.source, fn.Args[0].Binding.Loc)
				p.log.AddRangeError(&p.source, r, fmt.Sprintf("Getter %s must have zero arguments", p.keyNameForError(key)))
			}

		case js_ast.PropertySet:
			if len(fn.Args) != 1 {
				r := js_lexer.RangeOfIdentifier(p.source, key.Loc)
				if len(fn.Args) > 1 {
					r = js_lexer.RangeOfIdentifier(p.source, fn.Args[1].Binding.Loc)
				}
				p.log.AddRangeError(&p.source, r, fmt.Sprintf("Setter %s must have exactly one argument", p.keyNameForError(key)))
			}
		}

		// Special-case private identifiers
		if private, ok := key.Data.(*js_ast.EPrivateIdentifier); ok {
			var declare js_ast.SymbolKind
			var suffix string
			switch kind {
			case js_ast.PropertyGet:
				if opts.isStatic {
					declare = js_ast.SymbolPrivateStaticGet
				} else {
					declare = js_ast.SymbolPrivateGet
				}
				suffix = "_get"
			case js_ast.PropertySet:
				if opts.isStatic {
					declare = js_ast.SymbolPrivateStaticSet
				} else {
					declare = js_ast.SymbolPrivateSet
				}
				suffix = "_set"
			default:
				if opts.isStatic {
					declare = js_ast.SymbolPrivateStaticMethod
				} else {
					declare = js_ast.SymbolPrivateMethod
				}
				suffix = "_fn"
			}
			name := p.loadNameFromRef(private.Ref)
			if name == "#constructor" {
				p.log.AddRangeError(&p.source, keyRange, fmt.Sprintf("Invalid method name %q", name))
			}
			private.Ref = p.declareSymbol(declare, key.Loc, name)
			if p.options.unsupportedJSFeatures.Has(declare.Feature()) {
				methodRef := p.newSymbol(js_ast.SymbolOther, name[1:]+suffix)
				if kind == js_ast.PropertySet {
					p.privateSetters[private.Ref] = methodRef
				} else {
					p.privateGetters[private.Ref] = methodRef
				}
			}
		}

		return js_ast.Property{
			TSDecorators: opts.tsDecorators,
			Kind:         kind,
			IsComputed:   isComputed,
			IsMethod:     true,
			IsStatic:     opts.isStatic,
			Key:          key,
			Value:        &value,
		}, true
	}

	// Parse an object key/value pair
	p.lexer.Expect(js_lexer.TColon)
	value := p.parseExprOrBindings(js_ast.LComma, errors)
	return js_ast.Property{
		Kind:       kind,
		IsComputed: isComputed,
		Key:        key,
		Value:      &value,
	}, true
}

func (p *parser) parsePropertyBinding() js_ast.PropertyBinding {
	var key js_ast.Expr
	isComputed := false

	switch p.lexer.Token {
	case js_lexer.TDotDotDot:
		p.lexer.Next()
		value := js_ast.Binding{Loc: p.lexer.Loc(), Data: &js_ast.BIdentifier{Ref: p.storeNameInRef(p.lexer.Identifier)}}
		p.lexer.Expect(js_lexer.TIdentifier)
		return js_ast.PropertyBinding{
			IsSpread: true,
			Value:    value,
		}

	case js_lexer.TNumericLiteral:
		key = js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.ENumber{Value: p.lexer.Number}}
		p.lexer.Next()

	case js_lexer.TStringLiteral:
		key = js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.EString{Value: p.lexer.StringLiteral}}
		p.lexer.Next()

	case js_lexer.TBigIntegerLiteral:
		key = js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.EBigInt{Value: p.lexer.Identifier}}
		p.markSyntaxFeature(compat.BigInt, p.lexer.Range())
		p.lexer.Next()

	case js_lexer.TOpenBracket:
		isComputed = true
		p.lexer.Next()
		key = p.parseExpr(js_ast.LComma)
		p.lexer.Expect(js_lexer.TCloseBracket)

	default:
		name := p.lexer.Identifier
		loc := p.lexer.Loc()
		if !p.lexer.IsIdentifierOrKeyword() {
			p.lexer.Expect(js_lexer.TIdentifier)
		}
		p.lexer.Next()
		key = js_ast.Expr{Loc: loc, Data: &js_ast.EString{Value: js_lexer.StringToUTF16(name)}}

		if p.lexer.Token != js_lexer.TColon && p.lexer.Token != js_lexer.TOpenParen {
			ref := p.storeNameInRef(name)
			value := js_ast.Binding{Loc: loc, Data: &js_ast.BIdentifier{Ref: ref}}

			var defaultValue *js_ast.Expr
			if p.lexer.Token == js_lexer.TEquals {
				p.lexer.Next()
				init := p.parseExpr(js_ast.LComma)
				defaultValue = &init
			}

			return js_ast.PropertyBinding{
				Key:          key,
				Value:        value,
				DefaultValue: defaultValue,
			}
		}
	}

	p.lexer.Expect(js_lexer.TColon)
	value := p.parseBinding()

	var defaultValue *js_ast.Expr
	if p.lexer.Token == js_lexer.TEquals {
		p.lexer.Next()
		init := p.parseExpr(js_ast.LComma)
		defaultValue = &init
	}

	return js_ast.PropertyBinding{
		IsComputed:   isComputed,
		Key:          key,
		Value:        value,
		DefaultValue: defaultValue,
	}
}

func (p *parser) parseArrowBody(args []js_ast.Arg, data fnOrArrowDataParse) *js_ast.EArrow {
	arrowLoc := p.lexer.Loc()

	// Newlines are not allowed before "=>"
	if p.lexer.HasNewlineBefore {
		p.log.AddRangeError(&p.source, p.lexer.Range(), "Unexpected newline before \"=>\"")
		panic(js_lexer.LexerPanic{})
	}

	p.lexer.Expect(js_lexer.TEqualsGreaterThan)

	for _, arg := range args {
		p.declareBinding(js_ast.SymbolHoisted, arg.Binding, parseStmtOpts{})
	}

	// The ability to call "super()" is inherited by arrow functions
	data.allowSuperCall = p.fnOrArrowDataParse.allowSuperCall

	if p.lexer.Token == js_lexer.TOpenBrace {
		return &js_ast.EArrow{
			Args: args,
			Body: p.parseFnBody(data),
		}
	}

	p.pushScopeForParsePass(js_ast.ScopeFunctionBody, arrowLoc)
	defer p.popScope()

	oldFnOrArrowData := p.fnOrArrowDataParse
	p.fnOrArrowDataParse = data
	expr := p.parseExpr(js_ast.LComma)
	p.fnOrArrowDataParse = oldFnOrArrowData
	return &js_ast.EArrow{
		Args:       args,
		PreferExpr: true,
		Body:       js_ast.FnBody{Loc: arrowLoc, Stmts: []js_ast.Stmt{{Loc: expr.Loc, Data: &js_ast.SReturn{Value: &expr}}}},
	}
}

func (p *parser) isAsyncExprSuffix() bool {
	switch p.lexer.Token {
	case js_lexer.TFunction, js_lexer.TEqualsGreaterThan:
		return true
	}
	return false
}

// This parses an expression. This assumes we've already parsed the "async"
// keyword and are currently looking at the following token.
func (p *parser) parseAsyncPrefixExpr(asyncRange logger.Range) js_ast.Expr {
	// Make sure this matches the switch statement in isAsyncExprSuffix()
	if !p.lexer.HasNewlineBefore {
		switch p.lexer.Token {
		// "async function() {}"
		case js_lexer.TFunction:
			return p.parseFnExpr(asyncRange.Loc, true /* isAsync */, asyncRange)

			// "async => {}"
		case js_lexer.TEqualsGreaterThan:
			arg := js_ast.Arg{Binding: js_ast.Binding{Loc: asyncRange.Loc, Data: &js_ast.BIdentifier{Ref: p.storeNameInRef("async")}}}

			p.pushScopeForParsePass(js_ast.ScopeFunctionArgs, asyncRange.Loc)
			defer p.popScope()

			return js_ast.Expr{Loc: asyncRange.Loc, Data: p.parseArrowBody([]js_ast.Arg{arg}, fnOrArrowDataParse{})}

			// "async x => {}"
		case js_lexer.TIdentifier:
			p.markLoweredSyntaxFeature(compat.AsyncAwait, asyncRange, compat.Generator)
			ref := p.storeNameInRef(p.lexer.Identifier)
			arg := js_ast.Arg{Binding: js_ast.Binding{Loc: p.lexer.Loc(), Data: &js_ast.BIdentifier{Ref: ref}}}
			p.lexer.Next()

			p.pushScopeForParsePass(js_ast.ScopeFunctionArgs, asyncRange.Loc)
			defer p.popScope()

			arrow := p.parseArrowBody([]js_ast.Arg{arg}, fnOrArrowDataParse{allowAwait: true})
			arrow.IsAsync = true
			return js_ast.Expr{Loc: asyncRange.Loc, Data: arrow}

			// "async()"
			// "async () => {}"
		case js_lexer.TOpenParen:
			p.lexer.Next()
			return p.parseParenExpr(asyncRange.Loc, parenExprOpts{isAsync: true, asyncRange: asyncRange})
		}
	}

	// "async"
	// "async + 1"
	// Distinguish between a call like "async<T>()" and an arrow like "async <T>() => {}"
	if p.options.ts.Parse && p.lexer.Token == js_lexer.TLessThan && p.trySkipTypeScriptTypeParametersThenOpenParenWithBacktracking() {
		p.lexer.Next()
		return p.parseParenExpr(asyncRange.Loc, parenExprOpts{isAsync: true, asyncRange: asyncRange})
	}

	return js_ast.Expr{Loc: asyncRange.Loc, Data: &js_ast.EIdentifier{Ref: p.storeNameInRef("async")}}
}

func (p *parser) parseFnExpr(loc logger.Loc, isAsync bool, asyncRange logger.Range) js_ast.Expr {
	p.lexer.Next()
	isGenerator := p.lexer.Token == js_lexer.TAsterisk
	if isGenerator {
		p.markSyntaxFeature(compat.Generator, p.lexer.Range())
		p.lexer.Next()
	} else if isAsync {
		p.markLoweredSyntaxFeature(compat.AsyncAwait, asyncRange, compat.Generator)
	}
	var name *js_ast.LocRef

	p.pushScopeForParsePass(js_ast.ScopeFunctionArgs, loc)
	defer p.popScope()

	// The name is optional
	if p.lexer.Token == js_lexer.TIdentifier {
		// Don't declare the name "arguments" since it's shadowed and inaccessible
		name = &js_ast.LocRef{Loc: p.lexer.Loc()}
		if text := p.lexer.Identifier; text != "arguments" {
			name.Ref = p.declareSymbol(js_ast.SymbolHoistedFunction, name.Loc, text)
		} else {
			name.Ref = p.newSymbol(js_ast.SymbolHoistedFunction, text)
		}
		p.lexer.Next()
	}

	// Even anonymous functions can have TypeScript type parameters
	if p.options.ts.Parse {
		p.skipTypeScriptTypeParameters()
	}

	fn, _ := p.parseFn(name, fnOrArrowDataParse{
		asyncRange: asyncRange,
		allowAwait: isAsync,
		allowYield: isGenerator,
	})
	return js_ast.Expr{Loc: loc, Data: &js_ast.EFunction{Fn: fn}}
}

type parenExprOpts struct {
	asyncRange   logger.Range
	isAsync      bool
	forceArrowFn bool
}

// This assumes that the open parenthesis has already been parsed by the caller
func (p *parser) parseParenExpr(loc logger.Loc, opts parenExprOpts) js_ast.Expr {
	items := []js_ast.Expr{}
	errors := deferredErrors{}
	arrowArgErrors := deferredArrowArgErrors{}
	spreadRange := logger.Range{}
	typeColonRange := logger.Range{}

	// Push a scope assuming this is an arrow function. It may not be, in which
	// case we'll need to roll this change back. This has to be done ahead of
	// parsing the arguments instead of later on when we hit the "=>" token and
	// we know it's an arrow function because the arguments may have default
	// values that introduce new scopes and declare new symbols. If this is an
	// arrow function, then those new scopes will need to be parented under the
	// scope of the arrow function itself.
	scopeIndex := p.pushScopeForParsePass(js_ast.ScopeFunctionArgs, loc)

	// Allow "in" inside parentheses
	oldAllowIn := p.allowIn
	p.allowIn = true

	// Forbid "await" and "yield", but only for arrow functions
	oldFnOrArrowData := p.fnOrArrowDataParse
	p.fnOrArrowDataParse.arrowArgErrors = &arrowArgErrors

	// Scan over the comma-separated arguments or expressions
	for p.lexer.Token != js_lexer.TCloseParen {
		itemLoc := p.lexer.Loc()
		isSpread := p.lexer.Token == js_lexer.TDotDotDot

		if isSpread {
			spreadRange = p.lexer.Range()
			p.markSyntaxFeature(compat.RestArgument, spreadRange)
			p.lexer.Next()
		}

		// We don't know yet whether these are arguments or expressions, so parse
		// a superset of the expression syntax. Errors about things that are valid
		// in one but not in the other are deferred.
		p.latestArrowArgLoc = p.lexer.Loc()
		item := p.parseExprOrBindings(js_ast.LComma, &errors)

		if isSpread {
			item = js_ast.Expr{Loc: itemLoc, Data: &js_ast.ESpread{Value: item}}
		}

		// Skip over types
		if p.options.ts.Parse && p.lexer.Token == js_lexer.TColon {
			typeColonRange = p.lexer.Range()
			p.lexer.Next()
			p.skipTypeScriptType(js_ast.LLowest)
		}

		// There may be a "=" after the type (but not after an "as" cast)
		if p.options.ts.Parse && p.lexer.Token == js_lexer.TEquals && p.lexer.Loc() != p.forbidSuffixAfterAsLoc {
			p.lexer.Next()
			item = js_ast.Assign(item, p.parseExpr(js_ast.LComma))
		}

		items = append(items, item)
		if p.lexer.Token != js_lexer.TComma {
			break
		}

		// Spread arguments must come last. If there's a spread argument followed
		// by a comma, throw an error if we use these expressions as bindings.
		if isSpread {
			errors.invalidBindingCommaAfterSpread = p.lexer.Range()
		}

		// Eat the comma token
		p.lexer.Next()
	}

	// The parenthetical construct must end with a close parenthesis
	p.lexer.Expect(js_lexer.TCloseParen)

	// Restore "in" operator status before we parse the arrow function body
	p.allowIn = oldAllowIn

	// Also restore "await" and "yield" expression errors
	p.fnOrArrowDataParse = oldFnOrArrowData

	// Are these arguments to an arrow function?
	if p.lexer.Token == js_lexer.TEqualsGreaterThan || opts.forceArrowFn || (p.options.ts.Parse && p.lexer.Token == js_lexer.TColon) {
		invalidLog := []logger.Loc{}
		args := []js_ast.Arg{}

		if opts.isAsync {
			p.markLoweredSyntaxFeature(compat.AsyncAwait, opts.asyncRange, compat.Generator)
		}

		// First, try converting the expressions to bindings
		for _, item := range items {
			isSpread := false
			if spread, ok := item.Data.(*js_ast.ESpread); ok {
				item = spread.Value
				isSpread = true
			}
			binding, initializer, log := p.convertExprToBindingAndInitializer(item, invalidLog)
			if initializer != nil {
				equalsRange := p.source.RangeOfOperatorBefore(initializer.Loc, "=")
				if isSpread {
					p.log.AddRangeError(&p.source, equalsRange, "A rest argument cannot have a default initializer")
				} else {
					p.markSyntaxFeature(compat.DefaultArgument, equalsRange)
				}
			}
			invalidLog = log
			args = append(args, js_ast.Arg{Binding: binding, Default: initializer})
		}

		// Avoid parsing TypeScript code like "a ? (1 + 2) : (3 + 4)" as an arrow
		// function. The ":" after the ")" may be a return type annotation, so we
		// attempt to convert the expressions to bindings first before deciding
		// whether this is an arrow function, and only pick an arrow function if
		// there were no conversion errors.
		if p.lexer.Token == js_lexer.TEqualsGreaterThan || (len(invalidLog) == 0 &&
			p.trySkipTypeScriptArrowReturnTypeWithBacktracking()) || opts.forceArrowFn {
			p.logBindingErrors(&errors)
			p.logArrowArgErrors(&arrowArgErrors)

			// Now that we've decided we're an arrow function, report binding pattern
			// conversion errors
			if len(invalidLog) > 0 {
				for _, loc := range invalidLog {
					p.log.AddError(&p.source, loc, "Invalid binding pattern")
				}
				panic(js_lexer.LexerPanic{})
			}

			arrow := p.parseArrowBody(args, fnOrArrowDataParse{allowAwait: opts.isAsync})
			arrow.IsAsync = opts.isAsync
			arrow.HasRestArg = spreadRange.Len > 0
			p.popScope()
			return js_ast.Expr{Loc: loc, Data: arrow}
		}
	}

	// If we get here, it's not an arrow function so undo the pushing of the
	// scope we did earlier. This needs to flatten any child scopes into the
	// parent scope as if the scope was never pushed in the first place.
	p.popAndFlattenScope(scopeIndex)

	// If this isn't an arrow function, then types aren't allowed
	if typeColonRange.Len > 0 {
		p.log.AddRangeError(&p.source, typeColonRange, "Unexpected \":\"")
		panic(js_lexer.LexerPanic{})
	}

	// Are these arguments for a call to a function named "async"?
	if opts.isAsync {
		p.logExprErrors(&errors)
		async := js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: p.storeNameInRef("async")}}
		return js_ast.Expr{Loc: loc, Data: &js_ast.ECall{
			Target: async,
			Args:   items,
		}}
	}

	// Is this a chain of expressions and comma operators?
	if len(items) > 0 {
		p.logExprErrors(&errors)
		if spreadRange.Len > 0 {
			p.log.AddRangeError(&p.source, spreadRange, "Unexpected \"...\"")
			panic(js_lexer.LexerPanic{})
		}
		value := js_ast.JoinAllWithComma(items)
		markExprAsParenthesized(value)
		return value
	}

	// Indicate that we expected an arrow function
	p.lexer.Expected(js_lexer.TEqualsGreaterThan)
	return js_ast.Expr{}
}

func markExprAsParenthesized(value js_ast.Expr) {
	if e, ok := value.Data.(*js_ast.EArrow); ok {
		e.IsParenthesized = true
	}
}

func markExprAsTypeScriptCast(value js_ast.Expr) {
	if e, ok := value.Data.(*js_ast.EIdentifier); ok {
		e.WasTypeScriptCast = true
	}
}

func (p *parser) convertExprToBindingAndInitializer(expr js_ast.Expr, invalidLog []logger.Loc) (js_ast.Binding, *js_ast.Expr, []logger.Loc) {
	var initializer *js_ast.Expr
	if assign, ok := expr.Data.(*js_ast.EBinary); ok && assign.Op == js_ast.BinOpAssign {
		initializer = &assign.Right
		expr = assign.Left
	}
	binding, invalidLog := p.convertExprToBinding(expr, invalidLog)
	return binding, initializer, invalidLog
}

func (p *parser) convertExprToBinding(expr js_ast.Expr, invalidLog []logger.Loc) (js_ast.Binding, []logger.Loc) {
	switch e := expr.Data.(type) {
	case *js_ast.EMissing:
		return js_ast.Binding{Loc: expr.Loc, Data: &js_ast.BMissing{}}, invalidLog

	case *js_ast.EIdentifier:
		return js_ast.Binding{Loc: expr.Loc, Data: &js_ast.BIdentifier{Ref: e.Ref}}, invalidLog

	case *js_ast.EArray:
		p.markSyntaxFeature(compat.Destructuring, p.source.RangeOfOperatorAfter(expr.Loc, "["))
		items := []js_ast.ArrayBinding{}
		isSpread := false
		for _, item := range e.Items {
			if i, ok := item.Data.(*js_ast.ESpread); ok {
				isSpread = true
				item = i.Value
				if _, ok := item.Data.(*js_ast.EIdentifier); !ok {
					p.markSyntaxFeature(compat.NestedRestBinding, p.source.RangeOfOperatorAfter(item.Loc, "["))
				}
			}
			binding, initializer, log := p.convertExprToBindingAndInitializer(item, invalidLog)
			invalidLog = log
			items = append(items, js_ast.ArrayBinding{Binding: binding, DefaultValue: initializer})
		}
		return js_ast.Binding{Loc: expr.Loc, Data: &js_ast.BArray{
			Items:        items,
			HasSpread:    isSpread,
			IsSingleLine: e.IsSingleLine,
		}}, invalidLog

	case *js_ast.EObject:
		p.markSyntaxFeature(compat.Destructuring, p.source.RangeOfOperatorAfter(expr.Loc, "{"))
		properties := []js_ast.PropertyBinding{}
		for _, item := range e.Properties {
			if item.IsMethod || item.Kind == js_ast.PropertyGet || item.Kind == js_ast.PropertySet {
				invalidLog = append(invalidLog, item.Key.Loc)
				continue
			}
			binding, initializer, log := p.convertExprToBindingAndInitializer(*item.Value, invalidLog)
			invalidLog = log
			if initializer == nil {
				initializer = item.Initializer
			}
			properties = append(properties, js_ast.PropertyBinding{
				IsSpread:     item.Kind == js_ast.PropertySpread,
				IsComputed:   item.IsComputed,
				Key:          item.Key,
				Value:        binding,
				DefaultValue: initializer,
			})
		}
		return js_ast.Binding{Loc: expr.Loc, Data: &js_ast.BObject{
			Properties:   properties,
			IsSingleLine: e.IsSingleLine,
		}}, invalidLog

	default:
		invalidLog = append(invalidLog, expr.Loc)
		return js_ast.Binding{}, invalidLog
	}
}

func (p *parser) convertBindingToExpr(binding js_ast.Binding, wrapIdentifier func(logger.Loc, js_ast.Ref) js_ast.Expr) js_ast.Expr {
	loc := binding.Loc

	switch b := binding.Data.(type) {
	case *js_ast.BMissing:
		return js_ast.Expr{Loc: loc, Data: &js_ast.EMissing{}}

	case *js_ast.BIdentifier:
		if wrapIdentifier != nil {
			return wrapIdentifier(loc, b.Ref)
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: b.Ref}}

	case *js_ast.BArray:
		exprs := make([]js_ast.Expr, len(b.Items))
		for i, item := range b.Items {
			expr := p.convertBindingToExpr(item.Binding, wrapIdentifier)
			if b.HasSpread && i+1 == len(b.Items) {
				expr = js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ESpread{Value: expr}}
			} else if item.DefaultValue != nil {
				expr = js_ast.Assign(expr, *item.DefaultValue)
			}
			exprs[i] = expr
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EArray{
			Items:        exprs,
			IsSingleLine: b.IsSingleLine,
		}}

	case *js_ast.BObject:
		properties := make([]js_ast.Property, len(b.Properties))
		for i, property := range b.Properties {
			value := p.convertBindingToExpr(property.Value, wrapIdentifier)
			kind := js_ast.PropertyNormal
			if property.IsSpread {
				kind = js_ast.PropertySpread
			}
			properties[i] = js_ast.Property{
				Kind:        kind,
				IsComputed:  property.IsComputed,
				Key:         property.Key,
				Value:       &value,
				Initializer: property.DefaultValue,
			}
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EObject{
			Properties:   properties,
			IsSingleLine: b.IsSingleLine,
		}}

	default:
		panic("Internal error")
	}
}

type exprFlag uint8

const (
	exprFlagTSDecorator exprFlag = 1 << iota
)

func (p *parser) parsePrefix(level js_ast.L, errors *deferredErrors, flags exprFlag) js_ast.Expr {
	loc := p.lexer.Loc()

	switch p.lexer.Token {
	case js_lexer.TSuper:
		p.lexer.Next()

		switch p.lexer.Token {
		case js_lexer.TOpenParen:
			if level < js_ast.LCall && p.fnOrArrowDataParse.allowSuperCall {
				return js_ast.Expr{Loc: loc, Data: &js_ast.ESuper{}}
			}

		case js_lexer.TDot, js_lexer.TOpenBracket:
			return js_ast.Expr{Loc: loc, Data: &js_ast.ESuper{}}
		}

		p.lexer.Unexpected()
		return js_ast.Expr{}

	case js_lexer.TOpenParen:
		p.lexer.Next()

		// Arrow functions aren't allowed in the middle of expressions
		if level > js_ast.LAssign {
			// Allow "in" inside parentheses
			oldAllowIn := p.allowIn
			p.allowIn = true

			value := p.parseExpr(js_ast.LLowest)
			markExprAsParenthesized(value)
			p.lexer.Expect(js_lexer.TCloseParen)

			p.allowIn = oldAllowIn
			return value
		}

		value := p.parseParenExpr(loc, parenExprOpts{})
		return value

	case js_lexer.TFalse:
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EBoolean{Value: false}}

	case js_lexer.TTrue:
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EBoolean{Value: true}}

	case js_lexer.TNull:
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.ENull{}}

	case js_lexer.TThis:
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EThis{}}

	case js_lexer.TIdentifier:
		name := p.lexer.Identifier
		nameRange := p.lexer.Range()
		raw := p.lexer.Raw()
		p.lexer.Next()

		// Handle async and await expressions
		switch name {
		case "async":
			if raw == "async" {
				return p.parseAsyncPrefixExpr(nameRange)
			}

		case "await":
			if p.fnOrArrowDataParse.allowAwait {
				if raw != "await" {
					p.log.AddRangeError(&p.source, nameRange, "The keyword \"await\" cannot be escaped")
				} else {
					if p.fnOrArrowDataParse.isTopLevel {
						p.markSyntaxFeature(compat.TopLevelAwait, nameRange)
					}
					if p.fnOrArrowDataParse.arrowArgErrors != nil {
						p.fnOrArrowDataParse.arrowArgErrors.invalidExprAwait = nameRange
					}
					return js_ast.Expr{Loc: loc, Data: &js_ast.EAwait{Value: p.parseExpr(js_ast.LPrefix)}}
				}
			}

		case "yield":
			if p.fnOrArrowDataParse.allowYield {
				if raw != "yield" {
					p.log.AddRangeError(&p.source, nameRange, "The keyword \"yield\" cannot be escaped")
				} else {
					if level > js_ast.LAssign {
						p.log.AddRangeError(&p.source, nameRange, "Cannot use a \"yield\" expression here without parentheses")
					}
					if p.fnOrArrowDataParse.arrowArgErrors != nil {
						p.fnOrArrowDataParse.arrowArgErrors.invalidExprYield = nameRange
					}
					return p.parseYieldExpr(loc)
				}
			} else if !p.lexer.HasNewlineBefore {
				// Try to gracefully recover if "yield" is used in the wrong place
				switch p.lexer.Token {
				case js_lexer.TNull, js_lexer.TIdentifier, js_lexer.TFalse, js_lexer.TTrue,
					js_lexer.TNumericLiteral, js_lexer.TBigIntegerLiteral, js_lexer.TStringLiteral:
					p.log.AddRangeError(&p.source, nameRange, "Cannot use \"yield\" outside a generator function")
					return p.parseYieldExpr(loc)
				}
			}
		}

		// Handle the start of an arrow expression
		if p.lexer.Token == js_lexer.TEqualsGreaterThan {
			ref := p.storeNameInRef(name)
			arg := js_ast.Arg{Binding: js_ast.Binding{Loc: loc, Data: &js_ast.BIdentifier{Ref: ref}}}

			p.pushScopeForParsePass(js_ast.ScopeFunctionArgs, loc)
			defer p.popScope()

			return js_ast.Expr{Loc: loc, Data: p.parseArrowBody([]js_ast.Arg{arg}, fnOrArrowDataParse{})}
		}

		ref := p.storeNameInRef(name)
		return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: ref}}

	case js_lexer.TStringLiteral:
		value := p.lexer.StringLiteral
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EString{Value: value}}

	case js_lexer.TNoSubstitutionTemplateLiteral:
		head := p.lexer.StringLiteral
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EString{Value: head, PreferTemplate: true}}

	case js_lexer.TTemplateHead:
		head := p.lexer.StringLiteral
		parts := p.parseTemplateParts(false /* includeRaw */)
		if p.options.unsupportedJSFeatures.Has(compat.TemplateLiteral) {
			var value js_ast.Expr
			if len(head) == 0 {
				// "`${x}y`" => "x + 'y'"
				part := parts[0]
				value = js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
					Op:    js_ast.BinOpAdd,
					Left:  part.Value,
					Right: js_ast.Expr{Loc: part.TailLoc, Data: &js_ast.EString{Value: part.Tail}},
				}}
				parts = parts[1:]
			} else {
				// "`x${y}`" => "'x' + y"
				value = js_ast.Expr{Loc: loc, Data: &js_ast.EString{Value: head}}
			}
			for _, part := range parts {
				value = js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
					Op:    js_ast.BinOpAdd,
					Left:  value,
					Right: part.Value,
				}}
				if len(part.Tail) > 0 {
					value = js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
						Op:    js_ast.BinOpAdd,
						Left:  value,
						Right: js_ast.Expr{Loc: part.TailLoc, Data: &js_ast.EString{Value: part.Tail}},
					}}
				}
			}
			return value
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.ETemplate{Head: head, Parts: parts}}

	case js_lexer.TNumericLiteral:
		value := p.lexer.Number
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.ENumber{Value: value}}

	case js_lexer.TBigIntegerLiteral:
		value := p.lexer.Identifier
		p.markSyntaxFeature(compat.BigInt, p.lexer.Range())
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EBigInt{Value: value}}

	case js_lexer.TSlash, js_lexer.TSlashEquals:
		p.lexer.ScanRegExp()
		value := p.lexer.Raw()
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.ERegExp{Value: value}}

	case js_lexer.TVoid:
		p.lexer.Next()
		value := p.parseExpr(js_ast.LPrefix)
		if p.lexer.Token == js_lexer.TAsteriskAsterisk {
			p.lexer.Unexpected()
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpVoid, Value: value}}

	case js_lexer.TTypeof:
		p.lexer.Next()
		value := p.parseExpr(js_ast.LPrefix)
		if p.lexer.Token == js_lexer.TAsteriskAsterisk {
			p.lexer.Unexpected()
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpTypeof, Value: value}}

	case js_lexer.TDelete:
		p.lexer.Next()
		value := p.parseExpr(js_ast.LPrefix)
		if p.lexer.Token == js_lexer.TAsteriskAsterisk {
			p.lexer.Unexpected()
		}
		if index, ok := value.Data.(*js_ast.EIndex); ok {
			if private, ok := index.Index.Data.(*js_ast.EPrivateIdentifier); ok {
				name := p.loadNameFromRef(private.Ref)
				r := logger.Range{Loc: index.Index.Loc, Len: int32(len(name))}
				p.log.AddRangeError(&p.source, r, fmt.Sprintf("Deleting the private name %q is forbidden", name))
			}
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpDelete, Value: value}}

	case js_lexer.TPlus:
		p.lexer.Next()
		value := p.parseExpr(js_ast.LPrefix)
		if p.lexer.Token == js_lexer.TAsteriskAsterisk {
			p.lexer.Unexpected()
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpPos, Value: value}}

	case js_lexer.TMinus:
		p.lexer.Next()
		value := p.parseExpr(js_ast.LPrefix)
		if p.lexer.Token == js_lexer.TAsteriskAsterisk {
			p.lexer.Unexpected()
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpNeg, Value: value}}

	case js_lexer.TTilde:
		p.lexer.Next()
		value := p.parseExpr(js_ast.LPrefix)
		if p.lexer.Token == js_lexer.TAsteriskAsterisk {
			p.lexer.Unexpected()
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpCpl, Value: value}}

	case js_lexer.TExclamation:
		p.lexer.Next()
		value := p.parseExpr(js_ast.LPrefix)
		if p.lexer.Token == js_lexer.TAsteriskAsterisk {
			p.lexer.Unexpected()
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpNot, Value: value}}

	case js_lexer.TMinusMinus:
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpPreDec, Value: p.parseExpr(js_ast.LPrefix)}}

	case js_lexer.TPlusPlus:
		p.lexer.Next()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EUnary{Op: js_ast.UnOpPreInc, Value: p.parseExpr(js_ast.LPrefix)}}

	case js_lexer.TFunction:
		return p.parseFnExpr(loc, false /* isAsync */, logger.Range{})

	case js_lexer.TClass:
		p.markSyntaxFeature(compat.Class, p.lexer.Range())
		p.lexer.Next()
		var name *js_ast.LocRef

		p.pushScopeForParsePass(js_ast.ScopeClassName, loc)

		// Parse an optional class name
		if p.lexer.Token == js_lexer.TIdentifier && !js_lexer.StrictModeReservedWords[p.lexer.Identifier] {
			name = &js_ast.LocRef{Loc: p.lexer.Loc(), Ref: p.newSymbol(js_ast.SymbolOther, p.lexer.Identifier)}
			p.lexer.Next()
		}

		// Even anonymous classes can have TypeScript type parameters
		if p.options.ts.Parse {
			p.skipTypeScriptTypeParameters()
		}

		class := p.parseClass(name, parseClassOpts{})

		p.popScope()
		return js_ast.Expr{Loc: loc, Data: &js_ast.EClass{Class: class}}

	case js_lexer.TNew:
		p.lexer.Next()

		// Special-case the weird "new.target" expression here
		if p.lexer.Token == js_lexer.TDot {
			p.lexer.Next()
			if p.lexer.Token != js_lexer.TIdentifier || p.lexer.Identifier != "target" {
				p.lexer.Unexpected()
			}
			r := logger.Range{Loc: loc, Len: p.lexer.Range().End() - loc.Start}
			p.markSyntaxFeature(compat.NewTarget, r)
			p.lexer.Next()
			return js_ast.Expr{Loc: loc, Data: &js_ast.ENewTarget{}}
		}

		target := p.parseExprWithFlags(js_ast.LMember, flags)
		args := []js_ast.Expr{}

		if p.options.ts.Parse {
			// Skip over TypeScript non-null assertions
			if p.lexer.Token == js_lexer.TExclamation && !p.lexer.HasNewlineBefore {
				p.lexer.Next()
			}

			// Skip over TypeScript type arguments here if there are any
			if p.lexer.Token == js_lexer.TLessThan {
				p.trySkipTypeScriptTypeArgumentsWithBacktracking()
			}
		}

		if p.lexer.Token == js_lexer.TOpenParen {
			args = p.parseCallArgs()
		}

		return js_ast.Expr{Loc: loc, Data: &js_ast.ENew{Target: target, Args: args}}

	case js_lexer.TOpenBracket:
		p.lexer.Next()
		isSingleLine := !p.lexer.HasNewlineBefore
		items := []js_ast.Expr{}
		selfErrors := deferredErrors{}

		// Allow "in" inside arrays
		oldAllowIn := p.allowIn
		p.allowIn = true

		for p.lexer.Token != js_lexer.TCloseBracket {
			switch p.lexer.Token {
			case js_lexer.TComma:
				items = append(items, js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.EMissing{}})

			case js_lexer.TDotDotDot:
				if errors != nil {
					errors.arraySpreadFeature = p.lexer.Range()
				} else {
					p.markSyntaxFeature(compat.ArraySpread, p.lexer.Range())
				}
				dotsLoc := p.lexer.Loc()
				p.lexer.Next()
				item := p.parseExprOrBindings(js_ast.LComma, &selfErrors)
				items = append(items, js_ast.Expr{Loc: dotsLoc, Data: &js_ast.ESpread{Value: item}})

				// Commas are not allowed here when destructuring
				if p.lexer.Token == js_lexer.TComma {
					selfErrors.invalidBindingCommaAfterSpread = p.lexer.Range()
				}

			default:
				item := p.parseExprOrBindings(js_ast.LComma, &selfErrors)
				items = append(items, item)
			}

			if p.lexer.Token != js_lexer.TComma {
				break
			}
			if p.lexer.HasNewlineBefore {
				isSingleLine = false
			}
			p.lexer.Next()
			if p.lexer.HasNewlineBefore {
				isSingleLine = false
			}
		}

		if p.lexer.HasNewlineBefore {
			isSingleLine = false
		}
		p.lexer.Expect(js_lexer.TCloseBracket)
		p.allowIn = oldAllowIn

		if p.willNeedBindingPattern() {
			// Is this a binding pattern?
			p.logBindingErrors(&selfErrors)
		} else if errors == nil {
			// Is this an expression?
			p.logExprErrors(&selfErrors)
		} else {
			// In this case, we can't distinguish between the two yet
			selfErrors.mergeInto(errors)
		}

		return js_ast.Expr{Loc: loc, Data: &js_ast.EArray{
			Items:        items,
			IsSingleLine: isSingleLine,
		}}

	case js_lexer.TOpenBrace:
		p.lexer.Next()
		isSingleLine := !p.lexer.HasNewlineBefore
		properties := []js_ast.Property{}
		selfErrors := deferredErrors{}

		// Allow "in" inside object literals
		oldAllowIn := p.allowIn
		p.allowIn = true

		for p.lexer.Token != js_lexer.TCloseBrace {
			if p.lexer.Token == js_lexer.TDotDotDot {
				p.lexer.Next()
				value := p.parseExpr(js_ast.LComma)
				properties = append(properties, js_ast.Property{
					Kind:  js_ast.PropertySpread,
					Value: &value,
				})

				// Commas are not allowed here when destructuring
				if p.lexer.Token == js_lexer.TComma {
					selfErrors.invalidBindingCommaAfterSpread = p.lexer.Range()
				}
			} else {
				// This property may turn out to be a type in TypeScript, which should be ignored
				if property, ok := p.parseProperty(js_ast.PropertyNormal, propertyOpts{}, &selfErrors); ok {
					properties = append(properties, property)
				}
			}

			if p.lexer.Token != js_lexer.TComma {
				break
			}
			if p.lexer.HasNewlineBefore {
				isSingleLine = false
			}
			p.lexer.Next()
			if p.lexer.HasNewlineBefore {
				isSingleLine = false
			}
		}

		if p.lexer.HasNewlineBefore {
			isSingleLine = false
		}
		p.lexer.Expect(js_lexer.TCloseBrace)
		p.allowIn = oldAllowIn

		if p.willNeedBindingPattern() {
			// Is this a binding pattern?
			p.logBindingErrors(&selfErrors)
		} else if errors == nil {
			// Is this an expression?
			p.logExprErrors(&selfErrors)
		} else {
			// In this case, we can't distinguish between the two yet
			selfErrors.mergeInto(errors)
		}

		return js_ast.Expr{Loc: loc, Data: &js_ast.EObject{
			Properties:   properties,
			IsSingleLine: isSingleLine,
		}}

	case js_lexer.TLessThan:
		// This is a very complicated and highly ambiguous area of TypeScript
		// syntax. Many similar-looking things are overloaded.
		//
		// TS:
		//
		//   A type cast:
		//     <A>(x)
		//     <[]>(x)
		//     <A[]>(x)
		//
		//   An arrow function with type parameters:
		//     <A>(x) => {}
		//     <A, B>(x) => {}
		//     <A = B>(x) => {}
		//     <A extends B>(x) => {}
		//
		// TSX:
		//
		//   A JSX element:
		//     <A>(x) => {}</A>
		//     <A extends>(x) => {}</A>
		//     <A extends={false}>(x) => {}</A>
		//
		//   An arrow function with type parameters:
		//     <A, B>(x) => {}
		//     <A extends B>(x) => {}
		//
		//   A syntax error:
		//     <[]>(x)
		//     <A[]>(x)
		//     <A>(x) => {}
		//     <A = B>(x) => {}

		if p.options.ts.Parse && p.options.jsx.Parse {
			oldLexer := p.lexer
			p.lexer.Next()

			// Look ahead to see if this should be an arrow function instead
			isTSArrowFn := false
			if p.lexer.Token == js_lexer.TIdentifier {
				p.lexer.Next()
				if p.lexer.Token == js_lexer.TComma {
					isTSArrowFn = true
				} else if p.lexer.Token == js_lexer.TExtends {
					p.lexer.Next()
					isTSArrowFn = p.lexer.Token != js_lexer.TEquals && p.lexer.Token != js_lexer.TGreaterThan
				}
			}

			// Restore the lexer
			p.lexer = oldLexer

			if isTSArrowFn {
				p.skipTypeScriptTypeParameters()
				p.lexer.Expect(js_lexer.TOpenParen)
				return p.parseParenExpr(loc, parenExprOpts{forceArrowFn: true})
			}
		}

		if p.options.jsx.Parse {
			// Use NextInsideJSXElement() instead of Next() so we parse "<<" as "<"
			p.lexer.NextInsideJSXElement()
			element := p.parseJSXElement(loc)

			// The call to parseJSXElement() above doesn't consume the last
			// TGreaterThan because the caller knows what Next() function to call.
			// Use Next() instead of NextInsideJSXElement() here since the next
			// token is an expression.
			p.lexer.Next()
			return element
		}

		if p.options.ts.Parse {
			// This is either an old-style type cast or a generic lambda function

			// "<T>(x)"
			// "<T>(x) => {}"
			if p.trySkipTypeScriptTypeParametersThenOpenParenWithBacktracking() {
				p.lexer.Expect(js_lexer.TOpenParen)
				return p.parseParenExpr(loc, parenExprOpts{})
			}

			// "<T>x"
			p.lexer.Next()
			p.skipTypeScriptType(js_ast.LLowest)
			p.lexer.ExpectGreaterThan(false /* isInsideJSXElement */)
			value := p.parsePrefix(level, errors, flags)
			markExprAsTypeScriptCast(value)
			return value
		}

		p.lexer.Unexpected()
		return js_ast.Expr{}

	case js_lexer.TImport:
		p.hasES6ImportSyntax = true
		p.lexer.Next()
		return p.parseImportExpr(loc, level)

	default:
		p.lexer.Unexpected()
		return js_ast.Expr{}
	}
}

func (p *parser) parseYieldExpr(loc logger.Loc) js_ast.Expr {
	// Parse a yield-from expression, which yields from an iterator
	isStar := p.lexer.Token == js_lexer.TAsterisk
	if isStar {
		if p.lexer.HasNewlineBefore {
			p.lexer.Unexpected()
		}
		p.lexer.Next()
	}

	var value *js_ast.Expr

	// The yield expression only has a value in certain cases
	switch p.lexer.Token {
	case js_lexer.TCloseBrace, js_lexer.TCloseBracket, js_lexer.TCloseParen,
		js_lexer.TColon, js_lexer.TComma, js_lexer.TSemicolon:

	default:
		if isStar || !p.lexer.HasNewlineBefore {
			expr := p.parseExpr(js_ast.LYield)
			value = &expr
		}
	}

	return js_ast.Expr{Loc: loc, Data: &js_ast.EYield{Value: value, IsStar: isStar}}
}

func (p *parser) willNeedBindingPattern() bool {
	switch p.lexer.Token {
	case js_lexer.TEquals:
		// "[a] = b;"
		return true

	case js_lexer.TIn:
		// "for ([a] in b) {}"
		return !p.allowIn

	case js_lexer.TIdentifier:
		// "for ([a] of b) {}"
		return !p.allowIn && p.lexer.IsContextualKeyword("of")

	default:
		return false
	}
}

func (p *parser) parseImportExpr(loc logger.Loc, level js_ast.L) js_ast.Expr {
	// Parse an "import.meta" expression
	if p.lexer.Token == js_lexer.TDot {
		p.lexer.Next()
		if p.lexer.IsContextualKeyword("meta") {
			r := p.lexer.Range()
			p.lexer.Next()
			p.hasImportMeta = true
			if p.options.unsupportedJSFeatures.Has(compat.ImportMeta) {
				r = logger.Range{Loc: loc, Len: r.End() - loc.Start}
				p.markSyntaxFeature(compat.ImportMeta, r)
			}
			return js_ast.Expr{Loc: loc, Data: &js_ast.EImportMeta{}}
		} else {
			p.lexer.ExpectedString("\"meta\"")
		}
	}

	if level > js_ast.LCall {
		r := js_lexer.RangeOfIdentifier(p.source, loc)
		p.log.AddRangeError(&p.source, r, "Cannot use an \"import\" expression here without parentheses")
	}

	// Allow "in" inside call arguments
	oldAllowIn := p.allowIn
	p.allowIn = true

	p.lexer.PreserveAllCommentsBefore = true
	p.lexer.Expect(js_lexer.TOpenParen)
	comments := p.lexer.CommentsToPreserveBefore
	p.lexer.PreserveAllCommentsBefore = false

	value := p.parseExpr(js_ast.LComma)
	p.lexer.Expect(js_lexer.TCloseParen)

	p.allowIn = oldAllowIn
	return js_ast.Expr{Loc: loc, Data: &js_ast.EImport{Expr: value, LeadingInteriorComments: comments}}
}

func (p *parser) parseExprOrBindings(level js_ast.L, errors *deferredErrors) js_ast.Expr {
	return p.parseExprCommon(level, errors, 0)
}

func (p *parser) parseExpr(level js_ast.L) js_ast.Expr {
	return p.parseExprCommon(level, nil, 0)
}

func (p *parser) parseExprWithFlags(level js_ast.L, flags exprFlag) js_ast.Expr {
	return p.parseExprCommon(level, nil, flags)
}

func (p *parser) parseExprCommon(level js_ast.L, errors *deferredErrors, flags exprFlag) js_ast.Expr {
	hadPureCommentBefore := p.lexer.HasPureCommentBefore && !p.options.ignoreDCEAnnotations
	expr := p.parsePrefix(level, errors, flags)

	// There is no formal spec for "__PURE__" comments but from reverse-
	// engineering, it looks like they apply to the next CallExpression or
	// NewExpression. So in "/* @__PURE__ */ a().b() + c()" the comment applies
	// to the expression "a().b()".
	if hadPureCommentBefore && level < js_ast.LCall {
		expr = p.parseSuffix(expr, js_ast.LCall-1, errors, flags)
		switch e := expr.Data.(type) {
		case *js_ast.ECall:
			e.CanBeUnwrappedIfUnused = true
		case *js_ast.ENew:
			e.CanBeUnwrappedIfUnused = true
		}
	}

	return p.parseSuffix(expr, level, errors, flags)
}

func (p *parser) parseSuffix(left js_ast.Expr, level js_ast.L, errors *deferredErrors, flags exprFlag) js_ast.Expr {
	// ArrowFunction is a special case in the grammar. Although it appears to be
	// a PrimaryExpression, it's actually an AssigmentExpression. This means if
	// a AssigmentExpression ends up producing an ArrowFunction then nothing can
	// come after it other than the comma operator, since the comma operator is
	// the only thing above AssignmentExpression under the Expression rule:
	//
	//   AssignmentExpression:
	//     ArrowFunction
	//     ConditionalExpression
	//     LeftHandSideExpression = AssignmentExpression
	//     LeftHandSideExpression AssignmentOperator AssignmentExpression
	//
	//   Expression:
	//     AssignmentExpression
	//     Expression , AssignmentExpression
	//
	if level < js_ast.LAssign {
		if arrow, ok := left.Data.(*js_ast.EArrow); ok && !arrow.IsParenthesized {
			for {
				switch p.lexer.Token {
				case js_lexer.TComma:
					if level >= js_ast.LComma {
						return left
					}
					p.lexer.Next()
					left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpComma, Left: left, Right: p.parseExpr(js_ast.LComma)}}

				default:
					return left
				}
			}
		}
	}

	optionalChain := js_ast.OptionalChainNone

	for {
		// Stop now if this token is forbidden to follow a TypeScript "as" cast
		if p.lexer.Loc() == p.forbidSuffixAfterAsLoc {
			return left
		}

		// Reset the optional chain flag by default. That way we won't accidentally
		// treat "c.d" as OptionalChainContinue in "a?.b + c.d".
		oldOptionalChain := optionalChain
		optionalChain = js_ast.OptionalChainNone

		switch p.lexer.Token {
		case js_lexer.TDot:
			p.lexer.Next()

			if p.lexer.Token == js_lexer.TPrivateIdentifier && p.allowPrivateIdentifiers {
				// "a.#b"
				// "a?.b.#c"
				if _, ok := left.Data.(*js_ast.ESuper); ok {
					p.lexer.Expected(js_lexer.TIdentifier)
				}
				name := p.lexer.Identifier
				nameLoc := p.lexer.Loc()
				p.lexer.Next()
				ref := p.storeNameInRef(name)
				left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EIndex{
					Target:        left,
					Index:         js_ast.Expr{Loc: nameLoc, Data: &js_ast.EPrivateIdentifier{Ref: ref}},
					OptionalChain: oldOptionalChain,
				}}
			} else {
				// "a.b"
				// "a?.b.c"
				if !p.lexer.IsIdentifierOrKeyword() {
					p.lexer.Expect(js_lexer.TIdentifier)
				}
				name := p.lexer.Identifier
				nameLoc := p.lexer.Loc()
				p.lexer.Next()
				left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EDot{
					Target:        left,
					Name:          name,
					NameLoc:       nameLoc,
					OptionalChain: oldOptionalChain,
				}}
			}

			optionalChain = oldOptionalChain

		case js_lexer.TQuestionDot:
			p.lexer.Next()

			switch p.lexer.Token {
			case js_lexer.TOpenBracket:
				// "a?.[b]"
				p.lexer.Next()

				// Allow "in" inside the brackets
				oldAllowIn := p.allowIn
				p.allowIn = true

				index := p.parseExpr(js_ast.LLowest)

				p.allowIn = oldAllowIn

				p.lexer.Expect(js_lexer.TCloseBracket)
				left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EIndex{
					Target:        left,
					Index:         index,
					OptionalChain: js_ast.OptionalChainStart,
				}}

			case js_lexer.TOpenParen:
				// "a?.()"
				if level >= js_ast.LCall {
					return left
				}
				left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.ECall{
					Target:        left,
					Args:          p.parseCallArgs(),
					OptionalChain: js_ast.OptionalChainStart,
				}}

			case js_lexer.TLessThan:
				// "a?.<T>()"
				if !p.options.ts.Parse {
					p.lexer.Expected(js_lexer.TIdentifier)
				}
				p.skipTypeScriptTypeArguments(false /* isInsideJSXElement */)
				if p.lexer.Token != js_lexer.TOpenParen {
					p.lexer.Expected(js_lexer.TOpenParen)
				}
				if level >= js_ast.LCall {
					return left
				}
				left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.ECall{
					Target:        left,
					Args:          p.parseCallArgs(),
					OptionalChain: js_ast.OptionalChainStart,
				}}

			default:
				if p.lexer.Token == js_lexer.TPrivateIdentifier && p.allowPrivateIdentifiers {
					// "a?.#b"
					name := p.lexer.Identifier
					nameLoc := p.lexer.Loc()
					p.lexer.Next()
					ref := p.storeNameInRef(name)
					left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EIndex{
						Target:        left,
						Index:         js_ast.Expr{Loc: nameLoc, Data: &js_ast.EPrivateIdentifier{Ref: ref}},
						OptionalChain: js_ast.OptionalChainStart,
					}}
				} else {
					// "a?.b"
					if !p.lexer.IsIdentifierOrKeyword() {
						p.lexer.Expect(js_lexer.TIdentifier)
					}
					name := p.lexer.Identifier
					nameLoc := p.lexer.Loc()
					p.lexer.Next()
					left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EDot{
						Target:        left,
						Name:          name,
						NameLoc:       nameLoc,
						OptionalChain: js_ast.OptionalChainStart,
					}}
				}
			}

			optionalChain = js_ast.OptionalChainContinue

		case js_lexer.TNoSubstitutionTemplateLiteral:
			p.markSyntaxFeature(compat.TemplateLiteral, p.lexer.Range())
			head := p.lexer.StringLiteral
			headRaw := p.lexer.RawTemplateContents()
			p.lexer.Next()
			tag := left
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.ETemplate{Tag: &tag, Head: head, HeadRaw: headRaw}}

		case js_lexer.TTemplateHead:
			p.markSyntaxFeature(compat.TemplateLiteral, p.lexer.Range())
			head := p.lexer.StringLiteral
			headRaw := p.lexer.RawTemplateContents()
			parts := p.parseTemplateParts(true /* includeRaw */)
			tag := left
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.ETemplate{Tag: &tag, Head: head, HeadRaw: headRaw, Parts: parts}}

		case js_lexer.TOpenBracket:
			// When parsing a decorator, ignore EIndex expressions since they may be
			// part of a computed property:
			//
			//   class Foo {
			//     @foo ['computed']() {}
			//   }
			//
			// This matches the behavior of the TypeScript compiler.
			if (flags & exprFlagTSDecorator) != 0 {
				return left
			}

			p.lexer.Next()

			// Allow "in" inside the brackets
			oldAllowIn := p.allowIn
			p.allowIn = true

			index := p.parseExpr(js_ast.LLowest)

			p.allowIn = oldAllowIn

			p.lexer.Expect(js_lexer.TCloseBracket)
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EIndex{
				Target:        left,
				Index:         index,
				OptionalChain: oldOptionalChain,
			}}
			optionalChain = oldOptionalChain

		case js_lexer.TOpenParen:
			if level >= js_ast.LCall {
				return left
			}
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.ECall{
				Target:        left,
				Args:          p.parseCallArgs(),
				OptionalChain: oldOptionalChain,
			}}
			optionalChain = oldOptionalChain

		case js_lexer.TQuestion:
			if level >= js_ast.LConditional {
				return left
			}
			p.lexer.Next()

			// Stop now if we're parsing one of these:
			// "(a?) => {}"
			// "(a?: b) => {}"
			// "(a?, b?) => {}"
			if p.options.ts.Parse && left.Loc == p.latestArrowArgLoc && (p.lexer.Token == js_lexer.TColon ||
				p.lexer.Token == js_lexer.TCloseParen || p.lexer.Token == js_lexer.TComma) {
				if errors == nil {
					p.lexer.Unexpected()
				}
				errors.invalidExprAfterQuestion = p.lexer.Range()
				return left
			}

			// Allow "in" in between "?" and ":"
			oldAllowIn := p.allowIn
			p.allowIn = true

			yes := p.parseExpr(js_ast.LComma)

			p.allowIn = oldAllowIn

			p.lexer.Expect(js_lexer.TColon)
			no := p.parseExpr(js_ast.LComma)
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EIf{Test: left, Yes: yes, No: no}}

		case js_lexer.TExclamation:
			// Skip over TypeScript non-null assertions
			if p.lexer.HasNewlineBefore {
				return left
			}
			if !p.options.ts.Parse {
				p.lexer.Unexpected()
			}
			if level >= js_ast.LPostfix {
				return left
			}
			p.lexer.Next()

			// Non-null assertions are a form of cast
			markExprAsTypeScriptCast(left)
			optionalChain = oldOptionalChain

		case js_lexer.TMinusMinus:
			if p.lexer.HasNewlineBefore || level >= js_ast.LPostfix {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EUnary{Op: js_ast.UnOpPostDec, Value: left}}

		case js_lexer.TPlusPlus:
			if p.lexer.HasNewlineBefore || level >= js_ast.LPostfix {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EUnary{Op: js_ast.UnOpPostInc, Value: left}}

		case js_lexer.TComma:
			if level >= js_ast.LComma {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpComma, Left: left, Right: p.parseExpr(js_ast.LComma)}}

		case js_lexer.TPlus:
			if level >= js_ast.LAdd {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpAdd, Left: left, Right: p.parseExpr(js_ast.LAdd)}}

		case js_lexer.TPlusEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpAddAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TMinus:
			if level >= js_ast.LAdd {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpSub, Left: left, Right: p.parseExpr(js_ast.LAdd)}}

		case js_lexer.TMinusEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpSubAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TAsterisk:
			if level >= js_ast.LMultiply {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpMul, Left: left, Right: p.parseExpr(js_ast.LMultiply)}}

		case js_lexer.TAsteriskAsterisk:
			if level >= js_ast.LExponentiation {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpPow, Left: left, Right: p.parseExpr(js_ast.LExponentiation - 1)}}

		case js_lexer.TAsteriskAsteriskEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpPowAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TAsteriskEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpMulAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TPercent:
			if level >= js_ast.LMultiply {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpRem, Left: left, Right: p.parseExpr(js_ast.LMultiply)}}

		case js_lexer.TPercentEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpRemAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TSlash:
			if level >= js_ast.LMultiply {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpDiv, Left: left, Right: p.parseExpr(js_ast.LMultiply)}}

		case js_lexer.TSlashEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpDivAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TEqualsEquals:
			if level >= js_ast.LEquals {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLooseEq, Left: left, Right: p.parseExpr(js_ast.LEquals)}}

		case js_lexer.TExclamationEquals:
			if level >= js_ast.LEquals {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLooseNe, Left: left, Right: p.parseExpr(js_ast.LEquals)}}

		case js_lexer.TEqualsEqualsEquals:
			if level >= js_ast.LEquals {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpStrictEq, Left: left, Right: p.parseExpr(js_ast.LEquals)}}

		case js_lexer.TExclamationEqualsEquals:
			if level >= js_ast.LEquals {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpStrictNe, Left: left, Right: p.parseExpr(js_ast.LEquals)}}

		case js_lexer.TLessThan:
			// TypeScript allows type arguments to be specified with angle brackets
			// inside an expression. Unlike in other languages, this unfortunately
			// appears to require backtracking to parse.
			if p.options.ts.Parse && p.trySkipTypeScriptTypeArgumentsWithBacktracking() {
				optionalChain = oldOptionalChain
				continue
			}

			if level >= js_ast.LCompare {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLt, Left: left, Right: p.parseExpr(js_ast.LCompare)}}

		case js_lexer.TLessThanEquals:
			if level >= js_ast.LCompare {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLe, Left: left, Right: p.parseExpr(js_ast.LCompare)}}

		case js_lexer.TGreaterThan:
			if level >= js_ast.LCompare {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpGt, Left: left, Right: p.parseExpr(js_ast.LCompare)}}

		case js_lexer.TGreaterThanEquals:
			if level >= js_ast.LCompare {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpGe, Left: left, Right: p.parseExpr(js_ast.LCompare)}}

		case js_lexer.TLessThanLessThan:
			if level >= js_ast.LShift {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpShl, Left: left, Right: p.parseExpr(js_ast.LShift)}}

		case js_lexer.TLessThanLessThanEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpShlAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TGreaterThanGreaterThan:
			if level >= js_ast.LShift {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpShr, Left: left, Right: p.parseExpr(js_ast.LShift)}}

		case js_lexer.TGreaterThanGreaterThanEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpShrAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TGreaterThanGreaterThanGreaterThan:
			if level >= js_ast.LShift {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpUShr, Left: left, Right: p.parseExpr(js_ast.LShift)}}

		case js_lexer.TGreaterThanGreaterThanGreaterThanEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpUShrAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TQuestionQuestion:
			if level >= js_ast.LNullishCoalescing {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpNullishCoalescing, Left: left, Right: p.parseExpr(js_ast.LNullishCoalescing)}}

		case js_lexer.TQuestionQuestionEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpNullishCoalescingAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TBarBar:
			if level >= js_ast.LLogicalOr {
				return left
			}

			// Prevent "||" inside "??" from the right
			if level == js_ast.LNullishCoalescing {
				p.lexer.Unexpected()
			}

			p.lexer.Next()
			right := p.parseExpr(js_ast.LLogicalOr)
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLogicalOr, Left: left, Right: right}}

			// Prevent "||" inside "??" from the left
			if level < js_ast.LNullishCoalescing {
				left = p.parseSuffix(left, js_ast.LNullishCoalescing+1, nil, flags)
				if p.lexer.Token == js_lexer.TQuestionQuestion {
					p.lexer.Unexpected()
				}
			}

		case js_lexer.TBarBarEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLogicalOrAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TAmpersandAmpersand:
			if level >= js_ast.LLogicalAnd {
				return left
			}

			// Prevent "&&" inside "??" from the right
			if level == js_ast.LNullishCoalescing {
				p.lexer.Unexpected()
			}

			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLogicalAnd, Left: left, Right: p.parseExpr(js_ast.LLogicalAnd)}}

			// Prevent "&&" inside "??" from the left
			if level < js_ast.LNullishCoalescing {
				left = p.parseSuffix(left, js_ast.LNullishCoalescing+1, nil, flags)
				if p.lexer.Token == js_lexer.TQuestionQuestion {
					p.lexer.Unexpected()
				}
			}

		case js_lexer.TAmpersandAmpersandEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLogicalAndAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TBar:
			if level >= js_ast.LBitwiseOr {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpBitwiseOr, Left: left, Right: p.parseExpr(js_ast.LBitwiseOr)}}

		case js_lexer.TBarEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpBitwiseOrAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TAmpersand:
			if level >= js_ast.LBitwiseAnd {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpBitwiseAnd, Left: left, Right: p.parseExpr(js_ast.LBitwiseAnd)}}

		case js_lexer.TAmpersandEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpBitwiseAndAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TCaret:
			if level >= js_ast.LBitwiseXor {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpBitwiseXor, Left: left, Right: p.parseExpr(js_ast.LBitwiseXor)}}

		case js_lexer.TCaretEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpBitwiseXorAssign, Left: left, Right: p.parseExpr(js_ast.LAssign - 1)}}

		case js_lexer.TEquals:
			if level >= js_ast.LAssign {
				return left
			}
			p.lexer.Next()
			right := p.parseExpr(js_ast.LAssign - 1)
			wasIdentifierAssign := false
			if _, ok := left.Data.(*js_ast.EIdentifier); ok {
				if _, ok := right.Data.(*js_ast.EIdentifier); ok {
					wasIdentifierAssign = true
				}
			}
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{
				Op:                  js_ast.BinOpAssign,
				Left:                left,
				Right:               right,
				WasIdentifierAssign: wasIdentifierAssign,
			}}

		case js_lexer.TIn:
			if level >= js_ast.LCompare || !p.allowIn {
				return left
			}

			// Warn about "!a in b" instead of "!(a in b)"
			if !p.options.suppressWarningsAboutWeirdCode {
				if e, ok := left.Data.(*js_ast.EUnary); ok && e.Op == js_ast.UnOpNot {
					p.log.AddWarning(&p.source, left.Loc,
						"Suspicious use of the \"!\" operator inside the \"in\" operator")
				}
			}

			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpIn, Left: left, Right: p.parseExpr(js_ast.LCompare)}}

		case js_lexer.TInstanceof:
			if level >= js_ast.LCompare {
				return left
			}

			// Warn about "!a instanceof b" instead of "!(a instanceof b)". Here's an
			// example of code with this problem: https://github.com/mrdoob/three.js/pull/11182.
			if !p.options.suppressWarningsAboutWeirdCode {
				if e, ok := left.Data.(*js_ast.EUnary); ok && e.Op == js_ast.UnOpNot {
					p.log.AddWarning(&p.source, left.Loc,
						"Suspicious use of the \"!\" operator inside the \"instanceof\" operator")
				}
			}

			p.lexer.Next()
			left = js_ast.Expr{Loc: left.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpInstanceof, Left: left, Right: p.parseExpr(js_ast.LCompare)}}

		default:
			// Handle the TypeScript "as" operator
			if p.options.ts.Parse && level < js_ast.LCompare && !p.lexer.HasNewlineBefore && p.lexer.IsContextualKeyword("as") {
				p.lexer.Next()
				p.skipTypeScriptType(js_ast.LLowest)
				markExprAsTypeScriptCast(left)

				// These tokens are not allowed to follow a cast expression. This isn't
				// an outright error because it may be on a new line, in which case it's
				// the start of a new expression when it's after a cast:
				//
				//   x = y as z
				//   (something);
				//
				switch p.lexer.Token {
				case js_lexer.TPlusPlus, js_lexer.TMinusMinus, js_lexer.TNoSubstitutionTemplateLiteral,
					js_lexer.TTemplateHead, js_lexer.TOpenParen, js_lexer.TOpenBracket, js_lexer.TQuestionDot:
					p.forbidSuffixAfterAsLoc = p.lexer.Loc()
					return left
				}
				if p.lexer.Token.IsAssign() {
					p.forbidSuffixAfterAsLoc = p.lexer.Loc()
					return left
				}
				continue
			}

			return left
		}
	}
}

func (p *parser) parseExprOrLetStmt(opts parseStmtOpts) (js_ast.Expr, js_ast.Stmt, []js_ast.Decl) {
	letRange := p.lexer.Range()
	raw := p.lexer.Raw()

	if p.lexer.Token != js_lexer.TIdentifier || raw != "let" {
		return p.parseExpr(js_ast.LLowest), js_ast.Stmt{}, nil
	}

	p.lexer.Next()

	switch p.lexer.Token {
	case js_lexer.TIdentifier, js_lexer.TOpenBracket, js_lexer.TOpenBrace:
		if opts.lexicalDecl == lexicalDeclAllowAll || !p.lexer.HasNewlineBefore || p.lexer.Token == js_lexer.TOpenBracket {
			if opts.lexicalDecl != lexicalDeclAllowAll {
				p.forbidLexicalDecl(letRange.Loc)
			}
			p.markSyntaxFeature(compat.Let, letRange)
			decls := p.parseAndDeclareDecls(js_ast.SymbolOther, opts)
			return js_ast.Expr{}, js_ast.Stmt{Loc: letRange.Loc, Data: &js_ast.SLocal{
				Kind:     js_ast.LocalLet,
				Decls:    decls,
				IsExport: opts.isExport,
			}}, decls
		}
	}

	ref := p.storeNameInRef(raw)
	expr := js_ast.Expr{Loc: letRange.Loc, Data: &js_ast.EIdentifier{Ref: ref}}
	return p.parseSuffix(expr, js_ast.LLowest, nil, 0), js_ast.Stmt{}, nil
}

func (p *parser) parseCallArgs() []js_ast.Expr {
	// Allow "in" inside call arguments
	oldAllowIn := p.allowIn
	p.allowIn = true

	args := []js_ast.Expr{}
	p.lexer.Expect(js_lexer.TOpenParen)

	for p.lexer.Token != js_lexer.TCloseParen {
		loc := p.lexer.Loc()
		isSpread := p.lexer.Token == js_lexer.TDotDotDot
		if isSpread {
			p.markSyntaxFeature(compat.RestArgument, p.lexer.Range())
			p.lexer.Next()
		}
		arg := p.parseExpr(js_ast.LComma)
		if isSpread {
			arg = js_ast.Expr{Loc: loc, Data: &js_ast.ESpread{Value: arg}}
		}
		args = append(args, arg)
		if p.lexer.Token != js_lexer.TComma {
			break
		}
		p.lexer.Next()
	}

	p.lexer.Expect(js_lexer.TCloseParen)
	p.allowIn = oldAllowIn
	return args
}

func (p *parser) parseJSXTag() (logger.Range, string, *js_ast.Expr) {
	loc := p.lexer.Loc()

	// A missing tag is a fragment
	if p.lexer.Token == js_lexer.TGreaterThan {
		return logger.Range{Loc: loc, Len: 0}, "", nil
	}

	// The tag is an identifier
	name := p.lexer.Identifier
	tagRange := p.lexer.Range()
	p.lexer.ExpectInsideJSXElement(js_lexer.TIdentifier)

	// Certain identifiers are strings
	if strings.ContainsRune(name, '-') || (p.lexer.Token != js_lexer.TDot && name[0] >= 'a' && name[0] <= 'z') {
		return tagRange, name, &js_ast.Expr{Loc: loc, Data: &js_ast.EString{Value: js_lexer.StringToUTF16(name)}}
	}

	// Otherwise, this is an identifier
	tag := &js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: p.storeNameInRef(name)}}

	// Parse a member expression chain
	for p.lexer.Token == js_lexer.TDot {
		p.lexer.NextInsideJSXElement()
		memberRange := p.lexer.Range()
		member := p.lexer.Identifier
		p.lexer.ExpectInsideJSXElement(js_lexer.TIdentifier)

		// Dashes are not allowed in member expression chains
		index := strings.IndexByte(member, '-')
		if index >= 0 {
			p.log.AddError(&p.source, logger.Loc{Start: memberRange.Loc.Start + int32(index)}, "Unexpected \"-\"")
			panic(js_lexer.LexerPanic{})
		}

		name += "." + member
		tag = &js_ast.Expr{Loc: loc, Data: &js_ast.EDot{
			Target:  *tag,
			Name:    member,
			NameLoc: memberRange.Loc,
		}}
		tagRange.Len = memberRange.Loc.Start + memberRange.Len - tagRange.Loc.Start
	}

	return tagRange, name, tag
}

func (p *parser) parseJSXElement(loc logger.Loc) js_ast.Expr {
	// Parse the tag
	startRange, startText, startTag := p.parseJSXTag()

	// The tag may have TypeScript type arguments: "<Foo<T>/>"
	if p.options.ts.Parse {
		// Pass a flag to the type argument skipper because we need to call
		// js_lexer.NextInsideJSXElement() after we hit the closing ">". The next
		// token after the ">" might be an attribute name with a dash in it
		// like this: "<Foo<T> data-disabled/>"
		p.skipTypeScriptTypeArguments(true /* isInsideJSXElement */)
	}

	// Parse attributes
	properties := []js_ast.Property{}
	if startTag != nil {
	parseAttributes:
		for {
			switch p.lexer.Token {
			case js_lexer.TIdentifier:
				// Parse the key
				keyRange := p.lexer.Range()
				key := js_ast.Expr{Loc: keyRange.Loc, Data: &js_ast.EString{Value: js_lexer.StringToUTF16(p.lexer.Identifier)}}
				p.lexer.NextInsideJSXElement()

				// Parse the value
				var value js_ast.Expr
				if p.lexer.Token != js_lexer.TEquals {
					// Implicitly true value
					value = js_ast.Expr{Loc: logger.Loc{Start: keyRange.Loc.Start + keyRange.Len}, Data: &js_ast.EBoolean{Value: true}}
				} else {
					// Use NextInsideJSXElement() not Next() so we can parse a JSX-style string literal
					p.lexer.NextInsideJSXElement()
					if p.lexer.Token == js_lexer.TStringLiteral {
						value = js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.EString{Value: p.lexer.StringLiteral}}
						p.lexer.NextInsideJSXElement()
					} else {
						// Use Expect() not ExpectInsideJSXElement() so we can parse expression tokens
						p.lexer.Expect(js_lexer.TOpenBrace)
						value = p.parseExpr(js_ast.LLowest)
						p.lexer.ExpectInsideJSXElement(js_lexer.TCloseBrace)
					}
				}

				// Add a property
				properties = append(properties, js_ast.Property{
					Key:   key,
					Value: &value,
				})

			case js_lexer.TOpenBrace:
				// Use Next() not ExpectInsideJSXElement() so we can parse "..."
				p.lexer.Next()
				p.lexer.Expect(js_lexer.TDotDotDot)
				value := p.parseExpr(js_ast.LComma)
				properties = append(properties, js_ast.Property{
					Kind:  js_ast.PropertySpread,
					Value: &value,
				})

				// Use NextInsideJSXElement() not Next() so we can parse ">>" as ">"
				p.lexer.NextInsideJSXElement()

			default:
				break parseAttributes
			}
		}
	}

	// A slash here is a self-closing element
	if p.lexer.Token == js_lexer.TSlash {
		// Use NextInsideJSXElement() not Next() so we can parse ">>" as ">"
		p.lexer.NextInsideJSXElement()
		if p.lexer.Token != js_lexer.TGreaterThan {
			p.lexer.Expected(js_lexer.TGreaterThan)
		}
		return js_ast.Expr{Loc: loc, Data: &js_ast.EJSXElement{Tag: startTag, Properties: properties}}
	}

	// Use ExpectJSXElementChild() so we parse child strings
	p.lexer.ExpectJSXElementChild(js_lexer.TGreaterThan)

	// Parse the children of this element
	children := []js_ast.Expr{}
	for {
		switch p.lexer.Token {
		case js_lexer.TStringLiteral:
			children = append(children, js_ast.Expr{Loc: p.lexer.Loc(), Data: &js_ast.EString{Value: p.lexer.StringLiteral}})
			p.lexer.NextJSXElementChild()

		case js_lexer.TOpenBrace:
			// Use Next() instead of NextJSXElementChild() here since the next token is an expression
			p.lexer.Next()

			// The "..." here is ignored (it's used to signal an array type in TypeScript)
			if p.lexer.Token == js_lexer.TDotDotDot && p.options.ts.Parse {
				p.lexer.Next()
			}

			// The expression is optional, and may be absent
			if p.lexer.Token != js_lexer.TCloseBrace {
				children = append(children, p.parseExpr(js_ast.LLowest))
			}

			// Use ExpectJSXElementChild() so we parse child strings
			p.lexer.ExpectJSXElementChild(js_lexer.TCloseBrace)

		case js_lexer.TLessThan:
			lessThanLoc := p.lexer.Loc()
			p.lexer.NextInsideJSXElement()

			if p.lexer.Token != js_lexer.TSlash {
				// This is a child element
				children = append(children, p.parseJSXElement(lessThanLoc))

				// The call to parseJSXElement() above doesn't consume the last
				// TGreaterThan because the caller knows what Next() function to call.
				// Use NextJSXElementChild() here since the next token is an element
				// child.
				p.lexer.NextJSXElementChild()
				continue
			}

			// This is the closing element
			p.lexer.NextInsideJSXElement()
			endRange, endText, _ := p.parseJSXTag()
			if startText != endText {
				p.log.AddRangeErrorWithNotes(&p.source, endRange, fmt.Sprintf("Expected closing tag %q to match opening tag %q", endText, startText),
					[]logger.MsgData{logger.RangeData(&p.source, startRange, fmt.Sprintf("The opening tag %q is here", startText))})
			}
			if p.lexer.Token != js_lexer.TGreaterThan {
				p.lexer.Expected(js_lexer.TGreaterThan)
			}

			return js_ast.Expr{Loc: loc, Data: &js_ast.EJSXElement{Tag: startTag, Properties: properties, Children: children}}

		default:
			p.lexer.Unexpected()
		}
	}
}

func (p *parser) parseTemplateParts(includeRaw bool) []js_ast.TemplatePart {
	parts := []js_ast.TemplatePart{}
	for {
		p.lexer.Next()
		value := p.parseExpr(js_ast.LLowest)
		tailLoc := p.lexer.Loc()
		p.lexer.RescanCloseBraceAsTemplateToken()
		tail := p.lexer.StringLiteral
		tailRaw := ""
		if includeRaw {
			tailRaw = p.lexer.RawTemplateContents()
		}
		parts = append(parts, js_ast.TemplatePart{Value: value, TailLoc: tailLoc, Tail: tail, TailRaw: tailRaw})
		if p.lexer.Token == js_lexer.TTemplateTail {
			p.lexer.Next()
			break
		}
	}
	return parts
}

func (p *parser) parseAndDeclareDecls(kind js_ast.SymbolKind, opts parseStmtOpts) []js_ast.Decl {
	decls := []js_ast.Decl{}

	for {
		// Forbid "let let" and "const let" but not "var let"
		if (kind == js_ast.SymbolOther || kind == js_ast.SymbolConst) && p.lexer.IsContextualKeyword("let") {
			p.log.AddRangeError(&p.source, p.lexer.Range(), "Cannot use \"let\" as an identifier here")
		}

		var value *js_ast.Expr
		local := p.parseBinding()
		p.declareBinding(kind, local, opts)

		// Skip over types
		if p.options.ts.Parse {
			// "let foo!"
			isDefiniteAssignmentAssertion := p.lexer.Token == js_lexer.TExclamation
			if isDefiniteAssignmentAssertion {
				p.lexer.Next()
			}

			// "let foo: number"
			if isDefiniteAssignmentAssertion || p.lexer.Token == js_lexer.TColon {
				p.lexer.Expect(js_lexer.TColon)
				p.skipTypeScriptType(js_ast.LLowest)
			}
		}

		if p.lexer.Token == js_lexer.TEquals {
			p.lexer.Next()
			expr := p.parseExpr(js_ast.LComma)
			value = &expr
		}

		decls = append(decls, js_ast.Decl{Binding: local, Value: value})

		if p.lexer.Token != js_lexer.TComma {
			break
		}
		p.lexer.Next()
	}

	return decls
}

func (p *parser) requireInitializers(decls []js_ast.Decl) {
	for _, d := range decls {
		if d.Value == nil {
			if id, ok := d.Binding.Data.(*js_ast.BIdentifier); ok {
				r := js_lexer.RangeOfIdentifier(p.source, d.Binding.Loc)
				p.log.AddRangeError(&p.source, r, fmt.Sprintf("The constant %q must be initialized",
					p.symbols[id.Ref.InnerIndex].OriginalName))
			} else {
				p.log.AddError(&p.source, d.Binding.Loc, "This constant must be initialized")
			}
		}
	}
}

func (p *parser) forbidInitializers(decls []js_ast.Decl, loopType string, isVar bool) {
	if len(decls) > 1 {
		p.log.AddError(&p.source, decls[0].Binding.Loc, fmt.Sprintf("for-%s loops must have a single declaration", loopType))
	} else if len(decls) == 1 && decls[0].Value != nil {
		if isVar {
			if _, ok := decls[0].Binding.Data.(*js_ast.BIdentifier); ok {
				// This is a weird special case. Initializers are allowed in "var"
				// statements with identifier bindings.
				return
			}
		}
		p.log.AddError(&p.source, decls[0].Value.Loc, fmt.Sprintf("for-%s loop variables cannot have an initializer", loopType))
	}
}

func (p *parser) parseImportClause() ([]js_ast.ClauseItem, bool) {
	items := []js_ast.ClauseItem{}
	p.lexer.Expect(js_lexer.TOpenBrace)
	isSingleLine := !p.lexer.HasNewlineBefore

	for p.lexer.Token != js_lexer.TCloseBrace {
		alias := p.lexer.Identifier
		aliasLoc := p.lexer.Loc()
		name := js_ast.LocRef{Loc: aliasLoc, Ref: p.storeNameInRef(alias)}
		originalName := alias

		// The alias may be a keyword
		isIdentifier := p.lexer.Token == js_lexer.TIdentifier
		if !p.lexer.IsIdentifierOrKeyword() {
			p.lexer.Expect(js_lexer.TIdentifier)
		}
		p.lexer.Next()

		if p.lexer.IsContextualKeyword("as") {
			p.lexer.Next()
			originalName = p.lexer.Identifier
			name = js_ast.LocRef{Loc: p.lexer.Loc(), Ref: p.storeNameInRef(originalName)}
			p.lexer.Expect(js_lexer.TIdentifier)
		} else if !isIdentifier {
			// An import where the name is a keyword must have an alias
			p.lexer.Unexpected()
		}

		// Reject forbidden names
		if originalName == "eval" || originalName == "arguments" {
			r := js_lexer.RangeOfIdentifier(p.source, name.Loc)
			p.log.AddRangeError(&p.source, r, fmt.Sprintf("Cannot use %q as an identifier here", originalName))
		}

		items = append(items, js_ast.ClauseItem{
			Alias:        alias,
			AliasLoc:     aliasLoc,
			Name:         name,
			OriginalName: originalName,
		})

		if p.lexer.Token != js_lexer.TComma {
			break
		}
		if p.lexer.HasNewlineBefore {
			isSingleLine = false
		}
		p.lexer.Next()
		if p.lexer.HasNewlineBefore {
			isSingleLine = false
		}
	}

	if p.lexer.HasNewlineBefore {
		isSingleLine = false
	}
	p.lexer.Expect(js_lexer.TCloseBrace)
	return items, isSingleLine
}

func (p *parser) parseExportClause() ([]js_ast.ClauseItem, bool) {
	items := []js_ast.ClauseItem{}
	firstKeywordItemLoc := logger.Loc{}
	p.lexer.Expect(js_lexer.TOpenBrace)
	isSingleLine := !p.lexer.HasNewlineBefore

	for p.lexer.Token != js_lexer.TCloseBrace {
		alias := p.lexer.Identifier
		aliasLoc := p.lexer.Loc()
		name := js_ast.LocRef{Loc: aliasLoc, Ref: p.storeNameInRef(alias)}
		originalName := alias

		// The name can actually be a keyword if we're really an "export from"
		// statement. However, we won't know until later. Allow keywords as
		// identifiers for now and throw an error later if there's no "from".
		//
		//   // This is fine
		//   export { default } from 'path'
		//
		//   // This is a syntax error
		//   export { default }
		//
		if p.lexer.Token != js_lexer.TIdentifier {
			if !p.lexer.IsIdentifierOrKeyword() {
				p.lexer.Expect(js_lexer.TIdentifier)
			}
			if firstKeywordItemLoc.Start == 0 {
				firstKeywordItemLoc = p.lexer.Loc()
			}
		}
		p.checkForNonBMPCodePoint(aliasLoc, alias)
		p.lexer.Next()

		if p.lexer.IsContextualKeyword("as") {
			p.lexer.Next()
			alias = p.lexer.Identifier
			aliasLoc = p.lexer.Loc()

			// The alias may be a keyword
			if !p.lexer.IsIdentifierOrKeyword() {
				p.lexer.Expect(js_lexer.TIdentifier)
			}
			p.checkForNonBMPCodePoint(aliasLoc, alias)
			p.lexer.Next()
		}

		items = append(items, js_ast.ClauseItem{
			Alias:        alias,
			AliasLoc:     aliasLoc,
			Name:         name,
			OriginalName: originalName,
		})

		if p.lexer.Token != js_lexer.TComma {
			break
		}
		if p.lexer.HasNewlineBefore {
			isSingleLine = false
		}
		p.lexer.Next()
		if p.lexer.HasNewlineBefore {
			isSingleLine = false
		}
	}

	if p.lexer.HasNewlineBefore {
		isSingleLine = false
	}
	p.lexer.Expect(js_lexer.TCloseBrace)

	// Throw an error here if we found a keyword earlier and this isn't an
	// "export from" statement after all
	if firstKeywordItemLoc.Start != 0 && !p.lexer.IsContextualKeyword("from") {
		r := js_lexer.RangeOfIdentifier(p.source, firstKeywordItemLoc)
		p.log.AddRangeError(&p.source, r, fmt.Sprintf("Expected identifier but found %q", p.source.TextForRange(r)))
		panic(js_lexer.LexerPanic{})
	}

	return items, isSingleLine
}

func (p *parser) parseBinding() js_ast.Binding {
	loc := p.lexer.Loc()

	switch p.lexer.Token {
	case js_lexer.TIdentifier:
		name := p.lexer.Identifier
		if (p.fnOrArrowDataParse.allowAwait && name == "await") || (p.fnOrArrowDataParse.allowYield && name == "yield") {
			p.log.AddRangeError(&p.source, p.lexer.Range(), fmt.Sprintf("Cannot use %q as an identifier here", name))
		}
		ref := p.storeNameInRef(name)
		p.lexer.Next()
		return js_ast.Binding{Loc: loc, Data: &js_ast.BIdentifier{Ref: ref}}

	case js_lexer.TOpenBracket:
		p.markSyntaxFeature(compat.Destructuring, p.lexer.Range())
		p.lexer.Next()
		isSingleLine := !p.lexer.HasNewlineBefore
		items := []js_ast.ArrayBinding{}
		hasSpread := false

		// "in" expressions are allowed
		oldAllowIn := p.allowIn
		p.allowIn = true

		for p.lexer.Token != js_lexer.TCloseBracket {
			if p.lexer.Token == js_lexer.TComma {
				binding := js_ast.Binding{Loc: p.lexer.Loc(), Data: &js_ast.BMissing{}}
				items = append(items, js_ast.ArrayBinding{Binding: binding})
			} else {
				if p.lexer.Token == js_lexer.TDotDotDot {
					p.lexer.Next()
					hasSpread = true

					// This was a bug in the ES2015 spec that was fixed in ES2016
					if p.lexer.Token != js_lexer.TIdentifier {
						p.markSyntaxFeature(compat.NestedRestBinding, p.lexer.Range())
					}
				}

				binding := p.parseBinding()

				var defaultValue *js_ast.Expr
				if !hasSpread && p.lexer.Token == js_lexer.TEquals {
					p.lexer.Next()
					value := p.parseExpr(js_ast.LComma)
					defaultValue = &value
				}

				items = append(items, js_ast.ArrayBinding{Binding: binding, DefaultValue: defaultValue})

				// Commas after spread elements are not allowed
				if hasSpread && p.lexer.Token == js_lexer.TComma {
					p.log.AddRangeError(&p.source, p.lexer.Range(), "Unexpected \",\" after rest pattern")
					panic(js_lexer.LexerPanic{})
				}
			}

			if p.lexer.Token != js_lexer.TComma {
				break
			}
			if p.lexer.HasNewlineBefore {
				isSingleLine = false
			}
			p.lexer.Next()
			if p.lexer.HasNewlineBefore {
				isSingleLine = false
			}
		}

		p.allowIn = oldAllowIn

		if p.lexer.HasNewlineBefore {
			isSingleLine = false
		}
		p.lexer.Expect(js_lexer.TCloseBracket)
		return js_ast.Binding{Loc: loc, Data: &js_ast.BArray{
			Items:        items,
			HasSpread:    hasSpread,
			IsSingleLine: isSingleLine,
		}}

	case js_lexer.TOpenBrace:
		p.markSyntaxFeature(compat.Destructuring, p.lexer.Range())
		p.lexer.Next()
		isSingleLine := !p.lexer.HasNewlineBefore
		properties := []js_ast.PropertyBinding{}

		// "in" expressions are allowed
		oldAllowIn := p.allowIn
		p.allowIn = true

		for p.lexer.Token != js_lexer.TCloseBrace {
			property := p.parsePropertyBinding()
			properties = append(properties, property)

			// Commas after spread elements are not allowed
			if property.IsSpread && p.lexer.Token == js_lexer.TComma {
				p.log.AddRangeError(&p.source, p.lexer.Range(), "Unexpected \",\" after rest pattern")
				panic(js_lexer.LexerPanic{})
			}

			if p.lexer.Token != js_lexer.TComma {
				break
			}
			if p.lexer.HasNewlineBefore {
				isSingleLine = false
			}
			p.lexer.Next()
			if p.lexer.HasNewlineBefore {
				isSingleLine = false
			}
		}

		p.allowIn = oldAllowIn

		if p.lexer.HasNewlineBefore {
			isSingleLine = false
		}
		p.lexer.Expect(js_lexer.TCloseBrace)
		return js_ast.Binding{Loc: loc, Data: &js_ast.BObject{
			Properties:   properties,
			IsSingleLine: isSingleLine,
		}}
	}

	p.lexer.Expect(js_lexer.TIdentifier)
	return js_ast.Binding{}
}

func (p *parser) parseFn(name *js_ast.LocRef, data fnOrArrowDataParse) (fn js_ast.Fn, hadBody bool) {
	if data.allowAwait && data.allowYield {
		p.markSyntaxFeature(compat.AsyncGenerator, data.asyncRange)
	}

	fn.Name = name
	fn.HasRestArg = false
	fn.IsAsync = data.allowAwait
	fn.IsGenerator = data.allowYield
	fn.ArgumentsRef = js_ast.InvalidRef
	fn.OpenParenLoc = p.lexer.Loc()
	p.lexer.Expect(js_lexer.TOpenParen)

	// Await and yield are not allowed in function arguments
	oldFnOrArrowData := p.fnOrArrowDataParse
	p.fnOrArrowDataParse.allowAwait = false
	p.fnOrArrowDataParse.allowYield = false

	for p.lexer.Token != js_lexer.TCloseParen {
		// Skip over "this" type annotations
		if p.options.ts.Parse && p.lexer.Token == js_lexer.TThis {
			p.lexer.Next()
			if p.lexer.Token == js_lexer.TColon {
				p.lexer.Next()
				p.skipTypeScriptType(js_ast.LLowest)
			}
			if p.lexer.Token != js_lexer.TComma {
				break
			}
			p.lexer.Next()
			continue
		}

		var tsDecorators []js_ast.Expr
		if data.allowTSDecorators {
			tsDecorators = p.parseTypeScriptDecorators()
		}

		if !fn.HasRestArg && p.lexer.Token == js_lexer.TDotDotDot {
			p.markSyntaxFeature(compat.RestArgument, p.lexer.Range())
			p.lexer.Next()
			fn.HasRestArg = true
		}

		isTypeScriptCtorField := false
		isIdentifier := p.lexer.Token == js_lexer.TIdentifier
		text := p.lexer.Identifier
		arg := p.parseBinding()

		if p.options.ts.Parse {
			// Skip over TypeScript accessibility modifiers, which turn this argument
			// into a class field when used inside a class constructor. This is known
			// as a "parameter property" in TypeScript.
			if isIdentifier && data.isConstructor {
				for p.lexer.Token == js_lexer.TIdentifier || p.lexer.Token == js_lexer.TOpenBrace || p.lexer.Token == js_lexer.TOpenBracket {
					if text != "public" && text != "private" && text != "protected" && text != "readonly" {
						break
					}
					isTypeScriptCtorField = true

					// TypeScript requires an identifier binding
					if p.lexer.Token != js_lexer.TIdentifier {
						p.lexer.Expect(js_lexer.TIdentifier)
					}
					text = p.lexer.Identifier

					// Re-parse the binding (the current binding is the TypeScript keyword)
					arg = p.parseBinding()
				}
			}

			// "function foo(a?) {}"
			if p.lexer.Token == js_lexer.TQuestion {
				p.lexer.Next()
			}

			// "function foo(a: any) {}"
			if p.lexer.Token == js_lexer.TColon {
				p.lexer.Next()
				p.skipTypeScriptType(js_ast.LLowest)
			}
		}

		p.declareBinding(js_ast.SymbolHoisted, arg, parseStmtOpts{})

		var defaultValue *js_ast.Expr
		if !fn.HasRestArg && p.lexer.Token == js_lexer.TEquals {
			p.markSyntaxFeature(compat.DefaultArgument, p.lexer.Range())
			p.lexer.Next()
			value := p.parseExpr(js_ast.LComma)
			defaultValue = &value
		}

		fn.Args = append(fn.Args, js_ast.Arg{
			TSDecorators: tsDecorators,
			Binding:      arg,
			Default:      defaultValue,

			// We need to track this because it affects code generation
			IsTypeScriptCtorField: isTypeScriptCtorField,
		})

		if p.lexer.Token != js_lexer.TComma {
			break
		}
		if fn.HasRestArg {
			// JavaScript does not allow a comma after a rest argument
			if data.isTypeScriptDeclare {
				// TypeScript does allow a comma after a rest argument in a "declare" context
				p.lexer.Next()
			} else {
				p.lexer.Expect(js_lexer.TCloseParen)
			}
			break
		}
		p.lexer.Next()
	}

	// Reserve the special name "arguments" in this scope. This ensures that it
	// shadows any variable called "arguments" in any parent scopes. But only do
	// this if it wasn't already declared above because arguments are allowed to
	// be called "arguments", in which case the real "arguments" is inaccessible.
	if _, ok := p.currentScope.Members["arguments"]; !ok {
		fn.ArgumentsRef = p.declareSymbol(js_ast.SymbolArguments, fn.OpenParenLoc, "arguments")
		p.symbols[fn.ArgumentsRef.InnerIndex].MustNotBeRenamed = true
	}

	p.lexer.Expect(js_lexer.TCloseParen)
	p.fnOrArrowDataParse = oldFnOrArrowData

	// "function foo(): any {}"
	if p.options.ts.Parse && p.lexer.Token == js_lexer.TColon {
		p.lexer.Next()
		p.skipTypeScriptReturnType()
	}

	// "function foo(): any;"
	if data.allowMissingBodyForTypeScript && p.lexer.Token != js_lexer.TOpenBrace {
		p.lexer.ExpectOrInsertSemicolon()
		return
	}

	fn.Body = p.parseFnBody(data)
	hadBody = true
	return
}

func (p *parser) parseClassStmt(loc logger.Loc, opts parseStmtOpts) js_ast.Stmt {
	var name *js_ast.LocRef
	if p.lexer.Token == js_lexer.TClass {
		p.markSyntaxFeature(compat.Class, p.lexer.Range())
		p.lexer.Next()
	} else {
		p.lexer.Expected(js_lexer.TClass)
	}

	isIdentifier := p.lexer.Token == js_lexer.TIdentifier
	isStrictModeReservedWord := isIdentifier && js_lexer.StrictModeReservedWords[p.lexer.Identifier]
	if !opts.isNameOptional || (isIdentifier && !isStrictModeReservedWord) {
		nameLoc := p.lexer.Loc()
		nameText := p.lexer.Identifier
		if isStrictModeReservedWord {
			p.lexer.Unexpected()
		}
		p.lexer.Expect(js_lexer.TIdentifier)
		name = &js_ast.LocRef{Loc: nameLoc, Ref: js_ast.InvalidRef}
		if !opts.isTypeScriptDeclare {
			name.Ref = p.declareSymbol(js_ast.SymbolClass, nameLoc, nameText)
		}
	}

	// Even anonymous classes can have TypeScript type parameters
	if p.options.ts.Parse {
		p.skipTypeScriptTypeParameters()
	}

	classOpts := parseClassOpts{
		allowTSDecorators:   true,
		isTypeScriptDeclare: opts.isTypeScriptDeclare,
	}
	if opts.tsDecorators != nil {
		classOpts.tsDecorators = opts.tsDecorators.values
	}
	scopeIndex := p.pushScopeForParsePass(js_ast.ScopeClassName, loc)
	class := p.parseClass(name, classOpts)
	if classOpts.isTypeScriptDeclare {
		p.popAndDiscardScope(scopeIndex)
	} else {
		p.popScope()
	}
	return js_ast.Stmt{Loc: loc, Data: &js_ast.SClass{Class: class, IsExport: opts.isExport}}
}

type parseClassOpts struct {
	tsDecorators        []js_ast.Expr
	allowTSDecorators   bool
	isTypeScriptDeclare bool
}

// By the time we call this, the identifier and type parameters have already
// been parsed. We need to start parsing from the "extends" clause.
func (p *parser) parseClass(name *js_ast.LocRef, classOpts parseClassOpts) js_ast.Class {
	var extends *js_ast.Expr

	if p.lexer.Token == js_lexer.TExtends {
		p.lexer.Next()
		value := p.parseExpr(js_ast.LNew)
		extends = &value

		// TypeScript's type argument parser inside expressions backtracks if the
		// first token after the end of the type parameter list is "{", so the
		// parsed expression above will have backtracked if there are any type
		// arguments. This means we have to re-parse for any type arguments here.
		// This seems kind of wasteful to me but it's what the official compiler
		// does and it probably doesn't have that high of a performance overhead
		// because "extends" clauses aren't that frequent, so it should be ok.
		if p.options.ts.Parse {
			p.skipTypeScriptTypeArguments(false /* isInsideJSXElement */)
		}
	}

	if p.options.ts.Parse && p.lexer.IsContextualKeyword("implements") {
		p.lexer.Next()
		for {
			p.skipTypeScriptType(js_ast.LLowest)
			if p.lexer.Token != js_lexer.TComma {
				break
			}
			p.lexer.Next()
		}
	}

	bodyLoc := p.lexer.Loc()
	p.lexer.Expect(js_lexer.TOpenBrace)
	properties := []js_ast.Property{}

	// Allow "in" and private fields inside class bodies
	oldAllowIn := p.allowIn
	oldAllowPrivateIdentifiers := p.allowPrivateIdentifiers
	p.allowIn = true
	p.allowPrivateIdentifiers = true

	// A scope is needed for private identifiers
	scopeIndex := p.pushScopeForParsePass(js_ast.ScopeClassBody, bodyLoc)

	// Make it an error to use "arguments" in a class body
	argumentsRef := p.declareSymbol(js_ast.SymbolError, bodyLoc, "arguments")
	p.symbols[argumentsRef.InnerIndex].MustNotBeRenamed = true

	for p.lexer.Token != js_lexer.TCloseBrace {
		if p.lexer.Token == js_lexer.TSemicolon {
			p.lexer.Next()
			continue
		}

		opts := propertyOpts{
			isClass:           true,
			allowTSDecorators: classOpts.allowTSDecorators,
			classHasExtends:   extends != nil,
		}

		// Parse decorators for this property
		if opts.allowTSDecorators {
			opts.tsDecorators = p.parseTypeScriptDecorators()
		}

		// This property may turn out to be a type in TypeScript, which should be ignored
		if property, ok := p.parseProperty(js_ast.PropertyNormal, opts, nil); ok {
			properties = append(properties, property)
		}
	}

	// Discard the private identifier scope inside a TypeScript "declare class"
	if classOpts.isTypeScriptDeclare {
		p.popAndDiscardScope(scopeIndex)
	} else {
		p.popScope()
	}

	p.allowIn = oldAllowIn
	p.allowPrivateIdentifiers = oldAllowPrivateIdentifiers

	p.lexer.Expect(js_lexer.TCloseBrace)
	return js_ast.Class{
		TSDecorators: classOpts.tsDecorators,
		Name:         name,
		Extends:      extends,
		BodyLoc:      bodyLoc,
		Properties:   properties,
	}
}

func (p *parser) parseLabelName() *js_ast.LocRef {
	if p.lexer.Token != js_lexer.TIdentifier || p.lexer.HasNewlineBefore {
		return nil
	}

	name := js_ast.LocRef{Loc: p.lexer.Loc(), Ref: p.storeNameInRef(p.lexer.Identifier)}
	p.lexer.Next()
	return &name
}

func (p *parser) parsePath() (logger.Loc, string) {
	pathLoc := p.lexer.Loc()
	pathText := js_lexer.UTF16ToString(p.lexer.StringLiteral)
	if p.lexer.Token == js_lexer.TNoSubstitutionTemplateLiteral {
		p.lexer.Next()
	} else {
		p.lexer.Expect(js_lexer.TStringLiteral)
	}
	return pathLoc, pathText
}

// This assumes the "function" token has already been parsed
func (p *parser) parseFnStmt(loc logger.Loc, opts parseStmtOpts, isAsync bool, asyncRange logger.Range) js_ast.Stmt {
	isGenerator := p.lexer.Token == js_lexer.TAsterisk
	if isGenerator {
		p.markSyntaxFeature(compat.Generator, p.lexer.Range())
		p.lexer.Next()
	} else if isAsync {
		p.markLoweredSyntaxFeature(compat.AsyncAwait, asyncRange, compat.Generator)
	}

	switch opts.lexicalDecl {
	case lexicalDeclForbid:
		p.forbidLexicalDecl(loc)

	// Allow certain function statements in certain single-statement contexts
	case lexicalDeclAllowFnInsideIf, lexicalDeclAllowFnInsideLabel:
		if opts.isTypeScriptDeclare || isGenerator || isAsync {
			p.forbidLexicalDecl(loc)
		}
	}

	var name *js_ast.LocRef
	var nameText string

	// The name is optional for "export default function() {}" pseudo-statements
	if !opts.isNameOptional || p.lexer.Token == js_lexer.TIdentifier {
		nameLoc := p.lexer.Loc()
		nameText = p.lexer.Identifier
		p.lexer.Expect(js_lexer.TIdentifier)
		name = &js_ast.LocRef{Loc: nameLoc, Ref: js_ast.InvalidRef}
	}

	// Even anonymous functions can have TypeScript type parameters
	if p.options.ts.Parse {
		p.skipTypeScriptTypeParameters()
	}

	// Introduce a fake block scope for function declarations inside if statements
	var ifStmtScopeIndex int
	hasIfScope := opts.lexicalDecl == lexicalDeclAllowFnInsideIf
	if hasIfScope {
		ifStmtScopeIndex = p.pushScopeForParsePass(js_ast.ScopeBlock, loc)
	}

	scopeIndex := p.pushScopeForParsePass(js_ast.ScopeFunctionArgs, p.lexer.Loc())

	fn, hadBody := p.parseFn(name, fnOrArrowDataParse{
		asyncRange:          asyncRange,
		allowAwait:          isAsync,
		allowYield:          isGenerator,
		isTypeScriptDeclare: opts.isTypeScriptDeclare,

		// Only allow omitting the body if we're parsing TypeScript
		allowMissingBodyForTypeScript: p.options.ts.Parse,
	})

	// Don't output anything if it's just a forward declaration of a function
	if opts.isTypeScriptDeclare || !hadBody {
		p.popAndDiscardScope(scopeIndex)

		// Balance the fake block scope introduced above
		if hasIfScope {
			p.popAndDiscardScope(ifStmtScopeIndex)
		}

		return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}
	}

	p.popScope()

	// Only declare the function after we know if it had a body or not. Otherwise
	// TypeScript code such as this will double-declare the symbol:
	//
	//     function foo(): void;
	//     function foo(): void {}
	//
	if name != nil {
		kind := js_ast.SymbolHoistedFunction
		if isGenerator || isAsync {
			kind = js_ast.SymbolGeneratorOrAsyncFunction
		}
		name.Ref = p.declareSymbol(kind, name.Loc, nameText)
	}

	// Balance the fake block scope introduced above
	if hasIfScope {
		p.popScope()
	}

	fn.HasIfScope = hasIfScope
	return js_ast.Stmt{Loc: loc, Data: &js_ast.SFunction{Fn: fn, IsExport: opts.isExport}}
}

type deferredTSDecorators struct {
	values []js_ast.Expr

	// If this turns out to be a "declare class" statement, we need to undo the
	// scopes that were potentially pushed while parsing the decorator arguments.
	scopeIndex int
}

type lexicalDecl uint8

const (
	lexicalDeclForbid lexicalDecl = iota
	lexicalDeclAllowAll
	lexicalDeclAllowFnInsideIf
	lexicalDeclAllowFnInsideLabel
)

type parseStmtOpts struct {
	tsDecorators        *deferredTSDecorators
	lexicalDecl         lexicalDecl
	isModuleScope       bool
	isNamespaceScope    bool
	isExport            bool
	isNameOptional      bool // For "export default" pseudo-statements
	isTypeScriptDeclare bool
}

func (p *parser) parseStmt(opts parseStmtOpts) js_ast.Stmt {
	loc := p.lexer.Loc()

	switch p.lexer.Token {
	case js_lexer.TSemicolon:
		p.lexer.Next()
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SEmpty{}}

	case js_lexer.TExport:
		if opts.isModuleScope {
			p.hasES6ExportSyntax = true
		} else if !opts.isNamespaceScope {
			p.lexer.Unexpected()
		}
		p.lexer.Next()

		// TypeScript decorators only work on class declarations
		// "@decorator export class Foo {}"
		// "@decorator export abstract class Foo {}"
		// "@decorator export default class Foo {}"
		// "@decorator export default abstract class Foo {}"
		// "@decorator export declare class Foo {}"
		// "@decorator export declare abstract class Foo {}"
		if opts.tsDecorators != nil && p.lexer.Token != js_lexer.TClass && p.lexer.Token != js_lexer.TDefault &&
			!p.lexer.IsContextualKeyword("abstract") && !p.lexer.IsContextualKeyword("declare") {
			p.lexer.Expected(js_lexer.TClass)
		}

		switch p.lexer.Token {
		case js_lexer.TClass, js_lexer.TConst, js_lexer.TFunction, js_lexer.TVar:
			opts.isExport = true
			return p.parseStmt(opts)

		case js_lexer.TImport:
			// "export import foo = bar"
			if p.options.ts.Parse && (opts.isModuleScope || opts.isNamespaceScope) {
				opts.isExport = true
				return p.parseStmt(opts)
			}

			p.lexer.Unexpected()
			return js_ast.Stmt{}

		case js_lexer.TEnum:
			if !p.options.ts.Parse {
				p.lexer.Unexpected()
			}
			opts.isExport = true
			return p.parseStmt(opts)

		case js_lexer.TIdentifier:
			if p.lexer.IsContextualKeyword("let") {
				opts.isExport = true
				return p.parseStmt(opts)
			}

			if opts.isTypeScriptDeclare && p.lexer.IsContextualKeyword("as") {
				// "export as namespace ns;"
				p.lexer.Next()
				p.lexer.ExpectContextualKeyword("namespace")
				p.lexer.Expect(js_lexer.TIdentifier)
				p.lexer.ExpectOrInsertSemicolon()
				return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}
			}

			if p.lexer.IsContextualKeyword("async") {
				// "export async function foo() {}"
				asyncRange := p.lexer.Range()
				p.lexer.Next()
				if p.lexer.HasNewlineBefore {
					p.log.AddError(&p.source, logger.Loc{Start: asyncRange.End()}, "Unexpected newline after \"async\"")
					panic(js_lexer.LexerPanic{})
				}
				p.lexer.Expect(js_lexer.TFunction)
				opts.isExport = true
				return p.parseFnStmt(loc, opts, true /* isAsync */, asyncRange)
			}

			if p.options.ts.Parse {
				switch p.lexer.Identifier {
				case "type":
					// "export type foo = ..."
					typeRange := p.lexer.Range()
					p.lexer.Next()
					if p.lexer.HasNewlineBefore {
						p.log.AddError(&p.source, logger.Loc{Start: typeRange.End()}, "Unexpected newline after \"type\"")
						panic(js_lexer.LexerPanic{})
					}
					p.skipTypeScriptTypeStmt(parseStmtOpts{isModuleScope: opts.isModuleScope, isExport: true})
					return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}

				case "namespace", "abstract", "module", "interface":
					// "export namespace Foo {}"
					// "export abstract class Foo {}"
					// "export module Foo {}"
					// "export interface Foo {}"
					opts.isExport = true
					return p.parseStmt(opts)

				case "declare":
					// "export declare class Foo {}"
					opts.isExport = true
					opts.lexicalDecl = lexicalDeclAllowAll
					opts.isTypeScriptDeclare = true
					return p.parseStmt(opts)
				}
			}

			p.lexer.Unexpected()
			return js_ast.Stmt{}

		case js_lexer.TDefault:
			if !opts.isModuleScope && (!opts.isNamespaceScope || !opts.isTypeScriptDeclare) {
				p.lexer.Unexpected()
			}

			defaultLoc := p.lexer.Loc()
			p.lexer.Next()

			// The default name is lazily generated only if no other name is present
			createDefaultName := func() js_ast.LocRef {
				defaultName := js_ast.LocRef{Loc: defaultLoc, Ref: p.newSymbol(js_ast.SymbolOther, p.source.IdentifierName+"_default")}
				p.currentScope.Generated = append(p.currentScope.Generated, defaultName.Ref)
				return defaultName
			}

			// TypeScript decorators only work on class declarations
			// "@decorator export default class Foo {}"
			// "@decorator export default abstract class Foo {}"
			if opts.tsDecorators != nil && p.lexer.Token != js_lexer.TClass && !p.lexer.IsContextualKeyword("abstract") {
				p.lexer.Expected(js_lexer.TClass)
			}

			if p.lexer.IsContextualKeyword("async") {
				asyncRange := p.lexer.Range()
				p.lexer.Next()

				if p.lexer.Token == js_lexer.TFunction && !p.lexer.HasNewlineBefore {
					p.lexer.Next()
					stmt := p.parseFnStmt(loc, parseStmtOpts{
						isNameOptional: true,
						lexicalDecl:    lexicalDeclAllowAll,
					}, true /* isAsync */, asyncRange)
					if _, ok := stmt.Data.(*js_ast.STypeScript); ok {
						return stmt // This was just a type annotation
					}

					// Use the statement name if present, since it's a better name
					var defaultName js_ast.LocRef
					if s, ok := stmt.Data.(*js_ast.SFunction); ok && s.Fn.Name != nil {
						defaultName = js_ast.LocRef{Loc: defaultLoc, Ref: s.Fn.Name.Ref}
					} else {
						defaultName = createDefaultName()
					}

					return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportDefault{DefaultName: defaultName, Value: js_ast.ExprOrStmt{Stmt: &stmt}}}
				}

				defaultName := createDefaultName()
				expr := p.parseSuffix(p.parseAsyncPrefixExpr(asyncRange), js_ast.LComma, nil, 0)
				p.lexer.ExpectOrInsertSemicolon()
				return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportDefault{DefaultName: defaultName, Value: js_ast.ExprOrStmt{Expr: &expr}}}
			}

			if p.lexer.Token == js_lexer.TFunction || p.lexer.Token == js_lexer.TClass || p.lexer.IsContextualKeyword("interface") {
				stmt := p.parseStmt(parseStmtOpts{
					tsDecorators:   opts.tsDecorators,
					isNameOptional: true,
					lexicalDecl:    lexicalDeclAllowAll,
				})
				if _, ok := stmt.Data.(*js_ast.STypeScript); ok {
					return stmt // This was just a type annotation
				}

				// Use the statement name if present, since it's a better name
				var defaultName js_ast.LocRef
				switch s := stmt.Data.(type) {
				case *js_ast.SFunction:
					if s.Fn.Name != nil {
						defaultName = js_ast.LocRef{Loc: defaultLoc, Ref: s.Fn.Name.Ref}
					} else {
						defaultName = createDefaultName()
					}
				case *js_ast.SClass:
					if s.Class.Name != nil {
						defaultName = js_ast.LocRef{Loc: defaultLoc, Ref: s.Class.Name.Ref}
					} else {
						defaultName = createDefaultName()
					}
				default:
					panic("Internal error")
				}

				return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportDefault{DefaultName: defaultName, Value: js_ast.ExprOrStmt{Stmt: &stmt}}}
			}

			isIdentifier := p.lexer.Token == js_lexer.TIdentifier
			name := p.lexer.Identifier
			expr := p.parseExpr(js_ast.LComma)

			// Handle the default export of an abstract class in TypeScript
			if p.options.ts.Parse && isIdentifier && name == "abstract" {
				if _, ok := expr.Data.(*js_ast.EIdentifier); ok && (p.lexer.Token == js_lexer.TClass || opts.tsDecorators != nil) {
					stmt := p.parseClassStmt(loc, parseStmtOpts{
						tsDecorators:   opts.tsDecorators,
						isNameOptional: true,
					})

					// Use the statement name if present, since it's a better name
					var defaultName js_ast.LocRef
					if s, ok := stmt.Data.(*js_ast.SClass); ok && s.Class.Name != nil {
						defaultName = js_ast.LocRef{Loc: defaultLoc, Ref: s.Class.Name.Ref}
					} else {
						defaultName = createDefaultName()
					}

					return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportDefault{DefaultName: defaultName, Value: js_ast.ExprOrStmt{Stmt: &stmt}}}
				}
			}

			p.lexer.ExpectOrInsertSemicolon()
			defaultName := createDefaultName()
			return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportDefault{DefaultName: defaultName, Value: js_ast.ExprOrStmt{Expr: &expr}}}

		case js_lexer.TAsterisk:
			if !opts.isModuleScope && (!opts.isNamespaceScope || !opts.isTypeScriptDeclare) {
				p.lexer.Unexpected()
			}

			p.lexer.Next()
			var namespaceRef js_ast.Ref
			var alias *js_ast.ExportStarAlias
			var pathLoc logger.Loc
			var pathText string

			if p.lexer.IsContextualKeyword("as") {
				// "export * as ns from 'path'"
				p.lexer.Next()
				name := p.lexer.Identifier
				namespaceRef = p.storeNameInRef(name)
				alias = &js_ast.ExportStarAlias{Loc: p.lexer.Loc(), OriginalName: name}
				if !p.lexer.IsIdentifierOrKeyword() {
					p.lexer.Expect(js_lexer.TIdentifier)
				}
				p.checkForNonBMPCodePoint(alias.Loc, name)
				p.lexer.Next()
				p.lexer.ExpectContextualKeyword("from")
				pathLoc, pathText = p.parsePath()
			} else {
				// "export * from 'path'"
				p.lexer.ExpectContextualKeyword("from")
				pathLoc, pathText = p.parsePath()
				name := js_ast.GenerateNonUniqueNameFromPath(pathText) + "_star"
				namespaceRef = p.storeNameInRef(name)
			}
			importRecordIndex := p.addImportRecord(ast.ImportStmt, pathLoc, pathText)

			p.lexer.ExpectOrInsertSemicolon()
			return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportStar{
				NamespaceRef:      namespaceRef,
				Alias:             alias,
				ImportRecordIndex: importRecordIndex,
			}}

		case js_lexer.TOpenBrace:
			if !opts.isModuleScope && (!opts.isNamespaceScope || !opts.isTypeScriptDeclare) {
				p.lexer.Unexpected()
			}

			items, isSingleLine := p.parseExportClause()
			if p.lexer.IsContextualKeyword("from") {
				p.lexer.Next()
				pathLoc, pathText := p.parsePath()
				importRecordIndex := p.addImportRecord(ast.ImportStmt, pathLoc, pathText)
				name := js_ast.GenerateNonUniqueNameFromPath(pathText)
				namespaceRef := p.storeNameInRef(name)
				p.lexer.ExpectOrInsertSemicolon()
				return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportFrom{
					Items:             items,
					NamespaceRef:      namespaceRef,
					ImportRecordIndex: importRecordIndex,
					IsSingleLine:      isSingleLine,
				}}
			}
			p.lexer.ExpectOrInsertSemicolon()
			return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportClause{Items: items, IsSingleLine: isSingleLine}}

		case js_lexer.TEquals:
			// "export = value;"
			if p.options.ts.Parse {
				p.lexer.Next()
				value := p.parseExpr(js_ast.LLowest)
				p.lexer.ExpectOrInsertSemicolon()
				return js_ast.Stmt{Loc: loc, Data: &js_ast.SExportEquals{Value: value}}
			}
			p.lexer.Unexpected()
			return js_ast.Stmt{}

		default:
			p.lexer.Unexpected()
			return js_ast.Stmt{}
		}

	case js_lexer.TFunction:
		p.lexer.Next()
		return p.parseFnStmt(loc, opts, false /* isAsync */, logger.Range{})

	case js_lexer.TEnum:
		if !p.options.ts.Parse {
			p.lexer.Unexpected()
		}
		return p.parseTypeScriptEnumStmt(loc, opts)

	case js_lexer.TAt:
		// Parse decorators before class statements, which are potentially exported
		if p.options.ts.Parse {
			scopeIndex := len(p.scopesInOrder)
			tsDecorators := p.parseTypeScriptDecorators()

			// If this turns out to be a "declare class" statement, we need to undo the
			// scopes that were potentially pushed while parsing the decorator arguments.
			// That can look like any one of the following:
			//
			//   "@decorator declare class Foo {}"
			//   "@decorator declare abstract class Foo {}"
			//   "@decorator export declare class Foo {}"
			//   "@decorator export declare abstract class Foo {}"
			//
			opts.tsDecorators = &deferredTSDecorators{
				values:     tsDecorators,
				scopeIndex: scopeIndex,
			}

			// "@decorator class Foo {}"
			// "@decorator abstract class Foo {}"
			// "@decorator declare class Foo {}"
			// "@decorator declare abstract class Foo {}"
			// "@decorator export class Foo {}"
			// "@decorator export abstract class Foo {}"
			// "@decorator export declare class Foo {}"
			// "@decorator export declare abstract class Foo {}"
			// "@decorator export default class Foo {}"
			// "@decorator export default abstract class Foo {}"
			if p.lexer.Token != js_lexer.TClass && p.lexer.Token != js_lexer.TExport &&
				!p.lexer.IsContextualKeyword("abstract") && !p.lexer.IsContextualKeyword("declare") {
				p.lexer.Expected(js_lexer.TClass)
			}

			return p.parseStmt(opts)
		}

		p.lexer.Unexpected()
		return js_ast.Stmt{}

	case js_lexer.TClass:
		if opts.lexicalDecl != lexicalDeclAllowAll {
			p.forbidLexicalDecl(loc)
		}
		return p.parseClassStmt(loc, opts)

	case js_lexer.TVar:
		p.lexer.Next()
		decls := p.parseAndDeclareDecls(js_ast.SymbolHoisted, opts)
		p.lexer.ExpectOrInsertSemicolon()
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SLocal{
			Kind:     js_ast.LocalVar,
			Decls:    decls,
			IsExport: opts.isExport,
		}}

	case js_lexer.TConst:
		if opts.lexicalDecl != lexicalDeclAllowAll {
			p.forbidLexicalDecl(loc)
		}
		p.markSyntaxFeature(compat.Const, p.lexer.Range())
		p.lexer.Next()

		if p.options.ts.Parse && p.lexer.Token == js_lexer.TEnum {
			return p.parseTypeScriptEnumStmt(loc, opts)
		}

		decls := p.parseAndDeclareDecls(js_ast.SymbolConst, opts)
		p.lexer.ExpectOrInsertSemicolon()
		if !opts.isTypeScriptDeclare {
			p.requireInitializers(decls)
		}
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SLocal{
			Kind:     js_ast.LocalConst,
			Decls:    decls,
			IsExport: opts.isExport,
		}}

	case js_lexer.TIf:
		p.lexer.Next()
		p.lexer.Expect(js_lexer.TOpenParen)
		test := p.parseExpr(js_ast.LLowest)
		p.lexer.Expect(js_lexer.TCloseParen)
		yes := p.parseStmt(parseStmtOpts{lexicalDecl: lexicalDeclAllowFnInsideIf})
		var no *js_ast.Stmt = nil
		if p.lexer.Token == js_lexer.TElse {
			p.lexer.Next()
			stmt := p.parseStmt(parseStmtOpts{lexicalDecl: lexicalDeclAllowFnInsideIf})
			no = &stmt
		}
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SIf{Test: test, Yes: yes, No: no}}

	case js_lexer.TDo:
		p.lexer.Next()
		body := p.parseStmt(parseStmtOpts{})
		p.lexer.Expect(js_lexer.TWhile)
		p.lexer.Expect(js_lexer.TOpenParen)
		test := p.parseExpr(js_ast.LLowest)
		p.lexer.Expect(js_lexer.TCloseParen)

		// This is a weird corner case where automatic semicolon insertion applies
		// even without a newline present
		if p.lexer.Token == js_lexer.TSemicolon {
			p.lexer.Next()
		}
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SDoWhile{Body: body, Test: test}}

	case js_lexer.TWhile:
		p.lexer.Next()
		p.lexer.Expect(js_lexer.TOpenParen)
		test := p.parseExpr(js_ast.LLowest)
		p.lexer.Expect(js_lexer.TCloseParen)
		body := p.parseStmt(parseStmtOpts{})
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SWhile{Test: test, Body: body}}

	case js_lexer.TWith:
		p.lexer.Next()
		p.lexer.Expect(js_lexer.TOpenParen)
		test := p.parseExpr(js_ast.LLowest)
		bodyLoc := p.lexer.Loc()
		p.lexer.Expect(js_lexer.TCloseParen)

		// Push a scope so we make sure to prevent any bare identifiers referenced
		// within the body from being renamed. Renaming them might change the
		// semantics of the code.
		p.pushScopeForParsePass(js_ast.ScopeWith, bodyLoc)
		body := p.parseStmt(parseStmtOpts{})
		p.popScope()

		return js_ast.Stmt{Loc: loc, Data: &js_ast.SWith{Value: test, BodyLoc: bodyLoc, Body: body}}

	case js_lexer.TSwitch:
		p.lexer.Next()
		p.lexer.Expect(js_lexer.TOpenParen)
		test := p.parseExpr(js_ast.LLowest)
		p.lexer.Expect(js_lexer.TCloseParen)

		bodyLoc := p.lexer.Loc()
		p.pushScopeForParsePass(js_ast.ScopeBlock, bodyLoc)
		defer p.popScope()

		p.lexer.Expect(js_lexer.TOpenBrace)
		cases := []js_ast.Case{}
		foundDefault := false

		for p.lexer.Token != js_lexer.TCloseBrace {
			var value *js_ast.Expr = nil
			body := []js_ast.Stmt{}

			if p.lexer.Token == js_lexer.TDefault {
				if foundDefault {
					p.log.AddRangeError(&p.source, p.lexer.Range(), "Multiple default clauses are not allowed")
					panic(js_lexer.LexerPanic{})
				}
				foundDefault = true
				p.lexer.Next()
				p.lexer.Expect(js_lexer.TColon)
			} else {
				p.lexer.Expect(js_lexer.TCase)
				expr := p.parseExpr(js_ast.LLowest)
				value = &expr
				p.lexer.Expect(js_lexer.TColon)
			}

		caseBody:
			for {
				switch p.lexer.Token {
				case js_lexer.TCloseBrace, js_lexer.TCase, js_lexer.TDefault:
					break caseBody

				default:
					body = append(body, p.parseStmt(parseStmtOpts{lexicalDecl: lexicalDeclAllowAll}))
				}
			}

			cases = append(cases, js_ast.Case{Value: value, Body: body})
		}

		p.lexer.Expect(js_lexer.TCloseBrace)
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SSwitch{
			Test:    test,
			BodyLoc: bodyLoc,
			Cases:   cases,
		}}

	case js_lexer.TTry:
		p.lexer.Next()
		p.lexer.Expect(js_lexer.TOpenBrace)
		p.pushScopeForParsePass(js_ast.ScopeBlock, loc)
		body := p.parseStmtsUpTo(js_lexer.TCloseBrace, parseStmtOpts{})
		p.popScope()
		p.lexer.Next()

		var catch *js_ast.Catch = nil
		var finally *js_ast.Finally = nil

		if p.lexer.Token == js_lexer.TCatch {
			catchLoc := p.lexer.Loc()
			p.pushScopeForParsePass(js_ast.ScopeBlock, catchLoc)
			p.lexer.Next()
			var binding *js_ast.Binding

			// The catch binding is optional, and can be omitted
			if p.lexer.Token == js_lexer.TOpenBrace {
				if p.options.unsupportedJSFeatures.Has(compat.OptionalCatchBinding) {
					// Generate a new symbol for the catch binding for older browsers
					ref := p.newSymbol(js_ast.SymbolOther, "e")
					p.currentScope.Generated = append(p.currentScope.Generated, ref)
					binding = &js_ast.Binding{Loc: p.lexer.Loc(), Data: &js_ast.BIdentifier{Ref: ref}}
				}
			} else {
				p.lexer.Expect(js_lexer.TOpenParen)
				value := p.parseBinding()

				// Skip over types
				if p.options.ts.Parse && p.lexer.Token == js_lexer.TColon {
					p.lexer.Expect(js_lexer.TColon)
					p.skipTypeScriptType(js_ast.LLowest)
				}

				p.lexer.Expect(js_lexer.TCloseParen)

				// Bare identifiers are a special case
				kind := js_ast.SymbolOther
				if _, ok := value.Data.(*js_ast.BIdentifier); ok {
					kind = js_ast.SymbolCatchIdentifier
				}
				p.declareBinding(kind, value, parseStmtOpts{})
				binding = &value
			}

			p.lexer.Expect(js_lexer.TOpenBrace)
			stmts := p.parseStmtsUpTo(js_lexer.TCloseBrace, parseStmtOpts{})
			p.lexer.Next()
			catch = &js_ast.Catch{Loc: catchLoc, Binding: binding, Body: stmts}
			p.popScope()
		}

		if p.lexer.Token == js_lexer.TFinally || catch == nil {
			finallyLoc := p.lexer.Loc()
			p.pushScopeForParsePass(js_ast.ScopeBlock, finallyLoc)
			p.lexer.Expect(js_lexer.TFinally)
			p.lexer.Expect(js_lexer.TOpenBrace)
			stmts := p.parseStmtsUpTo(js_lexer.TCloseBrace, parseStmtOpts{})
			p.lexer.Next()
			finally = &js_ast.Finally{Loc: finallyLoc, Stmts: stmts}
			p.popScope()
		}

		return js_ast.Stmt{Loc: loc, Data: &js_ast.STry{Body: body, Catch: catch, Finally: finally}}

	case js_lexer.TFor:
		p.pushScopeForParsePass(js_ast.ScopeBlock, loc)
		defer p.popScope()

		p.lexer.Next()

		// "for await (let x of y) {}"
		isForAwait := p.lexer.IsContextualKeyword("await")
		if isForAwait {
			awaitRange := p.lexer.Range()
			if !p.fnOrArrowDataParse.allowAwait {
				p.log.AddRangeError(&p.source, awaitRange, "Cannot use \"await\" outside an async function")
				isForAwait = false
			} else {
				didGenerateError := p.markSyntaxFeature(compat.ForAwait, awaitRange)
				if p.fnOrArrowDataParse.isTopLevel && !didGenerateError {
					p.markSyntaxFeature(compat.TopLevelAwait, awaitRange)
				}
			}
			p.lexer.Next()
		}

		p.lexer.Expect(js_lexer.TOpenParen)

		var init *js_ast.Stmt = nil
		var test *js_ast.Expr = nil
		var update *js_ast.Expr = nil

		// "in" expressions aren't allowed here
		p.allowIn = false

		decls := []js_ast.Decl{}
		initLoc := p.lexer.Loc()
		isVar := false
		switch p.lexer.Token {
		case js_lexer.TVar:
			isVar = true
			p.lexer.Next()
			decls = p.parseAndDeclareDecls(js_ast.SymbolHoisted, parseStmtOpts{})
			init = &js_ast.Stmt{Loc: initLoc, Data: &js_ast.SLocal{Kind: js_ast.LocalVar, Decls: decls}}

		case js_lexer.TConst:
			p.markSyntaxFeature(compat.Const, p.lexer.Range())
			p.lexer.Next()
			decls = p.parseAndDeclareDecls(js_ast.SymbolConst, parseStmtOpts{})
			init = &js_ast.Stmt{Loc: initLoc, Data: &js_ast.SLocal{Kind: js_ast.LocalConst, Decls: decls}}

		case js_lexer.TSemicolon:

		default:
			var expr js_ast.Expr
			var stmt js_ast.Stmt
			expr, stmt, decls = p.parseExprOrLetStmt(parseStmtOpts{lexicalDecl: lexicalDeclAllowAll})
			if stmt.Data != nil {
				init = &stmt
			} else {
				init = &js_ast.Stmt{Loc: initLoc, Data: &js_ast.SExpr{Value: expr}}
			}
		}

		// "in" expressions are allowed again
		p.allowIn = true

		// Detect for-of loops
		if p.lexer.IsContextualKeyword("of") || isForAwait {
			if isForAwait && !p.lexer.IsContextualKeyword("of") {
				if init != nil {
					p.lexer.ExpectedString("\"of\"")
				} else {
					p.lexer.Unexpected()
				}
			}
			p.forbidInitializers(decls, "of", false)
			p.markSyntaxFeature(compat.ForOf, p.lexer.Range())
			p.lexer.Next()
			value := p.parseExpr(js_ast.LComma)
			p.lexer.Expect(js_lexer.TCloseParen)
			body := p.parseStmt(parseStmtOpts{})
			return js_ast.Stmt{Loc: loc, Data: &js_ast.SForOf{IsAwait: isForAwait, Init: *init, Value: value, Body: body}}
		}

		// Detect for-in loops
		if p.lexer.Token == js_lexer.TIn {
			p.forbidInitializers(decls, "in", isVar)
			p.lexer.Next()
			value := p.parseExpr(js_ast.LLowest)
			p.lexer.Expect(js_lexer.TCloseParen)
			body := p.parseStmt(parseStmtOpts{})
			return js_ast.Stmt{Loc: loc, Data: &js_ast.SForIn{Init: *init, Value: value, Body: body}}
		}

		// Only require "const" statement initializers when we know we're a normal for loop
		if init != nil {
			if local, ok := init.Data.(*js_ast.SLocal); ok && local.Kind == js_ast.LocalConst {
				p.requireInitializers(decls)
			}
		}

		p.lexer.Expect(js_lexer.TSemicolon)

		if p.lexer.Token != js_lexer.TSemicolon {
			expr := p.parseExpr(js_ast.LLowest)
			test = &expr
		}

		p.lexer.Expect(js_lexer.TSemicolon)

		if p.lexer.Token != js_lexer.TCloseParen {
			expr := p.parseExpr(js_ast.LLowest)
			update = &expr
		}

		p.lexer.Expect(js_lexer.TCloseParen)
		body := p.parseStmt(parseStmtOpts{})
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SFor{Init: init, Test: test, Update: update, Body: body}}

	case js_lexer.TImport:
		p.hasES6ImportSyntax = true
		p.lexer.Next()
		stmt := js_ast.SImport{}
		wasOriginallyBareImport := false

		// "export import foo = bar"
		// "import foo = bar" in a namespace
		if (opts.isExport || (opts.isNamespaceScope && !opts.isTypeScriptDeclare)) && p.lexer.Token != js_lexer.TIdentifier {
			p.lexer.Expected(js_lexer.TIdentifier)
		}

		switch p.lexer.Token {
		case js_lexer.TOpenParen, js_lexer.TDot:
			// "import('path')"
			// "import.meta"
			expr := p.parseSuffix(p.parseImportExpr(loc, js_ast.LLowest), js_ast.LLowest, nil, 0)
			p.lexer.ExpectOrInsertSemicolon()
			return js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: expr}}

		case js_lexer.TStringLiteral, js_lexer.TNoSubstitutionTemplateLiteral:
			// "import 'path'"
			if !opts.isModuleScope && (!opts.isNamespaceScope || !opts.isTypeScriptDeclare) {
				p.lexer.Unexpected()
				return js_ast.Stmt{}
			}

			wasOriginallyBareImport = true

		case js_lexer.TAsterisk:
			// "import * as ns from 'path'"
			if !opts.isModuleScope && (!opts.isNamespaceScope || !opts.isTypeScriptDeclare) {
				p.lexer.Unexpected()
				return js_ast.Stmt{}
			}

			p.lexer.Next()
			p.lexer.ExpectContextualKeyword("as")
			stmt.NamespaceRef = p.storeNameInRef(p.lexer.Identifier)
			starLoc := p.lexer.Loc()
			stmt.StarNameLoc = &starLoc
			p.lexer.Expect(js_lexer.TIdentifier)
			p.lexer.ExpectContextualKeyword("from")

		case js_lexer.TOpenBrace:
			// "import {item1, item2} from 'path'"
			if !opts.isModuleScope && (!opts.isNamespaceScope || !opts.isTypeScriptDeclare) {
				p.lexer.Unexpected()
				return js_ast.Stmt{}
			}

			items, isSingleLine := p.parseImportClause()
			stmt.Items = &items
			stmt.IsSingleLine = isSingleLine
			p.lexer.ExpectContextualKeyword("from")

		case js_lexer.TIdentifier:
			// "import defaultItem from 'path'"
			// "import foo = bar"
			if !opts.isModuleScope && !opts.isNamespaceScope {
				p.lexer.Unexpected()
				return js_ast.Stmt{}
			}

			defaultName := p.lexer.Identifier
			stmt.DefaultName = &js_ast.LocRef{Loc: p.lexer.Loc(), Ref: p.storeNameInRef(defaultName)}
			p.lexer.Next()

			if p.options.ts.Parse {
				// Skip over type-only imports
				if defaultName == "type" {
					switch p.lexer.Token {
					case js_lexer.TIdentifier:
						if p.lexer.Identifier != "from" {
							// "import type foo from 'bar';"
							p.lexer.Next()
							p.lexer.ExpectContextualKeyword("from")
							p.parsePath()
							p.lexer.ExpectOrInsertSemicolon()
							return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}
						}

					case js_lexer.TAsterisk:
						// "import type * as foo from 'bar';"
						p.lexer.Next()
						p.lexer.ExpectContextualKeyword("as")
						p.lexer.Expect(js_lexer.TIdentifier)
						p.lexer.ExpectContextualKeyword("from")
						p.parsePath()
						p.lexer.ExpectOrInsertSemicolon()
						return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}

					case js_lexer.TOpenBrace:
						// "import type {foo} from 'bar';"
						p.parseImportClause()
						p.lexer.ExpectContextualKeyword("from")
						p.parsePath()
						p.lexer.ExpectOrInsertSemicolon()
						return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}
					}
				}

				// Parse TypeScript import assignment statements
				if p.lexer.Token == js_lexer.TEquals || opts.isExport || (opts.isNamespaceScope && !opts.isTypeScriptDeclare) {
					return p.parseTypeScriptImportEqualsStmt(loc, opts, stmt.DefaultName.Loc, defaultName)
				}
			}

			if p.lexer.Token == js_lexer.TComma {
				p.lexer.Next()
				switch p.lexer.Token {
				case js_lexer.TAsterisk:
					// "import defaultItem, * as ns from 'path'"
					p.lexer.Next()
					p.lexer.ExpectContextualKeyword("as")
					stmt.NamespaceRef = p.storeNameInRef(p.lexer.Identifier)
					starLoc := p.lexer.Loc()
					stmt.StarNameLoc = &starLoc
					p.lexer.Expect(js_lexer.TIdentifier)

				case js_lexer.TOpenBrace:
					// "import defaultItem, {item1, item2} from 'path'"
					items, isSingleLine := p.parseImportClause()
					stmt.Items = &items
					stmt.IsSingleLine = isSingleLine

				default:
					p.lexer.Unexpected()
				}
			}

			p.lexer.ExpectContextualKeyword("from")

		default:
			p.lexer.Unexpected()
			return js_ast.Stmt{}
		}

		pathLoc, pathText := p.parsePath()
		stmt.ImportRecordIndex = p.addImportRecord(ast.ImportStmt, pathLoc, pathText)
		p.importRecords[stmt.ImportRecordIndex].WasOriginallyBareImport = wasOriginallyBareImport
		p.lexer.ExpectOrInsertSemicolon()

		if stmt.StarNameLoc != nil {
			name := p.loadNameFromRef(stmt.NamespaceRef)
			stmt.NamespaceRef = p.declareSymbol(js_ast.SymbolImport, *stmt.StarNameLoc, name)
		} else {
			// Generate a symbol for the namespace
			name := js_ast.GenerateNonUniqueNameFromPath(pathText)
			stmt.NamespaceRef = p.newSymbol(js_ast.SymbolOther, name)
			p.currentScope.Generated = append(p.currentScope.Generated, stmt.NamespaceRef)
		}
		itemRefs := make(map[string]js_ast.LocRef)

		// Link the default item to the namespace
		if stmt.DefaultName != nil {
			name := p.loadNameFromRef(stmt.DefaultName.Ref)
			ref := p.declareSymbol(js_ast.SymbolImport, stmt.DefaultName.Loc, name)
			p.isImportItem[ref] = true
			stmt.DefaultName.Ref = ref
		}

		// Link each import item to the namespace
		if stmt.Items != nil {
			for i, item := range *stmt.Items {
				name := p.loadNameFromRef(item.Name.Ref)
				ref := p.declareSymbol(js_ast.SymbolImport, item.Name.Loc, name)
				p.checkForNonBMPCodePoint(item.AliasLoc, item.Alias)
				p.isImportItem[ref] = true
				(*stmt.Items)[i].Name.Ref = ref
				itemRefs[item.Alias] = js_ast.LocRef{Loc: item.Name.Loc, Ref: ref}
			}
		}

		// Track the items for this namespace
		p.importItemsForNamespace[stmt.NamespaceRef] = itemRefs

		return js_ast.Stmt{Loc: loc, Data: &stmt}

	case js_lexer.TBreak:
		p.lexer.Next()
		name := p.parseLabelName()
		p.lexer.ExpectOrInsertSemicolon()
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SBreak{Label: name}}

	case js_lexer.TContinue:
		p.lexer.Next()
		name := p.parseLabelName()
		p.lexer.ExpectOrInsertSemicolon()
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SContinue{Label: name}}

	case js_lexer.TReturn:
		p.lexer.Next()
		var value *js_ast.Expr
		if p.lexer.Token != js_lexer.TSemicolon &&
			!p.lexer.HasNewlineBefore &&
			p.lexer.Token != js_lexer.TCloseBrace &&
			p.lexer.Token != js_lexer.TEndOfFile {
			expr := p.parseExpr(js_ast.LLowest)
			value = &expr
		}
		p.latestReturnHadSemicolon = p.lexer.Token == js_lexer.TSemicolon
		p.lexer.ExpectOrInsertSemicolon()
		if p.fnOrArrowDataParse.isOutsideFn {
			p.hasTopLevelReturn = true
		}
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SReturn{Value: value}}

	case js_lexer.TThrow:
		p.lexer.Next()
		if p.lexer.HasNewlineBefore {
			p.log.AddError(&p.source, logger.Loc{Start: loc.Start + 5}, "Unexpected newline after \"throw\"")
			panic(js_lexer.LexerPanic{})
		}
		expr := p.parseExpr(js_ast.LLowest)
		p.lexer.ExpectOrInsertSemicolon()
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SThrow{Value: expr}}

	case js_lexer.TDebugger:
		p.lexer.Next()
		p.lexer.ExpectOrInsertSemicolon()
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SDebugger{}}

	case js_lexer.TOpenBrace:
		p.pushScopeForParsePass(js_ast.ScopeBlock, loc)
		defer p.popScope()

		p.lexer.Next()
		stmts := p.parseStmtsUpTo(js_lexer.TCloseBrace, parseStmtOpts{})
		p.lexer.Next()
		return js_ast.Stmt{Loc: loc, Data: &js_ast.SBlock{Stmts: stmts}}

	default:
		isIdentifier := p.lexer.Token == js_lexer.TIdentifier
		name := p.lexer.Identifier

		// Parse either an async function, an async expression, or a normal expression
		var expr js_ast.Expr
		if isIdentifier && p.lexer.Raw() == "async" {
			asyncRange := p.lexer.Range()
			p.lexer.Next()
			if p.lexer.Token == js_lexer.TFunction && !p.lexer.HasNewlineBefore {
				p.lexer.Next()
				return p.parseFnStmt(asyncRange.Loc, opts, true /* isAsync */, asyncRange)
			}
			expr = p.parseSuffix(p.parseAsyncPrefixExpr(asyncRange), js_ast.LLowest, nil, 0)
		} else {
			var stmt js_ast.Stmt
			expr, stmt, _ = p.parseExprOrLetStmt(opts)
			if stmt.Data != nil {
				p.lexer.ExpectOrInsertSemicolon()
				return stmt
			}
		}

		if isIdentifier {
			if ident, ok := expr.Data.(*js_ast.EIdentifier); ok {
				if p.lexer.Token == js_lexer.TColon && opts.tsDecorators == nil {
					p.pushScopeForParsePass(js_ast.ScopeLabel, loc)
					defer p.popScope()

					// Parse a labeled statement
					p.lexer.Next()
					name := js_ast.LocRef{Loc: expr.Loc, Ref: ident.Ref}
					nestedOpts := parseStmtOpts{}
					if opts.lexicalDecl == lexicalDeclAllowAll || opts.lexicalDecl == lexicalDeclAllowFnInsideLabel {
						nestedOpts.lexicalDecl = lexicalDeclAllowFnInsideLabel
					}
					stmt := p.parseStmt(nestedOpts)
					return js_ast.Stmt{Loc: loc, Data: &js_ast.SLabel{Name: name, Stmt: stmt}}
				}

				if p.options.ts.Parse {
					switch name {
					case "type":
						if p.lexer.Token == js_lexer.TIdentifier && !p.lexer.HasNewlineBefore {
							// "type Foo = any"
							p.skipTypeScriptTypeStmt(parseStmtOpts{isModuleScope: opts.isModuleScope})
							return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}
						}

					case "namespace", "module":
						// "namespace Foo {}"
						// "module Foo {}"
						// "declare module 'fs' {}"
						// "declare module 'fs';"
						if (opts.isModuleScope || opts.isNamespaceScope) && (p.lexer.Token == js_lexer.TIdentifier ||
							(p.lexer.Token == js_lexer.TStringLiteral && opts.isTypeScriptDeclare)) {
							return p.parseTypeScriptNamespaceStmt(loc, opts)
						}

					case "interface":
						// "interface Foo {}"
						p.skipTypeScriptInterfaceStmt(parseStmtOpts{isModuleScope: opts.isModuleScope})
						return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}

					case "abstract":
						if p.lexer.Token == js_lexer.TClass || opts.tsDecorators != nil {
							return p.parseClassStmt(loc, opts)
						}

					case "global":
						// "declare module 'fs' { global { namespace NodeJS {} } }"
						if opts.isNamespaceScope && opts.isTypeScriptDeclare && p.lexer.Token == js_lexer.TOpenBrace {
							p.lexer.Next()
							p.parseStmtsUpTo(js_lexer.TCloseBrace, opts)
							p.lexer.Next()
							return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}
						}

					case "declare":
						opts.lexicalDecl = lexicalDeclAllowAll
						opts.isTypeScriptDeclare = true

						// "@decorator declare class Foo {}"
						// "@decorator declare abstract class Foo {}"
						if opts.tsDecorators != nil && p.lexer.Token != js_lexer.TClass && !p.lexer.IsContextualKeyword("abstract") {
							p.lexer.Expected(js_lexer.TClass)
						}

						// "declare global { ... }"
						if p.lexer.IsContextualKeyword("global") {
							p.lexer.Next()
							p.lexer.Expect(js_lexer.TOpenBrace)
							p.parseStmtsUpTo(js_lexer.TCloseBrace, opts)
							p.lexer.Next()
							return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}
						}

						// "declare const x: any"
						stmt := p.parseStmt(opts)
						if opts.tsDecorators != nil {
							p.discardScopesUpTo(opts.tsDecorators.scopeIndex)
						}

						// Unlike almost all uses of "declare", statements that use
						// "export declare" with "var/let/const" inside a namespace affect
						// code generation. They cause any declared bindings to be
						// considered exports of the namespace. Identifier references to
						// those names must be converted into property accesses off the
						// namespace object:
						//
						//   namespace ns {
						//     export declare const x
						//     export function y() { return x }
						//   }
						//
						//   (ns as any).x = 1
						//   console.log(ns.y())
						//
						// In this example, "return x" must be replaced with "return ns.x".
						// This is handled by replacing each "export declare" statement
						// inside a namespace with an "export var" statement containing all
						// of the declared bindings. That "export var" statement will later
						// cause identifiers to be transformed into property accesses.
						if opts.isNamespaceScope && opts.isExport {
							var decls []js_ast.Decl
							if s, ok := stmt.Data.(*js_ast.SLocal); ok {
								for _, decl := range s.Decls {
									decls = extractDeclsForBinding(decl.Binding, decls)
								}
							}
							if len(decls) > 0 {
								return js_ast.Stmt{Loc: loc, Data: &js_ast.SLocal{
									Kind:     js_ast.LocalVar,
									IsExport: true,
									Decls:    decls,
								}}
							}
						}

						return js_ast.Stmt{Loc: loc, Data: &js_ast.STypeScript{}}
					}
				}
			}
		}

		p.lexer.ExpectOrInsertSemicolon()

		// Parse a "use strict" directive
		if str, ok := expr.Data.(*js_ast.EString); ok && js_lexer.UTF16EqualsString(str.Value, "use strict") {
			return js_ast.Stmt{Loc: loc, Data: &js_ast.SDirective{Value: str.Value}}
		}

		return js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: expr}}
	}
}

func extractDeclsForBinding(binding js_ast.Binding, decls []js_ast.Decl) []js_ast.Decl {
	switch b := binding.Data.(type) {
	case *js_ast.BMissing:

	case *js_ast.BIdentifier:
		decls = append(decls, js_ast.Decl{Binding: binding})

	case *js_ast.BArray:
		for _, item := range b.Items {
			decls = extractDeclsForBinding(item.Binding, decls)
		}

	case *js_ast.BObject:
		for _, property := range b.Properties {
			decls = extractDeclsForBinding(property.Value, decls)
		}

	default:
		panic("Internal error")
	}

	return decls
}

func (p *parser) addImportRecord(kind ast.ImportKind, loc logger.Loc, text string) uint32 {
	index := uint32(len(p.importRecords))
	p.importRecords = append(p.importRecords, ast.ImportRecord{
		Kind:  kind,
		Range: p.source.RangeOfString(loc),
		Path:  logger.Path{Text: text},
	})
	return index
}

func (p *parser) parseFnBody(data fnOrArrowDataParse) js_ast.FnBody {
	oldFnOrArrowData := p.fnOrArrowDataParse
	oldAllowIn := p.allowIn
	p.fnOrArrowDataParse = data
	p.allowIn = true

	loc := p.lexer.Loc()
	p.pushScopeForParsePass(js_ast.ScopeFunctionBody, loc)
	defer p.popScope()

	p.lexer.Expect(js_lexer.TOpenBrace)
	stmts := p.parseStmtsUpTo(js_lexer.TCloseBrace, parseStmtOpts{})
	p.lexer.Next()

	p.allowIn = oldAllowIn
	p.fnOrArrowDataParse = oldFnOrArrowData
	return js_ast.FnBody{Loc: loc, Stmts: stmts}
}

func (p *parser) forbidLexicalDecl(loc logger.Loc) {
	r := js_lexer.RangeOfIdentifier(p.source, loc)
	p.log.AddRangeError(&p.source, r, "Cannot use a declaration in a single-statement context")
}

func (p *parser) parseStmtsUpTo(end js_lexer.T, opts parseStmtOpts) []js_ast.Stmt {
	stmts := []js_ast.Stmt{}
	returnWithoutSemicolonStart := int32(-1)
	opts.lexicalDecl = lexicalDeclAllowAll

	for {
		// Preserve some statement-level comments
		comments := p.lexer.CommentsToPreserveBefore
		if len(comments) > 0 {
			for _, comment := range comments {
				stmts = append(stmts, js_ast.Stmt{
					Loc:  comment.Loc,
					Data: &js_ast.SComment{Text: comment.Text},
				})
			}
		}

		if p.lexer.Token == end {
			break
		}

		stmt := p.parseStmt(opts)

		// Skip TypeScript types entirely
		if p.options.ts.Parse {
			if _, ok := stmt.Data.(*js_ast.STypeScript); ok {
				continue
			}
		}

		stmts = append(stmts, stmt)

		// Warn about ASI and return statements. Here's an example of code with
		// this problem: https://github.com/rollup/rollup/issues/3729
		if !p.options.suppressWarningsAboutWeirdCode {
			if s, ok := stmt.Data.(*js_ast.SReturn); ok && s.Value == nil && !p.latestReturnHadSemicolon {
				returnWithoutSemicolonStart = stmt.Loc.Start
			} else {
				if returnWithoutSemicolonStart != -1 {
					if _, ok := stmt.Data.(*js_ast.SExpr); ok {
						p.log.AddWarning(&p.source, logger.Loc{Start: returnWithoutSemicolonStart + 6},
							"The following expression is not returned because of an automatically-inserted semicolon")
					}
				}
				returnWithoutSemicolonStart = -1
			}
		}
	}

	return stmts
}

type generateTempRefArg uint8

const (
	tempRefNeedsDeclare generateTempRefArg = iota
	tempRefNoDeclare
)

func (p *parser) generateTempRef(declare generateTempRefArg, optionalName string) js_ast.Ref {
	scope := p.currentScope
	for !scope.Kind.StopsHoisting() {
		scope = scope.Parent
	}
	if optionalName == "" {
		optionalName = "_" + js_ast.DefaultNameMinifier.NumberToMinifiedName(p.tempRefCount)
		p.tempRefCount++
	}
	ref := p.newSymbol(js_ast.SymbolOther, optionalName)
	if declare == tempRefNeedsDeclare {
		p.tempRefsToDeclare = append(p.tempRefsToDeclare, tempRef{ref: ref})
	}
	scope.Generated = append(scope.Generated, ref)
	return ref
}

func (p *parser) pushScopeForVisitPass(kind js_ast.ScopeKind, loc logger.Loc) {
	order := p.scopesInOrder[0]

	// Sanity-check that the scopes generated by the first and second passes match
	if order.loc != loc || order.scope.Kind != kind {
		panic(fmt.Sprintf("Expected scope (%d, %d) in %s, found scope (%d, %d)",
			kind, loc.Start,
			p.source.PrettyPath,
			order.scope.Kind, order.loc.Start))
	}

	p.scopesInOrder = p.scopesInOrder[1:]
	p.currentScope = order.scope
	p.scopesForCurrentPart = append(p.scopesForCurrentPart, order.scope)
}

type findSymbolResult struct {
	ref               js_ast.Ref
	declareLoc        logger.Loc
	isInsideWithScope bool
}

func (p *parser) findSymbol(loc logger.Loc, name string) findSymbolResult {
	var ref js_ast.Ref
	var declareLoc logger.Loc
	isInsideWithScope := false
	s := p.currentScope

	for {
		// Track if we're inside a "with" statement body
		if s.Kind == js_ast.ScopeWith {
			isInsideWithScope = true
		}

		// Is the symbol a member of this scope?
		if member, ok := s.Members[name]; ok {
			ref = member.Ref
			declareLoc = member.Loc
			if p.symbols[ref.InnerIndex].Kind == js_ast.SymbolError {
				r := js_lexer.RangeOfIdentifier(p.source, loc)
				p.log.AddRangeError(&p.source, r, fmt.Sprintf("Cannot access %q here", name))
			}
			break
		}

		s = s.Parent
		if s == nil {
			// Allocate an "unbound" symbol
			p.checkForNonBMPCodePoint(loc, name)
			ref = p.newSymbol(js_ast.SymbolUnbound, name)
			declareLoc = loc
			p.moduleScope.Members[name] = js_ast.ScopeMember{Ref: ref, Loc: logger.Loc{Start: -1}}
			break
		}
	}

	// If we had to pass through a "with" statement body to get to the symbol
	// declaration, then this reference could potentially also refer to a
	// property on the target object of the "with" statement. We must not rename
	// it or we risk changing the behavior of the code.
	if isInsideWithScope {
		p.symbols[ref.InnerIndex].MustNotBeRenamed = true
	}

	// Track how many times we've referenced this symbol
	p.recordUsage(ref)
	return findSymbolResult{ref, declareLoc, isInsideWithScope}
}

func (p *parser) findLabelSymbol(loc logger.Loc, name string) (ref js_ast.Ref, isLoop bool, ok bool) {
	for s := p.currentScope; s != nil && !s.Kind.StopsHoisting(); s = s.Parent {
		if s.Kind == js_ast.ScopeLabel && name == p.symbols[s.LabelRef.InnerIndex].OriginalName {
			// Track how many times we've referenced this symbol
			p.recordUsage(s.LabelRef)
			ref = s.LabelRef
			isLoop = s.LabelStmtIsLoop
			ok = true
			return
		}
	}

	r := js_lexer.RangeOfIdentifier(p.source, loc)
	p.log.AddRangeError(&p.source, r, fmt.Sprintf("There is no containing label named %q", name))

	// Allocate an "unbound" symbol
	ref = p.newSymbol(js_ast.SymbolUnbound, name)

	// Track how many times we've referenced this symbol
	p.recordUsage(ref)
	return
}

func findIdentifiers(binding js_ast.Binding, identifiers []js_ast.Decl) []js_ast.Decl {
	switch b := binding.Data.(type) {
	case *js_ast.BIdentifier:
		identifiers = append(identifiers, js_ast.Decl{Binding: binding})

	case *js_ast.BArray:
		for _, item := range b.Items {
			identifiers = findIdentifiers(item.Binding, identifiers)
		}

	case *js_ast.BObject:
		for _, property := range b.Properties {
			identifiers = findIdentifiers(property.Value, identifiers)
		}
	}

	return identifiers
}

// If this is in a dead branch, then we want to trim as much dead code as we
// can. Everything can be trimmed except for hoisted declarations ("var" and
// "function"), which affect the parent scope. For example:
//
//   function foo() {
//     if (false) { var x; }
//     x = 1;
//   }
//
// We can't trim the entire branch as dead or calling foo() will incorrectly
// assign to a global variable instead.
func shouldKeepStmtInDeadControlFlow(stmt js_ast.Stmt) bool {
	switch s := stmt.Data.(type) {
	case *js_ast.SEmpty, *js_ast.SExpr, *js_ast.SThrow, *js_ast.SReturn,
		*js_ast.SBreak, *js_ast.SContinue, *js_ast.SClass, *js_ast.SDebugger:
		// Omit these statements entirely
		return false

	case *js_ast.SLocal:
		if s.Kind != js_ast.LocalVar {
			// Omit these statements entirely
			return false
		}

		// Omit everything except the identifiers
		identifiers := []js_ast.Decl{}
		for _, decl := range s.Decls {
			identifiers = findIdentifiers(decl.Binding, identifiers)
		}
		s.Decls = identifiers
		return true

	default:
		// Everything else must be kept
		return true
	}
}

type prependTempRefsOpts struct {
	fnBodyLoc *logger.Loc
}

func (p *parser) visitStmtsAndPrependTempRefs(stmts []js_ast.Stmt, opts prependTempRefsOpts) []js_ast.Stmt {
	oldTempRefs := p.tempRefsToDeclare
	oldTempRefCount := p.tempRefCount
	p.tempRefsToDeclare = nil
	p.tempRefCount = 0

	stmts = p.visitStmts(stmts)

	// Prepend values for "this" and "arguments"
	if opts.fnBodyLoc != nil {
		// Capture "this"
		if ref := p.fnOnlyDataVisit.thisCaptureRef; ref != nil {
			p.tempRefsToDeclare = append(p.tempRefsToDeclare, tempRef{
				ref:   *ref,
				value: &js_ast.Expr{Loc: *opts.fnBodyLoc, Data: &js_ast.EThis{}},
			})
			p.currentScope.Generated = append(p.currentScope.Generated, *ref)
		}

		// Capture "arguments"
		if ref := p.fnOnlyDataVisit.argumentsCaptureRef; ref != nil {
			p.tempRefsToDeclare = append(p.tempRefsToDeclare, tempRef{
				ref:   *ref,
				value: &js_ast.Expr{Loc: *opts.fnBodyLoc, Data: &js_ast.EIdentifier{Ref: *p.fnOnlyDataVisit.argumentsRef}},
			})
			p.currentScope.Generated = append(p.currentScope.Generated, *ref)
		}
	}

	// Prepend the generated temporary variables to the beginning of the statement list
	if len(p.tempRefsToDeclare) > 0 {
		decls := []js_ast.Decl{}
		for _, temp := range p.tempRefsToDeclare {
			decls = append(decls, js_ast.Decl{Binding: js_ast.Binding{Data: &js_ast.BIdentifier{Ref: temp.ref}}, Value: temp.value})
			p.recordDeclaredSymbol(temp.ref)
		}

		// If the first statement is a super() call, make sure it stays that way
		stmt := js_ast.Stmt{Data: &js_ast.SLocal{Kind: js_ast.LocalVar, Decls: decls}}
		if len(stmts) > 0 && js_ast.IsSuperCall(stmts[0]) {
			stmts = append([]js_ast.Stmt{stmts[0], stmt}, stmts[1:]...)
		} else {
			stmts = append([]js_ast.Stmt{stmt}, stmts...)
		}
	}

	p.tempRefsToDeclare = oldTempRefs
	p.tempRefCount = oldTempRefCount
	return stmts
}

func (p *parser) visitStmts(stmts []js_ast.Stmt) []js_ast.Stmt {
	// Visit all statements first
	visited := make([]js_ast.Stmt, 0, len(stmts))
	var after []js_ast.Stmt
	for _, stmt := range stmts {
		if _, ok := stmt.Data.(*js_ast.SExportEquals); ok {
			// TypeScript "export = value;" becomes "module.exports = value;". This
			// must happen at the end after everything is parsed because TypeScript
			// moves this statement to the end when it generates code.
			after = p.visitAndAppendStmt(after, stmt)
		} else {
			visited = p.visitAndAppendStmt(visited, stmt)
		}
	}
	visited = append(visited, after...)

	// Stop now if we're not mangling
	if !p.options.mangleSyntax {
		return visited
	}

	// If this is in a dead branch, trim as much dead code as we can
	if p.isControlFlowDead {
		end := 0
		for _, stmt := range visited {
			if !shouldKeepStmtInDeadControlFlow(stmt) {
				continue
			}

			// Merge adjacent var statements
			if s, ok := stmt.Data.(*js_ast.SLocal); ok && s.Kind == js_ast.LocalVar && end > 0 {
				prevStmt := visited[end-1]
				if prevS, ok := prevStmt.Data.(*js_ast.SLocal); ok && prevS.Kind == js_ast.LocalVar && s.IsExport == prevS.IsExport {
					prevS.Decls = append(prevS.Decls, s.Decls...)
					continue
				}
			}

			visited[end] = stmt
			end++
		}
		return visited[:end]
	}

	// Merge adjacent statements during mangling
	result := make([]js_ast.Stmt, 0, len(visited))
	isControlFlowDead := false
	for _, stmt := range visited {
		if isControlFlowDead && !shouldKeepStmtInDeadControlFlow(stmt) {
			// Strip unnecessary statements if the control flow is dead here
			continue
		}

		switch s := stmt.Data.(type) {
		case *js_ast.SEmpty:
			// Strip empty statements
			continue

		case *js_ast.SLocal:
			// Merge adjacent local statements
			if len(result) > 0 {
				prevStmt := result[len(result)-1]
				if prevS, ok := prevStmt.Data.(*js_ast.SLocal); ok && s.Kind == prevS.Kind && s.IsExport == prevS.IsExport {
					prevS.Decls = append(prevS.Decls, s.Decls...)
					continue
				}
			}

		case *js_ast.SExpr:
			// Merge adjacent expression statements
			if len(result) > 0 {
				prevStmt := result[len(result)-1]
				if prevS, ok := prevStmt.Data.(*js_ast.SExpr); ok && !js_ast.IsSuperCall(prevStmt) {
					prevS.Value = js_ast.JoinWithComma(prevS.Value, s.Value)
					prevS.DoesNotAffectTreeShaking = prevS.DoesNotAffectTreeShaking && s.DoesNotAffectTreeShaking
					continue
				}
			}

		case *js_ast.SIf:
			// Absorb a previous expression statement
			if len(result) > 0 {
				prevStmt := result[len(result)-1]
				if prevS, ok := prevStmt.Data.(*js_ast.SExpr); ok && !js_ast.IsSuperCall(prevStmt) {
					s.Test = js_ast.JoinWithComma(prevS.Value, s.Test)
					result = result[:len(result)-1]
				}
			}

			if isJumpStatement(s.Yes.Data) && s.No != nil {
				// "if (a) return b; else if (c) return d; else return e;" => "if (a) return b; if (c) return d; return e;"
				for {
					result = append(result, stmt)
					stmt = *s.No
					s.No = nil
					var ok bool
					s, ok = stmt.Data.(*js_ast.SIf)
					if !ok || !isJumpStatement(s.Yes.Data) || s.No == nil {
						break
					}
				}
				result = appendIfBodyPreservingScope(result, stmt)
				continue
			}

		case *js_ast.SReturn:
			// Merge return statements with the previous expression statement
			if len(result) > 0 && s.Value != nil {
				prevStmt := result[len(result)-1]
				if prevS, ok := prevStmt.Data.(*js_ast.SExpr); ok {
					value := js_ast.JoinWithComma(prevS.Value, *s.Value)
					result[len(result)-1] = js_ast.Stmt{Loc: prevStmt.Loc, Data: &js_ast.SReturn{Value: &value}}
					continue
				}
			}

			isControlFlowDead = true

		case *js_ast.SThrow:
			// Merge throw statements with the previous expression statement
			if len(result) > 0 {
				prevStmt := result[len(result)-1]
				if prevS, ok := prevStmt.Data.(*js_ast.SExpr); ok {
					result[len(result)-1] = js_ast.Stmt{Loc: prevStmt.Loc, Data: &js_ast.SThrow{Value: js_ast.JoinWithComma(prevS.Value, s.Value)}}
					continue
				}
			}

			isControlFlowDead = true

		case *js_ast.SFor:
			if len(result) > 0 {
				prevStmt := result[len(result)-1]
				if prevS, ok := prevStmt.Data.(*js_ast.SExpr); ok {
					// Insert the previous expression into the for loop initializer
					if s.Init == nil {
						result[len(result)-1] = stmt
						s.Init = &js_ast.Stmt{Loc: prevStmt.Loc, Data: &js_ast.SExpr{Value: prevS.Value}}
						continue
					} else if s2, ok := s.Init.Data.(*js_ast.SExpr); ok {
						result[len(result)-1] = stmt
						s.Init = &js_ast.Stmt{Loc: prevStmt.Loc, Data: &js_ast.SExpr{Value: js_ast.JoinWithComma(prevS.Value, s2.Value)}}
						continue
					}
				} else {
					// Insert the previous variable declaration into the for loop
					// initializer if it's a "var" declaration, since the scope
					// doesn't matter due to scope hoisting
					if s.Init == nil {
						if s2, ok := prevStmt.Data.(*js_ast.SLocal); ok && s2.Kind == js_ast.LocalVar && !s2.IsExport {
							result[len(result)-1] = stmt
							s.Init = &prevStmt
							continue
						}
					} else {
						if s2, ok := prevStmt.Data.(*js_ast.SLocal); ok && s2.Kind == js_ast.LocalVar && !s2.IsExport {
							if s3, ok := s.Init.Data.(*js_ast.SLocal); ok && s3.Kind == js_ast.LocalVar {
								result[len(result)-1] = stmt
								s.Init.Data = &js_ast.SLocal{Kind: js_ast.LocalVar, Decls: append(s2.Decls, s3.Decls...)}
								continue
							}
						}
					}
				}
			}
		}

		result = append(result, stmt)
	}

	// Merge certain statements in reverse order
	if len(result) >= 2 {
		lastStmt := result[len(result)-1]

		if lastReturn, ok := lastStmt.Data.(*js_ast.SReturn); ok {
			// "if (a) return b; if (c) return d; return e;" => "return a ? b : c ? d : e;"
		returnLoop:
			for len(result) >= 2 {
				prevIndex := len(result) - 2
				prevStmt := result[prevIndex]

				switch prevS := prevStmt.Data.(type) {
				case *js_ast.SExpr:
					// This return statement must have a value
					if lastReturn.Value == nil {
						break returnLoop
					}

					// "a(); return b;" => "return a(), b;"
					lastValue := js_ast.JoinWithComma(prevS.Value, *lastReturn.Value)
					lastReturn = &js_ast.SReturn{Value: &lastValue}

					// Merge the last two statements
					lastStmt = js_ast.Stmt{Loc: prevStmt.Loc, Data: lastReturn}
					result[prevIndex] = lastStmt
					result = result[:len(result)-1]

				case *js_ast.SIf:
					// The previous statement must be an if statement with no else clause
					if prevS.No != nil {
						break returnLoop
					}

					// The then clause must be a return
					prevReturn, ok := prevS.Yes.Data.(*js_ast.SReturn)
					if !ok {
						break returnLoop
					}

					// Handle some or all of the values being undefined
					left := prevReturn.Value
					right := lastReturn.Value
					if left == nil {
						// "if (a) return; return b;" => "return a ? void 0 : b;"
						left = &js_ast.Expr{Loc: prevS.Yes.Loc, Data: &js_ast.EUndefined{}}
					}
					if right == nil {
						// "if (a) return a; return;" => "return a ? b : void 0;"
						right = &js_ast.Expr{Loc: lastStmt.Loc, Data: &js_ast.EUndefined{}}
					}

					// "if (!a) return b; return c;" => "return a ? c : b;"
					if not, ok := prevS.Test.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot {
						prevS.Test = not.Value
						left, right = right, left
					}

					// Handle the returned values being the same
					if boolean, ok := checkEqualityIfNoSideEffects(left.Data, right.Data); ok && boolean {
						// "if (a) return b; return b;" => "return a, b;"
						lastValue := js_ast.JoinWithComma(prevS.Test, *left)
						lastReturn = &js_ast.SReturn{Value: &lastValue}
					} else {
						if comma, ok := prevS.Test.Data.(*js_ast.EBinary); ok && comma.Op == js_ast.BinOpComma {
							// "if (a, b) return c; return d;" => "return a, b ? c : d;"
							value := js_ast.JoinWithComma(comma.Left, p.mangleIfExpr(comma.Right.Loc, &js_ast.EIf{Test: comma.Right, Yes: *left, No: *right}))
							lastReturn = &js_ast.SReturn{Value: &value}
						} else {
							// "if (a) return b; return c;" => "return a ? b : c;"
							value := p.mangleIfExpr(prevS.Test.Loc, &js_ast.EIf{Test: prevS.Test, Yes: *left, No: *right})
							lastReturn = &js_ast.SReturn{Value: &value}
						}
					}

					// Merge the last two statements
					lastStmt = js_ast.Stmt{Loc: prevStmt.Loc, Data: lastReturn}
					result[prevIndex] = lastStmt
					result = result[:len(result)-1]

				default:
					break returnLoop
				}
			}
		} else if lastThrow, ok := lastStmt.Data.(*js_ast.SThrow); ok {
			// "if (a) throw b; if (c) throw d; throw e;" => "throw a ? b : c ? d : e;"
		throwLoop:
			for len(result) >= 2 {
				prevIndex := len(result) - 2
				prevStmt := result[prevIndex]

				switch prevS := prevStmt.Data.(type) {
				case *js_ast.SExpr:
					// "a(); throw b;" => "throw a(), b;"
					lastThrow = &js_ast.SThrow{Value: js_ast.JoinWithComma(prevS.Value, lastThrow.Value)}

					// Merge the last two statements
					lastStmt = js_ast.Stmt{Loc: prevStmt.Loc, Data: lastThrow}
					result[prevIndex] = lastStmt
					result = result[:len(result)-1]

				case *js_ast.SIf:
					// The previous statement must be an if statement with no else clause
					if prevS.No != nil {
						break throwLoop
					}

					// The then clause must be a throw
					prevThrow, ok := prevS.Yes.Data.(*js_ast.SThrow)
					if !ok {
						break throwLoop
					}

					left := prevThrow.Value
					right := lastThrow.Value

					// "if (!a) throw b; throw c;" => "throw a ? c : b;"
					if not, ok := prevS.Test.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot {
						prevS.Test = not.Value
						left, right = right, left
					}

					// Merge the last two statements
					if comma, ok := prevS.Test.Data.(*js_ast.EBinary); ok && comma.Op == js_ast.BinOpComma {
						// "if (a, b) return c; return d;" => "return a, b ? c : d;"
						lastThrow = &js_ast.SThrow{Value: js_ast.JoinWithComma(comma.Left, p.mangleIfExpr(comma.Right.Loc, &js_ast.EIf{Test: comma.Right, Yes: left, No: right}))}
					} else {
						// "if (a) return b; return c;" => "return a ? b : c;"
						lastThrow = &js_ast.SThrow{Value: p.mangleIfExpr(prevS.Test.Loc, &js_ast.EIf{Test: prevS.Test, Yes: left, No: right})}
					}
					lastStmt = js_ast.Stmt{Loc: prevStmt.Loc, Data: lastThrow}
					result[prevIndex] = lastStmt
					result = result[:len(result)-1]

				default:
					break throwLoop
				}
			}
		}
	}

	return result
}

func (p *parser) visitLoopBody(stmt js_ast.Stmt) js_ast.Stmt {
	oldIsInsideLoop := p.fnOrArrowDataVisit.isInsideLoop
	p.fnOrArrowDataVisit.isInsideLoop = true
	stmt = p.visitSingleStmt(stmt)
	p.fnOrArrowDataVisit.isInsideLoop = oldIsInsideLoop
	return stmt
}

func (p *parser) visitSingleStmt(stmt js_ast.Stmt) js_ast.Stmt {
	// Introduce a fake block scope for function declarations inside if statements
	fn, ok := stmt.Data.(*js_ast.SFunction)
	hasIfScope := ok && fn.Fn.HasIfScope
	if hasIfScope {
		p.pushScopeForVisitPass(js_ast.ScopeBlock, stmt.Loc)
	}

	stmts := p.visitStmts([]js_ast.Stmt{stmt})

	// Balance the fake block scope introduced above
	if hasIfScope {
		p.popScope()
	}

	// This statement could potentially expand to several statements
	switch len(stmts) {
	case 0:
		return js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SEmpty{}}
	case 1:
		return stmts[0]
	default:
		return js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SBlock{Stmts: stmts}}
	}
}

func (p *parser) visitForLoopInit(stmt js_ast.Stmt, isInOrOf bool) js_ast.Stmt {
	switch s := stmt.Data.(type) {
	case *js_ast.SExpr:
		assignTarget := js_ast.AssignTargetNone
		if isInOrOf {
			assignTarget = js_ast.AssignTargetReplace
		}
		s.Value, _ = p.visitExprInOut(s.Value, exprIn{assignTarget: assignTarget})

	case *js_ast.SLocal:
		for _, d := range s.Decls {
			p.visitBinding(d.Binding)
			if d.Value != nil {
				*d.Value = p.visitExpr(*d.Value)
			}
		}
		s.Decls = p.lowerObjectRestInDecls(s.Decls)
		s.Kind = p.selectLocalKind(s.Kind)

	default:
		panic("Internal error")
	}

	return stmt
}

func (p *parser) recordDeclaredSymbol(ref js_ast.Ref) {
	p.declaredSymbols = append(p.declaredSymbols, js_ast.DeclaredSymbol{
		Ref:        ref,
		IsTopLevel: p.currentScope == p.moduleScope,
	})
}

func (p *parser) visitBinding(binding js_ast.Binding) {
	switch b := binding.Data.(type) {
	case *js_ast.BMissing:

	case *js_ast.BIdentifier:
		p.recordDeclaredSymbol(b.Ref)

	case *js_ast.BArray:
		for _, item := range b.Items {
			p.visitBinding(item.Binding)
			if item.DefaultValue != nil {
				wasAnonymousNamedExpr := p.isAnonymousNamedExpr(*item.DefaultValue)
				*item.DefaultValue = p.visitExpr(*item.DefaultValue)

				// Optionally preserve the name
				if id, ok := item.Binding.Data.(*js_ast.BIdentifier); ok {
					*item.DefaultValue = p.maybeKeepExprSymbolName(
						*item.DefaultValue, p.symbols[id.Ref.InnerIndex].OriginalName, wasAnonymousNamedExpr)
				}
			}
		}

	case *js_ast.BObject:
		for i, property := range b.Properties {
			if !property.IsSpread {
				property.Key = p.visitExpr(property.Key)
			}
			p.visitBinding(property.Value)
			if property.DefaultValue != nil {
				wasAnonymousNamedExpr := p.isAnonymousNamedExpr(*property.DefaultValue)
				*property.DefaultValue = p.visitExpr(*property.DefaultValue)

				// Optionally preserve the name
				if id, ok := property.Value.Data.(*js_ast.BIdentifier); ok {
					*property.DefaultValue = p.maybeKeepExprSymbolName(
						*property.DefaultValue, p.symbols[id.Ref.InnerIndex].OriginalName, wasAnonymousNamedExpr)
				}
			}
			b.Properties[i] = property
		}

	default:
		panic("Internal error")
	}
}

func statementCaresAboutScope(stmt js_ast.Stmt) bool {
	switch s := stmt.Data.(type) {
	case *js_ast.SBlock, *js_ast.SEmpty, *js_ast.SDebugger, *js_ast.SExpr, *js_ast.SIf,
		*js_ast.SFor, *js_ast.SForIn, *js_ast.SForOf, *js_ast.SDoWhile, *js_ast.SWhile,
		*js_ast.SWith, *js_ast.STry, *js_ast.SSwitch, *js_ast.SReturn, *js_ast.SThrow,
		*js_ast.SBreak, *js_ast.SContinue, *js_ast.SDirective:
		return false

	case *js_ast.SLocal:
		return s.Kind != js_ast.LocalVar

	default:
		return true
	}
}

func dropFirstStatement(body js_ast.Stmt, replace *js_ast.Stmt) js_ast.Stmt {
	if block, ok := body.Data.(*js_ast.SBlock); ok && len(block.Stmts) > 0 {
		if replace != nil {
			block.Stmts[0] = *replace
		} else if len(block.Stmts) == 2 && !statementCaresAboutScope(block.Stmts[1]) {
			return block.Stmts[1]
		} else {
			block.Stmts = block.Stmts[1:]
		}
		return body
	}
	if replace != nil {
		return *replace
	}
	return js_ast.Stmt{Loc: body.Loc, Data: &js_ast.SEmpty{}}
}

func mangleFor(s *js_ast.SFor) {
	// Get the first statement in the loop
	first := s.Body
	if block, ok := first.Data.(*js_ast.SBlock); ok && len(block.Stmts) > 0 {
		first = block.Stmts[0]
	}

	if ifS, ok := first.Data.(*js_ast.SIf); ok {
		// "for (;;) if (x) break;" => "for (; !x;) ;"
		// "for (; a;) if (x) break;" => "for (; a && !x;) ;"
		// "for (;;) if (x) break; else y();" => "for (; !x;) y();"
		// "for (; a;) if (x) break; else y();" => "for (; a && !x;) y();"
		if breakS, ok := ifS.Yes.Data.(*js_ast.SBreak); ok && breakS.Label == nil {
			var not js_ast.Expr
			if unary, ok := ifS.Test.Data.(*js_ast.EUnary); ok && unary.Op == js_ast.UnOpNot {
				not = unary.Value
			} else {
				not = js_ast.Not(ifS.Test)
			}
			if s.Test != nil {
				s.Test = &js_ast.Expr{Loc: s.Test.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLogicalAnd, Left: *s.Test, Right: not}}
			} else {
				s.Test = &not
			}
			s.Body = dropFirstStatement(s.Body, ifS.No)
			return
		}

		// "for (;;) if (x) y(); else break;" => "for (; x;) y();"
		// "for (; a;) if (x) y(); else break;" => "for (; a && x;) y();"
		if ifS.No != nil {
			if breakS, ok := ifS.No.Data.(*js_ast.SBreak); ok && breakS.Label == nil {
				if s.Test != nil {
					s.Test = &js_ast.Expr{Loc: s.Test.Loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLogicalAnd, Left: *s.Test, Right: ifS.Test}}
				} else {
					s.Test = &ifS.Test
				}
				s.Body = dropFirstStatement(s.Body, &ifS.Yes)
				return
			}
		}
	}
}

func appendIfBodyPreservingScope(stmts []js_ast.Stmt, body js_ast.Stmt) []js_ast.Stmt {
	if block, ok := body.Data.(*js_ast.SBlock); ok {
		keepBlock := false
		for _, stmt := range block.Stmts {
			if statementCaresAboutScope(stmt) {
				keepBlock = true
				break
			}
		}
		if !keepBlock {
			return append(stmts, block.Stmts...)
		}
	}

	if statementCaresAboutScope(body) {
		return append(stmts, js_ast.Stmt{Loc: body.Loc, Data: &js_ast.SBlock{Stmts: []js_ast.Stmt{body}}})
	}

	return append(stmts, body)
}

func (p *parser) mangleIf(stmts []js_ast.Stmt, loc logger.Loc, s *js_ast.SIf, isTestBooleanConstant bool, testBooleanValue bool) []js_ast.Stmt {
	// Constant folding using the test expression
	if isTestBooleanConstant {
		if testBooleanValue {
			// The test is true
			if s.No == nil || !shouldKeepStmtInDeadControlFlow(*s.No) {
				// We can drop the "no" branch
				return appendIfBodyPreservingScope(stmts, s.Yes)
			} else {
				// We have to keep the "no" branch
			}
		} else {
			// The test is false
			if !shouldKeepStmtInDeadControlFlow(s.Yes) {
				// We can drop the "yes" branch
				if s.No == nil {
					return stmts
				}
				return appendIfBodyPreservingScope(stmts, *s.No)
			} else {
				// We have to keep the "yes" branch
			}
		}
	}

	if yes, ok := s.Yes.Data.(*js_ast.SExpr); ok {
		// "yes" is an expression
		if s.No == nil {
			if not, ok := s.Test.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot {
				// "if (!a) b();" => "a || b();"
				return append(stmts, js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
					Op:    js_ast.BinOpLogicalOr,
					Left:  not.Value,
					Right: yes.Value,
				}}}})
			} else {
				// "if (a) b();" => "a && b();"
				return append(stmts, js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
					Op:    js_ast.BinOpLogicalAnd,
					Left:  s.Test,
					Right: yes.Value,
				}}}})
			}
		} else if no, ok := s.No.Data.(*js_ast.SExpr); ok {
			// "if (a) b(); else c();" => "a ? b() : c();"
			return append(stmts, js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: p.mangleIfExpr(loc, &js_ast.EIf{
				Test: s.Test,
				Yes:  yes.Value,
				No:   no.Value,
			})}})
		}
	} else if _, ok := s.Yes.Data.(*js_ast.SEmpty); ok {
		// "yes" is missing
		if s.No == nil {
			// "yes" and "no" are both missing
			if p.exprCanBeRemovedIfUnused(s.Test) {
				// "if (1) {}" => ""
				return stmts
			} else {
				// "if (a) {}" => "a;"
				return append(stmts, js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: s.Test}})
			}
		} else if no, ok := s.No.Data.(*js_ast.SExpr); ok {
			if not, ok := s.Test.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot {
				// "if (!a) {} else b();" => "a && b();"
				return append(stmts, js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
					Op:    js_ast.BinOpLogicalAnd,
					Left:  not.Value,
					Right: no.Value,
				}}}})
			} else {
				// "if (a) {} else b();" => "a || b();"
				return append(stmts, js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{Value: js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
					Op:    js_ast.BinOpLogicalOr,
					Left:  s.Test,
					Right: no.Value,
				}}}})
			}
		} else {
			// "yes" is missing and "no" is not missing (and is not an expression)
			if not, ok := s.Test.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot {
				// "if (!a) {} else throw b;" => "if (a) throw b;"
				s.Test = not.Value
				s.Yes = *s.No
				s.No = nil
			} else {
				// "if (a) {} else throw b;" => "if (!a) throw b;"
				s.Test = js_ast.Expr{Loc: s.Test.Loc, Data: &js_ast.EUnary{Op: js_ast.UnOpNot, Value: s.Test}}
				s.Yes = *s.No
				s.No = nil
			}
		}
	} else {
		// "yes" is not missing (and is not an expression)
		if s.No != nil {
			// "yes" is not missing (and is not an expression) and "no" is not missing
			if not, ok := s.Test.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot {
				// "if (!a) return b; else return c;" => "if (a) return c; else return b;"
				s.Test = not.Value
				s.Yes, *s.No = *s.No, s.Yes
			}
		} else {
			// "no" is missing
			if s2, ok := s.Yes.Data.(*js_ast.SIf); ok && s2.No == nil {
				// "if (a) if (b) return c;" => "if (a && b) return c;"
				s.Test.Data = &js_ast.EBinary{
					Op:    js_ast.BinOpLogicalAnd,
					Left:  s.Test,
					Right: s2.Test,
				}
				s.Yes = s2.Yes
			}
		}
	}

	return append(stmts, js_ast.Stmt{Loc: loc, Data: s})
}

func (p *parser) mangleIfExpr(loc logger.Loc, e *js_ast.EIf) js_ast.Expr {
	// "!a ? b : c" => "a ? c : b"
	if not, ok := e.Test.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot {
		e.Test = not.Value
		e.Yes, e.No = e.No, e.Yes
	}

	if valuesLookTheSame(e.Yes.Data, e.No.Data) {
		// "/* @__PURE__ */ a() ? b : b" => "b"
		if p.exprCanBeRemovedIfUnused(e.Test) {
			return e.Yes
		}

		// "a ? b : b" => "a, b"
		return js_ast.JoinWithComma(e.Test, e.Yes)
	}

	// "a ? true : false" => "!!a"
	// "a ? false : true" => "!a"
	if yes, ok := e.Yes.Data.(*js_ast.EBoolean); ok {
		if no, ok := e.No.Data.(*js_ast.EBoolean); ok {
			if yes.Value && !no.Value {
				return js_ast.Not(js_ast.Not(e.Test))
			}
			if !yes.Value && no.Value {
				return js_ast.Not(e.Test)
			}
		}
	}

	if id, ok := e.Test.Data.(*js_ast.EIdentifier); ok {
		// "a ? a : b" => "a || b"
		if id2, ok := e.Yes.Data.(*js_ast.EIdentifier); ok && id.Ref == id2.Ref {
			return js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLogicalOr, Left: e.Test, Right: e.No}}
		}

		// "a ? b : a" => "a && b"
		if id2, ok := e.No.Data.(*js_ast.EIdentifier); ok && id.Ref == id2.Ref {
			return js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{Op: js_ast.BinOpLogicalAnd, Left: e.Test, Right: e.Yes}}
		}
	}

	// "a ? b ? c : d : d" => "a && b ? c : d"
	if yesIf, ok := e.Yes.Data.(*js_ast.EIf); ok && valuesLookTheSame(yesIf.No.Data, e.No.Data) {
		e.Test.Data = &js_ast.EBinary{Op: js_ast.BinOpLogicalAnd, Left: e.Test, Right: yesIf.Test}
		e.Yes = yesIf.Yes
		return js_ast.Expr{Loc: loc, Data: e}
	}

	// "a ? b : c ? b : d" => "a || c ? b : d"
	if noIf, ok := e.No.Data.(*js_ast.EIf); ok && valuesLookTheSame(e.Yes.Data, noIf.Yes.Data) {
		e.Test.Data = &js_ast.EBinary{Op: js_ast.BinOpLogicalOr, Left: e.Test, Right: noIf.Test}
		e.No = noIf.No
		return js_ast.Expr{Loc: loc, Data: e}
	}

	// "a ? c : (b, c)" => "(a || b), c"
	if comma, ok := e.No.Data.(*js_ast.EBinary); ok && comma.Op == js_ast.BinOpComma && valuesLookTheSame(e.Yes.Data, comma.Right.Data) {
		return js_ast.JoinWithComma(js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
			Op:    js_ast.BinOpLogicalOr,
			Left:  e.Test,
			Right: comma.Left,
		}}, comma.Right)
	}

	// "a ? (b, c) : c" => "(a && b), c"
	if comma, ok := e.Yes.Data.(*js_ast.EBinary); ok && comma.Op == js_ast.BinOpComma && valuesLookTheSame(comma.Right.Data, e.No.Data) {
		return js_ast.JoinWithComma(js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
			Op:    js_ast.BinOpLogicalAnd,
			Left:  e.Test,
			Right: comma.Left,
		}}, comma.Right)
	}

	// "a ? b || c : c" => "(a && b) || c"
	if binary, ok := e.Yes.Data.(*js_ast.EBinary); ok && binary.Op == js_ast.BinOpLogicalOr &&
		valuesLookTheSame(binary.Right.Data, e.No.Data) {
		return js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
			Op: js_ast.BinOpLogicalOr,
			Left: js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
				Op:    js_ast.BinOpLogicalAnd,
				Left:  e.Test,
				Right: binary.Left,
			}},
			Right: binary.Right,
		}}
	}

	// "a ? c : b && c" => "(a || b) && c"
	if binary, ok := e.No.Data.(*js_ast.EBinary); ok && binary.Op == js_ast.BinOpLogicalAnd &&
		valuesLookTheSame(e.Yes.Data, binary.Right.Data) {
		return js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
			Op: js_ast.BinOpLogicalAnd,
			Left: js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
				Op:    js_ast.BinOpLogicalOr,
				Left:  e.Test,
				Right: binary.Left,
			}},
			Right: binary.Right,
		}}
	}

	// "a ? b(c, d) : b(e, d)" => "b(a ? c : e, d)"
	if y, ok := e.Yes.Data.(*js_ast.ECall); ok && len(y.Args) > 0 {
		if n, ok := e.No.Data.(*js_ast.ECall); ok && len(n.Args) == len(y.Args) &&
			y.HasSameFlagsAs(n) && valuesLookTheSame(y.Target.Data, n.Target.Data) {
			// Only do this if the condition can be reordered past the call target
			// without side effects. For example, if the test or the call target is
			// an unbound identifier, reordering could potentially mean evaluating
			// the code could throw a different ReferenceError.
			if p.exprCanBeRemovedIfUnused(e.Test) && p.exprCanBeRemovedIfUnused(y.Target) {
				sameTailArgs := true
				for i, count := 1, len(y.Args); i < count; i++ {
					if !valuesLookTheSame(y.Args[i].Data, n.Args[i].Data) {
						sameTailArgs = false
						break
					}
				}
				if sameTailArgs {
					yesSpread, yesIsSpread := y.Args[0].Data.(*js_ast.ESpread)
					noSpread, noIsSpread := n.Args[0].Data.(*js_ast.ESpread)

					// "a ? b(...c) : b(...e)" => "b(...a ? c : e)"
					if yesIsSpread && noIsSpread {
						e.Yes = yesSpread.Value
						e.No = noSpread.Value
						y.Args[0] = js_ast.Expr{Loc: loc, Data: &js_ast.ESpread{Value: p.mangleIfExpr(loc, e)}}
						return js_ast.Expr{Loc: loc, Data: y}
					}

					// "a ? b(c) : b(e)" => "b(a ? c : e)"
					if !yesIsSpread && !noIsSpread {
						e.Yes = y.Args[0]
						e.No = n.Args[0]
						y.Args[0] = p.mangleIfExpr(loc, e)
						return js_ast.Expr{Loc: loc, Data: y}
					}
				}
			}
		}
	}

	// Try using the "??" operator, but only if it's supported
	if !p.options.unsupportedJSFeatures.Has(compat.NullishCoalescing) {
		if binary, ok := e.Test.Data.(*js_ast.EBinary); ok {
			switch binary.Op {
			case js_ast.BinOpLooseEq:
				// "a == null ? b : a" => "a ?? b"
				if _, ok := binary.Right.Data.(*js_ast.ENull); ok && p.exprCanBeRemovedIfUnused(binary.Left) && valuesLookTheSame(binary.Left.Data, e.No.Data) {
					binary.Op = js_ast.BinOpNullishCoalescing
					binary.Right = e.Yes
					return js_ast.Expr{Loc: loc, Data: binary}
				}

				// "null == a ? b : a" => "a ?? b"
				if _, ok := binary.Left.Data.(*js_ast.ENull); ok && p.exprCanBeRemovedIfUnused(binary.Right) && valuesLookTheSame(binary.Right.Data, e.No.Data) {
					binary.Op = js_ast.BinOpNullishCoalescing
					binary.Left = binary.Right
					binary.Right = e.Yes
					return js_ast.Expr{Loc: loc, Data: binary}
				}

			case js_ast.BinOpLooseNe:
				// "a != null ? a : b" => "a ?? b"
				if _, ok := binary.Right.Data.(*js_ast.ENull); ok && p.exprCanBeRemovedIfUnused(binary.Left) && valuesLookTheSame(binary.Left.Data, e.Yes.Data) {
					binary.Op = js_ast.BinOpNullishCoalescing
					binary.Right = e.No
					return js_ast.Expr{Loc: loc, Data: binary}
				}

				// "null != a ? a : b" => "a ?? b"
				if _, ok := binary.Left.Data.(*js_ast.ENull); ok && p.exprCanBeRemovedIfUnused(binary.Right) && valuesLookTheSame(binary.Right.Data, e.Yes.Data) {
					binary.Op = js_ast.BinOpNullishCoalescing
					binary.Left = binary.Right
					binary.Right = e.No
					return js_ast.Expr{Loc: loc, Data: binary}
				}
			}
		}
	}

	return js_ast.Expr{Loc: loc, Data: e}
}

func (p *parser) isAnonymousNamedExpr(expr js_ast.Expr) bool {
	switch e := expr.Data.(type) {
	case *js_ast.EArrow:
		return true
	case *js_ast.EFunction:
		return e.Fn.Name == nil
	case *js_ast.EClass:
		return e.Class.Name == nil
	}
	return false
}

func (p *parser) maybeKeepExprSymbolName(value js_ast.Expr, name string, wasAnonymousNamedExpr bool) js_ast.Expr {
	if p.options.keepNames && wasAnonymousNamedExpr {
		return p.keepExprSymbolName(value, name)
	}
	return value
}

func (p *parser) keepExprSymbolName(value js_ast.Expr, name string) js_ast.Expr {
	value = p.callRuntime(value.Loc, "__name", []js_ast.Expr{value,
		{Loc: value.Loc, Data: &js_ast.EString{Value: js_lexer.StringToUTF16(name)}},
	})

	// Make sure tree shaking removes this if the function is never used
	value.Data.(*js_ast.ECall).CanBeUnwrappedIfUnused = true
	return value
}

func (p *parser) keepStmtSymbolName(loc logger.Loc, ref js_ast.Ref, name string) js_ast.Stmt {
	return js_ast.Stmt{Loc: loc, Data: &js_ast.SExpr{
		Value: p.callRuntime(loc, "__name", []js_ast.Expr{
			{Loc: loc, Data: &js_ast.EIdentifier{Ref: ref}},
			{Loc: loc, Data: &js_ast.EString{Value: js_lexer.StringToUTF16(name)}},
		}),

		// Make sure tree shaking removes this if the function is never used
		DoesNotAffectTreeShaking: true,
	}}
}

func (p *parser) visitAndAppendStmt(stmts []js_ast.Stmt, stmt js_ast.Stmt) []js_ast.Stmt {
	switch s := stmt.Data.(type) {
	case *js_ast.SDebugger, *js_ast.SEmpty, *js_ast.SDirective, *js_ast.SComment:
		// These don't contain anything to traverse

	case *js_ast.STypeScript:
		// Erase TypeScript constructs from the output completely
		return stmts

	case *js_ast.SImport:
		p.recordDeclaredSymbol(s.NamespaceRef)

		if s.DefaultName != nil {
			p.recordDeclaredSymbol(s.DefaultName.Ref)
		}

		if s.Items != nil {
			for _, item := range *s.Items {
				p.recordDeclaredSymbol(item.Name.Ref)
			}
		}

	case *js_ast.SExportClause:
		// "export {foo}"
		end := 0
		for _, item := range s.Items {
			name := p.loadNameFromRef(item.Name.Ref)
			ref := p.findSymbol(item.AliasLoc, name).ref

			if p.symbols[ref.InnerIndex].Kind == js_ast.SymbolUnbound {
				// Silently strip exports of non-local symbols in TypeScript, since
				// those likely correspond to type-only exports. But report exports of
				// non-local symbols as errors in JavaScript.
				if !p.options.ts.Parse {
					r := js_lexer.RangeOfIdentifier(p.source, item.Name.Loc)
					p.log.AddRangeError(&p.source, r, fmt.Sprintf("%q is not declared in this file", name))
				}
				continue
			}

			item.Name.Ref = ref
			s.Items[end] = item
			end++
		}
		if end == 0 {
			// Remove empty export statements entirely
			return stmts
		}
		s.Items = s.Items[:end]

	case *js_ast.SExportFrom:
		// "export {foo} from 'path'"
		name := p.loadNameFromRef(s.NamespaceRef)
		s.NamespaceRef = p.newSymbol(js_ast.SymbolOther, name)
		p.currentScope.Generated = append(p.currentScope.Generated, s.NamespaceRef)
		p.recordDeclaredSymbol(s.NamespaceRef)

		// This is a re-export and the symbols created here are used to reference
		// names in another file. This means the symbols are really aliases.
		for i, item := range s.Items {
			name := p.loadNameFromRef(item.Name.Ref)
			ref := p.newSymbol(js_ast.SymbolOther, name)
			p.currentScope.Generated = append(p.currentScope.Generated, ref)
			p.recordDeclaredSymbol(ref)
			s.Items[i].Name.Ref = ref
		}

	case *js_ast.SExportStar:
		// "export * from 'path'"
		// "export * as ns from 'path'"
		name := p.loadNameFromRef(s.NamespaceRef)
		s.NamespaceRef = p.newSymbol(js_ast.SymbolOther, name)
		p.currentScope.Generated = append(p.currentScope.Generated, s.NamespaceRef)
		p.recordDeclaredSymbol(s.NamespaceRef)

		// "export * as ns from 'path'"
		if s.Alias != nil {
			// "import * as ns from 'path'"
			// "export {ns}"
			if p.options.unsupportedJSFeatures.Has(compat.ExportStarAs) {
				p.recordUsage(s.NamespaceRef)
				return append(stmts,
					js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SImport{
						NamespaceRef:      s.NamespaceRef,
						StarNameLoc:       &s.Alias.Loc,
						ImportRecordIndex: s.ImportRecordIndex,
					}},
					js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SExportClause{
						Items: []js_ast.ClauseItem{{
							Alias:        s.Alias.OriginalName,
							OriginalName: s.Alias.OriginalName,
							AliasLoc:     s.Alias.Loc,
							Name:         js_ast.LocRef{Loc: s.Alias.Loc, Ref: s.NamespaceRef},
						}},
						IsSingleLine: true,
					}},
				)
			}
		}

	case *js_ast.SExportDefault:
		p.recordDeclaredSymbol(s.DefaultName.Ref)

		switch {
		case s.Value.Expr != nil:
			wasAnonymousNamedExpr := p.isAnonymousNamedExpr(*s.Value.Expr)
			*s.Value.Expr = p.visitExpr(*s.Value.Expr)

			// Optionally preserve the name
			*s.Value.Expr = p.maybeKeepExprSymbolName(*s.Value.Expr, "default", wasAnonymousNamedExpr)

			// Discard type-only export default statements
			if p.options.ts.Parse {
				if id, ok := (*s.Value.Expr).Data.(*js_ast.EIdentifier); ok {
					symbol := p.symbols[id.Ref.InnerIndex]
					if symbol.Kind == js_ast.SymbolUnbound && p.localTypeNames[symbol.OriginalName] {
						return stmts
					}
				}
			}

		case s.Value.Stmt != nil:
			switch s2 := s.Value.Stmt.Data.(type) {
			case *js_ast.SFunction:
				// If we need to preserve the name but there is no name, generate a name
				var name string
				if p.options.keepNames {
					if s2.Fn.Name == nil {
						clone := s.DefaultName
						s2.Fn.Name = &clone
						name = "default"
					} else {
						name = p.symbols[s2.Fn.Name.Ref.InnerIndex].OriginalName
					}
				}

				p.visitFn(&s2.Fn, s2.Fn.OpenParenLoc)
				stmts = append(stmts, stmt)

				// Optionally preserve the name
				if p.options.keepNames && s2.Fn.Name != nil {
					stmts = append(stmts, p.keepStmtSymbolName(s2.Fn.Name.Loc, s2.Fn.Name.Ref, name))
				}

				return stmts

			case *js_ast.SClass:
				shadowRef := p.visitClass(s.Value.Stmt.Loc, &s2.Class)

				// Lower class field syntax for browsers that don't support it
				classStmts, _ := p.lowerClass(stmt, js_ast.Expr{}, shadowRef)
				return append(stmts, classStmts...)

			default:
				panic("Internal error")
			}
		}

	case *js_ast.SExportEquals:
		// "module.exports = value"
		stmts = append(stmts, js_ast.AssignStmt(
			js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EDot{
				Target:  js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: p.moduleRef}},
				Name:    "exports",
				NameLoc: stmt.Loc,
			}},
			p.visitExpr(s.Value),
		))
		p.recordUsage(p.moduleRef)
		return stmts

	case *js_ast.SBreak:
		if s.Label != nil {
			name := p.loadNameFromRef(s.Label.Ref)
			s.Label.Ref, _, _ = p.findLabelSymbol(s.Label.Loc, name)
		} else if !p.fnOrArrowDataVisit.isInsideLoop && !p.fnOrArrowDataVisit.isInsideSwitch {
			r := js_lexer.RangeOfIdentifier(p.source, stmt.Loc)
			p.log.AddRangeError(&p.source, r, "Cannot use \"break\" here")
		}

	case *js_ast.SContinue:
		if s.Label != nil {
			name := p.loadNameFromRef(s.Label.Ref)
			var isLoop, ok bool
			s.Label.Ref, isLoop, ok = p.findLabelSymbol(s.Label.Loc, name)
			if ok && !isLoop {
				r := js_lexer.RangeOfIdentifier(p.source, s.Label.Loc)
				p.log.AddRangeError(&p.source, r, fmt.Sprintf("Cannot continue to label \"%s\"", name))
			}
		} else if !p.fnOrArrowDataVisit.isInsideLoop {
			r := js_lexer.RangeOfIdentifier(p.source, stmt.Loc)
			p.log.AddRangeError(&p.source, r, "Cannot use \"continue\" here")
		}

	case *js_ast.SLabel:
		p.pushScopeForVisitPass(js_ast.ScopeLabel, stmt.Loc)
		name := p.loadNameFromRef(s.Name.Ref)
		ref := p.newSymbol(js_ast.SymbolLabel, name)
		s.Name.Ref = ref
		p.currentScope.LabelRef = ref
		switch s.Stmt.Data.(type) {
		case *js_ast.SFor, *js_ast.SForIn, *js_ast.SForOf, *js_ast.SWhile, *js_ast.SDoWhile:
			p.currentScope.LabelStmtIsLoop = true
		}
		s.Stmt = p.visitSingleStmt(s.Stmt)
		p.popScope()

	case *js_ast.SLocal:
		for i, d := range s.Decls {
			p.visitBinding(d.Binding)
			if d.Value != nil {
				wasAnonymousNamedExpr := p.isAnonymousNamedExpr(*d.Value)
				*d.Value = p.visitExpr(*d.Value)

				// Optionally preserve the name
				if id, ok := d.Binding.Data.(*js_ast.BIdentifier); ok {
					*d.Value = p.maybeKeepExprSymbolName(
						*d.Value, p.symbols[id.Ref.InnerIndex].OriginalName, wasAnonymousNamedExpr)
				}

				// Initializing to undefined is implicit, but be careful to not
				// accidentally cause a syntax error or behavior change by removing
				// the value
				//
				// Good:
				//   "let a = undefined;" => "let a;"
				//
				// Bad (a syntax error):
				//   "let {} = undefined;" => "let {};"
				//
				// Bad (a behavior change):
				//   "a = 123; var a = undefined;" => "a = 123; var a;"
				//
				if p.options.mangleSyntax && s.Kind == js_ast.LocalLet {
					if _, ok := d.Binding.Data.(*js_ast.BIdentifier); ok {
						if _, ok := d.Value.Data.(*js_ast.EUndefined); ok {
							s.Decls[i].Value = nil
						}
					}
				}
			}
		}

		// Handle being exported inside a namespace
		if s.IsExport && p.enclosingNamespaceArgRef != nil {
			wrapIdentifier := func(loc logger.Loc, ref js_ast.Ref) js_ast.Expr {
				p.recordUsage(*p.enclosingNamespaceArgRef)
				return js_ast.Expr{Loc: loc, Data: &js_ast.EDot{
					Target:  js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: *p.enclosingNamespaceArgRef}},
					Name:    p.symbols[ref.InnerIndex].OriginalName,
					NameLoc: loc,
				}}
			}
			for _, decl := range s.Decls {
				if decl.Value != nil {
					target := p.convertBindingToExpr(decl.Binding, wrapIdentifier)
					if result, ok := p.lowerObjectRestInAssign(target, *decl.Value); ok {
						target = result
					} else {
						target = js_ast.Assign(target, *decl.Value)
					}
					stmts = append(stmts, js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SExpr{Value: target}})
				}
			}
			return stmts
		}

		s.Decls = p.lowerObjectRestInDecls(s.Decls)
		s.Kind = p.selectLocalKind(s.Kind)

		// Relocate "var" statements in nested scopes to the top-level scope when
		// bundling. This makes it easy to pick out all top-level declarations by
		// only looking at the array of top-level statements.
		if p.options.mode == config.ModeBundle && s.Kind == js_ast.LocalVar && p.currentScope != p.moduleScope {
			scope := p.currentScope
			for !scope.Kind.StopsHoisting() {
				scope = scope.Parent
			}
			if scope == p.moduleScope {
				wrapIdentifier := func(loc logger.Loc, ref js_ast.Ref) js_ast.Expr {
					p.relocatedTopLevelVars = append(p.relocatedTopLevelVars, js_ast.LocRef{Loc: loc, Ref: ref})
					p.recordUsage(ref)
					return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: ref}}
				}
				var value js_ast.Expr
				for _, decl := range s.Decls {
					binding := p.convertBindingToExpr(decl.Binding, wrapIdentifier)
					if decl.Value != nil {
						value = maybeJoinWithComma(value, js_ast.Assign(binding, *decl.Value))
					}
				}
				if value.Data != nil {
					stmts = append(stmts, js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SExpr{Value: value}})
				}
				return stmts
			}
		}

	case *js_ast.SExpr:
		s.Value = p.visitExpr(s.Value)

		// Trim expressions without side effects
		if p.options.mangleSyntax {
			s.Value = p.simplifyUnusedExpr(s.Value)
			if s.Value.Data == nil {
				stmt = js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SEmpty{}}
			}
		}

	case *js_ast.SThrow:
		s.Value = p.visitExpr(s.Value)

	case *js_ast.SReturn:
		if s.Value != nil {
			*s.Value = p.visitExpr(*s.Value)

			// Returning undefined is implicit
			if p.options.mangleSyntax {
				if _, ok := s.Value.Data.(*js_ast.EUndefined); ok {
					s.Value = nil
				}
			}
		}

	case *js_ast.SBlock:
		p.pushScopeForVisitPass(js_ast.ScopeBlock, stmt.Loc)
		s.Stmts = p.visitStmts(s.Stmts)
		p.popScope()

		if p.options.mangleSyntax {
			if len(s.Stmts) == 1 && !statementCaresAboutScope(s.Stmts[0]) {
				// Unwrap blocks containing a single statement
				stmt = s.Stmts[0]
			} else if len(s.Stmts) == 0 {
				// Trim empty blocks
				stmt = js_ast.Stmt{Loc: stmt.Loc, Data: &js_ast.SEmpty{}}
			}
		}

	case *js_ast.SWith:
		s.Value = p.visitExpr(s.Value)
		p.pushScopeForVisitPass(js_ast.ScopeWith, s.BodyLoc)
		s.Body = p.visitSingleStmt(s.Body)
		p.popScope()

	case *js_ast.SWhile:
		s.Test = p.visitBooleanExpr(s.Test)
		s.Body = p.visitLoopBody(s.Body)

		if p.options.mangleSyntax {
			// "while (a) {}" => "for (;a;) {}"
			test := &s.Test
			if boolean, ok := toBooleanWithoutSideEffects(s.Test.Data); ok && boolean {
				test = nil
			}
			forS := &js_ast.SFor{Test: test, Body: s.Body}
			mangleFor(forS)
			stmt = js_ast.Stmt{Loc: stmt.Loc, Data: forS}
		}

	case *js_ast.SDoWhile:
		s.Body = p.visitLoopBody(s.Body)
		s.Test = p.visitBooleanExpr(s.Test)

	case *js_ast.SIf:
		s.Test = p.visitBooleanExpr(s.Test)

		// Fold constants
		boolean, ok := toBooleanWithoutSideEffects(s.Test.Data)

		// Mark the control flow as dead if the branch is never taken
		if ok && !boolean {
			old := p.isControlFlowDead
			p.isControlFlowDead = true
			s.Yes = p.visitSingleStmt(s.Yes)
			p.isControlFlowDead = old
		} else {
			s.Yes = p.visitSingleStmt(s.Yes)
		}

		// The "else" clause is optional
		if s.No != nil {
			// Mark the control flow as dead if the branch is never taken
			if ok && boolean {
				old := p.isControlFlowDead
				p.isControlFlowDead = true
				*s.No = p.visitSingleStmt(*s.No)
				p.isControlFlowDead = old
			} else {
				*s.No = p.visitSingleStmt(*s.No)
			}

			// Trim unnecessary "else" clauses
			if p.options.mangleSyntax {
				if _, ok := s.No.Data.(*js_ast.SEmpty); ok {
					s.No = nil
				}
			}
		}

		if p.options.mangleSyntax {
			return p.mangleIf(stmts, stmt.Loc, s, ok, boolean)
		}

	case *js_ast.SFor:
		p.pushScopeForVisitPass(js_ast.ScopeBlock, stmt.Loc)
		if s.Init != nil {
			p.visitForLoopInit(*s.Init, false)
		}

		if s.Test != nil {
			*s.Test = p.visitBooleanExpr(*s.Test)

			// A true value is implied
			if p.options.mangleSyntax {
				if boolean, ok := toBooleanWithoutSideEffects(s.Test.Data); ok && boolean {
					s.Test = nil
				}
			}
		}

		if s.Update != nil {
			*s.Update = p.visitExpr(*s.Update)
		}
		s.Body = p.visitLoopBody(s.Body)
		p.popScope()

		if p.options.mangleSyntax {
			mangleFor(s)
		}

	case *js_ast.SForIn:
		p.pushScopeForVisitPass(js_ast.ScopeBlock, stmt.Loc)
		p.visitForLoopInit(s.Init, true)
		s.Value = p.visitExpr(s.Value)
		s.Body = p.visitLoopBody(s.Body)
		p.popScope()
		p.lowerObjectRestInForLoopInit(s.Init, &s.Body)

	case *js_ast.SForOf:
		p.pushScopeForVisitPass(js_ast.ScopeBlock, stmt.Loc)
		p.visitForLoopInit(s.Init, true)
		s.Value = p.visitExpr(s.Value)
		s.Body = p.visitLoopBody(s.Body)
		p.popScope()
		p.lowerObjectRestInForLoopInit(s.Init, &s.Body)

	case *js_ast.STry:
		p.pushScopeForVisitPass(js_ast.ScopeBlock, stmt.Loc)
		p.fnOrArrowDataVisit.tryBodyCount++
		s.Body = p.visitStmts(s.Body)
		p.fnOrArrowDataVisit.tryBodyCount--
		p.popScope()

		if s.Catch != nil {
			p.pushScopeForVisitPass(js_ast.ScopeBlock, s.Catch.Loc)
			if s.Catch.Binding != nil {
				p.visitBinding(*s.Catch.Binding)
			}
			s.Catch.Body = p.visitStmts(s.Catch.Body)
			p.lowerObjectRestInCatchBinding(s.Catch)
			p.popScope()
		}

		if s.Finally != nil {
			p.pushScopeForVisitPass(js_ast.ScopeBlock, s.Finally.Loc)
			s.Finally.Stmts = p.visitStmts(s.Finally.Stmts)
			p.popScope()
		}

	case *js_ast.SSwitch:
		s.Test = p.visitExpr(s.Test)
		p.pushScopeForVisitPass(js_ast.ScopeBlock, s.BodyLoc)
		oldIsInsideSwitch := p.fnOrArrowDataVisit.isInsideSwitch
		p.fnOrArrowDataVisit.isInsideSwitch = true
		for i, c := range s.Cases {
			if c.Value != nil {
				*c.Value = p.visitExpr(*c.Value)
				p.warnAboutEqualityCheck("case", *c.Value, c.Value.Loc)
				p.checkForTypeofAndString(s.Test, *c.Value)
			}
			c.Body = p.visitStmts(c.Body)

			// Make sure the assignment to the body above is preserved
			s.Cases[i] = c
		}
		p.fnOrArrowDataVisit.isInsideSwitch = oldIsInsideSwitch
		p.popScope()

		// Check for duplicate case values
		p.duplicateCaseChecker.reset()
		for _, c := range s.Cases {
			if c.Value != nil {
				p.duplicateCaseChecker.check(p, *c.Value)
			}
		}

	case *js_ast.SFunction:
		p.visitFn(&s.Fn, s.Fn.OpenParenLoc)

		// Handle exporting this function from a namespace
		if s.IsExport && p.enclosingNamespaceArgRef != nil {
			s.IsExport = false
			stmts = append(stmts, stmt, js_ast.AssignStmt(
				js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EDot{
					Target:  js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: *p.enclosingNamespaceArgRef}},
					Name:    p.symbols[s.Fn.Name.Ref.InnerIndex].OriginalName,
					NameLoc: s.Fn.Name.Loc,
				}},
				js_ast.Expr{Loc: s.Fn.Name.Loc, Data: &js_ast.EIdentifier{Ref: s.Fn.Name.Ref}},
			))
		} else {
			stmts = append(stmts, stmt)
		}

		// Optionally preserve the name
		if p.options.keepNames {
			stmts = append(stmts, p.keepStmtSymbolName(s.Fn.Name.Loc, s.Fn.Name.Ref, p.symbols[s.Fn.Name.Ref.InnerIndex].OriginalName))
		}
		return stmts

	case *js_ast.SClass:
		shadowRef := p.visitClass(stmt.Loc, &s.Class)

		// Remove the export flag inside a namespace
		wasExportInsideNamespace := s.IsExport && p.enclosingNamespaceArgRef != nil
		if wasExportInsideNamespace {
			s.IsExport = false
		}

		// Lower class field syntax for browsers that don't support it
		classStmts, _ := p.lowerClass(stmt, js_ast.Expr{}, shadowRef)
		stmts = append(stmts, classStmts...)

		// Handle exporting this class from a namespace
		if wasExportInsideNamespace {
			stmts = append(stmts, js_ast.AssignStmt(
				js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EDot{
					Target:  js_ast.Expr{Loc: stmt.Loc, Data: &js_ast.EIdentifier{Ref: *p.enclosingNamespaceArgRef}},
					Name:    p.symbols[s.Class.Name.Ref.InnerIndex].OriginalName,
					NameLoc: s.Class.Name.Loc,
				}},
				js_ast.Expr{Loc: s.Class.Name.Loc, Data: &js_ast.EIdentifier{Ref: s.Class.Name.Ref}},
			))
		}

		return stmts

	case *js_ast.SEnum:
		p.recordDeclaredSymbol(s.Name.Ref)
		p.pushScopeForVisitPass(js_ast.ScopeEntry, stmt.Loc)
		defer p.popScope()
		p.recordDeclaredSymbol(s.Arg)

		// Scan ahead for any variables inside this namespace. This must be done
		// ahead of time before visiting any statements inside the namespace
		// because we may end up visiting the uses before the declarations.
		// We need to convert the uses into property accesses on the namespace.
		for _, value := range s.Values {
			if value.Ref != js_ast.InvalidRef {
				p.isExportedInsideNamespace[value.Ref] = s.Arg
			}
		}

		// Values without initializers are initialized to one more than the
		// previous value if the previous value is numeric. Otherwise values
		// without initializers are initialized to undefined.
		nextNumericValue := float64(0)
		hasNumericValue := true
		valueExprs := []js_ast.Expr{}

		// Track values so they can be used by constant folding. We need to follow
		// links here in case the enum was merged with a preceding namespace.
		valuesSoFar := make(map[string]float64)
		p.knownEnumValues[s.Name.Ref] = valuesSoFar
		p.knownEnumValues[s.Arg] = valuesSoFar

		// We normally don't fold numeric constants because they might increase code
		// size, but it's important to fold numeric constants inside enums since
		// that's what the TypeScript compiler does.
		oldShouldFoldNumericConstants := p.shouldFoldNumericConstants
		p.shouldFoldNumericConstants = true

		// Create an assignment for each enum value
		for _, value := range s.Values {
			name := js_lexer.UTF16ToString(value.Name)
			var assignTarget js_ast.Expr
			hasStringValue := false

			if value.Value != nil {
				*value.Value = p.visitExpr(*value.Value)
				hasNumericValue = false
				switch e := value.Value.Data.(type) {
				case *js_ast.ENumber:
					valuesSoFar[name] = e.Value
					hasNumericValue = true
					nextNumericValue = e.Value + 1
				case *js_ast.EString:
					hasStringValue = true
				}
			} else if hasNumericValue {
				valuesSoFar[name] = nextNumericValue
				value.Value = &js_ast.Expr{Loc: value.Loc, Data: &js_ast.ENumber{Value: nextNumericValue}}
				nextNumericValue++
			} else {
				value.Value = &js_ast.Expr{Loc: value.Loc, Data: &js_ast.EUndefined{}}
			}

			if p.options.mangleSyntax && js_lexer.IsIdentifier(name) {
				// "Enum.Name = value"
				assignTarget = js_ast.Assign(
					js_ast.Expr{Loc: value.Loc, Data: &js_ast.EDot{
						Target:  js_ast.Expr{Loc: value.Loc, Data: &js_ast.EIdentifier{Ref: s.Arg}},
						Name:    name,
						NameLoc: value.Loc,
					}},
					*value.Value,
				)
			} else {
				// "Enum['Name'] = value"
				assignTarget = js_ast.Assign(
					js_ast.Expr{Loc: value.Loc, Data: &js_ast.EIndex{
						Target: js_ast.Expr{Loc: value.Loc, Data: &js_ast.EIdentifier{Ref: s.Arg}},
						Index:  js_ast.Expr{Loc: value.Loc, Data: &js_ast.EString{Value: value.Name}},
					}},
					*value.Value,
				)
			}
			p.recordUsage(s.Arg)

			// String-valued enums do not form a two-way map
			if hasStringValue {
				valueExprs = append(valueExprs, assignTarget)
			} else {
				// "Enum[assignTarget] = 'Name'"
				valueExprs = append(valueExprs, js_ast.Assign(
					js_ast.Expr{Loc: value.Loc, Data: &js_ast.EIndex{
						Target: js_ast.Expr{Loc: value.Loc, Data: &js_ast.EIdentifier{Ref: s.Arg}},
						Index:  assignTarget,
					}},
					js_ast.Expr{Loc: value.Loc, Data: &js_ast.EString{Value: value.Name}},
				))
			}
			p.recordUsage(s.Arg)
		}

		p.shouldFoldNumericConstants = oldShouldFoldNumericConstants

		// Generate statements from expressions
		valueStmts := []js_ast.Stmt{}
		if len(valueExprs) > 0 {
			if p.options.mangleSyntax {
				// "a; b; c;" => "a, b, c;"
				joined := js_ast.JoinAllWithComma(valueExprs)
				valueStmts = append(valueStmts, js_ast.Stmt{Loc: joined.Loc, Data: &js_ast.SExpr{Value: joined}})
			} else {
				for _, expr := range valueExprs {
					valueStmts = append(valueStmts, js_ast.Stmt{Loc: expr.Loc, Data: &js_ast.SExpr{Value: expr}})
				}
			}
		}

		// Wrap this enum definition in a closure
		stmts = p.generateClosureForTypeScriptNamespaceOrEnum(
			stmts, stmt.Loc, s.IsExport, s.Name.Loc, s.Name.Ref, s.Arg, valueStmts)
		return stmts

	case *js_ast.SNamespace:
		p.recordDeclaredSymbol(s.Name.Ref)

		// Scan ahead for any variables inside this namespace. This must be done
		// ahead of time before visiting any statements inside the namespace
		// because we may end up visiting the uses before the declarations.
		// We need to convert the uses into property accesses on the namespace.
		for _, childStmt := range s.Stmts {
			if local, ok := childStmt.Data.(*js_ast.SLocal); ok {
				if local.IsExport {
					p.markExportedDeclsInsideNamespace(s.Arg, local.Decls)
				}
			}
		}

		oldEnclosingNamespaceArgRef := p.enclosingNamespaceArgRef
		p.enclosingNamespaceArgRef = &s.Arg
		p.pushScopeForVisitPass(js_ast.ScopeEntry, stmt.Loc)
		p.recordDeclaredSymbol(s.Arg)
		stmtsInsideNamespace := p.visitStmtsAndPrependTempRefs(s.Stmts, prependTempRefsOpts{})
		p.popScope()
		p.enclosingNamespaceArgRef = oldEnclosingNamespaceArgRef

		// Generate a closure for this namespace
		stmts = p.generateClosureForTypeScriptNamespaceOrEnum(
			stmts, stmt.Loc, s.IsExport, s.Name.Loc, s.Name.Ref, s.Arg, stmtsInsideNamespace)
		return stmts

	default:
		panic("Internal error")
	}

	stmts = append(stmts, stmt)
	return stmts
}

func (p *parser) markExportedDeclsInsideNamespace(nsRef js_ast.Ref, decls []js_ast.Decl) {
	for _, decl := range decls {
		p.markExportedBindingInsideNamespace(nsRef, decl.Binding)
	}
}

func (p *parser) markExportedBindingInsideNamespace(nsRef js_ast.Ref, binding js_ast.Binding) {
	switch b := binding.Data.(type) {
	case *js_ast.BMissing:

	case *js_ast.BIdentifier:
		p.isExportedInsideNamespace[b.Ref] = nsRef

	case *js_ast.BArray:
		for _, item := range b.Items {
			p.markExportedBindingInsideNamespace(nsRef, item.Binding)
		}

	case *js_ast.BObject:
		for _, property := range b.Properties {
			p.markExportedBindingInsideNamespace(nsRef, property.Value)
		}

	default:
		panic("Internal error")
	}
}

func (p *parser) maybeTransposeIfExprChain(expr js_ast.Expr, visit func(js_ast.Expr) js_ast.Expr) js_ast.Expr {
	if e, ok := expr.Data.(*js_ast.EIf); ok {
		e.Yes = p.maybeTransposeIfExprChain(e.Yes, visit)
		e.No = p.maybeTransposeIfExprChain(e.No, visit)
		return expr
	}
	return visit(expr)
}

func maybeJoinWithComma(a js_ast.Expr, b js_ast.Expr) js_ast.Expr {
	if a.Data == nil {
		return b
	}
	if b.Data == nil {
		return a
	}
	return js_ast.JoinWithComma(a, b)
}

// This is a helper function to use when you need to capture a value that may
// have side effects so you can use it multiple times. It guarantees that the
// side effects take place exactly once.
//
// Example usage:
//
//   // "value" => "value + value"
//   // "value()" => "(_a = value(), _a + _a)"
//   valueFunc, wrapFunc := p.captureValueWithPossibleSideEffects(loc, 2, value)
//   return wrapFunc(js_ast.Expr{Loc: loc, Data: &js_ast.EBinary{
//     Op: js_ast.BinOpAdd,
//     Left: valueFunc(),
//     Right: valueFunc(),
//   }})
//
// This returns a function for generating references instead of a raw reference
// because AST nodes are supposed to be unique in memory, not aliases of other
// AST nodes. That way you can mutate one during lowering without having to
// worry about messing up other nodes.
func (p *parser) captureValueWithPossibleSideEffects(
	loc logger.Loc, // The location to use for the generated references
	count int, // The expected number of references to generate
	value js_ast.Expr, // The value that might have side effects
) (
	func() js_ast.Expr, // Generates reference expressions "_a"
	func(js_ast.Expr) js_ast.Expr, // Call this on the final expression
) {
	wrapFunc := func(expr js_ast.Expr) js_ast.Expr {
		// Make sure side effects still happen if no expression was generated
		if expr.Data == nil {
			return value
		}
		return expr
	}

	// Referencing certain expressions more than once has no side effects, so we
	// can just create them inline without capturing them in a temporary variable
	var valueFunc func() js_ast.Expr
	switch e := value.Data.(type) {
	case *js_ast.ENull:
		valueFunc = func() js_ast.Expr { return js_ast.Expr{Loc: loc, Data: &js_ast.ENull{}} }
	case *js_ast.EUndefined:
		valueFunc = func() js_ast.Expr { return js_ast.Expr{Loc: loc, Data: &js_ast.EUndefined{}} }
	case *js_ast.EThis:
		valueFunc = func() js_ast.Expr { return js_ast.Expr{Loc: loc, Data: &js_ast.EThis{}} }
	case *js_ast.EBoolean:
		valueFunc = func() js_ast.Expr { return js_ast.Expr{Loc: loc, Data: &js_ast.EBoolean{Value: e.Value}} }
	case *js_ast.ENumber:
		valueFunc = func() js_ast.Expr { return js_ast.Expr{Loc: loc, Data: &js_ast.ENumber{Value: e.Value}} }
	case *js_ast.EBigInt:
		valueFunc = func() js_ast.Expr { return js_ast.Expr{Loc: loc, Data: &js_ast.EBigInt{Value: e.Value}} }
	case *js_ast.EString:
		valueFunc = func() js_ast.Expr { return js_ast.Expr{Loc: loc, Data: &js_ast.EString{Value: e.Value}} }
	case *js_ast.EIdentifier:
		valueFunc = func() js_ast.Expr { return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: e.Ref}} }
	}
	if valueFunc != nil {
		return valueFunc, wrapFunc
	}

	// We don't need to worry about side effects if the value won't be used
	// multiple times. This special case lets us avoid generating a temporary
	// reference.
	if count < 2 {
		return func() js_ast.Expr {
			return value
		}, wrapFunc
	}

	// Otherwise, fall back to generating a temporary reference
	tempRef := js_ast.InvalidRef

	// If we're in a function argument scope, then we won't be able to generate
	// symbols in this scope to store stuff, since there's nowhere to put the
	// variable declaration. We don't want to put the variable declaration
	// outside the function since some code in the argument list may cause the
	// function to be reentrant, and we can't put the variable declaration in
	// the function body since that's not accessible by the argument list.
	//
	// Instead, we use an immediately-invoked arrow function to create a new
	// symbol inline by introducing a new scope. Make sure to only use it for
	// symbol declaration and still initialize the variable inline to preserve
	// side effect order.
	if p.currentScope.Kind == js_ast.ScopeFunctionArgs {
		return func() js_ast.Expr {
				if tempRef == js_ast.InvalidRef {
					tempRef = p.generateTempRef(tempRefNoDeclare, "")

					// Assign inline so the order of side effects remains the same
					p.recordUsage(tempRef)
					return js_ast.Assign(js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: tempRef}}, value)
				}
				p.recordUsage(tempRef)
				return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: tempRef}}
			}, func(expr js_ast.Expr) js_ast.Expr {
				// Make sure side effects still happen if no expression was generated
				if expr.Data == nil {
					return value
				}

				// Generate a new variable using an arrow function to avoid messing with "this"
				return js_ast.Expr{Loc: loc, Data: &js_ast.ECall{
					Target: js_ast.Expr{Loc: loc, Data: &js_ast.EArrow{
						Args:       []js_ast.Arg{{Binding: js_ast.Binding{Loc: loc, Data: &js_ast.BIdentifier{Ref: tempRef}}}},
						PreferExpr: true,
						Body:       js_ast.FnBody{Loc: loc, Stmts: []js_ast.Stmt{{Loc: loc, Data: &js_ast.SReturn{Value: &expr}}}},
					}},
					Args: []js_ast.Expr{},
				}}
			}
	}

	return func() js_ast.Expr {
		if tempRef == js_ast.InvalidRef {
			tempRef = p.generateTempRef(tempRefNeedsDeclare, "")
			p.recordUsage(tempRef)
			return js_ast.Assign(js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: tempRef}}, value)
		}
		p.recordUsage(tempRef)
		return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: tempRef}}
	}, wrapFunc
}

func (p *parser) visitTSDecorators(tsDecorators []js_ast.Expr) []js_ast.Expr {
	for i, decorator := range tsDecorators {
		tsDecorators[i] = p.visitExpr(decorator)
	}
	return tsDecorators
}

func (p *parser) visitClass(nameScopeLoc logger.Loc, class *js_ast.Class) js_ast.Ref {
	class.TSDecorators = p.visitTSDecorators(class.TSDecorators)

	if class.Name != nil {
		p.recordDeclaredSymbol(class.Name.Ref)
	}

	p.pushScopeForVisitPass(js_ast.ScopeClassName, nameScopeLoc)

	// Insert a shadowing name that spans the whole class, which matches
	// JavaScript's semantics. The class body (and extends clause) "captures" the
	// original value of the name. This matters for class statements because the
	// symbol can be re-assigned to something else later. The captured values
	// must be the original value of the name, not the re-assigned value.
	shadowRef := js_ast.InvalidRef
	if class.Name != nil {
		// Use "const" for this symbol to match JavaScript run-time semantics. You
		// are not allowed to assign to this symbol (it throws a TypeError).
		name := p.symbols[class.Name.Ref.InnerIndex].OriginalName
		shadowRef = p.newSymbol(js_ast.SymbolConst, name)
		p.recordDeclaredSymbol(shadowRef)
		p.currentScope.Members[name] = js_ast.ScopeMember{Loc: class.Name.Loc, Ref: shadowRef}
	}

	if class.Extends != nil {
		*class.Extends = p.visitExpr(*class.Extends)
	}

	oldIsThisCaptured := p.fnOnlyDataVisit.isThisNested
	p.fnOnlyDataVisit.isThisNested = true

	// A scope is needed for private identifiers
	p.pushScopeForVisitPass(js_ast.ScopeClassBody, class.BodyLoc)
	defer p.popScope()

	for i, property := range class.Properties {
		property.TSDecorators = p.visitTSDecorators(property.TSDecorators)

		// Special-case EPrivateIdentifier to allow it here
		if private, ok := property.Key.Data.(*js_ast.EPrivateIdentifier); ok {
			p.recordDeclaredSymbol(private.Ref)
		} else {
			class.Properties[i].Key = p.visitExpr(property.Key)
		}
		if property.Value != nil {
			*property.Value = p.visitExpr(*property.Value)
		}
		if property.Initializer != nil {
			*property.Initializer = p.visitExpr(*property.Initializer)
		}
	}

	p.fnOnlyDataVisit.isThisNested = oldIsThisCaptured

	p.popScope()

	// Don't generate a shadowing name if one isn't needed
	if shadowRef != js_ast.InvalidRef && p.symbols[shadowRef.InnerIndex].UseCountEstimate == 0 {
		shadowRef = js_ast.InvalidRef
	}

	return shadowRef
}

func (p *parser) visitArgs(args []js_ast.Arg) {
	for _, arg := range args {
		arg.TSDecorators = p.visitTSDecorators(arg.TSDecorators)
		p.visitBinding(arg.Binding)
		if arg.Default != nil {
			*arg.Default = p.visitExpr(*arg.Default)
		}
	}
}

func (p *parser) isDotDefineMatch(expr js_ast.Expr, parts []string) bool {
	if len(parts) > 1 {
		// Intermediates must be dot expressions
		e, ok := expr.Data.(*js_ast.EDot)
		last := len(parts) - 1
		return ok && parts[last] == e.Name && e.OptionalChain == js_ast.OptionalChainNone && p.isDotDefineMatch(e.Target, parts[:last])
	}

	// The last expression must be an identifier
	e, ok := expr.Data.(*js_ast.EIdentifier)
	if !ok {
		return false
	}

	// The name must match
	name := p.loadNameFromRef(e.Ref)
	if name != parts[0] {
		return false
	}

	result := p.findSymbol(expr.Loc, name)

	// We must not be in a "with" statement scope
	if result.isInsideWithScope {
		return false
	}

	// The last symbol must be unbound
	return p.symbols[result.ref.InnerIndex].Kind == js_ast.SymbolUnbound
}

func (p *parser) jsxStringsToMemberExpression(loc logger.Loc, parts []string) js_ast.Expr {
	// Check both user-specified defines and known globals
	if defines, ok := p.options.defines.DotDefines[parts[len(parts)-1]]; ok {
	next:
		for _, define := range defines {
			if len(define.Parts) == len(parts) {
				for i := range parts {
					if parts[i] != define.Parts[i] {
						continue next
					}
				}
			}

			// Substitute user-specified defines
			if define.Data.DefineFunc != nil {
				return p.valueForDefine(loc, js_ast.AssignTargetNone, false, define.Data.DefineFunc)
			}
		}
	}

	// Generate an identifier for the first part
	ref := p.findSymbol(loc, parts[0]).ref
	value := p.handleIdentifier(loc, js_ast.AssignTargetNone, false, &js_ast.EIdentifier{
		Ref: ref,

		// Enable tree shaking
		CanBeRemovedIfUnused: true,
	})

	// Build up a chain of property access expressions for subsequent parts
	for i := 1; i < len(parts); i++ {
		if expr, ok := p.maybeRewritePropertyAccess(loc, js_ast.AssignTargetNone, false, js_ast.OptionalChainNone, value, parts[i], loc, false); ok {
			value = expr
		} else {
			value = js_ast.Expr{Loc: loc, Data: &js_ast.EDot{
				Target:  value,
				Name:    parts[i],
				NameLoc: loc,

				// Enable tree shaking
				CanBeRemovedIfUnused: true,
			}}
		}
	}

	return value
}

func (p *parser) checkForNonBMPCodePoint(loc logger.Loc, name string) {
	if p.options.asciiOnly && p.options.unsupportedJSFeatures.Has(compat.UnicodeEscapes) &&
		js_lexer.ContainsNonBMPCodePoint(name) {
		if p.nonBMPIdentifiers == nil {
			p.nonBMPIdentifiers = make(map[string]bool)
		}
		if !p.nonBMPIdentifiers[name] {
			p.nonBMPIdentifiers[name] = true
			r := js_lexer.RangeOfIdentifier(p.source, loc)
			p.log.AddRangeError(&p.source, r, fmt.Sprintf("%q cannot be escaped in the target environment ("+
				"consider setting the charset to \"utf8\" or changing the target)", name))
		}
	}
}

func (p *parser) checkForTypeofAndString(a js_ast.Expr, b js_ast.Expr) bool {
	if typeof, ok := a.Data.(*js_ast.EUnary); ok && typeof.Op == js_ast.UnOpTypeof {
		if str, ok := b.Data.(*js_ast.EString); ok {
			value := js_lexer.UTF16ToString(str.Value)
			switch value {
			case "undefined", "object", "boolean", "number", "bigint", "string", "symbol", "function", "unknown":
			default:
				// Warn about typeof comparisons with values that will never be
				// returned. Here's an example of code with this problem:
				// https://github.com/olifolkerd/tabulator/issues/2962
				if !p.options.suppressWarningsAboutWeirdCode {
					r := p.source.RangeOfString(b.Loc)
					p.log.AddRangeWarning(&p.source, r, fmt.Sprintf("The \"typeof\" operator will never evaluate to %q", value))
				}
			}
			return true
		}
	}
	return false
}

func (p *parser) warnAboutEqualityCheck(op string, value js_ast.Expr, afterOpLoc logger.Loc) bool {
	if p.options.suppressWarningsAboutWeirdCode {
		return false
	}

	switch e := value.Data.(type) {
	case *js_ast.ENumber:
		// "0 === -0" is true in JavaScript. Here's an example of code with this
		// problem: https://github.com/mrdoob/three.js/pull/11183
		if e.Value == 0 && math.Signbit(e.Value) {
			r := logger.Range{Loc: value.Loc, Len: 0}
			if int(r.Loc.Start) < len(p.source.Contents) && p.source.Contents[r.Loc.Start] == '-' {
				zeroRange := p.source.RangeOfNumber(logger.Loc{Start: r.Loc.Start + 1})
				r.Len = zeroRange.Len + 1
			}
			text := fmt.Sprintf("Comparison with -0 using the %q operator will also match 0", op)
			if op == "case" {
				text = "Comparison with -0 using a case clause will also match 0"
			}
			p.log.AddRangeWarning(&p.source, r, text)
			return true
		}

		// "NaN === NaN" is false in JavaScript
		if math.IsNaN(e.Value) {
			text := fmt.Sprintf("Comparison with NaN using the %q operator here is always %v", op, op[0] == '!')
			if op == "case" {
				text = "This case clause will never be evaluated because equality with NaN is always false"
			}
			p.log.AddRangeWarning(&p.source, p.source.RangeOfOperatorBefore(afterOpLoc, op), text)
			return true
		}

	case *js_ast.EArray, *js_ast.EArrow, *js_ast.EClass,
		*js_ast.EFunction, *js_ast.EObject, *js_ast.ERegExp:
		// This warning only applies to strict equality because loose equality can
		// cause string conversions. For example, "x == []" is true if x is the
		// empty string. Here's an example of code with this problem:
		// https://github.com/aws/aws-sdk-js/issues/3325
		if len(op) > 2 {
			text := fmt.Sprintf("Comparison using the %q operator here is always %v", op, op[0] == '!')
			if op == "case" {
				text = "This case clause will never be evaluated because the comparison is always false"
			}
			p.log.AddRangeWarning(&p.source, p.source.RangeOfOperatorBefore(afterOpLoc, op), text)
			return true
		}
	}

	return false
}

func (p *parser) warnAboutLackOfDefine(name string, r logger.Range) {
	if p.options.mode == config.ModeBundle && p.options.platform == config.PlatformBrowser {
		if p.lackOfDefineWarnings == nil {
			p.lackOfDefineWarnings = make(map[string]bool)
		}
		if !p.lackOfDefineWarnings[name] {
			p.lackOfDefineWarnings[name] = true
			p.log.AddRangeWarning(&p.source, r,
				fmt.Sprintf("Define %q when bundling for the browser", name))
		}
	}
}

// EDot nodes represent a property access. This function may return an
// expression to replace the property access with. It assumes that the
// target of the EDot expression has already been visited.
func (p *parser) maybeRewritePropertyAccess(
	loc logger.Loc,
	assignTarget js_ast.AssignTarget,
	isDeleteTarget bool,
	optionalChain js_ast.OptionalChain,
	target js_ast.Expr,
	name string,
	nameLoc logger.Loc,
	isCallTarget bool,
) (js_ast.Expr, bool) {
	if id, ok := target.Data.(*js_ast.EIdentifier); ok {
		// Rewrite property accesses on explicit namespace imports as an identifier.
		// This lets us replace them easily in the printer to rebind them to
		// something else without paying the cost of a whole-tree traversal during
		// module linking just to rewrite these EDot expressions.
		if p.options.mode == config.ModeBundle {
			if importItems, ok := p.importItemsForNamespace[id.Ref]; ok {
				// Cache translation so each property access resolves to the same import
				item, ok := importItems[name]
				if !ok {
					// Generate a new import item symbol in the module scope
					item = js_ast.LocRef{Loc: nameLoc, Ref: p.newSymbol(js_ast.SymbolImport, name)}
					p.moduleScope.Generated = append(p.moduleScope.Generated, item.Ref)

					// Link the namespace import and the import item together
					importItems[name] = item
					p.isImportItem[item.Ref] = true

					symbol := &p.symbols[item.Ref.InnerIndex]
					if p.options.mode == config.ModePassThrough {
						// Make sure the printer prints this as a property access
						symbol.NamespaceAlias = &js_ast.NamespaceAlias{
							NamespaceRef: id.Ref,
							Alias:        name,
						}
					} else {
						// Mark this as generated in case it's missing. We don't want to
						// generate errors for missing import items that are automatically
						// generated.
						symbol.ImportItemStatus = js_ast.ImportItemGenerated
					}
				}

				// Undo the usage count for the namespace itself. This is used later
				// to detect whether the namespace symbol has ever been "captured"
				// or whether it has just been used to read properties off of.
				//
				// The benefit of doing this is that if both this module and the
				// imported module end up in the same module group and the namespace
				// symbol has never been captured, then we don't need to generate
				// any code for the namespace at all.
				p.ignoreUsage(id.Ref)

				// Track how many times we've referenced this symbol
				p.recordUsage(item.Ref)
				return p.handleIdentifier(nameLoc, assignTarget, isDeleteTarget, &js_ast.EIdentifier{Ref: item.Ref}), true
			}

			// Rewrite "module.require()" to "require()" for Webpack compatibility.
			// See https://github.com/webpack/webpack/pull/7750 for more info.
			if isCallTarget && id.Ref == p.moduleRef && name == "require" {
				p.ignoreUsage(p.moduleRef)
				p.recordUsage(p.requireRef)
				return js_ast.Expr{Loc: nameLoc, Data: &js_ast.EIdentifier{Ref: p.requireRef}}, true
			}
		}

		// If this is a known enum value, inline the value of the enum
		if p.options.ts.Parse && optionalChain == js_ast.OptionalChainNone {
			if enumValueMap, ok := p.knownEnumValues[id.Ref]; ok {
				if number, ok := enumValueMap[name]; ok {
					return js_ast.Expr{Loc: loc, Data: &js_ast.ENumber{Value: number}}, true
				}
			}
		}
	}

	return js_ast.Expr{}, false
}

func joinStrings(a []uint16, b []uint16) []uint16 {
	data := make([]uint16, len(a)+len(b))
	copy(data[:len(a)], a)
	copy(data[len(a):], b)
	return data
}

func foldStringAddition(left js_ast.Expr, right js_ast.Expr) *js_ast.Expr {
	switch l := left.Data.(type) {
	case *js_ast.EString:
		switch r := right.Data.(type) {
		case *js_ast.EString:
			return &js_ast.Expr{Loc: left.Loc, Data: &js_ast.EString{
				Value:          joinStrings(l.Value, r.Value),
				PreferTemplate: l.PreferTemplate || r.PreferTemplate,
			}}

		case *js_ast.ETemplate:
			if r.Tag == nil {
				return &js_ast.Expr{Loc: left.Loc, Data: &js_ast.ETemplate{Head: joinStrings(l.Value, r.Head), Parts: r.Parts}}
			}
		}

	case *js_ast.ETemplate:
		if l.Tag == nil {
			switch r := right.Data.(type) {
			case *js_ast.EString:
				n := len(l.Parts)
				head := l.Head
				parts := make([]js_ast.TemplatePart, n)
				if n == 0 {
					head = joinStrings(head, r.Value)
				} else {
					copy(parts, l.Parts)
					parts[n-1].Tail = joinStrings(parts[n-1].Tail, r.Value)
				}
				return &js_ast.Expr{Loc: left.Loc, Data: &js_ast.ETemplate{Head: head, Parts: parts}}

			case *js_ast.ETemplate:
				if r.Tag == nil {
					n := len(l.Parts)
					head := l.Head
					parts := make([]js_ast.TemplatePart, n+len(r.Parts))
					copy(parts[n:], r.Parts)
					if n == 0 {
						head = joinStrings(head, r.Head)
					} else {
						copy(parts[:n], l.Parts)
						parts[n-1].Tail = joinStrings(parts[n-1].Tail, r.Head)
					}
					return &js_ast.Expr{Loc: left.Loc, Data: &js_ast.ETemplate{Head: head, Parts: parts}}
				}
			}
		}
	}

	return nil
}

func (p *parser) visitBooleanExpr(expr js_ast.Expr) js_ast.Expr {
	expr = p.visitExpr(expr)

	// Simplify syntax when we know it's used inside a boolean context
	if p.options.mangleSyntax {
		for {
			// "!!a" => "a"
			if not, ok := expr.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot {
				if not2, ok2 := not.Value.Data.(*js_ast.EUnary); ok2 && not2.Op == js_ast.UnOpNot {
					expr = not2.Value
					continue
				}
			}

			break
		}
	}

	return expr
}

func toInt32(f float64) int32 {
	// The easy way
	i := int32(f)
	if float64(i) == f {
		return i
	}

	// The hard way
	i = int32(uint32(math.Mod(math.Abs(f), 4294967296)))
	if math.Signbit(f) {
		return -i
	}
	return i
}

func toUint32(f float64) uint32 {
	return uint32(toInt32(f))
}

type exprIn struct {
	// This tells us if there are optional chain expressions (EDot, EIndex, or
	// ECall) that are chained on to this expression. Because of the way the AST
	// works, chaining expressions on to this expression means they are our
	// parent expressions.
	//
	// Some examples:
	//
	//   a?.b.c  // EDot
	//   a?.b[c] // EIndex
	//   a?.b()  // ECall
	//
	// Note that this is false if our parent is a node with a OptionalChain
	// value of OptionalChainStart. That means it's the start of a new chain, so
	// it's not considered part of this one.
	//
	// Some examples:
	//
	//   a?.b?.c   // EDot
	//   a?.b?.[c] // EIndex
	//   a?.b?.()  // ECall
	//
	// Also note that this is false if our parent is a node with a OptionalChain
	// value of OptionalChainNone. That means it's outside parentheses, which
	// means it's no longer part of the chain.
	//
	// Some examples:
	//
	//   (a?.b).c  // EDot
	//   (a?.b)[c] // EIndex
	//   (a?.b)()  // ECall
	//
	hasChainParent bool

	// If our parent is an ECall node with an OptionalChain value of
	// OptionalChainStart, then we will need to store the value for the "this" of
	// that call somewhere if the current expression is an optional chain that
	// ends in a property access. That's because the value for "this" will be
	// used twice: once for the inner optional chain and once for the outer
	// optional chain.
	//
	// Example:
	//
	//   // Original
	//   a?.b?.();
	//
	//   // Lowered
	//   var _a;
	//   (_a = a == null ? void 0 : a.b) == null ? void 0 : _a.call(a);
	//
	// In the example above we need to store "a" as the value for "this" so we
	// can substitute it back in when we call "_a" if "_a" is indeed present.
	storeThisArgForParentOptionalChain func(js_ast.Expr) js_ast.Expr

	// Certain substitutions of identifiers are disallowed for assignment targets.
	// For example, we shouldn't transform "undefined = 1" into "void 0 = 1". This
	// isn't something real-world code would do but it matters for conformance
	// tests.
	assignTarget js_ast.AssignTarget
}

type exprOut struct {
	// True if the child node is an optional chain node (EDot, EIndex, or ECall
	// with an IsOptionalChain value of true)
	childContainsOptionalChain bool
}

func (p *parser) visitExpr(expr js_ast.Expr) js_ast.Expr {
	expr, _ = p.visitExprInOut(expr, exprIn{})
	return expr
}

func (p *parser) valueForThis(loc logger.Loc) (js_ast.Expr, bool) {
	if p.options.mode != config.ModePassThrough && !p.fnOnlyDataVisit.isThisNested {
		if p.hasES6ImportSyntax || p.hasES6ExportSyntax {
			// In an ES6 module, "this" is supposed to be undefined. Instead of
			// doing this at runtime using "fn.call(undefined)", we do it at
			// compile time using expression substitution here.
			return js_ast.Expr{Loc: loc, Data: &js_ast.EUndefined{}}, true
		} else {
			// In a CommonJS module, "this" is supposed to be the same as "exports".
			// Instead of doing this at runtime using "fn.call(module.exports)", we
			// do it at compile time using expression substitution here.
			p.recordUsage(p.exportsRef)
			return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: p.exportsRef}}, true
		}
	}

	return js_ast.Expr{}, false
}

func isBinaryNullAndUndefined(left js_ast.Expr, right js_ast.Expr, op js_ast.OpCode) (js_ast.Expr, js_ast.Expr, bool) {
	if a, ok := left.Data.(*js_ast.EBinary); ok && a.Op == op {
		if b, ok := right.Data.(*js_ast.EBinary); ok && b.Op == op {
			if idA, ok := a.Left.Data.(*js_ast.EIdentifier); ok {
				if idB, ok := b.Left.Data.(*js_ast.EIdentifier); ok && idA.Ref == idB.Ref {
					// "a === null || a === void 0"
					if _, ok := a.Right.Data.(*js_ast.ENull); ok {
						if _, ok := b.Right.Data.(*js_ast.EUndefined); ok {
							return a.Left, a.Right, true
						}
					}

					// "a === void 0 || a === null"
					if _, ok := a.Right.Data.(*js_ast.EUndefined); ok {
						if _, ok := b.Right.Data.(*js_ast.ENull); ok {
							return b.Left, b.Right, true
						}
					}
				}
			}
		}
	}

	return js_ast.Expr{}, js_ast.Expr{}, false
}

func inlineSpreadsOfArrayLiterals(values []js_ast.Expr) (results []js_ast.Expr) {
	for _, value := range values {
		if spread, ok := value.Data.(*js_ast.ESpread); ok {
			if array, ok := spread.Value.Data.(*js_ast.EArray); ok {
				for _, item := range array.Items {
					if _, ok := item.Data.(*js_ast.EMissing); ok {
						results = append(results, js_ast.Expr{Loc: item.Loc, Data: &js_ast.EUndefined{}})
					} else {
						results = append(results, item)
					}
				}
				continue
			}
		}
		results = append(results, value)
	}
	return
}

func locAfterOp(e *js_ast.EBinary) logger.Loc {
	if e.Left.Loc.Start < e.Right.Loc.Start {
		return e.Right.Loc
	} else {
		// Handle the case when we have transposed the operands
		return e.Left.Loc
	}
}

func canBeDeleted(expr js_ast.Expr) bool {
	switch e := expr.Data.(type) {
	case *js_ast.EIdentifier, *js_ast.EDot, *js_ast.EIndex:
		return true
	case *js_ast.ENumber:
		return math.IsInf(e.Value, 1) || math.IsNaN(e.Value)
	}
	return false
}

func (p *parser) isValidAssignmentTarget(expr js_ast.Expr) bool {
	switch e := expr.Data.(type) {
	case *js_ast.EIdentifier, *js_ast.EObject, *js_ast.EArray:
		// Don't worry about recursive checking for objects and arrays. This will
		// already be handled naturally by passing down the assign target flag.
		return true
	case *js_ast.EDot:
		return e.OptionalChain == js_ast.OptionalChainNone
	case *js_ast.EIndex:
		return e.OptionalChain == js_ast.OptionalChainNone
	}
	return false
}

// This function takes "exprIn" as input from the caller and produces "exprOut"
// for the caller to pass along extra data. This is mostly for optional chaining.
func (p *parser) visitExprInOut(expr js_ast.Expr, in exprIn) (js_ast.Expr, exprOut) {
	if in.assignTarget != js_ast.AssignTargetNone && !p.isValidAssignmentTarget(expr) {
		p.log.AddError(&p.source, expr.Loc, "Invalid assignment target")
	}

	switch e := expr.Data.(type) {
	case *js_ast.ENull, *js_ast.ESuper, *js_ast.EString,
		*js_ast.EBoolean, *js_ast.ENumber, *js_ast.EBigInt,
		*js_ast.ERegExp, *js_ast.ENewTarget, *js_ast.EUndefined:

	case *js_ast.EThis:
		if value, ok := p.valueForThis(expr.Loc); ok {
			return value, exprOut{}
		}

		// Capture "this" inside arrow functions that will be lowered into normal
		// function expressions for older language environments
		if p.fnOrArrowDataVisit.isArrow && p.options.unsupportedJSFeatures.Has(compat.Arrow) && p.fnOnlyDataVisit.isThisNested {
			return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EIdentifier{Ref: p.captureThis()}}, exprOut{}
		}

	case *js_ast.EImportMeta:
		if p.importMetaRef != js_ast.InvalidRef {
			// Replace "import.meta" with a reference to the symbol
			p.recordUsage(p.importMetaRef)
			return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EIdentifier{Ref: p.importMetaRef}}, exprOut{}
		}

	case *js_ast.ESpread:
		e.Value = p.visitExpr(e.Value)

	case *js_ast.EIdentifier:
		isDeleteTarget := e == p.deleteTarget
		name := p.loadNameFromRef(e.Ref)
		result := p.findSymbol(expr.Loc, name)
		e.Ref = result.ref

		// Handle assigning to a constant
		if in.assignTarget != js_ast.AssignTargetNone && p.symbols[result.ref.InnerIndex].Kind == js_ast.SymbolConst {
			r := js_lexer.RangeOfIdentifier(p.source, expr.Loc)
			notes := []logger.MsgData{logger.RangeData(&p.source, js_lexer.RangeOfIdentifier(p.source, result.declareLoc),
				fmt.Sprintf("%q was declared a constant here", name))}

			// Make this an error when bundling because we may need to convert this
			// "const" into a "var" during bundling.
			if p.options.mode == config.ModeBundle {
				p.log.AddRangeErrorWithNotes(&p.source, r, fmt.Sprintf("Cannot assign to %q because it is a constant", name), notes)
			} else {
				p.log.AddRangeWarningWithNotes(&p.source, r, fmt.Sprintf("This assignment will throw because %q is a constant", name), notes)
			}
		}

		// Substitute user-specified defines for unbound symbols
		if p.symbols[e.Ref.InnerIndex].Kind == js_ast.SymbolUnbound && !result.isInsideWithScope && e != p.deleteTarget {
			if data, ok := p.options.defines.IdentifierDefines[name]; ok {
				if data.DefineFunc != nil {
					new := p.valueForDefine(expr.Loc, in.assignTarget, isDeleteTarget, data.DefineFunc)

					// Don't substitute an identifier for a non-identifier if this is an
					// assignment target, since it'll cause a syntax error
					if _, ok := new.Data.(*js_ast.EIdentifier); in.assignTarget == js_ast.AssignTargetNone || ok {
						return new, exprOut{}
					}
				}

				// Copy the side effect flags over in case this expression is unused
				if data.CanBeRemovedIfUnused {
					e.CanBeRemovedIfUnused = true
				}
				if data.CallCanBeUnwrappedIfUnused && !p.options.ignoreDCEAnnotations {
					e.CallCanBeUnwrappedIfUnused = true
				}
				if data.WarnAboutLackOfDefine {
					p.warnAboutLackOfDefine(name, js_lexer.RangeOfIdentifier(p.source, expr.Loc))
				}
			}
		}

		return p.handleIdentifier(expr.Loc, in.assignTarget, isDeleteTarget, e), exprOut{}

	case *js_ast.EPrivateIdentifier:
		// We should never get here
		panic("Internal error")

	case *js_ast.EJSXElement:
		// A missing tag is a fragment
		tag := e.Tag
		if tag == nil {
			value := p.jsxStringsToMemberExpression(expr.Loc, p.options.jsx.Fragment)
			tag = &value
		} else {
			*tag = p.visitExpr(*tag)
		}

		// Visit properties
		for i, property := range e.Properties {
			if property.Kind != js_ast.PropertySpread {
				property.Key = p.visitExpr(property.Key)
			}
			if property.Value != nil {
				*property.Value = p.visitExpr(*property.Value)
			}
			if property.Initializer != nil {
				*property.Initializer = p.visitExpr(*property.Initializer)
			}
			e.Properties[i] = property
		}

		// Arguments to createElement()
		args := []js_ast.Expr{*tag}
		if len(e.Properties) > 0 {
			args = append(args, p.lowerObjectSpread(expr.Loc, &js_ast.EObject{
				Properties: e.Properties,
			}))
		} else {
			args = append(args, js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENull{}})
		}
		if len(e.Children) > 0 {
			for _, child := range e.Children {
				args = append(args, p.visitExpr(child))
			}
		}

		// Call createElement()
		return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ECall{
			Target: p.jsxStringsToMemberExpression(expr.Loc, p.options.jsx.Factory),
			Args:   args,

			// Enable tree shaking
			CanBeUnwrappedIfUnused: !p.options.ignoreDCEAnnotations,
		}}, exprOut{}

	case *js_ast.ETemplate:
		if e.Tag != nil {
			*e.Tag = p.visitExpr(*e.Tag)
		}
		for i, part := range e.Parts {
			e.Parts[i].Value = p.visitExpr(part.Value)
		}

		// "`a${'b'}c`" => "`abc`"
		if p.options.mangleSyntax && e.Tag == nil {
			end := 0
			for _, part := range e.Parts {
				if str, ok := part.Value.Data.(*js_ast.EString); ok {
					if end == 0 {
						e.Head = append(append(e.Head, str.Value...), part.Tail...)
					} else {
						prevPart := &e.Parts[end-1]
						prevPart.Tail = append(append(prevPart.Tail, str.Value...), part.Tail...)
					}
				} else {
					e.Parts[end] = part
					end++
				}
			}
			e.Parts = e.Parts[:end]
		}

	case *js_ast.EBinary:
		isCallTarget := e == p.callTarget
		wasAnonymousNamedExpr := p.isAnonymousNamedExpr(e.Right)
		e.Left, _ = p.visitExprInOut(e.Left, exprIn{assignTarget: e.Op.BinaryAssignTarget()})

		// Pattern-match "typeof require == 'function' && ___" from browserify
		if e.Op == js_ast.BinOpLogicalAnd && e.Left.Data == p.typeofRequireEqualsFn {
			p.typeofRequireEqualsFnTarget = e.Right.Data
		}

		// Mark the control flow as dead if the branch is never taken
		switch e.Op {
		case js_ast.BinOpLogicalOr:
			if boolean, ok := toBooleanWithoutSideEffects(e.Left.Data); ok && boolean {
				// "true || dead"
				old := p.isControlFlowDead
				p.isControlFlowDead = true
				e.Right = p.visitExpr(e.Right)
				p.isControlFlowDead = old
			} else {
				e.Right = p.visitExpr(e.Right)
			}

		case js_ast.BinOpLogicalAnd:
			if boolean, ok := toBooleanWithoutSideEffects(e.Left.Data); ok && !boolean {
				// "false && dead"
				old := p.isControlFlowDead
				p.isControlFlowDead = true
				e.Right = p.visitExpr(e.Right)
				p.isControlFlowDead = old
			} else {
				e.Right = p.visitExpr(e.Right)
			}

		case js_ast.BinOpNullishCoalescing:
			if isNullOrUndefined, ok := toNullOrUndefinedWithoutSideEffects(e.Left.Data); ok && !isNullOrUndefined {
				// "notNullOrUndefined ?? dead"
				old := p.isControlFlowDead
				p.isControlFlowDead = true
				e.Right = p.visitExpr(e.Right)
				p.isControlFlowDead = old
			} else {
				e.Right = p.visitExpr(e.Right)
			}

		default:
			e.Right = p.visitExpr(e.Right)
		}

		// Always put constants on the right for equality comparisons to help
		// reduce the number of cases we have to check during pattern matching. We
		// can only reorder expressions that do not have any side effects.
		switch e.Op {
		case js_ast.BinOpLooseEq, js_ast.BinOpLooseNe, js_ast.BinOpStrictEq, js_ast.BinOpStrictNe:
			if isPrimitiveToReorder(e.Left.Data) && !isPrimitiveToReorder(e.Right.Data) {
				e.Left, e.Right = e.Right, e.Left
			}
		}

		// Post-process the binary expression
		switch e.Op {
		case js_ast.BinOpComma:
			// "(1, 2)" => "2"
			// "(sideEffects(), 2)" => "(sideEffects(), 2)"
			if p.options.mangleSyntax {
				e.Left = p.simplifyUnusedExpr(e.Left)
				if e.Left.Data == nil {
					// "(1, fn)()" => "fn()"
					// "(1, this.fn)" => "this.fn"
					// "(1, this.fn)()" => "(0, this.fn)()"
					if isCallTarget && hasValueForThisInCall(e.Right) {
						return js_ast.JoinWithComma(js_ast.Expr{Loc: e.Left.Loc, Data: &js_ast.ENumber{}}, e.Right), exprOut{}
					}
					return e.Right, exprOut{}
				}
			}

		case js_ast.BinOpLooseEq:
			if result, ok := checkEqualityIfNoSideEffects(e.Left.Data, e.Right.Data); ok {
				data := &js_ast.EBoolean{Value: result}

				// Pattern-match "typeof require == 'function'" from browserify. Also
				// match "'function' == typeof require" because some minifiers such as
				// terser transpose the left and right operands to "==" to form a
				// different but equivalent expression.
				if result && (e.Left.Data == p.typeofRequire || e.Right.Data == p.typeofRequire) {
					p.typeofRequireEqualsFn = data
				}

				return js_ast.Expr{Loc: expr.Loc, Data: data}, exprOut{}
			}
			afterOpLoc := locAfterOp(e)
			if !p.warnAboutEqualityCheck("==", e.Left, afterOpLoc) {
				p.warnAboutEqualityCheck("==", e.Right, afterOpLoc)
			}
			p.checkForTypeofAndString(e.Left, e.Right)

			if p.options.mangleSyntax {
				// "x == void 0" => "x == null"
				if _, ok := e.Right.Data.(*js_ast.EUndefined); ok {
					e.Right.Data = &js_ast.ENull{}
				}
			}

		case js_ast.BinOpStrictEq:
			if result, ok := checkEqualityIfNoSideEffects(e.Left.Data, e.Right.Data); ok {
				return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EBoolean{Value: result}}, exprOut{}
			}
			afterOpLoc := locAfterOp(e)
			if !p.warnAboutEqualityCheck("===", e.Left, afterOpLoc) {
				p.warnAboutEqualityCheck("===", e.Right, afterOpLoc)
			}
			if p.checkForTypeofAndString(e.Left, e.Right) {
				// "typeof x === 'undefined'" => "typeof x == 'undefined'"
				if p.options.mangleSyntax {
					e.Op = js_ast.BinOpLooseEq
				}
			}

		case js_ast.BinOpLooseNe:
			if result, ok := checkEqualityIfNoSideEffects(e.Left.Data, e.Right.Data); ok {
				return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EBoolean{Value: !result}}, exprOut{}
			}
			afterOpLoc := locAfterOp(e)
			if !p.warnAboutEqualityCheck("!=", e.Left, afterOpLoc) {
				p.warnAboutEqualityCheck("!=", e.Right, afterOpLoc)
			}
			p.checkForTypeofAndString(e.Left, e.Right)

			if p.options.mangleSyntax {
				// "x != void 0" => "x != null"
				if _, ok := e.Right.Data.(*js_ast.EUndefined); ok {
					e.Right.Data = &js_ast.ENull{}
				}
			}

		case js_ast.BinOpStrictNe:
			if result, ok := checkEqualityIfNoSideEffects(e.Left.Data, e.Right.Data); ok {
				return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EBoolean{Value: !result}}, exprOut{}
			}
			afterOpLoc := locAfterOp(e)
			if !p.warnAboutEqualityCheck("!==", e.Left, afterOpLoc) {
				p.warnAboutEqualityCheck("!==", e.Right, afterOpLoc)
			}
			if p.checkForTypeofAndString(e.Left, e.Right) {
				// "typeof x !== 'undefined'" => "typeof x != 'undefined'"
				if p.options.mangleSyntax {
					e.Op = js_ast.BinOpLooseNe
				}
			}

		case js_ast.BinOpNullishCoalescing:
			if isNullOrUndefined, ok := toNullOrUndefinedWithoutSideEffects(e.Left.Data); ok {
				if !isNullOrUndefined {
					return e.Left, exprOut{}
				}

				// "(null ?? fn)()" => "fn()"
				// "(null ?? this.fn)" => "this.fn"
				// "(null ?? this.fn)()" => "(0, this.fn)()"
				if isCallTarget && hasValueForThisInCall(e.Right) {
					return js_ast.JoinWithComma(js_ast.Expr{Loc: e.Left.Loc, Data: &js_ast.ENumber{}}, e.Right), exprOut{}
				}

				return e.Right, exprOut{}
			}

			if p.options.unsupportedJSFeatures.Has(compat.NullishCoalescing) {
				return p.lowerNullishCoalescing(expr.Loc, e.Left, e.Right), exprOut{}
			}

		case js_ast.BinOpLogicalOr:
			if boolean, ok := toBooleanWithoutSideEffects(e.Left.Data); ok {
				if boolean {
					return e.Left, exprOut{}
				} else {
					// "(0 || fn)()" => "fn()"
					// "(0 || this.fn)" => "this.fn"
					// "(0 || this.fn)()" => "(0, this.fn)()"
					if isCallTarget && hasValueForThisInCall(e.Right) {
						return js_ast.JoinWithComma(js_ast.Expr{Loc: e.Left.Loc, Data: &js_ast.ENumber{}}, e.Right), exprOut{}
					}
					return e.Right, exprOut{}
				}
			}

			if p.options.mangleSyntax {
				// "a || (b || c)" => "a || b || c"
				if right, ok := e.Right.Data.(*js_ast.EBinary); ok && right.Op == js_ast.BinOpLogicalOr {
					e.Left.Data = &js_ast.EBinary{Op: js_ast.BinOpLogicalOr, Left: e.Left, Right: right.Left}
					e.Right = right.Right
				}

				// "a === null || a === undefined" => "a == null"
				if left, right, ok := isBinaryNullAndUndefined(e.Left, e.Right, js_ast.BinOpStrictEq); ok {
					e.Op = js_ast.BinOpLooseEq
					e.Left = left
					e.Right = right
				}
			}

		case js_ast.BinOpLogicalAnd:
			if boolean, ok := toBooleanWithoutSideEffects(e.Left.Data); ok {
				if boolean {
					// "(1 && fn)()" => "fn()"
					// "(1 && this.fn)" => "this.fn"
					// "(1 && this.fn)()" => "(0, this.fn)()"
					if isCallTarget && hasValueForThisInCall(e.Right) {
						return js_ast.JoinWithComma(js_ast.Expr{Loc: e.Left.Loc, Data: &js_ast.ENumber{}}, e.Right), exprOut{}
					}
					return e.Right, exprOut{}
				} else {
					return e.Left, exprOut{}
				}
			}

			if p.options.mangleSyntax {
				// "a && (b && c)" => "a && b && c"
				if right, ok := e.Right.Data.(*js_ast.EBinary); ok && right.Op == js_ast.BinOpLogicalAnd {
					e.Left.Data = &js_ast.EBinary{Op: js_ast.BinOpLogicalAnd, Left: e.Left, Right: right.Left}
					e.Right = right.Right
				}

				// "a !== null && a !== undefined" => "a != null"
				if left, right, ok := isBinaryNullAndUndefined(e.Left, e.Right, js_ast.BinOpStrictNe); ok {
					e.Op = js_ast.BinOpLooseNe
					e.Left = left
					e.Right = right
				}
			}

		case js_ast.BinOpAdd:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: left + right}}, exprOut{}
				}
			}

			// "'abc' + 'xyz'" => "'abcxyz'"
			if result := foldStringAddition(e.Left, e.Right); result != nil {
				return *result, exprOut{}
			}

			if left, ok := e.Left.Data.(*js_ast.EBinary); ok && left.Op == js_ast.BinOpAdd {
				// "x + 'abc' + 'xyz'" => "x + 'abcxyz'"
				if result := foldStringAddition(left.Right, e.Right); result != nil {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EBinary{Op: left.Op, Left: left.Left, Right: *result}}, exprOut{}
				}
			}

		case js_ast.BinOpSub:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: left - right}}, exprOut{}
				}
			}

		case js_ast.BinOpMul:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: left * right}}, exprOut{}
				}
			}

		case js_ast.BinOpDiv:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: left / right}}, exprOut{}
				}
			}

		case js_ast.BinOpRem:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: math.Mod(left, right)}}, exprOut{}
				}
			}

		case js_ast.BinOpPow:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: math.Pow(left, right)}}, exprOut{}
				}
			}

			// Lower the exponentiation operator for browsers that don't support it
			if p.options.unsupportedJSFeatures.Has(compat.ExponentOperator) {
				return p.callRuntime(expr.Loc, "__pow", []js_ast.Expr{e.Left, e.Right}), exprOut{}
			}

		case js_ast.BinOpShl:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: float64(toInt32(left) << (toUint32(right) & 31))}}, exprOut{}
				}
			}

		case js_ast.BinOpShr:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: float64(toInt32(left) >> (toUint32(right) & 31))}}, exprOut{}
				}
			}

		case js_ast.BinOpUShr:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: float64(toUint32(left) >> (toUint32(right) & 31))}}, exprOut{}
				}
			}

		case js_ast.BinOpBitwiseAnd:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: float64(toInt32(left) & toInt32(right))}}, exprOut{}
				}
			}

		case js_ast.BinOpBitwiseOr:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: float64(toInt32(left) | toInt32(right))}}, exprOut{}
				}
			}

		case js_ast.BinOpBitwiseXor:
			if p.shouldFoldNumericConstants {
				if left, right, ok := extractNumericValues(e.Left, e.Right); ok {
					return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: float64(toInt32(left) ^ toInt32(right))}}, exprOut{}
				}
			}

			////////////////////////////////////////////////////////////////////////////////
			// All assignment operators below here

		case js_ast.BinOpAssign:
			// Warn if an identifier is re-assigned to itself
			if in.assignTarget == js_ast.AssignTargetNone && e.WasIdentifierAssign && !p.options.suppressWarningsAboutWeirdCode {
				if left, ok := e.Left.Data.(*js_ast.EIdentifier); ok && !left.WasTypeScriptCast {
					if right, ok := e.Right.Data.(*js_ast.EIdentifier); ok && !right.WasTypeScriptCast {
						if left.Ref == right.Ref && p.symbols[left.Ref.InnerIndex].Kind != js_ast.SymbolUnbound {
							a := js_lexer.RangeOfIdentifier(p.source, e.Left.Loc)
							b := js_lexer.RangeOfIdentifier(p.source, e.Right.Loc)
							r := logger.Range{Loc: a.Loc, Len: b.End() - a.Loc.Start}
							p.log.AddRangeWarning(&p.source, r, fmt.Sprintf("Assignment of %q to itself has no effect",
								p.symbols[left.Ref.InnerIndex].OriginalName))
						}
					}
				}
			}

			// Optionally preserve the name
			if id, ok := e.Left.Data.(*js_ast.EIdentifier); ok {
				e.Right = p.maybeKeepExprSymbolName(e.Right, p.symbols[id.Ref.InnerIndex].OriginalName, wasAnonymousNamedExpr)
			}

			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSet(target, loc, private, e.Right), exprOut{}
			}

			// Lower object rest patterns for browsers that don't support them. Note
			// that assignment expressions are used to represent initializers in
			// binding patterns, so only do this if we're not ourselves the target of
			// an assignment. Example: "[a = b] = c"
			if in.assignTarget == js_ast.AssignTargetNone {
				if result, ok := p.lowerObjectRestInAssign(e.Left, e.Right); ok {
					return result, exprOut{}
				}
			}

		case js_ast.BinOpAddAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpAdd, e.Right), exprOut{}
			}

		case js_ast.BinOpSubAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpSub, e.Right), exprOut{}
			}

		case js_ast.BinOpMulAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpMul, e.Right), exprOut{}
			}

		case js_ast.BinOpDivAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpDiv, e.Right), exprOut{}
			}

		case js_ast.BinOpRemAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpRem, e.Right), exprOut{}
			}

		case js_ast.BinOpPowAssign:
			// Lower the exponentiation operator for browsers that don't support it
			if p.options.unsupportedJSFeatures.Has(compat.ExponentOperator) {
				return p.lowerExponentiationAssignmentOperator(expr.Loc, e), exprOut{}
			}

			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpPow, e.Right), exprOut{}
			}

		case js_ast.BinOpShlAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpShl, e.Right), exprOut{}
			}

		case js_ast.BinOpShrAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpShr, e.Right), exprOut{}
			}

		case js_ast.BinOpUShrAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpUShr, e.Right), exprOut{}
			}

		case js_ast.BinOpBitwiseOrAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpBitwiseOr, e.Right), exprOut{}
			}

		case js_ast.BinOpBitwiseAndAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpBitwiseAnd, e.Right), exprOut{}
			}

		case js_ast.BinOpBitwiseXorAssign:
			if target, loc, private := p.extractPrivateIndex(e.Left); private != nil {
				return p.lowerPrivateSetBinOp(target, loc, private, js_ast.BinOpBitwiseXor, e.Right), exprOut{}
			}

		case js_ast.BinOpNullishCoalescingAssign:
			if p.options.unsupportedJSFeatures.Has(compat.LogicalAssignment) {
				return p.lowerNullishCoalescingAssignmentOperator(expr.Loc, e), exprOut{}
			}

		case js_ast.BinOpLogicalAndAssign:
			if p.options.unsupportedJSFeatures.Has(compat.LogicalAssignment) {
				return p.lowerLogicalAssignmentOperator(expr.Loc, e, js_ast.BinOpLogicalAnd), exprOut{}
			}

		case js_ast.BinOpLogicalOrAssign:
			if p.options.unsupportedJSFeatures.Has(compat.LogicalAssignment) {
				return p.lowerLogicalAssignmentOperator(expr.Loc, e, js_ast.BinOpLogicalOr), exprOut{}
			}
		}

	case *js_ast.EIndex:
		// "a['b']" => "a.b"
		if p.options.mangleSyntax {
			if str, ok := e.Index.Data.(*js_ast.EString); ok && js_lexer.IsIdentifierUTF16(str.Value) {
				return p.visitExprInOut(js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EDot{
					Target:        e.Target,
					Name:          js_lexer.UTF16ToString(str.Value),
					NameLoc:       e.Index.Loc,
					OptionalChain: e.OptionalChain,
				}}, in)
			}
		}

		isCallTarget := e == p.callTarget
		isDeleteTarget := e == p.deleteTarget
		target, out := p.visitExprInOut(e.Target, exprIn{
			hasChainParent: e.OptionalChain == js_ast.OptionalChainContinue,
		})
		e.Target = target

		// Special-case EPrivateIdentifier to allow it here
		if private, ok := e.Index.Data.(*js_ast.EPrivateIdentifier); ok {
			name := p.loadNameFromRef(private.Ref)
			result := p.findSymbol(e.Index.Loc, name)
			private.Ref = result.ref

			// Unlike regular identifiers, there are no unbound private identifiers
			kind := p.symbols[result.ref.InnerIndex].Kind
			if !kind.IsPrivate() {
				r := logger.Range{Loc: e.Index.Loc, Len: int32(len(name))}
				p.log.AddRangeError(&p.source, r, fmt.Sprintf("Private name %q must be declared in an enclosing class", name))
			} else if !p.options.suppressWarningsAboutWeirdCode {
				if in.assignTarget != js_ast.AssignTargetNone && (kind == js_ast.SymbolPrivateGet || kind == js_ast.SymbolPrivateStaticGet) {
					r := logger.Range{Loc: e.Index.Loc, Len: int32(len(name))}
					p.log.AddRangeWarning(&p.source, r, fmt.Sprintf("Writing to getter-only property %q will throw", name))
				} else if in.assignTarget != js_ast.AssignTargetReplace && (kind == js_ast.SymbolPrivateSet || kind == js_ast.SymbolPrivateStaticSet) {
					r := logger.Range{Loc: e.Index.Loc, Len: int32(len(name))}
					p.log.AddRangeWarning(&p.source, r, fmt.Sprintf("Reading from setter-only property %q will throw", name))
				}
			}

			// Lower private member access only if we're sure the target isn't needed
			// for the value of "this" for a call expression. All other cases will be
			// taken care of by the enclosing call expression.
			if p.options.unsupportedJSFeatures.Has(kind.Feature()) && e.OptionalChain == js_ast.OptionalChainNone &&
				in.assignTarget == js_ast.AssignTargetNone && !isCallTarget {
				// "foo.#bar" => "__privateGet(foo, #bar)"
				return p.lowerPrivateGet(e.Target, e.Index.Loc, private), exprOut{}
			}
		} else {
			e.Index = p.visitExpr(e.Index)
		}

		// Lower "super[prop]" if necessary
		if !isCallTarget && p.shouldLowerSuperPropertyAccess(e.Target) {
			return p.lowerSuperPropertyAccess(expr.Loc, e.Index), exprOut{}
		}

		// Lower optional chaining if we're the top of the chain
		containsOptionalChain := e.OptionalChain != js_ast.OptionalChainNone
		if containsOptionalChain && !in.hasChainParent {
			return p.lowerOptionalChain(expr, in, out, nil)
		}

		// Potentially rewrite this property access
		out = exprOut{childContainsOptionalChain: containsOptionalChain}
		if str, ok := e.Index.Data.(*js_ast.EString); ok {
			name := js_lexer.UTF16ToString(str.Value)
			if value, ok := p.maybeRewritePropertyAccess(
				expr.Loc, in.assignTarget, isDeleteTarget, e.OptionalChain, e.Target, name, e.Index.Loc, isCallTarget); ok {
				return value, out
			}
		}

		// Create an error for assigning to an import namespace when bundling. Even
		// though this is a run-time error, we make it a compile-time error when
		// bundling because scope hoisting means these will no longer be run-time
		// errors.
		if p.options.mode == config.ModeBundle && (in.assignTarget != js_ast.AssignTargetNone || isDeleteTarget) {
			if id, ok := e.Target.Data.(*js_ast.EIdentifier); ok && p.symbols[id.Ref.InnerIndex].Kind == js_ast.SymbolImport {
				r := js_lexer.RangeOfIdentifier(p.source, e.Target.Loc)
				p.log.AddRangeError(&p.source, r, fmt.Sprintf("Cannot assign to property on import %q", p.symbols[id.Ref.InnerIndex].OriginalName))
			}
		}

		return js_ast.Expr{Loc: expr.Loc, Data: e}, out

	case *js_ast.EUnary:
		switch e.Op {
		case js_ast.UnOpTypeof:
			p.typeofTarget = e.Value.Data

			_, idBefore := e.Value.Data.(*js_ast.EIdentifier)
			e.Value, _ = p.visitExprInOut(e.Value, exprIn{assignTarget: e.Op.UnaryAssignTarget()})
			id, idAfter := e.Value.Data.(*js_ast.EIdentifier)

			// The expression "typeof (0, x)" must not become "typeof x" if "x"
			// is unbound because that could suppress a ReferenceError from "x"
			if !idBefore && idAfter && p.symbols[id.Ref.InnerIndex].Kind == js_ast.SymbolUnbound {
				e.Value = js_ast.JoinWithComma(js_ast.Expr{Loc: e.Value.Loc, Data: &js_ast.ENumber{}}, e.Value)
			}

			// "typeof require" => "'function'"
			if p.options.mode == config.ModeBundle {
				if id, ok := e.Value.Data.(*js_ast.EIdentifier); ok && id.Ref == p.requireRef {
					p.ignoreUsage(p.requireRef)
					p.typeofRequire = &js_ast.EString{Value: js_lexer.StringToUTF16("function")}
					return js_ast.Expr{Loc: expr.Loc, Data: p.typeofRequire}, exprOut{}
				}
			}

			if typeof, ok := typeofWithoutSideEffects(e.Value.Data); ok {
				return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EString{Value: js_lexer.StringToUTF16(typeof)}}, exprOut{}
			}

			return expr, exprOut{}

		case js_ast.UnOpDelete:
			// Warn about code that tries to do "delete super.foo"
			var superPropLoc logger.Loc
			switch e2 := e.Value.Data.(type) {
			case *js_ast.EDot:
				if _, ok := e2.Target.Data.(*js_ast.ESuper); ok {
					superPropLoc = e2.Target.Loc
				}
			case *js_ast.EIndex:
				if _, ok := e2.Target.Data.(*js_ast.ESuper); ok {
					superPropLoc = e2.Target.Loc
				}
			}
			if !p.options.suppressWarningsAboutWeirdCode && superPropLoc.Start != 0 {
				r := js_lexer.RangeOfIdentifier(p.source, superPropLoc)
				p.log.AddRangeWarning(&p.source, r, "Attempting to delete a property of \"super\" will throw a ReferenceError")
			}

			p.deleteTarget = e.Value.Data
			canBeDeletedBefore := canBeDeleted(e.Value)
			value, out := p.visitExprInOut(e.Value, exprIn{hasChainParent: true})
			e.Value = value
			canBeDeletedAfter := canBeDeleted(e.Value)

			// Lower optional chaining if present since we're guaranteed to be the
			// end of the chain
			if out.childContainsOptionalChain {
				return p.lowerOptionalChain(expr, in, out, nil)
			}

			// Make sure we don't accidentally change the return value
			//
			//   Returns false:
			//     "var a; delete (a)"
			//     "var a = Object.freeze({b: 1}); delete (a.b)"
			//     "var a = Object.freeze({b: 1}); delete (a?.b)"
			//     "var a = Object.freeze({b: 1}); delete (a['b'])"
			//     "var a = Object.freeze({b: 1}); delete (a?.['b'])"
			//
			//   Returns true:
			//     "var a; delete (0, a)"
			//     "var a = Object.freeze({b: 1}); delete (true && a.b)"
			//     "var a = Object.freeze({b: 1}); delete (false || a?.b)"
			//     "var a = Object.freeze({b: 1}); delete (null ?? a?.['b'])"
			//     "var a = Object.freeze({b: 1}); delete (true ? a['b'] : a['b'])"
			//
			if canBeDeletedAfter && !canBeDeletedBefore {
				e.Value = js_ast.JoinWithComma(js_ast.Expr{Loc: e.Value.Loc, Data: &js_ast.ENumber{}}, e.Value)
			}

			return expr, exprOut{}
		}

		e.Value, _ = p.visitExprInOut(e.Value, exprIn{assignTarget: e.Op.UnaryAssignTarget()})

		// Post-process the unary expression
		switch e.Op {
		case js_ast.UnOpNot:
			if boolean, ok := toBooleanWithoutSideEffects(e.Value.Data); ok {
				return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EBoolean{Value: !boolean}}, exprOut{}
			}

			// "!!!a" => "!a"
			if not, ok := e.Value.Data.(*js_ast.EUnary); ok && not.Op == js_ast.UnOpNot && js_ast.IsBooleanValue(not.Value) {
				return not.Value, exprOut{}
			}

		case js_ast.UnOpVoid:
			if p.exprCanBeRemovedIfUnused(e.Value) {
				return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EUndefined{}}, exprOut{}
			}

		case js_ast.UnOpPos:
			if number, ok := toNumberWithoutSideEffects(e.Value.Data); ok {
				return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: number}}, exprOut{}
			}

		case js_ast.UnOpNeg:
			if number, ok := toNumberWithoutSideEffects(e.Value.Data); ok {
				return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.ENumber{Value: -number}}, exprOut{}
			}

			////////////////////////////////////////////////////////////////////////////////
			// All assignment operators below here

		case js_ast.UnOpPreDec:
			if target, loc, private := p.extractPrivateIndex(e.Value); private != nil {
				return p.lowerPrivateSetUnOp(target, loc, private, js_ast.BinOpSub, false), exprOut{}
			}

		case js_ast.UnOpPreInc:
			if target, loc, private := p.extractPrivateIndex(e.Value); private != nil {
				return p.lowerPrivateSetUnOp(target, loc, private, js_ast.BinOpAdd, false), exprOut{}
			}

		case js_ast.UnOpPostDec:
			if target, loc, private := p.extractPrivateIndex(e.Value); private != nil {
				return p.lowerPrivateSetUnOp(target, loc, private, js_ast.BinOpSub, true), exprOut{}
			}

		case js_ast.UnOpPostInc:
			if target, loc, private := p.extractPrivateIndex(e.Value); private != nil {
				return p.lowerPrivateSetUnOp(target, loc, private, js_ast.BinOpAdd, true), exprOut{}
			}
		}

	case *js_ast.EDot:
		isDeleteTarget := e == p.deleteTarget

		// Check both user-specified defines and known globals
		if defines, ok := p.options.defines.DotDefines[e.Name]; ok {
			for _, define := range defines {
				if p.isDotDefineMatch(expr, define.Parts) {
					// Substitute user-specified defines
					if define.Data.DefineFunc != nil {
						return p.valueForDefine(expr.Loc, in.assignTarget, isDeleteTarget, define.Data.DefineFunc), exprOut{}
					}

					// Copy the side effect flags over in case this expression is unused
					if define.Data.CanBeRemovedIfUnused {
						e.CanBeRemovedIfUnused = true
					}
					if define.Data.CallCanBeUnwrappedIfUnused && !p.options.ignoreDCEAnnotations {
						e.CallCanBeUnwrappedIfUnused = true
					}
					if define.Data.WarnAboutLackOfDefine {
						r := js_lexer.RangeOfIdentifier(p.source, e.NameLoc)
						r = logger.Range{Loc: expr.Loc, Len: r.End() - expr.Loc.Start}
						p.warnAboutLackOfDefine(strings.Join(define.Parts, "."), r)
					}
					break
				}
			}
		}

		// Pattern-match "require.main" from node
		if p.options.outputFormat == config.FormatCommonJS && e.Name == "main" {
			p.cjsDotMainTarget = e.Target.Data
		}

		isCallTarget := e == p.callTarget
		target, out := p.visitExprInOut(e.Target, exprIn{
			hasChainParent: e.OptionalChain == js_ast.OptionalChainContinue,
		})
		e.Target = target

		// Lower "super.prop" if necessary
		if !isCallTarget && p.shouldLowerSuperPropertyAccess(e.Target) {
			key := js_ast.Expr{Loc: e.NameLoc, Data: &js_ast.EString{Value: js_lexer.StringToUTF16(e.Name)}}
			return p.lowerSuperPropertyAccess(expr.Loc, key), exprOut{}
		}

		// Lower optional chaining if we're the top of the chain
		containsOptionalChain := e.OptionalChain != js_ast.OptionalChainNone
		if containsOptionalChain && !in.hasChainParent {
			return p.lowerOptionalChain(expr, in, out, nil)
		}

		// Potentially rewrite this property access
		out = exprOut{childContainsOptionalChain: containsOptionalChain}
		if value, ok := p.maybeRewritePropertyAccess(expr.Loc, in.assignTarget, isDeleteTarget, e.OptionalChain, e.Target, e.Name, e.NameLoc, isCallTarget); ok {
			return value, out
		}
		return js_ast.Expr{Loc: expr.Loc, Data: e}, out

	case *js_ast.EIf:
		isCallTarget := e == p.callTarget
		e.Test = p.visitBooleanExpr(e.Test)

		// Fold constants
		if boolean, ok := toBooleanWithoutSideEffects(e.Test.Data); !ok {
			e.Yes = p.visitExpr(e.Yes)
			e.No = p.visitExpr(e.No)
		} else {
			// Mark the control flow as dead if the branch is never taken
			if boolean {
				// "true ? live : dead"
				e.Yes = p.visitExpr(e.Yes)
				old := p.isControlFlowDead
				p.isControlFlowDead = true
				e.No = p.visitExpr(e.No)
				p.isControlFlowDead = old

				// "(1 ? fn : 2)()" => "fn()"
				// "(1 ? this.fn : 2)" => "this.fn"
				// "(1 ? this.fn : 2)()" => "(0, this.fn)()"
				if isCallTarget && hasValueForThisInCall(e.Yes) {
					return js_ast.JoinWithComma(js_ast.Expr{Loc: e.Test.Loc, Data: &js_ast.ENumber{}}, e.Yes), exprOut{}
				}
				return e.Yes, exprOut{}
			} else {
				// "false ? dead : live"
				old := p.isControlFlowDead
				p.isControlFlowDead = true
				e.Yes = p.visitExpr(e.Yes)
				p.isControlFlowDead = old
				e.No = p.visitExpr(e.No)

				// "(0 ? 1 : fn)()" => "fn()"
				// "(0 ? 1 : this.fn)" => "this.fn"
				// "(0 ? 1 : this.fn)()" => "(0, this.fn)()"
				if isCallTarget && hasValueForThisInCall(e.No) {
					return js_ast.JoinWithComma(js_ast.Expr{Loc: e.Test.Loc, Data: &js_ast.ENumber{}}, e.No), exprOut{}
				}
				return e.No, exprOut{}
			}
		}

		if p.options.mangleSyntax {
			return p.mangleIfExpr(expr.Loc, e), exprOut{}
		}

	case *js_ast.EAwait:
		e.Value = p.visitExpr(e.Value)

		// "await" expressions turn into "yield" expressions when lowering
		if p.options.unsupportedJSFeatures.Has(compat.AsyncAwait) {
			return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EYield{Value: &e.Value}}, exprOut{}
		}

	case *js_ast.EYield:
		if e.Value != nil {
			*e.Value = p.visitExpr(*e.Value)
		}

	case *js_ast.EArray:
		if in.assignTarget != js_ast.AssignTargetNone {
			p.markSyntaxFeature(compat.Destructuring, logger.Range{Loc: expr.Loc, Len: 1})
		}
		hasSpread := false
		for i, item := range e.Items {
			switch e2 := item.Data.(type) {
			case *js_ast.EMissing:
			case *js_ast.ESpread:
				e2.Value, _ = p.visitExprInOut(e2.Value, exprIn{assignTarget: in.assignTarget})
				hasSpread = true
			case *js_ast.EBinary:
				if in.assignTarget != js_ast.AssignTargetNone && e2.Op == js_ast.BinOpAssign {
					wasAnonymousNamedExpr := p.isAnonymousNamedExpr(e2.Right)
					e2.Left, _ = p.visitExprInOut(e2.Left, exprIn{assignTarget: js_ast.AssignTargetReplace})
					e2.Right = p.visitExpr(e2.Right)

					// Optionally preserve the name
					if id, ok := e2.Left.Data.(*js_ast.EIdentifier); ok {
						e2.Right = p.maybeKeepExprSymbolName(
							e2.Right, p.symbols[id.Ref.InnerIndex].OriginalName, wasAnonymousNamedExpr)
					}
				} else {
					item, _ = p.visitExprInOut(item, exprIn{assignTarget: in.assignTarget})
				}
			default:
				item, _ = p.visitExprInOut(item, exprIn{assignTarget: in.assignTarget})
			}
			e.Items[i] = item
		}

		// "[1, ...[2, 3], 4]" => "[1, 2, 3, 4]"
		if p.options.mangleSyntax && hasSpread && in.assignTarget == js_ast.AssignTargetNone {
			e.Items = inlineSpreadsOfArrayLiterals(e.Items)
		}

	case *js_ast.EObject:
		if in.assignTarget != js_ast.AssignTargetNone {
			p.markSyntaxFeature(compat.Destructuring, logger.Range{Loc: expr.Loc, Len: 1})
		}
		hasSpread := false
		hasProto := false
		for i := range e.Properties {
			property := &e.Properties[i]

			if property.Kind != js_ast.PropertySpread {
				key := p.visitExpr(property.Key)
				e.Properties[i].Key = key

				// Forbid duplicate "__proto__" properties according to the specification
				if !property.IsComputed && !property.WasShorthand && !property.IsMethod && in.assignTarget == js_ast.AssignTargetNone {
					if str, ok := key.Data.(*js_ast.EString); ok && js_lexer.UTF16EqualsString(str.Value, "__proto__") {
						if hasProto {
							r := js_lexer.RangeOfIdentifier(p.source, key.Loc)
							p.log.AddRangeError(&p.source, r, "Cannot specify the \"__proto__\" property more than once per object")
						}
						hasProto = true
					}
				}
			} else {
				hasSpread = true
			}

			// Extract the initializer for expressions like "({ a: b = c } = d)"
			if in.assignTarget != js_ast.AssignTargetNone && property.Initializer == nil && property.Value != nil {
				if binary, ok := property.Value.Data.(*js_ast.EBinary); ok && binary.Op == js_ast.BinOpAssign {
					property.Initializer = &binary.Right
					property.Value = &binary.Left
				}
			}

			if property.Value != nil {
				*property.Value, _ = p.visitExprInOut(*property.Value, exprIn{assignTarget: in.assignTarget})
			}
			if property.Initializer != nil {
				wasAnonymousNamedExpr := p.isAnonymousNamedExpr(*property.Initializer)
				*property.Initializer = p.visitExpr(*property.Initializer)

				// Optionally preserve the name
				if property.Value != nil {
					if id, ok := property.Value.Data.(*js_ast.EIdentifier); ok {
						*property.Initializer = p.maybeKeepExprSymbolName(
							*property.Initializer, p.symbols[id.Ref.InnerIndex].OriginalName, wasAnonymousNamedExpr)
					}
				}
			}
		}

		if in.assignTarget == js_ast.AssignTargetNone {
			// "{a, ...{b, c}, d}" => "{a, b, c, d}"
			if p.options.mangleSyntax && hasSpread {
				var properties []js_ast.Property
				for _, property := range e.Properties {
					if property.Kind == js_ast.PropertySpread {
						switch v := property.Value.Data.(type) {
						case *js_ast.EBoolean, *js_ast.ENull, *js_ast.EUndefined, *js_ast.ENumber,
							*js_ast.EBigInt, *js_ast.ERegExp, *js_ast.EFunction, *js_ast.EArrow:
							// This value is ignored because it doesn't have any of its own properties
							continue

						case *js_ast.EObject:
							for i, p := range v.Properties {
								// Getters are evaluated at iteration time. The property
								// descriptor is not inlined into the caller. Since we are not
								// evaluating code at compile time, just bail if we hit one
								// and preserve the spread with the remaining properties.
								if p.Kind == js_ast.PropertyGet || p.Kind == js_ast.PropertySet {
									v.Properties = v.Properties[i:]
									properties = append(properties, property)
									break
								}
								properties = append(properties, p)
							}
							continue
						}
					}
					properties = append(properties, property)
				}
				e.Properties = properties
			}

			// Object expressions represent both object literals and binding patterns.
			// Only lower object spread if we're an object literal, not a binding pattern.
			return p.lowerObjectSpread(expr.Loc, e), exprOut{}
		}

	case *js_ast.EImport:
		e.Expr = p.visitExpr(e.Expr)

		return p.maybeTransposeIfExprChain(e.Expr, func(arg js_ast.Expr) js_ast.Expr {
			// The argument must be a string
			if str, ok := arg.Data.(*js_ast.EString); ok {
				// Ignore calls to import() if the control flow is provably dead here.
				// We don't want to spend time scanning the required files if they will
				// never be used.
				if p.isControlFlowDead {
					return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ENull{}}
				}

				importRecordIndex := p.addImportRecord(ast.ImportDynamic, arg.Loc, js_lexer.UTF16ToString(str.Value))
				p.importRecordsForCurrentPart = append(p.importRecordsForCurrentPart, importRecordIndex)
				return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.EImport{
					Expr:                    arg,
					ImportRecordIndex:       &importRecordIndex,
					LeadingInteriorComments: e.LeadingInteriorComments,
				}}
			}

			if p.options.mode == config.ModeBundle {
				r := js_lexer.RangeOfIdentifier(p.source, expr.Loc)
				p.log.AddRangeWarning(&p.source, r,
					"This dynamic import will not be bundled because the argument is not a string literal")
			}

			// We need to convert this into a call to "require()" if ES6 syntax is
			// not supported in the current output format. The full conversion:
			//
			//   Before:
			//     import(foo)
			//
			//   After:
			//     Promise.resolve().then(() => require(foo))
			//
			// This is normally done by the printer since we don't know during the
			// parsing stage whether this module is external or not. However, it's
			// guaranteed to be external if the argument isn't a string. We handle
			// this case here instead of in the printer because both the printer
			// and the linker currently need an import record to handle this case
			// correctly, and you need a string literal to get an import record.
			if !p.options.outputFormat.KeepES6ImportExportSyntax() {
				var then js_ast.Expr
				value := p.callRuntime(arg.Loc, "__toModule", []js_ast.Expr{{Loc: arg.Loc, Data: &js_ast.ECall{
					Target: js_ast.Expr{Loc: arg.Loc, Data: &js_ast.EIdentifier{Ref: p.requireRef}},
					Args:   []js_ast.Expr{arg},
				}}})
				body := js_ast.FnBody{Loc: arg.Loc, Stmts: []js_ast.Stmt{{Loc: arg.Loc, Data: &js_ast.SReturn{Value: &value}}}}
				if p.options.unsupportedJSFeatures.Has(compat.Arrow) {
					then = js_ast.Expr{Loc: arg.Loc, Data: &js_ast.EFunction{Fn: js_ast.Fn{Body: body}}}
				} else {
					then = js_ast.Expr{Loc: arg.Loc, Data: &js_ast.EArrow{Body: body, PreferExpr: true}}
				}
				return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ECall{
					Target: js_ast.Expr{Loc: arg.Loc, Data: &js_ast.EDot{
						Target: js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ECall{
							Target: js_ast.Expr{Loc: arg.Loc, Data: &js_ast.EDot{
								Target:  js_ast.Expr{Loc: arg.Loc, Data: &js_ast.EIdentifier{Ref: p.makePromiseRef()}},
								Name:    "resolve",
								NameLoc: arg.Loc,
							}},
						}},
						Name:    "then",
						NameLoc: arg.Loc,
					}},
					Args: []js_ast.Expr{then},
				}}
			}

			return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.EImport{
				Expr:                    arg,
				LeadingInteriorComments: e.LeadingInteriorComments,
			}}
		}), exprOut{}

	case *js_ast.ECall:
		var storeThisArg func(js_ast.Expr) js_ast.Expr
		var thisArgFunc func() js_ast.Expr
		var thisArgWrapFunc func(js_ast.Expr) js_ast.Expr
		p.callTarget = e.Target.Data
		if e.OptionalChain == js_ast.OptionalChainStart {
			// Signal to our child if this is an ECall at the start of an optional
			// chain. If so, the child will need to stash the "this" context for us
			// that we need for the ".call(this, ...args)".
			storeThisArg = func(thisArg js_ast.Expr) js_ast.Expr {
				thisArgFunc, thisArgWrapFunc = p.captureValueWithPossibleSideEffects(thisArg.Loc, 2, thisArg)
				return thisArgFunc()
			}
		}

		// Prepare to recognize "require.resolve()" calls
		couldBeRequireResolve := false
		if len(e.Args) == 1 && p.options.mode != config.ModePassThrough {
			if dot, ok := e.Target.Data.(*js_ast.EDot); ok && dot.OptionalChain == js_ast.OptionalChainNone && dot.Name == "resolve" {
				p.resolveCallTarget = dot.Target.Data
				couldBeRequireResolve = true
			}
		}

		_, wasIdentifierBeforeVisit := e.Target.Data.(*js_ast.EIdentifier)
		target, out := p.visitExprInOut(e.Target, exprIn{
			hasChainParent:                     e.OptionalChain == js_ast.OptionalChainContinue,
			storeThisArgForParentOptionalChain: storeThisArg,
		})
		e.Target = target
		hasSpread := false
		for i, arg := range e.Args {
			arg = p.visitExpr(arg)
			if _, ok := arg.Data.(*js_ast.ESpread); ok {
				hasSpread = true
			}
			e.Args[i] = arg
		}

		// Recognize "require.resolve()" calls
		if couldBeRequireResolve {
			if dot, ok := e.Target.Data.(*js_ast.EDot); ok {
				if id, ok := dot.Target.Data.(*js_ast.EIdentifier); ok && id.Ref == p.requireRef {
					return p.maybeTransposeIfExprChain(e.Args[0], func(arg js_ast.Expr) js_ast.Expr {
						if str, ok := e.Args[0].Data.(*js_ast.EString); ok {
							// Ignore calls to require.resolve() if the control flow is provably
							// dead here. We don't want to spend time scanning the required files
							// if they will never be used.
							if p.isControlFlowDead {
								return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ENull{}}
							}

							importRecordIndex := p.addImportRecord(ast.ImportRequireResolve, e.Args[0].Loc, js_lexer.UTF16ToString(str.Value))
							p.importRecords[importRecordIndex].IsInsideTryBody = p.fnOrArrowDataVisit.tryBodyCount != 0
							p.importRecordsForCurrentPart = append(p.importRecordsForCurrentPart, importRecordIndex)

							// Create a new expression to represent the operation
							p.ignoreUsage(p.requireRef)
							return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ERequireResolve{ImportRecordIndex: importRecordIndex}}
						}

						// Otherwise just return a clone of the "require.resolve()" call
						return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ECall{
							Target: js_ast.Expr{Loc: e.Target.Loc, Data: &js_ast.EDot{
								Target:  js_ast.Expr{Loc: dot.Target.Loc, Data: &js_ast.EIdentifier{Ref: id.Ref}},
								Name:    dot.Name,
								NameLoc: dot.NameLoc,
							}},
							Args: []js_ast.Expr{arg},
						}}
					}), exprOut{}
				}
			}
		}

		// "foo(1, ...[2, 3], 4)" => "foo(1, 2, 3, 4)"
		if p.options.mangleSyntax && hasSpread && in.assignTarget == js_ast.AssignTargetNone {
			e.Args = inlineSpreadsOfArrayLiterals(e.Args)
		}

		// Detect if this is a direct eval. Note that "(1 ? eval : 0)(x)" will
		// become "eval(x)" after we visit the target due to dead code elimination,
		// but that doesn't mean it should become a direct eval.
		if wasIdentifierBeforeVisit {
			if id, ok := e.Target.Data.(*js_ast.EIdentifier); ok {
				if symbol := p.symbols[id.Ref.InnerIndex]; symbol.OriginalName == "eval" {
					e.IsDirectEval = true

					// Mark this scope and all parent scopes as containing a direct eval.
					// This will prevent us from renaming any symbols.
					for s := p.currentScope; s != nil; s = s.Parent {
						s.ContainsDirectEval = true
					}
				}
			}
		}

		// Copy the call side effect flag over if this is a known target
		switch t := target.Data.(type) {
		case *js_ast.EIdentifier:
			if t.CallCanBeUnwrappedIfUnused {
				e.CanBeUnwrappedIfUnused = true
			}
		case *js_ast.EDot:
			if t.CallCanBeUnwrappedIfUnused {
				e.CanBeUnwrappedIfUnused = true
			}
		}

		// Lower optional chaining if we're the top of the chain
		containsOptionalChain := e.OptionalChain != js_ast.OptionalChainNone
		if containsOptionalChain && !in.hasChainParent {
			result, out := p.lowerOptionalChain(expr, in, out, thisArgFunc)
			if thisArgWrapFunc != nil {
				result = thisArgWrapFunc(result)
			}
			return result, out
		}

		// If this is a plain call expression (instead of an optional chain), lower
		// private member access in the call target now if there is one
		if !containsOptionalChain {
			if target, loc, private := p.extractPrivateIndex(e.Target); private != nil {
				// "foo.#bar(123)" => "__privateGet(foo, #bar).call(foo, 123)"
				targetFunc, targetWrapFunc := p.captureValueWithPossibleSideEffects(target.Loc, 2, target)
				return targetWrapFunc(js_ast.Expr{Loc: target.Loc, Data: &js_ast.ECall{
					Target: js_ast.Expr{Loc: target.Loc, Data: &js_ast.EDot{
						Target:  p.lowerPrivateGet(targetFunc(), loc, private),
						Name:    "call",
						NameLoc: target.Loc,
					}},
					Args:                   append([]js_ast.Expr{targetFunc()}, e.Args...),
					CanBeUnwrappedIfUnused: e.CanBeUnwrappedIfUnused,
				}}), exprOut{}
			}
			p.maybeLowerSuperPropertyAccessInsideCall(e)
		}

		// Track calls to require() so we can use them while bundling
		if p.options.mode != config.ModePassThrough && e.OptionalChain == js_ast.OptionalChainNone {
			if id, ok := e.Target.Data.(*js_ast.EIdentifier); ok && id.Ref == p.requireRef {
				// Heuristic: omit warnings inside try/catch blocks because presumably
				// the try/catch statement is there to handle the potential run-time
				// error from the unbundled require() call failing.
				omitWarnings := p.fnOrArrowDataVisit.tryBodyCount != 0

				if p.options.mode == config.ModeBundle {
					// There must be one argument
					if len(e.Args) == 1 {
						return p.maybeTransposeIfExprChain(e.Args[0], func(arg js_ast.Expr) js_ast.Expr {
							// The argument must be a string
							if str, ok := arg.Data.(*js_ast.EString); ok {
								// Ignore calls to require() if the control flow is provably dead here.
								// We don't want to spend time scanning the required files if they will
								// never be used.
								if p.isControlFlowDead {
									return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ENull{}}
								}

								importRecordIndex := p.addImportRecord(ast.ImportRequire, arg.Loc, js_lexer.UTF16ToString(str.Value))
								p.importRecords[importRecordIndex].IsInsideTryBody = p.fnOrArrowDataVisit.tryBodyCount != 0
								p.importRecordsForCurrentPart = append(p.importRecordsForCurrentPart, importRecordIndex)

								// Create a new expression to represent the operation
								p.ignoreUsage(p.requireRef)
								return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ERequire{ImportRecordIndex: importRecordIndex}}
							}

							if !omitWarnings {
								r := js_lexer.RangeOfIdentifier(p.source, e.Target.Loc)
								p.log.AddRangeWarning(&p.source, r,
									"This call to \"require\" will not be bundled because the argument is not a string literal")
							}

							// Otherwise just return a clone of the "require()" call
							return js_ast.Expr{Loc: arg.Loc, Data: &js_ast.ECall{
								Target: js_ast.Expr{Loc: e.Target.Loc, Data: &js_ast.EIdentifier{Ref: id.Ref}},
								Args:   []js_ast.Expr{arg},
							}}
						}), exprOut{}
					} else if !omitWarnings {
						r := js_lexer.RangeOfIdentifier(p.source, e.Target.Loc)
						p.log.AddRangeWarning(&p.source, r, fmt.Sprintf(
							"This call to \"require\" will not be bundled because it has %d arguments", len(e.Args)))
					}
				} else if p.options.outputFormat == config.FormatESModule && !omitWarnings {
					r := js_lexer.RangeOfIdentifier(p.source, e.Target.Loc)
					p.log.AddRangeWarning(&p.source, r, "Converting \"require\" to \"esm\" is currently not supported")
				}
			}
		}

		return expr, exprOut{
			childContainsOptionalChain: containsOptionalChain,
		}

	case *js_ast.ENew:
		e.Target = p.visitExpr(e.Target)
		for i, arg := range e.Args {
			e.Args[i] = p.visitExpr(arg)
		}

	case *js_ast.EArrow:
		oldFnOrArrowData := p.fnOrArrowDataVisit
		p.fnOrArrowDataVisit = fnOrArrowDataVisit{
			isArrow: true,
			isAsync: e.IsAsync,
		}

		// Mark if we're inside an async arrow function. This value should be true
		// even if we're inside multiple arrow functions and the closest inclosing
		// arrow function isn't async, as long as at least one enclosing arrow
		// function within the current enclosing function is async.
		oldInsideAsyncArrowFn := p.fnOnlyDataVisit.isInsideAsyncArrowFn
		if e.IsAsync {
			p.fnOnlyDataVisit.isInsideAsyncArrowFn = true
		}

		p.pushScopeForVisitPass(js_ast.ScopeFunctionArgs, expr.Loc)
		p.visitArgs(e.Args)
		p.pushScopeForVisitPass(js_ast.ScopeFunctionBody, e.Body.Loc)
		e.Body.Stmts = p.visitStmtsAndPrependTempRefs(e.Body.Stmts, prependTempRefsOpts{})
		p.popScope()
		p.lowerFunction(&e.IsAsync, &e.Args, e.Body.Loc, &e.Body.Stmts, &e.PreferExpr, &e.HasRestArg, true /* isArrow */)
		p.popScope()

		if p.options.mangleSyntax && len(e.Body.Stmts) == 1 {
			if s, ok := e.Body.Stmts[0].Data.(*js_ast.SReturn); ok {
				if s.Value == nil {
					// "() => { return }" => "() => {}"
					e.Body.Stmts = []js_ast.Stmt{}
				} else {
					// "() => { return x }" => "() => x"
					e.PreferExpr = true
				}
			}
		}

		p.fnOnlyDataVisit.isInsideAsyncArrowFn = oldInsideAsyncArrowFn
		p.fnOrArrowDataVisit = oldFnOrArrowData

		// Convert arrow functions to function expressions when lowering
		if p.options.unsupportedJSFeatures.Has(compat.Arrow) {
			return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EFunction{Fn: js_ast.Fn{
				Args:         e.Args,
				Body:         e.Body,
				ArgumentsRef: js_ast.InvalidRef,
				IsAsync:      e.IsAsync,
				HasRestArg:   e.HasRestArg,
			}}}, exprOut{}
		}

	case *js_ast.EFunction:
		p.visitFn(&e.Fn, expr.Loc)
		name := e.Fn.Name

		// Remove unused function names when minifying
		if p.options.mangleSyntax && name != nil && p.symbols[name.Ref.InnerIndex].UseCountEstimate == 0 {
			e.Fn.Name = nil
		}

		// Optionally preserve the name
		if p.options.keepNames && name != nil {
			expr = p.keepExprSymbolName(expr, p.symbols[name.Ref.InnerIndex].OriginalName)
		}

	case *js_ast.EClass:
		shadowRef := p.visitClass(expr.Loc, &e.Class)

		// Lower class field syntax for browsers that don't support it
		_, expr = p.lowerClass(js_ast.Stmt{}, expr, shadowRef)

	default:
		panic("Internal error")
	}

	return expr, exprOut{}
}

func (p *parser) valueForDefine(loc logger.Loc, assignTarget js_ast.AssignTarget, isDeleteTarget bool, defineFunc config.DefineFunc) js_ast.Expr {
	expr := js_ast.Expr{Loc: loc, Data: defineFunc(loc, p.findSymbolHelper)}
	if id, ok := expr.Data.(*js_ast.EIdentifier); ok {
		return p.handleIdentifier(loc, assignTarget, isDeleteTarget, id)
	}
	return expr
}

func (p *parser) handleIdentifier(loc logger.Loc, assignTarget js_ast.AssignTarget, isDeleteTarget bool, e *js_ast.EIdentifier) js_ast.Expr {
	ref := e.Ref

	// Capture the "arguments" variable if necessary
	if p.fnOnlyDataVisit.argumentsRef != nil && ref == *p.fnOnlyDataVisit.argumentsRef {
		isInsideUnsupportedArrow := p.fnOrArrowDataVisit.isArrow && p.options.unsupportedJSFeatures.Has(compat.Arrow)
		isInsideUnsupportedAsyncArrow := p.fnOnlyDataVisit.isInsideAsyncArrowFn && p.options.unsupportedJSFeatures.Has(compat.AsyncAwait)
		if isInsideUnsupportedArrow || isInsideUnsupportedAsyncArrow {
			return js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: p.captureArguments()}}
		}
	}

	if p.options.mode == config.ModeBundle && (assignTarget != js_ast.AssignTargetNone || isDeleteTarget) {
		if p.symbols[ref.InnerIndex].Kind == js_ast.SymbolImport {
			// Create an error for assigning to an import namespace
			r := js_lexer.RangeOfIdentifier(p.source, loc)
			p.log.AddRangeError(&p.source, r, fmt.Sprintf("Cannot assign to import %q", p.symbols[ref.InnerIndex].OriginalName))
		} else {
			// Remember that this part assigns to this symbol for code splitting
			use := p.symbolUses[ref]
			use.IsAssigned = true
			p.symbolUses[ref] = use
		}
	}

	// Substitute an EImportIdentifier now if this is an import item
	if p.isImportItem[ref] {
		return js_ast.Expr{Loc: loc, Data: &js_ast.EImportIdentifier{Ref: ref}}
	}

	// Substitute a namespace export reference now if appropriate
	if p.options.ts.Parse {
		if nsRef, ok := p.isExportedInsideNamespace[ref]; ok {
			name := p.symbols[ref.InnerIndex].OriginalName

			// If this is a known enum value, inline the value of the enum
			if enumValueMap, ok := p.knownEnumValues[nsRef]; ok {
				if number, ok := enumValueMap[name]; ok {
					return js_ast.Expr{Loc: loc, Data: &js_ast.ENumber{Value: number}}
				}
			}

			// Otherwise, create a property access on the namespace
			p.recordUsage(nsRef)
			return js_ast.Expr{Loc: loc, Data: &js_ast.EDot{
				Target:  js_ast.Expr{Loc: loc, Data: &js_ast.EIdentifier{Ref: nsRef}},
				Name:    name,
				NameLoc: loc,
			}}
		}
	}

	// Warn about uses of "require" other than a direct call
	if ref == p.requireRef && e != p.callTarget && e != p.typeofTarget && e != p.cjsDotMainTarget && p.fnOrArrowDataVisit.tryBodyCount == 0 {
		// "typeof require == 'function' && require"
		if e == p.typeofRequireEqualsFnTarget {
			// Become "false" in the browser and "require" in node
			if p.options.platform == config.PlatformBrowser {
				return js_ast.Expr{Loc: loc, Data: &js_ast.EBoolean{Value: false}}
			}
		} else if e != p.resolveCallTarget {
			r := js_lexer.RangeOfIdentifier(p.source, loc)
			p.log.AddRangeWarning(&p.source, r,
				"Indirect calls to \"require\" will not be bundled (surround with a try/catch to silence this warning)")
		}
	}

	return js_ast.Expr{Loc: loc, Data: e}
}

func extractNumericValues(left js_ast.Expr, right js_ast.Expr) (float64, float64, bool) {
	if a, ok := left.Data.(*js_ast.ENumber); ok {
		if b, ok := right.Data.(*js_ast.ENumber); ok {
			return a.Value, b.Value, true
		}
	}
	return 0, 0, false
}

func (p *parser) visitFn(fn *js_ast.Fn, scopeLoc logger.Loc) {
	oldFnOrArrowData := p.fnOrArrowDataVisit
	oldFnOnlyData := p.fnOnlyDataVisit
	p.fnOrArrowDataVisit = fnOrArrowDataVisit{
		isAsync: fn.IsAsync,
	}
	p.fnOnlyDataVisit = fnOnlyDataVisit{
		isThisNested: true,
		argumentsRef: &fn.ArgumentsRef,
	}

	if fn.Name != nil {
		p.recordDeclaredSymbol(fn.Name.Ref)
	}

	p.pushScopeForVisitPass(js_ast.ScopeFunctionArgs, scopeLoc)
	p.visitArgs(fn.Args)
	p.pushScopeForVisitPass(js_ast.ScopeFunctionBody, fn.Body.Loc)
	fn.Body.Stmts = p.visitStmtsAndPrependTempRefs(fn.Body.Stmts, prependTempRefsOpts{fnBodyLoc: &fn.Body.Loc})
	p.popScope()
	p.lowerFunction(&fn.IsAsync, &fn.Args, fn.Body.Loc, &fn.Body.Stmts, nil, &fn.HasRestArg, false /* isArrow */)
	p.popScope()

	p.fnOrArrowDataVisit = oldFnOrArrowData
	p.fnOnlyDataVisit = oldFnOnlyData
}

func (p *parser) recordExport(loc logger.Loc, alias string, ref js_ast.Ref) {
	if name, ok := p.namedExports[alias]; ok {
		// Duplicate exports are an error
		p.log.AddRangeErrorWithNotes(&p.source, js_lexer.RangeOfIdentifier(p.source, loc),
			fmt.Sprintf("Multiple exports with the same name %q", alias),
			[]logger.MsgData{logger.RangeData(&p.source, js_lexer.RangeOfIdentifier(p.source, name.AliasLoc),
				fmt.Sprintf("%q was originally exported here", alias))})
	} else {
		p.namedExports[alias] = js_ast.NamedExport{AliasLoc: loc, Ref: ref}
	}
}

func (p *parser) recordExportedBinding(binding js_ast.Binding) {
	switch b := binding.Data.(type) {
	case *js_ast.BMissing:

	case *js_ast.BIdentifier:
		p.recordExport(binding.Loc, p.symbols[b.Ref.InnerIndex].OriginalName, b.Ref)

	case *js_ast.BArray:
		for _, item := range b.Items {
			p.recordExportedBinding(item.Binding)
		}

	case *js_ast.BObject:
		for _, item := range b.Properties {
			p.recordExportedBinding(item.Value)
		}
	default:
		panic("Internal error")
	}
}

type scanForImportsAndExportsResult struct {
	stmts               []js_ast.Stmt
	keptImportEquals    bool
	removedImportEquals bool
}

func (p *parser) scanForImportsAndExports(stmts []js_ast.Stmt) (result scanForImportsAndExportsResult) {
	stmtsEnd := 0

	for _, stmt := range stmts {
		switch s := stmt.Data.(type) {
		case *js_ast.SImport:
			// TypeScript always trims unused imports. This is important for
			// correctness since some imports might be fake (only in the type
			// system and used for type-only imports).
			if p.options.mangleSyntax || p.options.ts.Parse {
				foundImports := false
				isUnusedInTypeScript := true

				// Remove the default name if it's unused
				if s.DefaultName != nil {
					foundImports = true
					symbol := p.symbols[s.DefaultName.Ref.InnerIndex]

					// TypeScript has a separate definition of unused
					if p.options.ts.Parse && p.tsUseCounts[s.DefaultName.Ref.InnerIndex] != 0 {
						isUnusedInTypeScript = false
					}

					// Remove the symbol if it's never used outside a dead code region
					if symbol.UseCountEstimate == 0 {
						s.DefaultName = nil
					}
				}

				// Remove the star import if it's unused
				if s.StarNameLoc != nil {
					foundImports = true
					symbol := p.symbols[s.NamespaceRef.InnerIndex]

					// TypeScript has a separate definition of unused
					if p.options.ts.Parse && p.tsUseCounts[s.NamespaceRef.InnerIndex] != 0 {
						isUnusedInTypeScript = false
					}

					// Remove the symbol if it's never used outside a dead code region
					if symbol.UseCountEstimate == 0 {
						// Make sure we don't remove this if it was used for a property
						// access while bundling
						if importItems, ok := p.importItemsForNamespace[s.NamespaceRef]; ok && len(importItems) == 0 {
							s.StarNameLoc = nil
						}
					}
				}

				// Remove items if they are unused
				if s.Items != nil {
					foundImports = true
					itemsEnd := 0

					for _, item := range *s.Items {
						symbol := p.symbols[item.Name.Ref.InnerIndex]

						// TypeScript has a separate definition of unused
						if p.options.ts.Parse && p.tsUseCounts[item.Name.Ref.InnerIndex] != 0 {
							isUnusedInTypeScript = false
						}

						// Remove the symbol if it's never used outside a dead code region
						if symbol.UseCountEstimate != 0 {
							(*s.Items)[itemsEnd] = item
							itemsEnd++
						}
					}

					// Filter the array by taking a slice
					if itemsEnd == 0 {
						s.Items = nil
					} else {
						*s.Items = (*s.Items)[:itemsEnd]
					}
				}

				// Omit this statement if we're parsing TypeScript and all imports are
				// unused. Note that this is distinct from the case where there were
				// no imports at all (e.g. "import 'foo'"). In that case we want to keep
				// the statement because the user is clearly trying to import the module
				// for side effects.
				//
				// This culling is important for correctness when parsing TypeScript
				// because a) the TypeScript compiler does ths and we want to match it
				// and b) this may be a fake module that only exists in the type system
				// and doesn't actually exist in reality.
				//
				// We do not want to do this culling in JavaScript though because the
				// module may have side effects even if all imports are unused.
				if p.options.ts.Parse && foundImports && isUnusedInTypeScript && !p.options.preserveUnusedImportsTS {
					// Ignore import records with a pre-filled source index. These are
					// for injected files and we definitely do not want to trim these.
					if record := &p.importRecords[s.ImportRecordIndex]; record.SourceIndex == nil {
						record.IsUnused = true
						continue
					}
				}
			}

			if p.options.mode != config.ModePassThrough {
				if s.StarNameLoc != nil {
					// If we're bundling a star import and the namespace is only ever
					// used for property accesses, then convert each unique property to
					// a clause item in the import statement and remove the star import.
					// That will cause the bundler to bundle them more efficiently when
					// both this module and the imported module are in the same group.
					//
					// Before:
					//
					//   import * as ns from 'foo'
					//   console.log(ns.a, ns.b)
					//
					// After:
					//
					//   import {a, b} from 'foo'
					//   console.log(a, b)
					//
					// This is not done if the namespace itself is used, because in that
					// case the code for the namespace will have to be generated. This is
					// determined by the symbol count because the parser only counts the
					// star import as used if it was used for something other than a
					// property access:
					//
					//   import * as ns from 'foo'
					//   console.log(ns, ns.a, ns.b)
					//
					convertStarToClause := p.symbols[s.NamespaceRef.InnerIndex].UseCountEstimate == 0
					if convertStarToClause {
						s.StarNameLoc = nil
					}

					// "importItemsForNamespace" has property accesses off the namespace
					if importItems, ok := p.importItemsForNamespace[s.NamespaceRef]; ok && len(importItems) > 0 {
						// Sort keys for determinism
						sorted := make([]string, 0, len(importItems))
						for alias := range importItems {
							sorted = append(sorted, alias)
						}
						sort.Strings(sorted)

						if convertStarToClause {
							// Create an import clause for these items. Named imports will be
							// automatically created later on since there is now a clause.
							items := make([]js_ast.ClauseItem, 0, len(importItems))
							for _, alias := range sorted {
								name := importItems[alias]
								originalName := p.symbols[name.Ref.InnerIndex].OriginalName
								items = append(items, js_ast.ClauseItem{
									Alias:        alias,
									AliasLoc:     name.Loc,
									Name:         name,
									OriginalName: originalName,
								})
								p.declaredSymbols = append(p.declaredSymbols, js_ast.DeclaredSymbol{
									Ref:        name.Ref,
									IsTopLevel: true,
								})
							}
							if s.Items != nil {
								// The syntax "import {x}, * as y from 'path'" isn't valid
								panic("Internal error")
							}
							s.Items = &items
						} else {
							// If we aren't converting this star import to a clause, still
							// create named imports for these property accesses. This will
							// cause missing imports to generate useful warnings.
							//
							// It will also improve bundling efficiency for internal imports
							// by still converting property accesses off the namespace into
							// bare identifiers even if the namespace is still needed.
							for _, alias := range sorted {
								name := importItems[alias]
								p.namedImports[name.Ref] = js_ast.NamedImport{
									Alias:             alias,
									AliasLoc:          name.Loc,
									NamespaceRef:      s.NamespaceRef,
									ImportRecordIndex: s.ImportRecordIndex,
								}

								// Make sure the printer prints this as a property access
								p.symbols[name.Ref.InnerIndex].NamespaceAlias = &js_ast.NamespaceAlias{
									NamespaceRef: s.NamespaceRef,
									Alias:        alias,
								}
							}
						}
					}
				}

				if s.DefaultName != nil {
					p.namedImports[s.DefaultName.Ref] = js_ast.NamedImport{
						Alias:             "default",
						AliasLoc:          s.DefaultName.Loc,
						NamespaceRef:      s.NamespaceRef,
						ImportRecordIndex: s.ImportRecordIndex,
					}
				}

				if s.StarNameLoc != nil {
					p.namedImports[s.NamespaceRef] = js_ast.NamedImport{
						Alias:             "*",
						AliasLoc:          *s.StarNameLoc,
						NamespaceRef:      js_ast.InvalidRef,
						ImportRecordIndex: s.ImportRecordIndex,
					}
				}

				if s.Items != nil {
					for _, item := range *s.Items {
						p.namedImports[item.Name.Ref] = js_ast.NamedImport{
							Alias:             item.Alias,
							AliasLoc:          item.AliasLoc,
							NamespaceRef:      s.NamespaceRef,
							ImportRecordIndex: s.ImportRecordIndex,
						}
					}
				}
			}

			p.importRecordsForCurrentPart = append(p.importRecordsForCurrentPart, s.ImportRecordIndex)

			if s.StarNameLoc != nil {
				p.importRecords[s.ImportRecordIndex].ContainsImportStar = true
			}

		case *js_ast.SFunction:
			if s.IsExport {
				p.recordExport(s.Fn.Name.Loc, p.symbols[s.Fn.Name.Ref.InnerIndex].OriginalName, s.Fn.Name.Ref)
			}

		case *js_ast.SClass:
			if s.IsExport {
				p.recordExport(s.Class.Name.Loc, p.symbols[s.Class.Name.Ref.InnerIndex].OriginalName, s.Class.Name.Ref)
			}

		case *js_ast.SLocal:
			if s.IsExport {
				for _, decl := range s.Decls {
					p.recordExportedBinding(decl.Binding)
				}
			}

			// Remove unused import-equals statements, since those likely
			// correspond to types instead of values
			if s.WasTSImportEquals && !s.IsExport {
				decl := s.Decls[0]

				// Skip to the underlying reference
				value := *s.Decls[0].Value
				for {
					if dot, ok := value.Data.(*js_ast.EDot); ok {
						value = dot.Target
					} else {
						break
					}
				}

				// Is this an identifier reference and not a require() call?
				if id, ok := value.Data.(*js_ast.EIdentifier); ok {
					// Is this import statement unused?
					if ref := decl.Binding.Data.(*js_ast.BIdentifier).Ref; p.symbols[ref.InnerIndex].UseCountEstimate == 0 {
						// Also don't count the referenced identifier
						p.ignoreUsage(id.Ref)

						// Import-equals statements can come in any order. Removing one
						// could potentially cause another one to be removable too.
						// Continue iterating until a fixed point has been reached to make
						// sure we get them all.
						result.removedImportEquals = true
						continue
					} else {
						result.keptImportEquals = true
					}
				}
			}

		case *js_ast.SExportDefault:
			p.recordExport(s.DefaultName.Loc, "default", s.DefaultName.Ref)

		case *js_ast.SExportClause:
			for _, item := range s.Items {
				p.recordExport(item.AliasLoc, item.Alias, item.Name.Ref)
			}

		case *js_ast.SExportStar:
			p.importRecordsForCurrentPart = append(p.importRecordsForCurrentPart, s.ImportRecordIndex)

			if s.Alias != nil {
				// "export * as ns from 'path'"
				p.namedImports[s.NamespaceRef] = js_ast.NamedImport{
					Alias:             "*",
					AliasLoc:          s.Alias.Loc,
					NamespaceRef:      js_ast.InvalidRef,
					ImportRecordIndex: s.ImportRecordIndex,
					IsExported:        true,
				}
				p.recordExport(s.Alias.Loc, s.Alias.OriginalName, s.NamespaceRef)
			} else {
				// "export * from 'path'"
				p.exportStarImportRecords = append(p.exportStarImportRecords, s.ImportRecordIndex)
			}

		case *js_ast.SExportFrom:
			p.importRecordsForCurrentPart = append(p.importRecordsForCurrentPart, s.ImportRecordIndex)

			for _, item := range s.Items {
				// Note that the imported alias is not item.Alias, which is the
				// exported alias. This is somewhat confusing because each
				// SExportFrom statement is basically SImport + SExportClause in one.
				p.namedImports[item.Name.Ref] = js_ast.NamedImport{
					Alias:             item.OriginalName,
					AliasLoc:          item.Name.Loc,
					NamespaceRef:      s.NamespaceRef,
					ImportRecordIndex: s.ImportRecordIndex,
					IsExported:        true,
				}
				p.recordExport(item.Name.Loc, item.Alias, item.Name.Ref)
			}
		}

		// Filter out statements we skipped over
		stmts[stmtsEnd] = stmt
		stmtsEnd++
	}

	result.stmts = stmts[:stmtsEnd]
	return
}

func (p *parser) appendPart(parts []js_ast.Part, stmts []js_ast.Stmt) []js_ast.Part {
	p.symbolUses = make(map[js_ast.Ref]js_ast.SymbolUse)
	p.declaredSymbols = nil
	p.importRecordsForCurrentPart = nil
	p.scopesForCurrentPart = nil
	part := js_ast.Part{
		Stmts:      p.visitStmtsAndPrependTempRefs(stmts, prependTempRefsOpts{}),
		SymbolUses: p.symbolUses,
	}

	// Insert any relocated variable statements now
	if len(p.relocatedTopLevelVars) > 0 {
		alreadyDeclared := make(map[js_ast.Ref]bool)
		for _, local := range p.relocatedTopLevelVars {
			// Follow links because "var" declarations may be merged due to hoisting
			for {
				link := p.symbols[local.Ref.InnerIndex].Link
				if link == js_ast.InvalidRef {
					break
				}
				local.Ref = link
			}

			// Only declare a given relocated variable once
			if !alreadyDeclared[local.Ref] {
				alreadyDeclared[local.Ref] = true
				part.Stmts = append(part.Stmts, js_ast.Stmt{Loc: local.Loc, Data: &js_ast.SLocal{
					Decls: []js_ast.Decl{{
						Binding: js_ast.Binding{Loc: local.Loc, Data: &js_ast.BIdentifier{Ref: local.Ref}},
					}},
				}})
			}
		}
		p.relocatedTopLevelVars = nil
	}

	if len(part.Stmts) > 0 {
		part.CanBeRemovedIfUnused = p.stmtsCanBeRemovedIfUnused(part.Stmts)
		part.DeclaredSymbols = p.declaredSymbols
		part.ImportRecordIndices = p.importRecordsForCurrentPart
		part.Scopes = p.scopesForCurrentPart
		parts = append(parts, part)
	}
	return parts
}

func (p *parser) stmtsCanBeRemovedIfUnused(stmts []js_ast.Stmt) bool {
	for _, stmt := range stmts {
		switch s := stmt.Data.(type) {
		case *js_ast.SFunction, *js_ast.SEmpty:
			// These never have side effects

		case *js_ast.SImport:
			// Let these be removed if they are unused. Note that we also need to
			// check if the imported file is marked as "sideEffects: false" before we
			// can remove a SImport statement. Otherwise the import must be kept for
			// its side effects.

		case *js_ast.SClass:
			if !p.classCanBeRemovedIfUnused(s.Class) {
				return false
			}

		case *js_ast.SExpr:
			if s.DoesNotAffectTreeShaking {
				// Expressions marked with this are automatically generated and have
				// no side effects by construction.
				break
			}

			if !p.exprCanBeRemovedIfUnused(s.Value) {
				return false
			}

		case *js_ast.SLocal:
			for _, decl := range s.Decls {
				if !p.bindingCanBeRemovedIfUnused(decl.Binding) {
					return false
				}
				if decl.Value != nil && !p.exprCanBeRemovedIfUnused(*decl.Value) {
					return false
				}
			}

		case *js_ast.SExportClause:
			// Exports are tracked separately, so this isn't necessary

		case *js_ast.SExportDefault:
			switch {
			case s.Value.Expr != nil:
				if !p.exprCanBeRemovedIfUnused(*s.Value.Expr) {
					return false
				}

			case s.Value.Stmt != nil:
				switch s2 := s.Value.Stmt.Data.(type) {
				case *js_ast.SFunction:
					// These never have side effects

				case *js_ast.SClass:
					if !p.classCanBeRemovedIfUnused(s2.Class) {
						return false
					}

				default:
					panic("Internal error")
				}
			}

		default:
			// Assume that all statements not explicitly special-cased here have side
			// effects, and cannot be removed even if unused
			return false
		}
	}

	return true
}

func (p *parser) classCanBeRemovedIfUnused(class js_ast.Class) bool {
	if class.Extends != nil && !p.exprCanBeRemovedIfUnused(*class.Extends) {
		return false
	}

	for _, property := range class.Properties {
		if !p.exprCanBeRemovedIfUnused(property.Key) {
			return false
		}
		if property.Value != nil && !p.exprCanBeRemovedIfUnused(*property.Value) {
			return false
		}
		if property.Initializer != nil && !p.exprCanBeRemovedIfUnused(*property.Initializer) {
			return false
		}
	}

	return true
}

func (p *parser) bindingCanBeRemovedIfUnused(binding js_ast.Binding) bool {
	switch b := binding.Data.(type) {
	case *js_ast.BArray:
		for _, item := range b.Items {
			if !p.bindingCanBeRemovedIfUnused(item.Binding) {
				return false
			}
			if item.DefaultValue != nil && !p.exprCanBeRemovedIfUnused(*item.DefaultValue) {
				return false
			}
		}

	case *js_ast.BObject:
		for _, property := range b.Properties {
			if !property.IsSpread && !p.exprCanBeRemovedIfUnused(property.Key) {
				return false
			}
			if !p.bindingCanBeRemovedIfUnused(property.Value) {
				return false
			}
			if property.DefaultValue != nil && !p.exprCanBeRemovedIfUnused(*property.DefaultValue) {
				return false
			}
		}
	}

	return true
}

func (p *parser) exprCanBeRemovedIfUnused(expr js_ast.Expr) bool {
	switch e := expr.Data.(type) {
	case *js_ast.ENull, *js_ast.EUndefined, *js_ast.EMissing, *js_ast.EBoolean, *js_ast.ENumber, *js_ast.EBigInt,
		*js_ast.EString, *js_ast.EThis, *js_ast.ERegExp, *js_ast.EFunction, *js_ast.EArrow, *js_ast.EImportMeta:
		return true

	case *js_ast.EDot:
		return e.CanBeRemovedIfUnused

	case *js_ast.EClass:
		return p.classCanBeRemovedIfUnused(e.Class)

	case *js_ast.EIdentifier:
		if e.CanBeRemovedIfUnused || p.symbols[e.Ref.InnerIndex].Kind != js_ast.SymbolUnbound {
			return true
		}

	case *js_ast.EIf:
		return p.exprCanBeRemovedIfUnused(e.Test) && p.exprCanBeRemovedIfUnused(e.Yes) && p.exprCanBeRemovedIfUnused(e.No)

	case *js_ast.EArray:
		for _, item := range e.Items {
			if !p.exprCanBeRemovedIfUnused(item) {
				return false
			}
		}
		return true

	case *js_ast.EObject:
		for _, property := range e.Properties {
			// The key must still be evaluated if it's computed or a spread
			if property.Kind == js_ast.PropertySpread || property.IsComputed {
				return false
			}
			if property.Value != nil && !p.exprCanBeRemovedIfUnused(*property.Value) {
				return false
			}
		}
		return true

	case *js_ast.ECall:
		// A call that has been marked "__PURE__" can be removed if all arguments
		// can be removed. The annotation causes us to ignore the target.
		if e.CanBeUnwrappedIfUnused {
			for _, arg := range e.Args {
				if !p.exprCanBeRemovedIfUnused(arg) {
					return false
				}
			}
			return true
		}

	case *js_ast.ENew:
		// A constructor call that has been marked "__PURE__" can be removed if all
		// arguments can be removed. The annotation causes us to ignore the target.
		if e.CanBeUnwrappedIfUnused {
			for _, arg := range e.Args {
				if !p.exprCanBeRemovedIfUnused(arg) {
					return false
				}
			}
			return true
		}
	}

	// Assume all other expression types have side effects and cannot be removed
	return false
}

// This will return a nil expression if the expression can be totally removed
func (p *parser) simplifyUnusedExpr(expr js_ast.Expr) js_ast.Expr {
	switch e := expr.Data.(type) {
	case *js_ast.ENull, *js_ast.EUndefined, *js_ast.EMissing, *js_ast.EBoolean, *js_ast.ENumber, *js_ast.EBigInt,
		*js_ast.EString, *js_ast.EThis, *js_ast.ERegExp, *js_ast.EFunction, *js_ast.EArrow, *js_ast.EImportMeta:
		return js_ast.Expr{}

	case *js_ast.EDot:
		if e.CanBeRemovedIfUnused {
			return js_ast.Expr{}
		}

	case *js_ast.EIdentifier:
		if e.CanBeRemovedIfUnused || p.symbols[e.Ref.InnerIndex].Kind != js_ast.SymbolUnbound {
			return js_ast.Expr{}
		}

	case *js_ast.ETemplate:
		if e.Tag == nil {
			var result js_ast.Expr
			for _, part := range e.Parts {
				// Make sure "ToString" is still evaluated on the value
				if result.Data == nil {
					result = js_ast.Expr{Loc: part.Value.Loc, Data: &js_ast.EString{}}
				}
				result = js_ast.Expr{Loc: part.Value.Loc, Data: &js_ast.EBinary{
					Op:    js_ast.BinOpAdd,
					Left:  result,
					Right: part.Value,
				}}
			}
			return result
		}

	case *js_ast.EArray:
		// Arrays with "..." spread expressions can't be unwrapped because the
		// "..." triggers code evaluation via iterators. In that case, just trim
		// the other items instead and leave the array expression there.
		for _, spread := range e.Items {
			if _, ok := spread.Data.(*js_ast.ESpread); ok {
				end := 0
				for _, item := range e.Items {
					item = p.simplifyUnusedExpr(item)
					if item.Data != nil {
						e.Items[end] = item
						end++
					}
				}
				e.Items = e.Items[:end]
				return expr
			}
		}

		// Otherwise, the array can be completely removed. We only need to keep any
		// array items with side effects. Apply this simplification recursively.
		var result js_ast.Expr
		for _, item := range e.Items {
			result = maybeJoinWithComma(result, p.simplifyUnusedExpr(item))
		}
		return result

	case *js_ast.EObject:
		// Objects with "..." spread expressions can't be unwrapped because the
		// "..." triggers code evaluation via getters. In that case, just trim
		// the other items instead and leave the object expression there.
		for _, spread := range e.Properties {
			if spread.Kind == js_ast.PropertySpread {
				end := 0
				for _, property := range e.Properties {
					// Spread properties must always be evaluated
					if property.Kind != js_ast.PropertySpread {
						value := p.simplifyUnusedExpr(*property.Value)
						if value.Data != nil {
							// Keep the value
							*property.Value = value
						} else if !property.IsComputed {
							// Skip this property if the key doesn't need to be computed
							continue
						} else {
							// Replace values without side effects with "0" because it's short
							property.Value.Data = &js_ast.ENumber{}
						}
					}
					e.Properties[end] = property
					end++
				}
				e.Properties = e.Properties[:end]
				return expr
			}
		}

		// Otherwise, the object can be completely removed. We only need to keep any
		// object properties with side effects. Apply this simplification recursively.
		var result js_ast.Expr
		for _, property := range e.Properties {
			if property.IsComputed {
				// Make sure "ToString" is still evaluated on the key
				result = maybeJoinWithComma(result, js_ast.Expr{Loc: property.Key.Loc, Data: &js_ast.EBinary{
					Op:    js_ast.BinOpAdd,
					Left:  property.Key,
					Right: js_ast.Expr{Loc: property.Key.Loc, Data: &js_ast.EString{}},
				}})
			}
			result = maybeJoinWithComma(result, p.simplifyUnusedExpr(*property.Value))
		}
		return result

	case *js_ast.EIf:
		e.Yes = p.simplifyUnusedExpr(e.Yes)
		e.No = p.simplifyUnusedExpr(e.No)

		// "foo() ? 1 : 2" => "foo()"
		if e.Yes.Data == nil && e.No.Data == nil {
			return p.simplifyUnusedExpr(e.Test)
		}

		// "foo() ? 1 : bar()" => "foo() || bar()"
		if e.Yes.Data == nil {
			return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EBinary{
				Op:    js_ast.BinOpLogicalOr,
				Left:  e.Test,
				Right: e.No,
			}}
		}

		// "foo() ? bar() : 2" => "foo() && bar()"
		if e.No.Data == nil {
			return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EBinary{
				Op:    js_ast.BinOpLogicalAnd,
				Left:  e.Test,
				Right: e.Yes,
			}}
		}

	case *js_ast.EBinary:
		switch e.Op {
		case js_ast.BinOpComma:
			e.Left = p.simplifyUnusedExpr(e.Left)
			e.Right = p.simplifyUnusedExpr(e.Right)
			if e.Left.Data == nil {
				return e.Right
			}
			if e.Right.Data == nil {
				return e.Left
			}

		case js_ast.BinOpLogicalAnd, js_ast.BinOpLogicalOr, js_ast.BinOpNullishCoalescing:
			e.Right = p.simplifyUnusedExpr(e.Right)
			if e.Right.Data == nil {
				return p.simplifyUnusedExpr(e.Left)
			}

		case js_ast.BinOpAdd:
			if result, isStringAddition := simplifyUnusedStringAdditionChain(expr); isStringAddition {
				return result
			}
		}

	case *js_ast.ECall:
		// A call that has been marked "__PURE__" can be removed if all arguments
		// can be removed. The annotation causes us to ignore the target.
		if e.CanBeUnwrappedIfUnused {
			expr = js_ast.Expr{}
			for _, arg := range e.Args {
				expr = maybeJoinWithComma(expr, p.simplifyUnusedExpr(arg))
			}
		}

	case *js_ast.ENew:
		// A constructor call that has been marked "__PURE__" can be removed if all
		// arguments can be removed. The annotation causes us to ignore the target.
		if e.CanBeUnwrappedIfUnused {
			expr = js_ast.Expr{}
			for _, arg := range e.Args {
				expr = maybeJoinWithComma(expr, p.simplifyUnusedExpr(arg))
			}
		}
	}

	return expr
}

func simplifyUnusedStringAdditionChain(expr js_ast.Expr) (js_ast.Expr, bool) {
	switch e := expr.Data.(type) {
	case *js_ast.EString:
		// "'x' + y" => "'' + y"
		return js_ast.Expr{Loc: expr.Loc, Data: &js_ast.EString{}}, true

	case *js_ast.EBinary:
		if e.Op == js_ast.BinOpAdd {
			left, leftIsStringAddition := simplifyUnusedStringAdditionChain(e.Left)
			e.Left = left

			if _, rightIsString := e.Right.Data.(*js_ast.EString); rightIsString {
				// "('' + x) + 'y'" => "'' + x"
				if leftIsStringAddition {
					return left, true
				}

				// "x + 'y'" => "x + ''"
				if !leftIsStringAddition {
					e.Right.Data = &js_ast.EString{}
					return expr, true
				}
			}

			return expr, leftIsStringAddition
		}
	}

	return expr, false
}

func newParser(log logger.Log, source logger.Source, lexer js_lexer.Lexer, options *Options) *parser {
	if options.defines == nil {
		defaultDefines := config.ProcessDefines(nil)
		options.defines = &defaultDefines
	}

	p := &parser{
		log:                log,
		source:             source,
		lexer:              lexer,
		allowIn:            true,
		options:            *options,
		fnOrArrowDataParse: fnOrArrowDataParse{isOutsideFn: true},
		runtimeImports:     make(map[string]js_ast.Ref),
		promiseRef:         js_ast.InvalidRef,

		// For lowering private methods
		weakMapRef:     js_ast.InvalidRef,
		weakSetRef:     js_ast.InvalidRef,
		privateGetters: make(map[js_ast.Ref]js_ast.Ref),
		privateSetters: make(map[js_ast.Ref]js_ast.Ref),

		// These are for TypeScript
		emittedNamespaceVars:      make(map[js_ast.Ref]bool),
		isExportedInsideNamespace: make(map[js_ast.Ref]js_ast.Ref),
		knownEnumValues:           make(map[js_ast.Ref]map[string]float64),
		localTypeNames:            make(map[string]bool),

		// These are for handling ES6 imports and exports
		importItemsForNamespace: make(map[js_ast.Ref]map[string]js_ast.LocRef),
		isImportItem:            make(map[js_ast.Ref]bool),
		namedImports:            make(map[js_ast.Ref]js_ast.NamedImport),
		namedExports:            make(map[string]js_ast.NamedExport),
	}

	p.findSymbolHelper = func(loc logger.Loc, name string) js_ast.Ref { return p.findSymbol(loc, name).ref }
	p.pushScopeForParsePass(js_ast.ScopeEntry, logger.Loc{Start: locModuleScope})

	return p
}

var defaultJSXFactory = []string{"React", "createElement"}
var defaultJSXFragment = []string{"React", "Fragment"}

func Parse(log logger.Log, source logger.Source, options Options) (result js_ast.AST, ok bool) {
	ok = true
	defer func() {
		r := recover()
		if _, isLexerPanic := r.(js_lexer.LexerPanic); isLexerPanic {
			ok = false
		} else if r != nil {
			panic(r)
		}
	}()

	// Default options for JSX elements
	if len(options.jsx.Factory) == 0 {
		options.jsx.Factory = defaultJSXFactory
	}
	if len(options.jsx.Fragment) == 0 {
		options.jsx.Fragment = defaultJSXFragment
	}

	// Non-TypeScript files get the real JavaScript class field behavior
	if !options.ts.Parse {
		options.useDefineForClassFields = true
	}

	p := newParser(log, source, js_lexer.NewLexer(log, source), &options)

	// Consume a leading hashbang comment
	hashbang := ""
	if p.lexer.Token == js_lexer.THashbang {
		hashbang = p.lexer.Identifier
		p.lexer.Next()
	}

	// Allow top-level await
	p.fnOrArrowDataParse.allowAwait = true
	p.fnOrArrowDataParse.isTopLevel = true

	// Parse the file in the first pass, but do not bind symbols
	stmts := p.parseStmtsUpTo(js_lexer.TEndOfFile, parseStmtOpts{isModuleScope: true})
	p.prepareForVisitPass()

	// Strip off a leading "use strict" directive when not bundling
	directive := ""
	if p.options.mode != config.ModeBundle && len(stmts) > 0 {
		if s, ok := stmts[0].Data.(*js_ast.SDirective); ok {
			directive = js_lexer.UTF16ToString(s.Value)
			stmts = stmts[1:]
		}
	}

	// Insert a variable for "import.meta" at the top of the file if it was used.
	// We don't need to worry about "use strict" directives because this only
	// happens when bundling, in which case we are flatting the module scopes of
	// all modules together anyway so such directives are meaningless.
	if p.importMetaRef != js_ast.InvalidRef {
		importMetaStmt := js_ast.Stmt{Data: &js_ast.SLocal{
			Kind: p.selectLocalKind(js_ast.LocalConst),
			Decls: []js_ast.Decl{{
				Binding: js_ast.Binding{Data: &js_ast.BIdentifier{Ref: p.importMetaRef}},
				Value:   &js_ast.Expr{Data: &js_ast.EObject{}},
			}},
		}}
		stmts = append(append(make([]js_ast.Stmt, 0, len(stmts)+1), importMetaStmt), stmts...)
	}

	var before []js_ast.Part
	var parts []js_ast.Part
	var after []js_ast.Part

	// Insert any injected import statements now that symbols have been declared
	for _, file := range p.options.injectedFiles {
		exportsNoConflict := make([]string, 0, len(file.Exports))
		symbols := make(map[string]js_ast.Ref)
		for _, alias := range file.Exports {
			if _, ok := p.moduleScope.Members[alias]; !ok {
				ref := p.newSymbol(js_ast.SymbolOther, alias)
				p.moduleScope.Members[alias] = js_ast.ScopeMember{Ref: ref}
				symbols[alias] = ref
				exportsNoConflict = append(exportsNoConflict, alias)
			}
		}
		before = p.generateImportStmt(file.Path, exportsNoConflict, file.SourceIndex, before, symbols)
	}

	// Bind symbols in a second pass over the AST. I started off doing this in a
	// single pass, but it turns out it's pretty much impossible to do this
	// correctly while handling arrow functions because of the grammar
	// ambiguities.
	if p.options.mode != config.ModeBundle {
		// When not bundling, everything comes in a single part
		parts = p.appendPart(parts, stmts)
	} else {
		// When bundling, each top-level statement is potentially a separate part
		for _, stmt := range stmts {
			switch s := stmt.Data.(type) {
			case *js_ast.SLocal:
				// Split up top-level multi-declaration variable statements
				for _, decl := range s.Decls {
					clone := *s
					clone.Decls = []js_ast.Decl{decl}
					parts = p.appendPart(parts, []js_ast.Stmt{{Loc: stmt.Loc, Data: &clone}})
				}

			case *js_ast.SImport, *js_ast.SExportFrom, *js_ast.SExportStar:
				// Move imports (and import-like exports) to the top of the file to
				// ensure that if they are converted to a require() call, the effects
				// will take place before any other statements are evaluated.
				before = p.appendPart(before, []js_ast.Stmt{stmt})

			case *js_ast.SExportEquals:
				// TypeScript "export = value;" becomes "module.exports = value;". This
				// must happen at the end after everything is parsed because TypeScript
				// moves this statement to the end when it generates code.
				after = p.appendPart(after, []js_ast.Stmt{stmt})

			default:
				parts = p.appendPart(parts, []js_ast.Stmt{stmt})
			}
		}
	}

	// Pop the module scope to apply the "ContainsDirectEval" rules
	p.popScope()

	parts = append(append(before, parts...), after...)
	result = p.toAST(source, parts, hashbang, directive)
	result.SourceMapComment = p.lexer.SourceMappingURL
	return
}

func LazyExportAST(log logger.Log, source logger.Source, options Options, expr js_ast.Expr, apiCall string) js_ast.AST {
	// Don't create a new lexer using js_lexer.NewLexer() here since that will
	// actually attempt to parse the first token, which might cause a syntax
	// error.
	p := newParser(log, source, js_lexer.Lexer{}, &options)
	p.prepareForVisitPass()

	// Optionally call a runtime API function to transform the expression
	if apiCall != "" {
		p.symbolUses = make(map[js_ast.Ref]js_ast.SymbolUse)
		expr = p.callRuntime(expr.Loc, apiCall, []js_ast.Expr{expr})
	}

	// Defer the actual code generation until linking
	part := js_ast.Part{
		Stmts:      []js_ast.Stmt{{Loc: expr.Loc, Data: &js_ast.SLazyExport{Value: expr}}},
		SymbolUses: p.symbolUses,
	}
	p.symbolUses = nil

	ast := p.toAST(source, []js_ast.Part{part}, "", "")
	ast.HasLazyExport = true
	return ast
}

func (p *parser) validateJSX(span js_ast.Span, name string) []string {
	if span.Text == "" {
		return nil
	}
	parts := strings.Split(span.Text, ".")
	for _, part := range parts {
		if !js_lexer.IsIdentifier(part) {
			p.log.AddRangeWarning(&p.source, span.Range, fmt.Sprintf("Invalid JSX %s: %s", name, span.Text))
			return nil
		}
	}
	return parts
}

func (p *parser) prepareForVisitPass() {
	p.pushScopeForVisitPass(js_ast.ScopeEntry, logger.Loc{Start: locModuleScope})
	p.moduleScope = p.currentScope
	p.hoistSymbols(p.moduleScope)

	if p.options.mode != config.ModePassThrough {
		p.exportsRef = p.declareCommonJSSymbol(js_ast.SymbolHoisted, "exports")
		p.requireRef = p.declareCommonJSSymbol(js_ast.SymbolUnbound, "require")
		p.moduleRef = p.declareCommonJSSymbol(js_ast.SymbolHoisted, "module")
	} else {
		p.exportsRef = p.newSymbol(js_ast.SymbolHoisted, "exports")
		p.requireRef = p.newSymbol(js_ast.SymbolUnbound, "require")
		p.moduleRef = p.newSymbol(js_ast.SymbolHoisted, "module")
	}

	// Convert "import.meta" to a variable if it's not supported in the output format
	if p.hasImportMeta && (p.options.unsupportedJSFeatures.Has(compat.ImportMeta) || (p.options.mode != config.ModePassThrough && !p.options.outputFormat.KeepES6ImportExportSyntax())) {
		p.importMetaRef = p.newSymbol(js_ast.SymbolOther, "import_meta")
		p.moduleScope.Generated = append(p.moduleScope.Generated, p.importMetaRef)
	} else {
		p.importMetaRef = js_ast.InvalidRef
	}

	// Handle "@jsx" and "@jsxFrag" pragmas now that lexing is done
	if p.options.jsx.Parse {
		if value := p.validateJSX(p.lexer.JSXFactoryPragmaComment, "factory"); value != nil {
			p.options.jsx.Factory = value
		}
		if value := p.validateJSX(p.lexer.JSXFragmentPragmaComment, "fragment"); value != nil {
			p.options.jsx.Fragment = value
		}
	}
}

func (p *parser) declareCommonJSSymbol(kind js_ast.SymbolKind, name string) js_ast.Ref {
	member, ok := p.moduleScope.Members[name]

	// If the code declared this symbol using "var name", then this is actually
	// not a collision. For example, node will let you do this:
	//
	//   var exports;
	//   module.exports.foo = 123;
	//   console.log(exports.foo);
	//
	// This works because node's implementation of CommonJS wraps the entire
	// source file like this:
	//
	//   (function(require, exports, module, __filename, __dirname) {
	//     var exports;
	//     module.exports.foo = 123;
	//     console.log(exports.foo);
	//   })
	//
	// Both the "exports" argument and "var exports" are hoisted variables, so
	// they don't collide.
	if ok && p.symbols[member.Ref.InnerIndex].Kind == js_ast.SymbolHoisted &&
		kind == js_ast.SymbolHoisted && !p.hasES6ImportSyntax && !p.hasES6ExportSyntax {
		return member.Ref
	}

	// Create a new symbol if we didn't merge with an existing one above
	ref := p.newSymbol(kind, name)

	// If the variable wasn't declared, declare it now. This means any references
	// to this name will become bound to this symbol after this (since we haven't
	// run the visit pass yet).
	if !ok {
		p.moduleScope.Members[name] = js_ast.ScopeMember{Ref: ref, Loc: logger.Loc{Start: -1}}
		return ref
	}

	// If the variable was declared, then it shadows this symbol. The code in
	// this module will be unable to reference this symbol. However, we must
	// still add the symbol to the scope so it gets minified (automatically-
	// generated code may still reference the symbol).
	p.moduleScope.Generated = append(p.moduleScope.Generated, ref)
	return ref
}

// Compute a character frequency histogram for everything that's not a bound
// symbol. This is used to modify how minified names are generated for slightly
// better gzip compression. Even though it's a very small win, we still do it
// because it's simple to do and very cheap to compute.
func (p *parser) computeCharacterFrequency() *js_ast.CharFreq {
	if !p.options.minifyIdentifiers || p.source.Index == runtime.SourceIndex {
		return nil
	}

	// Add everything in the file to the histogram
	charFreq := &js_ast.CharFreq{}
	charFreq.Scan(p.source.Contents, 1)

	// Subtract out all comments
	for _, comment := range p.lexer.AllOriginalComments {
		charFreq.Scan(comment.Text, -1)
	}

	// Subtract out all symbols that will be minified
	var visit func(*js_ast.Scope)
	visit = func(scope *js_ast.Scope) {
		for _, member := range scope.Members {
			symbol := &p.symbols[member.Ref.InnerIndex]
			if symbol.SlotNamespace() != js_ast.SlotMustNotBeRenamed {
				charFreq.Scan(symbol.OriginalName, -int32(symbol.UseCountEstimate))
			}
		}
		if scope.LabelRef != js_ast.InvalidRef {
			symbol := &p.symbols[scope.LabelRef.InnerIndex]
			if symbol.SlotNamespace() != js_ast.SlotMustNotBeRenamed {
				charFreq.Scan(symbol.OriginalName, -int32(symbol.UseCountEstimate)-1)
			}
		}
		for _, child := range scope.Children {
			visit(child)
		}
	}
	visit(p.moduleScope)

	return charFreq
}

func (p *parser) generateImportStmt(
	path string,
	imports []string,
	sourceIndex uint32,
	parts []js_ast.Part,
	symbols map[string]js_ast.Ref,
) []js_ast.Part {
	namespaceRef := p.newSymbol(js_ast.SymbolOther, js_ast.GenerateNonUniqueNameFromPath(path))
	p.moduleScope.Generated = append(p.moduleScope.Generated, namespaceRef)
	declaredSymbols := make([]js_ast.DeclaredSymbol, len(imports))
	clauseItems := make([]js_ast.ClauseItem, len(imports))
	importRecordIndex := p.addImportRecord(ast.ImportStmt, logger.Loc{}, path)
	p.importRecords[importRecordIndex].SourceIndex = &sourceIndex

	// Create per-import information
	for i, alias := range imports {
		ref := symbols[alias]
		declaredSymbols[i] = js_ast.DeclaredSymbol{Ref: ref, IsTopLevel: true}
		clauseItems[i] = js_ast.ClauseItem{Alias: alias, Name: js_ast.LocRef{Ref: ref}}
		p.isImportItem[ref] = true
		p.namedImports[ref] = js_ast.NamedImport{
			Alias:             alias,
			NamespaceRef:      namespaceRef,
			ImportRecordIndex: importRecordIndex,
		}
	}

	// Append a single import to the end of the file (ES6 imports are hoisted
	// so we don't need to worry about where the import statement goes)
	return append(parts, js_ast.Part{
		DeclaredSymbols:     declaredSymbols,
		ImportRecordIndices: []uint32{importRecordIndex},
		Stmts: []js_ast.Stmt{{Data: &js_ast.SImport{
			NamespaceRef:      namespaceRef,
			Items:             &clauseItems,
			ImportRecordIndex: importRecordIndex,
		}}},
	})
}

func (p *parser) toAST(source logger.Source, parts []js_ast.Part, hashbang string, directive string) js_ast.AST {
	// Insert an import statement for any runtime imports we generated
	if len(p.runtimeImports) > 0 && !p.options.omitRuntimeForTests {
		// Sort the imports for determinism
		keys := make([]string, 0, len(p.runtimeImports))
		for key := range p.runtimeImports {
			keys = append(keys, key)
		}
		sort.Strings(keys)
		parts = p.generateImportStmt("<runtime>", keys, runtime.SourceIndex, parts, p.runtimeImports)
	}

	// Handle import paths after the whole file has been visited because we need
	// symbol usage counts to be able to remove unused type-only imports in
	// TypeScript code.
	for {
		keptImportEquals := false
		removedImportEquals := false

		// Potentially remove some statements, then filter out parts to remove any
		// with no statements
		partsEnd := 0
		for _, part := range parts {
			p.importRecordsForCurrentPart = nil
			p.declaredSymbols = nil

			result := p.scanForImportsAndExports(part.Stmts)
			part.Stmts = result.stmts
			keptImportEquals = keptImportEquals || result.keptImportEquals
			removedImportEquals = removedImportEquals || result.removedImportEquals

			part.ImportRecordIndices = append(part.ImportRecordIndices, p.importRecordsForCurrentPart...)
			part.DeclaredSymbols = append(part.DeclaredSymbols, p.declaredSymbols...)

			if len(part.Stmts) > 0 {
				if p.moduleScope.ContainsDirectEval && len(part.DeclaredSymbols) > 0 {
					// If this file contains a direct call to "eval()", all parts that
					// declare top-level symbols must be kept since the eval'd code may
					// reference those symbols.
					part.CanBeRemovedIfUnused = false
				}
				parts[partsEnd] = part
				partsEnd++
			}
		}
		parts = parts[:partsEnd]

		// We need to iterate multiple times if an import-equals statement was
		// removed and there are more import-equals statements that may be removed
		if !keptImportEquals || !removedImportEquals {
			break
		}
	}

	// Do a second pass for exported items now that imported items are filled out
	for _, part := range parts {
		for _, stmt := range part.Stmts {
			if s, ok := stmt.Data.(*js_ast.SExportClause); ok {
				for _, item := range s.Items {
					// Mark re-exported imports as such
					if namedImport, ok := p.namedImports[item.Name.Ref]; ok {
						namedImport.IsExported = true
						p.namedImports[item.Name.Ref] = namedImport
					}
				}
			}
		}
	}

	// Analyze cross-part dependencies for tree shaking and code splitting
	{
		// Map locals to parts
		p.topLevelSymbolToParts = make(map[js_ast.Ref][]uint32)
		for partIndex, part := range parts {
			for _, declared := range part.DeclaredSymbols {
				if declared.IsTopLevel {
					p.topLevelSymbolToParts[declared.Ref] = append(
						p.topLevelSymbolToParts[declared.Ref], uint32(partIndex))
				}
			}
		}

		// Each part tracks the other parts it depends on within this file
		for partIndex, part := range parts {
			localDependencies := make(map[uint32]bool)
			for ref := range part.SymbolUses {
				for _, otherPart := range p.topLevelSymbolToParts[ref] {
					localDependencies[otherPart] = true
				}

				// Also map from imports to parts that use them
				if namedImport, ok := p.namedImports[ref]; ok {
					namedImport.LocalPartsWithUses = append(namedImport.LocalPartsWithUses, uint32(partIndex))
					p.namedImports[ref] = namedImport
				}
			}
			parts[partIndex].LocalDependencies = localDependencies
		}
	}

	// Make a wrapper symbol in case we need to be wrapped in a closure
	wrapperRef := p.newSymbol(js_ast.SymbolOther, "require_"+p.source.IdentifierName)

	// Assign slots to symbols in nested scopes. This is some precomputation for
	// the symbol renaming pass that will happen later in the linker. It's done
	// now in the parser because we want it to be done in parallel per file and
	// we're already executing code in a dedicated goroutine for this file.
	var nestedScopeSlotCounts js_ast.SlotCounts
	if p.options.minifyIdentifiers {
		nestedScopeSlotCounts = renamer.AssignNestedScopeSlots(p.moduleScope, p.symbols)
	}

	return js_ast.AST{
		Parts:                   parts,
		ModuleScope:             p.moduleScope,
		CharFreq:                p.computeCharacterFrequency(),
		Symbols:                 p.symbols,
		ExportsRef:              p.exportsRef,
		ModuleRef:               p.moduleRef,
		WrapperRef:              wrapperRef,
		Hashbang:                hashbang,
		Directive:               directive,
		NamedImports:            p.namedImports,
		NamedExports:            p.namedExports,
		NestedScopeSlotCounts:   nestedScopeSlotCounts,
		TopLevelSymbolToParts:   p.topLevelSymbolToParts,
		ExportStarImportRecords: p.exportStarImportRecords,
		ImportRecords:           p.importRecords,
		ApproximateLineCount:    int32(p.lexer.ApproximateNewlineCount) + 1,

		// CommonJS features
		HasTopLevelReturn: p.hasTopLevelReturn,
		UsesExportsRef:    p.symbols[p.exportsRef.InnerIndex].UseCountEstimate > 0,
		UsesModuleRef:     p.symbols[p.moduleRef.InnerIndex].UseCountEstimate > 0,

		// ES6 features
		HasES6Imports: p.hasES6ImportSyntax,
		HasES6Exports: p.hasES6ExportSyntax,
	}
}
