ts_parser_test.go

package js_parser

import (
	"testing"

	"github.com/evanw/esbuild/internal/compat"
	"github.com/evanw/esbuild/internal/config"
)

func expectParseErrorTS(t *testing.T, contents string, expected string) {
	t.Helper()
	expectParseErrorCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse: true,
		},
	})
}

func expectParseErrorTargetTS(t *testing.T, esVersion int, contents string, expected string) {
	t.Helper()
	expectParseErrorCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse: true,
		},
		UnsupportedJSFeatures: compat.UnsupportedJSFeatures(map[compat.Engine][]int{
			compat.ES: {esVersion},
		}),
	})
}

func expectPrintedTS(t *testing.T, contents string, expected string) {
	t.Helper()
	expectPrintedCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse: true,
		},
	})
}

func expectPrintedMangleTS(t *testing.T, contents string, expected string) {
	t.Helper()
	expectPrintedCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse: true,
		},
		MinifySyntax: true,
	})
}

func expectPrintedTargetTS(t *testing.T, esVersion int, contents string, expected string) {
	t.Helper()
	expectPrintedCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse: true,
		},
		UnsupportedJSFeatures: compat.UnsupportedJSFeatures(map[compat.Engine][]int{
			compat.ES: {esVersion},
		}),
	})
}

func expectParseErrorTSNoAmbiguousLessThan(t *testing.T, contents string, expected string) {
	t.Helper()
	expectParseErrorCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse:               true,
			NoAmbiguousLessThan: true,
		},
	})
}

func expectPrintedTSNoAmbiguousLessThan(t *testing.T, contents string, expected string) {
	t.Helper()
	expectPrintedCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse:               true,
			NoAmbiguousLessThan: true,
		},
	})
}

func expectParseErrorTSX(t *testing.T, contents string, expected string) {
	t.Helper()
	expectParseErrorCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse: true,
		},
		JSX: config.JSXOptions{
			Parse: true,
		},
	})
}

func expectPrintedTSX(t *testing.T, contents string, expected string) {
	t.Helper()
	expectPrintedCommon(t, contents, expected, config.Options{
		TS: config.TSOptions{
			Parse: true,
		},
		JSX: config.JSXOptions{
			Parse: true,
		},
	})
}

func TestTSTypes(t *testing.T) {
	expectPrintedTS(t, "let x: T extends number\n ? T\n : number", "let x;\n")
	expectPrintedTS(t, "let x: {y: T extends number ? T : number}", "let x;\n")
	expectPrintedTS(t, "let x: {y: T \n extends: number}", "let x;\n")
	expectPrintedTS(t, "let x: {y: T \n extends?: number}", "let x;\n")
	expectPrintedTS(t, "let x: (number | string)[]", "let x;\n")
	expectPrintedTS(t, "let x: [string[]?]", "let x;\n")
	expectPrintedTS(t, "let x: [number?, string?]", "let x;\n")
	expectPrintedTS(t, "let x: [a: number, b?: string, ...c: number[]]", "let x;\n")
	expectPrintedTS(t, "type x =\n A\n | B\n C", "C;\n")
	expectPrintedTS(t, "type x =\n | A\n | B\n C", "C;\n")
	expectPrintedTS(t, "type x =\n A\n & B\n C", "C;\n")
	expectPrintedTS(t, "type x =\n & A\n & B\n C", "C;\n")
	expectPrintedTS(t, "type x = [-1, 0, 1]\n[]", "[];\n")
	expectPrintedTS(t, "type x = [-1n, 0n, 1n]\n[]", "[];\n")
	expectPrintedTS(t, "type x = {0: number, readonly 1: boolean}\n[]", "[];\n")
	expectPrintedTS(t, "type x = {'a': number, readonly 'b': boolean}\n[]", "[];\n")
	expectPrintedTS(t, "type\nFoo = {}", "type;\nFoo = {};\n")
	expectParseErrorTS(t, "export type\nFoo = {}", "<stdin>: ERROR: Unexpected newline after \"type\"\n")
	expectPrintedTS(t, "let x: {x: 'a', y: false, z: null}", "let x;\n")
	expectPrintedTS(t, "let x: {foo(): void}", "let x;\n")
	expectPrintedTS(t, "let x: {['x']: number}", "let x;\n")
	expectPrintedTS(t, "let x: {['x'](): void}", "let x;\n")
	expectPrintedTS(t, "let x: {[key: string]: number}", "let x;\n")
	expectPrintedTS(t, "let x: {[keyof: string]: number}", "let x;\n")
	expectPrintedTS(t, "let x: {[readonly: string]: number}", "let x;\n")
	expectPrintedTS(t, "let x: {[infer: string]: number}", "let x;\n")
	expectPrintedTS(t, "let x: [keyof: string]", "let x;\n")
	expectPrintedTS(t, "let x: [readonly: string]", "let x;\n")
	expectPrintedTS(t, "let x: [infer: string]", "let x;\n")
	expectParseErrorTS(t, "let x: A extends B ? keyof : string", "<stdin>: ERROR: Unexpected \":\"\n")
	expectParseErrorTS(t, "let x: A extends B ? readonly : string", "<stdin>: ERROR: Unexpected \":\"\n")
	expectParseErrorTS(t, "let x: A extends B ? infer : string", "<stdin>: ERROR: Unexpected \":\"\n")
	expectParseErrorTS(t, "let x: {[new: string]: number}", "<stdin>: ERROR: Expected \"(\" but found \":\"\n")
	expectParseErrorTS(t, "let x: {[import: string]: number}", "<stdin>: ERROR: Expected \"(\" but found \":\"\n")
	expectParseErrorTS(t, "let x: {[typeof: string]: number}", "<stdin>: ERROR: Expected identifier but found \":\"\n")
	expectPrintedTS(t, "let x: () => void = Foo", "let x = Foo;\n")
	expectPrintedTS(t, "let x: new () => void = Foo", "let x = Foo;\n")
	expectPrintedTS(t, "let x = 'x' as keyof T", "let x = \"x\";\n")
	expectPrintedTS(t, "let x = [1] as readonly [number]", "let x = [1];\n")
	expectPrintedTS(t, "let x = 'x' as keyof typeof Foo", "let x = \"x\";\n")
	expectPrintedTS(t, "let fs: typeof import('fs') = require('fs')", "let fs = require(\"fs\");\n")
	expectPrintedTS(t, "let fs: typeof import('fs').exists = require('fs').exists", "let fs = require(\"fs\").exists;\n")
	expectPrintedTS(t, "let fs: typeof import('fs', { assert: { type: 'json' } }) = require('fs')", "let fs = require(\"fs\");\n")
	expectPrintedTS(t, "let fs: typeof import('fs', { assert: { 'resolution-mode': 'import' } }) = require('fs')", "let fs = require(\"fs\");\n")
	expectPrintedTS(t, "let x: <T>() => Foo<T>", "let x;\n")
	expectPrintedTS(t, "let x: new <T>() => Foo<T>", "let x;\n")
	expectPrintedTS(t, "let x: <T extends object>() => Foo<T>", "let x;\n")
	expectPrintedTS(t, "let x: new <T extends object>() => Foo<T>", "let x;\n")
	expectPrintedTS(t, "type Foo<T> = {[P in keyof T]?: T[P]}", "")
	expectPrintedTS(t, "type Foo<T> = {[P in keyof T]+?: T[P]}", "")
	expectPrintedTS(t, "type Foo<T> = {[P in keyof T]-?: T[P]}", "")
	expectPrintedTS(t, "type Foo<T> = {readonly [P in keyof T]: T[P]}", "")
	expectPrintedTS(t, "type Foo<T> = {-readonly [P in keyof T]: T[P]}", "")
	expectPrintedTS(t, "type Foo<T> = {+readonly [P in keyof T]: T[P]}", "")
	expectPrintedTS(t, "let x: number! = y", "let x = y;\n")
	expectPrintedTS(t, "let x: number \n !y", "let x;\n!y;\n")
	expectPrintedTS(t, "const x: unique = y", "const x = y;\n")
	expectPrintedTS(t, "const x: unique<T> = y", "const x = y;\n")
	expectPrintedTS(t, "const x: unique\nsymbol = y", "const x = y;\n")
	expectPrintedTS(t, "let x: typeof a = y", "let x = y;\n")
	expectPrintedTS(t, "let x: typeof a.b = y", "let x = y;\n")
	expectPrintedTS(t, "let x: typeof a.if = y", "let x = y;\n")
	expectPrintedTS(t, "let x: typeof if.a = y", "let x = y;\n")
	expectPrintedTS(t, "let x: typeof readonly = y", "let x = y;\n")
	expectParseErrorTS(t, "let x: typeof readonly Array", "<stdin>: ERROR: Expected \";\" but found \"Array\"\n")
	expectPrintedTS(t, "let x: `y`", "let x;\n")
	expectParseErrorTS(t, "let x: tag`y`", "<stdin>: ERROR: Expected \";\" but found \"`y`\"\n")
	expectPrintedTS(t, "let x: { <A extends B>(): c.d \n <E extends F>(): g.h }", "let x;\n")
	expectPrintedTSX(t, "type x = a.b \n <c></c>", "/* @__PURE__ */ React.createElement(\"c\", null);\n")
	expectPrintedTS(t, "type Foo = a.b \n | c.d", "")
	expectPrintedTS(t, "type Foo = a.b \n & c.d", "")
	expectPrintedTS(t, "type Foo = \n | a.b \n | c.d", "")
	expectPrintedTS(t, "type Foo = \n & a.b \n & c.d", "")

	expectPrintedTS(t, "let x: A.B<X.Y>", "let x;\n")
	expectPrintedTS(t, "let x: A.B<X.Y>=2", "let x = 2;\n")
	expectPrintedTS(t, "let x: A.B<X.Y<Z>>", "let x;\n")
	expectPrintedTS(t, "let x: A.B<X.Y<Z>>=2", "let x = 2;\n")
	expectPrintedTS(t, "let x: A.B<X.Y<Z<T>>>", "let x;\n")
	expectPrintedTS(t, "let x: A.B<X.Y<Z<T>>>=2", "let x = 2;\n")

	expectPrintedTS(t, "(): A<T>=> 0", "() => 0;\n")
	expectPrintedTS(t, "(): A<B<T>>=> 0", "() => 0;\n")
	expectPrintedTS(t, "(): A<B<C<T>>>=> 0", "() => 0;\n")

	expectPrintedTS(t, "let foo: any\n<x>y", "let foo;\ny;\n")
	expectPrintedTSX(t, "let foo: any\n<x>y</x>", "let foo;\n/* @__PURE__ */ React.createElement(\"x\", null, \"y\");\n")
	expectParseErrorTS(t, "let foo: (any\n<x>y)", "<stdin>: ERROR: Expected \")\" but found \"<\"\n")

	expectPrintedTS(t, "let foo = bar as (null)", "let foo = bar;\n")
	expectPrintedTS(t, "let foo = bar\nas (null)", "let foo = bar;\nas(null);\n")
	expectParseErrorTS(t, "let foo = (bar\nas (null))", "<stdin>: ERROR: Expected \")\" but found \"as\"\n")

	expectPrintedTS(t, "a as any ? b : c;", "a ? b : c;\n")
	expectPrintedTS(t, "a as any ? async () => b : c;", "a ? async () => b : c;\n")
	expectPrintedTS(t, "foo as number extends Object ? any : any;", "foo;\n")
	expectPrintedTS(t, "foo as number extends Object ? () => void : any;", "foo;\n")
	expectPrintedTS(t, "let a = b ? c : d as T extends T ? T extends T ? T : never : never ? e : f;", "let a = b ? c : d ? e : f;\n")
	expectParseErrorTS(t, "type a = b extends c", "<stdin>: ERROR: Expected \"?\" but found end of file\n")
	expectParseErrorTS(t, "type a = b extends c extends d", "<stdin>: ERROR: Expected \"?\" but found \"extends\"\n")
	expectParseErrorTS(t, "type a = b ? c : d", "<stdin>: ERROR: Expected \";\" but found \"?\"\n")

	expectPrintedTS(t, "let foo: keyof Object = 'toString'", "let foo = \"toString\";\n")
	expectPrintedTS(t, "let foo: keyof\nObject = 'toString'", "let foo = \"toString\";\n")
	expectPrintedTS(t, "let foo: (keyof\nObject) = 'toString'", "let foo = \"toString\";\n")

	expectPrintedTS(t, "type Foo = Array<<T>(x: T) => T>\n x", "x;\n")
	expectPrintedTSX(t, "<Foo<<T>(x: T) => T>/>", "/* @__PURE__ */ React.createElement(Foo, null);\n")

	// Certain built-in types do not accept type parameters
	expectPrintedTS(t, "x as 1 < 1", "x < 1;\n")
	expectPrintedTS(t, "x as 1n < 1", "x < 1;\n")
	expectPrintedTS(t, "x as -1 < 1", "x < 1;\n")
	expectPrintedTS(t, "x as -1n < 1", "x < 1;\n")
	expectPrintedTS(t, "x as '' < 1", "x < 1;\n")
	expectPrintedTS(t, "x as `` < 1", "x < 1;\n")
	expectPrintedTS(t, "x as any < 1", "x < 1;\n")
	expectPrintedTS(t, "x as bigint < 1", "x < 1;\n")
	expectPrintedTS(t, "x as false < 1", "x < 1;\n")
	expectPrintedTS(t, "x as never < 1", "x < 1;\n")
	expectPrintedTS(t, "x as null < 1", "x < 1;\n")
	expectPrintedTS(t, "x as number < 1", "x < 1;\n")
	expectPrintedTS(t, "x as object < 1", "x < 1;\n")
	expectPrintedTS(t, "x as string < 1", "x < 1;\n")
	expectPrintedTS(t, "x as symbol < 1", "x < 1;\n")
	expectPrintedTS(t, "x as this < 1", "x < 1;\n")
	expectPrintedTS(t, "x as true < 1", "x < 1;\n")
	expectPrintedTS(t, "x as undefined < 1", "x < 1;\n")
	expectPrintedTS(t, "x as unique symbol < 1", "x < 1;\n")
	expectPrintedTS(t, "x as unknown < 1", "x < 1;\n")
	expectPrintedTS(t, "x as void < 1", "x < 1;\n")
	expectParseErrorTS(t, "x as Foo < 1", "<stdin>: ERROR: Expected \">\" but found end of file\n")

	// These keywords are valid tuple labels
	expectPrintedTS(t, "type _false = [false: string]", "")
	expectPrintedTS(t, "type _function = [function: string]", "")
	expectPrintedTS(t, "type _import = [import: string]", "")
	expectPrintedTS(t, "type _new = [new: string]", "")
	expectPrintedTS(t, "type _null = [null: string]", "")
	expectPrintedTS(t, "type _this = [this: string]", "")
	expectPrintedTS(t, "type _true = [true: string]", "")
	expectPrintedTS(t, "type _typeof = [typeof: string]", "")
	expectPrintedTS(t, "type _void = [void: string]", "")

	// These keywords are invalid tuple labels
	expectParseErrorTS(t, "type _break = [break: string]", "<stdin>: ERROR: Unexpected \"break\"\n")
	expectParseErrorTS(t, "type _case = [case: string]", "<stdin>: ERROR: Unexpected \"case\"\n")
	expectParseErrorTS(t, "type _catch = [catch: string]", "<stdin>: ERROR: Unexpected \"catch\"\n")
	expectParseErrorTS(t, "type _class = [class: string]", "<stdin>: ERROR: Unexpected \"class\"\n")
	expectParseErrorTS(t, "type _const = [const: string]", "<stdin>: ERROR: Unexpected \"const\"\n")
	expectParseErrorTS(t, "type _continue = [continue: string]", "<stdin>: ERROR: Unexpected \"continue\"\n")
	expectParseErrorTS(t, "type _debugger = [debugger: string]", "<stdin>: ERROR: Unexpected \"debugger\"\n")
	expectParseErrorTS(t, "type _default = [default: string]", "<stdin>: ERROR: Unexpected \"default\"\n")
	expectParseErrorTS(t, "type _delete = [delete: string]", "<stdin>: ERROR: Unexpected \"delete\"\n")
	expectParseErrorTS(t, "type _do = [do: string]", "<stdin>: ERROR: Unexpected \"do\"\n")
	expectParseErrorTS(t, "type _else = [else: string]", "<stdin>: ERROR: Unexpected \"else\"\n")
	expectParseErrorTS(t, "type _enum = [enum: string]", "<stdin>: ERROR: Unexpected \"enum\"\n")
	expectParseErrorTS(t, "type _export = [export: string]", "<stdin>: ERROR: Unexpected \"export\"\n")
	expectParseErrorTS(t, "type _extends = [extends: string]", "<stdin>: ERROR: Unexpected \"extends\"\n")
	expectParseErrorTS(t, "type _finally = [finally: string]", "<stdin>: ERROR: Unexpected \"finally\"\n")
	expectParseErrorTS(t, "type _for = [for: string]", "<stdin>: ERROR: Unexpected \"for\"\n")
	expectParseErrorTS(t, "type _if = [if: string]", "<stdin>: ERROR: Unexpected \"if\"\n")
	expectParseErrorTS(t, "type _in = [in: string]", "<stdin>: ERROR: Unexpected \"in\"\n")
	expectParseErrorTS(t, "type _instanceof = [instanceof: string]", "<stdin>: ERROR: Unexpected \"instanceof\"\n")
	expectParseErrorTS(t, "type _return = [return: string]", "<stdin>: ERROR: Unexpected \"return\"\n")
	expectParseErrorTS(t, "type _super = [super: string]", "<stdin>: ERROR: Unexpected \"super\"\n")
	expectParseErrorTS(t, "type _switch = [switch: string]", "<stdin>: ERROR: Unexpected \"switch\"\n")
	expectParseErrorTS(t, "type _throw = [throw: string]", "<stdin>: ERROR: Unexpected \"throw\"\n")
	expectParseErrorTS(t, "type _try = [try: string]", "<stdin>: ERROR: Unexpected \"try\"\n")
	expectParseErrorTS(t, "type _var = [var: string]", "<stdin>: ERROR: Unexpected \"var\"\n")
	expectParseErrorTS(t, "type _while = [while: string]", "<stdin>: ERROR: Unexpected \"while\"\n")
	expectParseErrorTS(t, "type _with = [with: string]", "<stdin>: ERROR: Unexpected \"with\"\n")

	// TypeScript 4.1
	expectPrintedTS(t, "let foo: `${'a' | 'b'}-${'c' | 'd'}` = 'a-c'", "let foo = \"a-c\";\n")

	// TypeScript 4.2
	expectPrintedTS(t, "let x: abstract new () => void = Foo", "let x = Foo;\n")
	expectPrintedTS(t, "let x: abstract new <T>() => Foo<T>", "let x;\n")
	expectPrintedTS(t, "let x: abstract new <T extends object>() => Foo<T>", "let x;\n")
	expectParseErrorTS(t, "let x: abstract () => void = Foo", "<stdin>: ERROR: Expected \";\" but found \"(\"\n")
	expectParseErrorTS(t, "let x: abstract <T>() => Foo<T>", "<stdin>: ERROR: Expected \";\" but found \"(\"\n")
	expectParseErrorTS(t, "let x: abstract <T extends object>() => Foo<T>", "<stdin>: ERROR: Expected \"?\" but found \">\"\n")
}

func TestTSAsCast(t *testing.T) {
	expectPrintedTS(t, "x as any\n(y);", "x;\ny;\n")
	expectPrintedTS(t, "x as any\n`y`;", "x;\n`y`;\n")
	expectPrintedTS(t, "x as any\n`${y}`;", "x;\n`${y}`;\n")
	expectPrintedTS(t, "x as any\n--y;", "x;\n--y;\n")
	expectPrintedTS(t, "x as any\n++y;", "x;\n++y;\n")
	expectPrintedTS(t, "x + y as any\n(z as any) + 1;", "x + y;\nz + 1;\n")
	expectPrintedTS(t, "x + y as any\n(z as any) = 1;", "x + y;\nz = 1;\n")
	expectPrintedTS(t, "x = y as any\n(z as any) + 1;", "x = y;\nz + 1;\n")
	expectPrintedTS(t, "x = y as any\n(z as any) = 1;", "x = y;\nz = 1;\n")
	expectPrintedTS(t, "x * y as any\n['z'];", "x * y;\n[\"z\"];\n")
	expectPrintedTS(t, "x * y as any\n.z;", "x * y;\n")
	expectPrintedTS(t, "x as y['x'];", "x;\n")
	expectPrintedTS(t, "x as y!['x'];", "x;\n")
	expectPrintedTS(t, "x as y\n['x'];", "x;\n[\"x\"];\n")
	expectPrintedTS(t, "x as y\n!['x'];", "x;\n![\"x\"];\n")
	expectParseErrorTS(t, "x = y as any `z`;", "<stdin>: ERROR: Expected \";\" but found \"`z`\"\n")
	expectParseErrorTS(t, "x = y as any `${z}`;", "<stdin>: ERROR: Expected \";\" but found \"`${\"\n")
	expectParseErrorTS(t, "x = y as any?.z;", "<stdin>: ERROR: Expected \";\" but found \"?.\"\n")
	expectParseErrorTS(t, "x = y as any--;", "<stdin>: ERROR: Expected \";\" but found \"--\"\n")
	expectParseErrorTS(t, "x = y as any++;", "<stdin>: ERROR: Expected \";\" but found \"++\"\n")
	expectParseErrorTS(t, "x = y as any(z);", "<stdin>: ERROR: Expected \";\" but found \"(\"\n")
	expectParseErrorTS(t, "x = y as any\n= z;", "<stdin>: ERROR: Unexpected \"=\"\n")
	expectParseErrorTS(t, "a, x as y `z`;", "<stdin>: ERROR: Expected \";\" but found \"`z`\"\n")
	expectParseErrorTS(t, "a ? b : x as y `z`;", "<stdin>: ERROR: Expected \";\" but found \"`z`\"\n")
	expectParseErrorTS(t, "x as any = y;", "<stdin>: ERROR: Expected \";\" but found \"=\"\n")
	expectParseErrorTS(t, "(x as any = y);", "<stdin>: ERROR: Expected \")\" but found \"=\"\n")
	expectParseErrorTS(t, "(x = y as any(z));", "<stdin>: ERROR: Expected \")\" but found \"(\"\n")
}

func TestTSClass(t *testing.T) {
	expectPrintedTS(t, "export default class Foo {}", "export default class Foo {\n}\n")
	expectPrintedTS(t, "export default class Foo extends Bar<T> {}", "export default class Foo extends Bar {\n}\n")
	expectPrintedTS(t, "export default class Foo extends Bar<T>() {}", "export default class Foo extends Bar() {\n}\n")
	expectPrintedTS(t, "export default class Foo implements Bar<T> {}", "export default class Foo {\n}\n")
	expectPrintedTS(t, "export default class Foo<T> {}", "export default class Foo {\n}\n")
	expectPrintedTS(t, "export default class Foo<T> extends Bar<T> {}", "export default class Foo extends Bar {\n}\n")
	expectPrintedTS(t, "export default class Foo<T> extends Bar<T>() {}", "export default class Foo extends Bar() {\n}\n")
	expectPrintedTS(t, "export default class Foo<T> implements Bar<T> {}", "export default class Foo {\n}\n")
	expectPrintedTS(t, "(class Foo<T> {})", "(class Foo {\n});\n")
	expectPrintedTS(t, "(class Foo<T> extends Bar<T> {})", "(class Foo extends Bar {\n});\n")
	expectPrintedTS(t, "(class Foo<T> extends Bar<T>() {})", "(class Foo extends Bar() {\n});\n")
	expectPrintedTS(t, "(class Foo<T> implements Bar<T> {})", "(class Foo {\n});\n")

	expectPrintedTS(t, "export default class {}", "export default class {\n}\n")
	expectPrintedTS(t, "export default class extends Foo<T> {}", "export default class extends Foo {\n}\n")
	expectPrintedTS(t, "export default class implements Foo<T> {}", "export default class {\n}\n")
	expectPrintedTS(t, "export default class <T> {}", "export default class {\n}\n")
	expectPrintedTS(t, "export default class <T> extends Foo<T> {}", "export default class extends Foo {\n}\n")
	expectPrintedTS(t, "export default class <T> implements Foo<T> {}", "export default class {\n}\n")
	expectPrintedTS(t, "(class <T> {})", "(class {\n});\n")
	expectPrintedTS(t, "(class extends Foo<T> {})", "(class extends Foo {\n});\n")
	expectPrintedTS(t, "(class extends Foo<T>() {})", "(class extends Foo() {\n});\n")
	expectPrintedTS(t, "(class implements Foo<T> {})", "(class {\n});\n")
	expectPrintedTS(t, "(class <T> extends Foo<T> {})", "(class extends Foo {\n});\n")
	expectPrintedTS(t, "(class <T> extends Foo<T>() {})", "(class extends Foo() {\n});\n")
	expectPrintedTS(t, "(class <T> implements Foo<T> {})", "(class {\n});\n")

	expectPrintedTS(t, "abstract class A { abstract foo(): void; bar(): void {} }", "class A {\n  bar() {\n  }\n}\n")
	expectPrintedTS(t, "export abstract class A { abstract foo(): void; bar(): void {} }", "export class A {\n  bar() {\n  }\n}\n")
	expectPrintedTS(t, "export default abstract", "export default abstract;\n")
	expectPrintedTS(t, "export default abstract - after", "export default abstract - after;\n")
	expectPrintedTS(t, "export default abstract class { abstract foo(): void; bar(): void {} } - after", "export default class {\n  bar() {\n  }\n}\n-after;\n")
	expectPrintedTS(t, "export default abstract class A { abstract foo(): void; bar(): void {} } - after", "export default class A {\n  bar() {\n  }\n}\n-after;\n")

	expectPrintedTS(t, "class A<T extends number> extends B.C<D, E> {}", "class A extends B.C {\n}\n")
	expectPrintedTS(t, "class A<T extends number> implements B.C<D, E>, F.G<H, I> {}", "class A {\n}\n")
	expectPrintedTS(t, "class A<T extends number> extends X implements B.C<D, E>, F.G<H, I> {}", "class A extends X {\n}\n")

	reservedWordError :=
		" is a reserved word and cannot be used in strict mode\n" +
			"<stdin>: NOTE: All code inside a class is implicitly in strict mode\n"

	expectParseErrorTS(t, "class Foo { constructor(public) {} }", "<stdin>: ERROR: \"public\""+reservedWordError)
	expectParseErrorTS(t, "class Foo { constructor(protected) {} }", "<stdin>: ERROR: \"protected\""+reservedWordError)
	expectParseErrorTS(t, "class Foo { constructor(private) {} }", "<stdin>: ERROR: \"private\""+reservedWordError)
	expectPrintedTS(t, "class Foo { constructor(readonly) {} }", "class Foo {\n  constructor(readonly) {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(override) {} }", "class Foo {\n  constructor(override) {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(public x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(protected x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(private x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(readonly x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(override x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(public readonly x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(protected readonly x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(private readonly x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { constructor(override readonly x) {} }", "class Foo {\n  constructor(x) {\n    this.x = x;\n  }\n}\n")

	expectParseErrorTS(t, "class Foo { constructor(public {x}) {} }", "<stdin>: ERROR: Expected identifier but found \"{\"\n")
	expectParseErrorTS(t, "class Foo { constructor(protected {x}) {} }", "<stdin>: ERROR: Expected identifier but found \"{\"\n")
	expectParseErrorTS(t, "class Foo { constructor(private {x}) {} }", "<stdin>: ERROR: Expected identifier but found \"{\"\n")
	expectParseErrorTS(t, "class Foo { constructor(readonly {x}) {} }", "<stdin>: ERROR: Expected identifier but found \"{\"\n")
	expectParseErrorTS(t, "class Foo { constructor(override {x}) {} }", "<stdin>: ERROR: Expected identifier but found \"{\"\n")

	expectParseErrorTS(t, "class Foo { constructor(public [x]) {} }", "<stdin>: ERROR: Expected identifier but found \"[\"\n")
	expectParseErrorTS(t, "class Foo { constructor(protected [x]) {} }", "<stdin>: ERROR: Expected identifier but found \"[\"\n")
	expectParseErrorTS(t, "class Foo { constructor(private [x]) {} }", "<stdin>: ERROR: Expected identifier but found \"[\"\n")
	expectParseErrorTS(t, "class Foo { constructor(readonly [x]) {} }", "<stdin>: ERROR: Expected identifier but found \"[\"\n")
	expectParseErrorTS(t, "class Foo { constructor(override [x]) {} }", "<stdin>: ERROR: Expected identifier but found \"[\"\n")

	expectPrintedTS(t, "class Foo { foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { foo: number = 0 }", "class Foo {\n  constructor() {\n    this.foo = 0;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { foo(): void {} }", "class Foo {\n  foo() {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { foo(): void; foo(): void {} }", "class Foo {\n  foo() {\n  }\n}\n")
	expectParseErrorTS(t, "class Foo { foo(): void foo(): void {} }", "<stdin>: ERROR: Expected \";\" but found \"foo\"\n")

	expectPrintedTS(t, "class Foo { foo?: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { foo?: number = 0 }", "class Foo {\n  constructor() {\n    this.foo = 0;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { foo?(): void {} }", "class Foo {\n  foo() {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { foo?(): void; foo(): void {} }", "class Foo {\n  foo() {\n  }\n}\n")
	expectParseErrorTS(t, "class Foo { foo?(): void foo(): void {} }", "<stdin>: ERROR: Expected \";\" but found \"foo\"\n")

	expectPrintedTS(t, "class Foo { foo!: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { foo!: number = 0 }", "class Foo {\n  constructor() {\n    this.foo = 0;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { foo!(): void {} }", "class Foo {\n  foo() {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { foo!(): void; foo(): void {} }", "class Foo {\n  foo() {\n  }\n}\n")
	expectParseErrorTS(t, "class Foo { foo!(): void foo(): void {} }", "<stdin>: ERROR: Expected \";\" but found \"foo\"\n")

	expectPrintedTS(t, "class Foo { 'foo' = 0 }", "class Foo {\n  constructor() {\n    this[\"foo\"] = 0;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { ['foo'] = 0 }", "class Foo {\n  constructor() {\n    this[\"foo\"] = 0;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { [foo] = 0 }", "var _a;\nclass Foo {\n  constructor() {\n    this[_a] = 0;\n  }\n}\n_a = foo;\n")
	expectPrintedMangleTS(t, "class Foo { 'foo' = 0 }", "class Foo {\n  constructor() {\n    this.foo = 0;\n  }\n}\n")
	expectPrintedMangleTS(t, "class Foo { ['foo'] = 0 }", "class Foo {\n  constructor() {\n    this.foo = 0;\n  }\n}\n")

	expectPrintedTS(t, "class Foo { foo \n ?: number }", "class Foo {\n}\n")
	expectParseErrorTS(t, "class Foo { foo \n !: number }", "<stdin>: ERROR: Expected identifier but found \"!\"\n")

	expectPrintedTS(t, "class Foo { public foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { private foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { protected foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { declare foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { declare public foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { public declare foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { override foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { override public foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { public override foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { declare override public foo: number }", "class Foo {\n}\n")
	expectParseErrorTS(t, "class Foo { declare foo = 123 }", "<stdin>: ERROR: Class fields that use \"declare\" cannot be initialized\n")

	expectPrintedTS(t, "class Foo { public static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { private static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { protected static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { declare static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { declare public static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { public declare static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { public static declare foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { override static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { override public static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { public override static foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { public static override foo: number }", "class Foo {\n}\n")
	expectPrintedTS(t, "class Foo { declare override public static foo: number }", "class Foo {\n}\n")
	expectParseErrorTS(t, "class Foo { declare static foo = 123 }", "<stdin>: ERROR: Class fields that use \"declare\" cannot be initialized\n")
	expectParseErrorTS(t, "class Foo { static declare foo = 123 }", "<stdin>: ERROR: Class fields that use \"declare\" cannot be initialized\n")

	expectParseErrorTS(t, "class Foo { declare #foo }", "<stdin>: ERROR: \"declare\" cannot be used with a private identifier\n")
	expectParseErrorTS(t, "class Foo { declare [foo: string]: number }", "<stdin>: ERROR: \"declare\" cannot be used with an index signature\n")
	expectParseErrorTS(t, "class Foo { declare foo() }", "<stdin>: ERROR: \"declare\" cannot be used with a method\n")
	expectParseErrorTS(t, "class Foo { declare get foo() }", "<stdin>: ERROR: \"declare\" cannot be used with a getter\n")
	expectParseErrorTS(t, "class Foo { declare set foo(x) }", "<stdin>: ERROR: \"declare\" cannot be used with a setter\n")

	expectParseErrorTS(t, "class Foo { declare static #foo }", "<stdin>: ERROR: \"declare\" cannot be used with a private identifier\n")
	expectParseErrorTS(t, "class Foo { declare static [foo: string]: number }", "<stdin>: ERROR: \"declare\" cannot be used with an index signature\n")
	expectParseErrorTS(t, "class Foo { declare static foo() }", "<stdin>: ERROR: \"declare\" cannot be used with a method\n")
	expectParseErrorTS(t, "class Foo { declare static get foo() }", "<stdin>: ERROR: \"declare\" cannot be used with a getter\n")
	expectParseErrorTS(t, "class Foo { declare static set foo(x) }", "<stdin>: ERROR: \"declare\" cannot be used with a setter\n")

	expectParseErrorTS(t, "class Foo { static declare #foo }", "<stdin>: ERROR: \"declare\" cannot be used with a private identifier\n")
	expectParseErrorTS(t, "class Foo { static declare [foo: string]: number }", "<stdin>: ERROR: \"declare\" cannot be used with an index signature\n")
	expectParseErrorTS(t, "class Foo { static declare foo() }", "<stdin>: ERROR: \"declare\" cannot be used with a method\n")
	expectParseErrorTS(t, "class Foo { static declare get foo() }", "<stdin>: ERROR: \"declare\" cannot be used with a getter\n")
	expectParseErrorTS(t, "class Foo { static declare set foo(x) }", "<stdin>: ERROR: \"declare\" cannot be used with a setter\n")

	expectPrintedTS(t, "class Foo { [key: string]: any\nfoo = 0 }", "class Foo {\n  constructor() {\n    this.foo = 0;\n  }\n}\n")
	expectPrintedTS(t, "class Foo { [key: string]: any; foo = 0 }", "class Foo {\n  constructor() {\n    this.foo = 0;\n  }\n}\n")

	expectParseErrorTS(t, "class Foo<> {}", "<stdin>: ERROR: Expected identifier but found \">\"\n")
	expectParseErrorTS(t, "class Foo<,> {}", "<stdin>: ERROR: Expected identifier but found \",\"\n")
	expectParseErrorTS(t, "class Foo<T><T> {}", "<stdin>: ERROR: Expected \"{\" but found \"<\"\n")
}

func TestTSPrivateIdentifiers(t *testing.T) {
	// The TypeScript compiler still moves private field initializers into the
	// constructor, but it has to leave the private field declaration in place so
	// the private field is still declared.
	expectPrintedTS(t, "class Foo { #foo }", "class Foo {\n  #foo;\n}\n")
	expectPrintedTS(t, "class Foo { #foo = 1 }", "class Foo {\n  #foo = 1;\n}\n")
	expectPrintedTS(t, "class Foo { #foo() {} }", "class Foo {\n  #foo() {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { get #foo() {} }", "class Foo {\n  get #foo() {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { set #foo(x) {} }", "class Foo {\n  set #foo(x) {\n  }\n}\n")

	// The TypeScript compiler doesn't currently support static private fields
	// because it moves static field initializers to after the class body and
	// private fields can't be used outside the class body. It remains to be seen
	// how the TypeScript compiler will transform private static fields once it
	// finally does support them. For now just leave the initializer in place.
	expectPrintedTS(t, "class Foo { static #foo }", "class Foo {\n  static #foo;\n}\n")
	expectPrintedTS(t, "class Foo { static #foo = 1 }", "class Foo {\n  static #foo = 1;\n}\n")
	expectPrintedTS(t, "class Foo { static #foo() {} }", "class Foo {\n  static #foo() {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { static get #foo() {} }", "class Foo {\n  static get #foo() {\n  }\n}\n")
	expectPrintedTS(t, "class Foo { static set #foo(x) {} }", "class Foo {\n  static set #foo(x) {\n  }\n}\n")
}

func TestTSInterface(t *testing.T) {
	expectPrintedTS(t, "interface A { a } x", "x;\n")
	expectPrintedTS(t, "interface A { a; b } x", "x;\n")
	expectPrintedTS(t, "interface A { a() } x", "x;\n")
	expectPrintedTS(t, "interface A { a(); b } x", "x;\n")
	expectPrintedTS(t, "interface Foo { foo(): Foo \n is: Bar } x", "x;\n")
	expectPrintedTS(t, "interface A<T extends number> extends B.C<D, E>, F.G<H, I> {} x", "x;\n")
	expectPrintedTS(t, "export interface A<T extends number> extends B.C<D, E>, F.G<H, I> {} x", "x;\n")
	expectPrintedTS(t, "export default interface Foo {} x", "x;\n")
}

func TestTSNamespace(t *testing.T) {
	// Check ES5 emit
	expectPrintedTargetTS(t, 5, "namespace x { export var y = 1 }", "var x;\n(function(x) {\n  x.y = 1;\n})(x || (x = {}));\n")
	expectPrintedTargetTS(t, 2015, "namespace x { export var y = 1 }", "var x;\n((x) => {\n  x.y = 1;\n})(x || (x = {}));\n")

	// Certain syntax isn't allowed inside a namespace block
	expectParseErrorTS(t, "namespace x { return }", "<stdin>: ERROR: A return statement cannot be used here:\n")
	expectParseErrorTS(t, "namespace x { await 1 }", "<stdin>: ERROR: \"await\" can only be used inside an \"async\" function\n")
	expectParseErrorTS(t, "namespace x { if (y) return }", "<stdin>: ERROR: A return statement cannot be used here:\n")
	expectParseErrorTS(t, "namespace x { if (y) await 1 }", "<stdin>: ERROR: \"await\" can only be used inside an \"async\" function\n")
	expectParseErrorTS(t, "namespace x { this }", "<stdin>: ERROR: Cannot use \"this\" here:\n")
	expectParseErrorTS(t, "namespace x { () => this }", "<stdin>: ERROR: Cannot use \"this\" here:\n")
	expectParseErrorTS(t, "namespace x { class y { [this] } }", "<stdin>: ERROR: Cannot use \"this\" here:\n")
	expectParseErrorTS(t, "namespace x { (function() { this }) }", "")
	expectParseErrorTS(t, "namespace x { function y() { this } }", "")
	expectParseErrorTS(t, "namespace x { class y { x = this } }", "")
	expectParseErrorTS(t, "export namespace x { export let yield = 1 }",
		"<stdin>: ERROR: \"yield\" is a reserved word and cannot be used in an ECMAScript module\n"+
			"<stdin>: NOTE: This file is considered to be an ECMAScript module because of the \"export\" keyword here:\n")
	expectPrintedTS(t, "namespace x { export let await = 1, y = await }", `var x;
((x) => {
  x.await = 1;
  x.y = x.await;
})(x || (x = {}));
`)
	expectPrintedTS(t, "namespace x { export let yield = 1, y = yield }", `var x;
((x) => {
  x.yield = 1;
  x.y = x.yield;
})(x || (x = {}));
`)

	expectPrintedTS(t, "namespace Foo { 0 }", `var Foo;
((Foo) => {
  0;
})(Foo || (Foo = {}));
`)
	expectPrintedTS(t, "export namespace Foo { 0 }", `export var Foo;
((Foo) => {
  0;
})(Foo || (Foo = {}));
`)

	// Namespaces should introduce a scope that prevents name collisions
	expectPrintedTS(t, "namespace Foo { let x } let x", `var Foo;
((Foo) => {
  let x;
})(Foo || (Foo = {}));
let x;
`)

	// Exports in namespaces shouldn't collide with module exports
	expectPrintedTS(t, "namespace Foo { export let x } export let x", `var Foo;
((Foo) => {
})(Foo || (Foo = {}));
export let x;
`)
	expectPrintedTS(t, "declare namespace Foo { export let x } namespace x { 0 }", `var x;
((x) => {
  0;
})(x || (x = {}));
`)

	errorText := `<stdin>: ERROR: The symbol "foo" has already been declared
<stdin>: NOTE: The symbol "foo" was originally declared here:
`

	// Namespaces with values are not allowed to merge
	expectParseErrorTS(t, "var foo; namespace foo { 0 }", errorText)
	expectParseErrorTS(t, "let foo; namespace foo { 0 }", errorText)
	expectParseErrorTS(t, "const foo = 0; namespace foo { 0 }", errorText)
	expectParseErrorTS(t, "namespace foo { 0 } var foo", errorText)
	expectParseErrorTS(t, "namespace foo { 0 } let foo", errorText)
	expectParseErrorTS(t, "namespace foo { 0 } const foo = 0", errorText)

	// Namespaces without values are allowed to merge
	expectPrintedTS(t, "var foo; namespace foo {}", "var foo;\n")
	expectPrintedTS(t, "let foo; namespace foo {}", "let foo;\n")
	expectPrintedTS(t, "const foo = 0; namespace foo {}", "const foo = 0;\n")
	expectPrintedTS(t, "namespace foo {} var foo", "var foo;\n")
	expectPrintedTS(t, "namespace foo {} let foo", "let foo;\n")
	expectPrintedTS(t, "namespace foo {} const foo = 0", "const foo = 0;\n")

	// Namespaces with types but no values are allowed to merge
	expectPrintedTS(t, "var foo; namespace foo { export type bar = number }", "var foo;\n")
	expectPrintedTS(t, "let foo; namespace foo { export type bar = number }", "let foo;\n")
	expectPrintedTS(t, "const foo = 0; namespace foo { export type bar = number }", "const foo = 0;\n")
	expectPrintedTS(t, "namespace foo { export type bar = number } var foo", "var foo;\n")
	expectPrintedTS(t, "namespace foo { export type bar = number } let foo", "let foo;\n")
	expectPrintedTS(t, "namespace foo { export type bar = number } const foo = 0", "const foo = 0;\n")

	// Namespaces are allowed to merge with certain symbols
	expectPrintedTS(t, "function foo() {} namespace foo { 0 }", `function foo() {
}
((foo) => {
  0;
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "function* foo() {} namespace foo { 0 }", `function* foo() {
}
((foo) => {
  0;
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "async function foo() {} namespace foo { 0 }", `async function foo() {
}
((foo) => {
  0;
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "class foo {} namespace foo { 0 }", `class foo {
}
((foo) => {
  0;
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "enum foo { a } namespace foo { 0 }", `var foo = /* @__PURE__ */ ((foo) => {
  foo[foo["a"] = 0] = "a";
  return foo;
})(foo || {});
((foo) => {
  0;
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "namespace foo {} namespace foo { 0 }", `var foo;
((foo) => {
  0;
})(foo || (foo = {}));
`)
	expectParseErrorTS(t, "namespace foo { 0 } function foo() {}", errorText)
	expectParseErrorTS(t, "namespace foo { 0 } function* foo() {}", errorText)
	expectParseErrorTS(t, "namespace foo { 0 } async function foo() {}", errorText)
	expectParseErrorTS(t, "namespace foo { 0 } class foo {}", errorText)
	expectPrintedTS(t, "namespace foo { 0 } enum foo { a }", `var foo;
((foo) => {
  0;
})(foo || (foo = {}));
var foo = /* @__PURE__ */ ((foo) => {
  foo[foo["a"] = 0] = "a";
  return foo;
})(foo || {});
`)
	expectPrintedTS(t, "namespace foo { 0 } namespace foo {}", `var foo;
((foo) => {
  0;
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "namespace foo { 0 } namespace foo { 0 }", `var foo;
((foo) => {
  0;
})(foo || (foo = {}));
((foo) => {
  0;
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "function foo() {} namespace foo { 0 } function foo() {}", `function foo() {
}
((foo) => {
  0;
})(foo || (foo = {}));
function foo() {
}
`)
	expectPrintedTS(t, "function* foo() {} namespace foo { 0 } function* foo() {}", `function* foo() {
}
((foo) => {
  0;
})(foo || (foo = {}));
function* foo() {
}
`)
	expectPrintedTS(t, "async function foo() {} namespace foo { 0 } async function foo() {}", `async function foo() {
}
((foo) => {
  0;
})(foo || (foo = {}));
async function foo() {
}
`)

	// Namespace merging shouldn't allow for other merging
	expectParseErrorTS(t, "class foo {} namespace foo { 0 } class foo {}", errorText)
	expectParseErrorTS(t, "class foo {} namespace foo { 0 } enum foo {}", errorText)
	expectParseErrorTS(t, "enum foo {} namespace foo { 0 } class foo {}", errorText)
	expectParseErrorTS(t, "namespace foo { 0 } namespace foo { 0 } let foo", errorText)
	expectParseErrorTS(t, "namespace foo { 0 } enum foo {} class foo {}", errorText)

	// Test dot nested namespace syntax
	expectPrintedTS(t, "namespace foo.bar { foo(bar) }", `var foo;
((foo) => {
  let bar;
  ((bar) => {
    foo(bar);
  })(bar = foo.bar || (foo.bar = {}));
})(foo || (foo = {}));
`)

	// "module" is a deprecated alias for "namespace"
	expectPrintedTS(t, "module foo { export namespace bar { foo(bar) } }", `var foo;
((foo) => {
  let bar;
  ((bar) => {
    foo(bar);
  })(bar = foo.bar || (foo.bar = {}));
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "namespace foo { export module bar { foo(bar) } }", `var foo;
((foo) => {
  let bar;
  ((bar) => {
    foo(bar);
  })(bar = foo.bar || (foo.bar = {}));
})(foo || (foo = {}));
`)
	expectPrintedTS(t, "module foo.bar { foo(bar) }", `var foo;
((foo) => {
  let bar;
  ((bar) => {
    foo(bar);
  })(bar = foo.bar || (foo.bar = {}));
})(foo || (foo = {}));
`)
}

func TestTSNamespaceExports(t *testing.T) {
	expectPrintedTS(t, `
		namespace A {
			export namespace B {
				export function fn() {}
			}
			namespace C {
				export function fn() {}
			}
			namespace D {
				function fn() {}
			}
		}
	`, `var A;
((A) => {
  let B;
  ((B) => {
    function fn() {
    }
    B.fn = fn;
  })(B = A.B || (A.B = {}));
  let C;
  ((C) => {
    function fn() {
    }
    C.fn = fn;
  })(C || (C = {}));
  let D;
  ((D) => {
    function fn() {
    }
  })(D || (D = {}));
})(A || (A = {}));
`)

	expectPrintedTS(t, `
		namespace A {
			export namespace B {
				export class Class {}
			}
			namespace C {
				export class Class {}
			}
			namespace D {
				class Class {}
			}
		}
	`, `var A;
((A) => {
  let B;
  ((B) => {
    class Class {
    }
    B.Class = Class;
  })(B = A.B || (A.B = {}));
  let C;
  ((C) => {
    class Class {
    }
    C.Class = Class;
  })(C || (C = {}));
  let D;
  ((D) => {
    class Class {
    }
  })(D || (D = {}));
})(A || (A = {}));
`)

	expectPrintedTS(t, `
		namespace A {
			export namespace B {
				export enum Enum {}
			}
			namespace C {
				export enum Enum {}
			}
			namespace D {
				enum Enum {}
			}
		}
	`, `var A;
((A) => {
  let B;
  ((B) => {
    let Enum;
    ((Enum) => {
    })(Enum = B.Enum || (B.Enum = {}));
  })(B = A.B || (A.B = {}));
  let C;
  ((C) => {
    let Enum;
    ((Enum) => {
    })(Enum = C.Enum || (C.Enum = {}));
  })(C || (C = {}));
  let D;
  ((D) => {
    let Enum;
    ((Enum) => {
    })(Enum || (Enum = {}));
  })(D || (D = {}));
})(A || (A = {}));
`)

	expectPrintedTS(t, `
		namespace A {
			export namespace B {
				export let foo = 1
				foo += foo
			}
			namespace C {
				export let foo = 1
				foo += foo
			}
			namespace D {
				let foo = 1
				foo += foo
			}
		}
	`, `var A;
((A) => {
  let B;
  ((B) => {
    B.foo = 1;
    B.foo += B.foo;
  })(B = A.B || (A.B = {}));
  let C;
  ((C) => {
    C.foo = 1;
    C.foo += C.foo;
  })(C || (C = {}));
  let D;
  ((D) => {
    let foo = 1;
    foo += foo;
  })(D || (D = {}));
})(A || (A = {}));
`)

	expectPrintedTS(t, `
		namespace A {
			export namespace B {
				export const foo = 1
			}
			namespace C {
				export const foo = 1
			}
			namespace D {
				const foo = 1
			}
		}
	`, `var A;
((A) => {
  let B;
  ((B) => {
    B.foo = 1;
  })(B = A.B || (A.B = {}));
  let C;
  ((C) => {
    C.foo = 1;
  })(C || (C = {}));
  let D;
  ((D) => {
    const foo = 1;
  })(D || (D = {}));
})(A || (A = {}));
`)

	expectPrintedTS(t, `
		namespace A {
			export namespace B {
				export var foo = 1
				foo += foo
			}
			namespace C {
				export var foo = 1
				foo += foo
			}
			namespace D {
				var foo = 1
				foo += foo
			}
		}
	`, `var A;
((A) => {
  let B;
  ((B) => {
    B.foo = 1;
    B.foo += B.foo;
  })(B = A.B || (A.B = {}));
  let C;
  ((C) => {
    C.foo = 1;
    C.foo += C.foo;
  })(C || (C = {}));
  let D;
  ((D) => {
    var foo = 1;
    foo += foo;
  })(D || (D = {}));
})(A || (A = {}));
`)

	expectPrintedTS(t, `
		namespace ns {
			export declare const L1
			console.log(L1)

			export declare let [[L2 = x, { [y]: L3 }]]
			console.log(L2, L3)

			export declare function F()
			console.log(F)

			export declare function F2() { }
			console.log(F2)

			export declare class C { }
			console.log(C)

			export declare enum E { }
			console.log(E)

			export declare namespace N { }
			console.log(N)
		}
	`, `var ns;
((ns) => {
  console.log(ns.L1);
  console.log(ns.L2, ns.L3);
  console.log(F);
  console.log(F2);
  console.log(C);
  console.log(E);
  console.log(N);
})(ns || (ns = {}));
`)

	expectPrintedTS(t, `
		namespace a { export var a = 123; log(a) }
		namespace b { export let b = 123; log(b) }
		namespace c { export enum c {} log(c) }
		namespace d { export class d {} log(d) }
		namespace e { export namespace e {} log(e) }
		namespace f { export function f() {} log(f) }
	`, `var a;
((_a) => {
  _a.a = 123;
  log(_a.a);
})(a || (a = {}));
var b;
((_b) => {
  _b.b = 123;
  log(_b.b);
})(b || (b = {}));
var c;
((_c) => {
  let c;
  ((c) => {
  })(c = _c.c || (_c.c = {}));
  log(c);
})(c || (c = {}));
var d;
((_d) => {
  class d {
  }
  _d.d = d;
  log(d);
})(d || (d = {}));
var e;
((e) => {
  log(e);
})(e || (e = {}));
var f;
((_f) => {
  function f() {
  }
  _f.f = f;
  log(f);
})(f || (f = {}));
`)

	expectPrintedTS(t, `
		namespace a { export declare var a }
		namespace b { export declare let b }
		namespace c { export declare enum c {} }
		namespace d { export declare class d {} }
		namespace e { export declare namespace e {} }
		namespace f { export declare function f() {} }
	`, `var a;
((_a) => {
})(a || (a = {}));
var b;
((_b) => {
})(b || (b = {}));
var c;
((c) => {
})(c || (c = {}));
var d;
((d) => {
})(d || (d = {}));
var f;
((f) => {
})(f || (f = {}));
`)
}

func TestTSNamespaceDestructuring(t *testing.T) {
	expectPrintedTS(t, `
		namespace A {
			export var [
				a,
				[, b = c, ...d],
				{[x]: [[y]] = z, ...o},
			] = ref
		}
	`, `var A;
((A) => {
  [
    A.a,
    [, A.b = c, ...A.d],
    { [x]: [[A.y]] = z, ...A.o }
  ] = ref;
})(A || (A = {}));
`)
}

func TestTSEnum(t *testing.T) {
	expectParseErrorTS(t, "enum x { y z }", "<stdin>: ERROR: Expected \",\" after \"y\" in enum\n")
	expectParseErrorTS(t, "enum x { 'y' 'z' }", "<stdin>: ERROR: Expected \",\" after \"y\" in enum\n")
	expectParseErrorTS(t, "enum x { y = 0 z }", "<stdin>: ERROR: Expected \",\" before \"z\" in enum\n")
	expectParseErrorTS(t, "enum x { 'y' = 0 'z' }", "<stdin>: ERROR: Expected \",\" before \"z\" in enum\n")

	// Check ES5 emit
	expectPrintedTargetTS(t, 5, "enum x { y = 1 }", "var x = /* @__PURE__ */ function(x) {\n  x[x[\"y\"] = 1] = \"y\";\n  return x;\n}(x || {});\n")
	expectPrintedTargetTS(t, 2015, "enum x { y = 1 }", "var x = /* @__PURE__ */ ((x) => {\n  x[x[\"y\"] = 1] = \"y\";\n  return x;\n})(x || {});\n")

	// Certain syntax isn't allowed inside an enum block
	expectParseErrorTS(t, "enum x { y = this }", "<stdin>: ERROR: Cannot use \"this\" here:\n")
	expectParseErrorTS(t, "enum x { y = () => this }", "<stdin>: ERROR: Cannot use \"this\" here:\n")
	expectParseErrorTS(t, "enum x { y = function() { this } }", "")

	expectPrintedTS(t, "enum Foo { A, B }", `var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["A"] = 0] = "A";
  Foo[Foo["B"] = 1] = "B";
  return Foo;
})(Foo || {});
`)
	expectPrintedTS(t, "export enum Foo { A; B }", `export var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["A"] = 0] = "A";
  Foo[Foo["B"] = 1] = "B";
  return Foo;
})(Foo || {});
`)
	expectPrintedTS(t, "enum Foo { A, B, C = 3.3, D, E }", `var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["A"] = 0] = "A";
  Foo[Foo["B"] = 1] = "B";
  Foo[Foo["C"] = 3.3] = "C";
  Foo[Foo["D"] = 4.3] = "D";
  Foo[Foo["E"] = 5.3] = "E";
  return Foo;
})(Foo || {});
`)
	expectPrintedTS(t, "enum Foo { A, B, C = 'x', D, E, F = `y`, G = `${z}`, H = tag`` }", `var Foo = ((Foo) => {
  Foo[Foo["A"] = 0] = "A";
  Foo[Foo["B"] = 1] = "B";
  Foo["C"] = "x";
  Foo[Foo["D"] = void 0] = "D";
  Foo[Foo["E"] = void 0] = "E";
  Foo["F"] = `+"`y`"+`;
  Foo[Foo["G"] = `+"`${z}`"+`] = "G";
  Foo[Foo["H"] = tag`+"``"+`] = "H";
  return Foo;
})(Foo || {});
`)

	// TypeScript allows splitting an enum into multiple blocks
	expectPrintedTS(t, "enum Foo { A = 1 } enum Foo { B = 2 }", `var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["A"] = 1] = "A";
  return Foo;
})(Foo || {});
var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["B"] = 2] = "B";
  return Foo;
})(Foo || {});
`)

	expectPrintedTS(t, `
		enum Foo {
			'a' = 10.01,
			'a b' = 100,
			c = a + Foo.a + Foo['a b'],
			d,
			e = a + Foo.a + Foo['a b'] + Math.random(),
			f,
		}
		enum Bar {
			a = Foo.a
		}
	`, `var Foo = ((Foo) => {
  Foo[Foo["a"] = 10.01] = "a";
  Foo[Foo["a b"] = 100] = "a b";
  Foo[Foo["c"] = 120.02] = "c";
  Foo[Foo["d"] = 121.02] = "d";
  Foo[Foo["e"] = 120.02 + Math.random()] = "e";
  Foo[Foo["f"] = void 0] = "f";
  return Foo;
})(Foo || {});
var Bar = /* @__PURE__ */ ((Bar) => {
  Bar[Bar["a"] = 10.01 /* a */] = "a";
  return Bar;
})(Bar || {});
`)

	expectPrintedTS(t, `
		enum Foo { A }
		x = [Foo.A, Foo?.A, Foo?.A()]
		y = [Foo['A'], Foo?.['A'], Foo?.['A']()]
	`, `var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["A"] = 0] = "A";
  return Foo;
})(Foo || {});
x = [0 /* A */, Foo?.A, Foo?.A()];
y = [0 /* A */, Foo?.["A"], Foo?.["A"]()];
`)

	// Check shadowing
	expectPrintedTS(t, "enum Foo { Foo }", `var Foo = /* @__PURE__ */ ((_Foo) => {
  _Foo[_Foo["Foo"] = 0] = "Foo";
  return _Foo;
})(Foo || {});
`)
	expectPrintedTS(t, "enum Foo { Bar = Foo }", `var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["Bar"] = Foo] = "Bar";
  return Foo;
})(Foo || {});
`)
	expectPrintedTS(t, "enum Foo { Foo = 1, Bar = Foo }", `var Foo = /* @__PURE__ */ ((_Foo) => {
  _Foo[_Foo["Foo"] = 1] = "Foo";
  _Foo[_Foo["Bar"] = 1 /* Foo */] = "Bar";
  return _Foo;
})(Foo || {});
`)

	// Check top-level "var" and nested "let"
	expectPrintedTS(t, "enum a { b = 1 }", "var a = /* @__PURE__ */ ((a) => {\n  a[a[\"b\"] = 1] = \"b\";\n  return a;\n})(a || {});\n")
	expectPrintedTS(t, "{ enum a { b = 1 } }", "{\n  let a;\n  ((a) => {\n    a[a[\"b\"] = 1] = \"b\";\n  })(a || (a = {}));\n}\n")

	// Check "await" and "yield"
	expectPrintedTS(t, "enum x { await = 1, y = await }", `var x = /* @__PURE__ */ ((x) => {
  x[x["await"] = 1] = "await";
  x[x["y"] = 1 /* await */] = "y";
  return x;
})(x || {});
`)
	expectPrintedTS(t, "enum x { yield = 1, y = yield }", `var x = /* @__PURE__ */ ((x) => {
  x[x["yield"] = 1] = "yield";
  x[x["y"] = 1 /* yield */] = "y";
  return x;
})(x || {});
`)
	expectParseErrorTS(t, "enum x { y = await 1 }", "<stdin>: ERROR: \"await\" can only be used inside an \"async\" function\n")
	expectParseErrorTS(t, "function *f() { enum x { y = yield 1 } }", "<stdin>: ERROR: Cannot use \"yield\" outside a generator function\n")
	expectParseErrorTS(t, "async function f() { enum x { y = await 1 } }", "<stdin>: ERROR: \"await\" can only be used inside an \"async\" function\n")
	expectParseErrorTS(t, "export enum x { yield = 1, y = yield }",
		"<stdin>: ERROR: \"yield\" is a reserved word and cannot be used in an ECMAScript module\n"+
			"<stdin>: NOTE: This file is considered to be an ECMAScript module because of the \"export\" keyword here:\n")
}

func TestTSEnumConstantFolding(t *testing.T) {
	expectPrintedTS(t, `
		enum Foo {
			add = 1 + 2,
			sub = -1 - 2,
			mul = 10 * 20,

			div_pos_inf = 1 / 0,
			div_neg_inf = 1 / -0,
			div_nan = 0 / 0,
			div_neg_zero = 1 / (1 / -0),

			div0 = 10 / 20,
			div1 = 10 / -20,
			div2 = -10 / 20,
			div3 = -10 / -20,

			mod0 = 123 % 100,
			mod1 = 123 % -100,
			mod2 = -123 % 100,
			mod3 = -123 % -100,

			fmod0 = 1.375 % 0.75,
			fmod1 = 1.375 % -0.75,
			fmod2 = -1.375 % 0.75,
			fmod3 = -1.375 % -0.75,

			pow0 = 2.25 ** 3,
			pow1 = 2.25 ** -3,
			pow2 = (-2.25) ** 3,
			pow3 = (-2.25) ** -3,
		}
	`, `var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["add"] = 3] = "add";
  Foo[Foo["sub"] = -3] = "sub";
  Foo[Foo["mul"] = 200] = "mul";
  Foo[Foo["div_pos_inf"] = Infinity] = "div_pos_inf";
  Foo[Foo["div_neg_inf"] = -Infinity] = "div_neg_inf";
  Foo[Foo["div_nan"] = NaN] = "div_nan";
  Foo[Foo["div_neg_zero"] = -0] = "div_neg_zero";
  Foo[Foo["div0"] = 0.5] = "div0";
  Foo[Foo["div1"] = -0.5] = "div1";
  Foo[Foo["div2"] = -0.5] = "div2";
  Foo[Foo["div3"] = 0.5] = "div3";
  Foo[Foo["mod0"] = 23] = "mod0";
  Foo[Foo["mod1"] = 23] = "mod1";
  Foo[Foo["mod2"] = -23] = "mod2";
  Foo[Foo["mod3"] = -23] = "mod3";
  Foo[Foo["fmod0"] = 0.625] = "fmod0";
  Foo[Foo["fmod1"] = 0.625] = "fmod1";
  Foo[Foo["fmod2"] = -0.625] = "fmod2";
  Foo[Foo["fmod3"] = -0.625] = "fmod3";
  Foo[Foo["pow0"] = 11.390625] = "pow0";
  Foo[Foo["pow1"] = 0.0877914951989026] = "pow1";
  Foo[Foo["pow2"] = -11.390625] = "pow2";
  Foo[Foo["pow3"] = -0.0877914951989026] = "pow3";
  return Foo;
})(Foo || {});
`)

	expectPrintedTS(t, `
		enum Foo {
			pos = +54321012345,
			neg = -54321012345,
			cpl = ~54321012345,

			shl0 = 987654321 << 2,
			shl1 = 987654321 << 31,
			shl2 = 987654321 << 34,

			shr0 = -987654321 >> 2,
			shr1 = -987654321 >> 31,
			shr2 = -987654321 >> 34,

			ushr0 = -987654321 >>> 2,
			ushr1 = -987654321 >>> 31,
			ushr2 = -987654321 >>> 34,

			bitand = 0xDEADF00D & 0xBADCAFE,
			bitor = 0xDEADF00D | 0xBADCAFE,
			bitxor = 0xDEADF00D ^ 0xBADCAFE,
		}
	`, `var Foo = /* @__PURE__ */ ((Foo) => {
  Foo[Foo["pos"] = 54321012345] = "pos";
  Foo[Foo["neg"] = -54321012345] = "neg";
  Foo[Foo["cpl"] = 1513562502] = "cpl";
  Foo[Foo["shl0"] = -344350012] = "shl0";
  Foo[Foo["shl1"] = -2147483648] = "shl1";
  Foo[Foo["shl2"] = -344350012] = "shl2";
  Foo[Foo["shr0"] = -246913581] = "shr0";
  Foo[Foo["shr1"] = -1] = "shr1";
  Foo[Foo["shr2"] = -246913581] = "shr2";
  Foo[Foo["ushr0"] = 826828243] = "ushr0";
  Foo[Foo["ushr1"] = 1] = "ushr1";
  Foo[Foo["ushr2"] = 826828243] = "ushr2";
  Foo[Foo["bitand"] = 179159052] = "bitand";
  Foo[Foo["bitor"] = -542246145] = "bitor";
  Foo[Foo["bitxor"] = -721405197] = "bitxor";
  return Foo;
})(Foo || {});
`)
}

func TestTSFunction(t *testing.T) {
	expectPrintedTS(t, "function foo(): void; function foo(): void {}", "function foo() {\n}\n")

	expectPrintedTS(t, "function foo<A>() {}", "function foo() {\n}\n")
	expectPrintedTS(t, "function foo<A extends B<A>>() {}", "function foo() {\n}\n")
	expectPrintedTS(t, "function foo<A extends B<C<A>>>() {}", "function foo() {\n}\n")
	expectPrintedTS(t, "function foo<A,B,C,>() {}", "function foo() {\n}\n")
	expectPrintedTS(t, "function foo<A extends B<C>= B<C>>() {}", "function foo() {\n}\n")
	expectPrintedTS(t, "function foo<A extends B<C<D>>= B<C<D>>>() {}", "function foo() {\n}\n")
	expectPrintedTS(t, "function foo<A extends B<C<D<E>>>= B<C<D<E>>>>() {}", "function foo() {\n}\n")

	expectParseErrorTS(t, "function foo<>() {}", "<stdin>: ERROR: Expected identifier but found \">\"\n")
	expectParseErrorTS(t, "function foo<,>() {}", "<stdin>: ERROR: Expected identifier but found \",\"\n")
	expectParseErrorTS(t, "function foo<T><T>() {}", "<stdin>: ERROR: Expected \"(\" but found \"<\"\n")

	expectPrintedTS(t, "export default function <T>() {}", "export default function() {\n}\n")
	expectParseErrorTS(t, "export default function <>() {}", "<stdin>: ERROR: Expected identifier but found \">\"\n")
	expectParseErrorTS(t, "export default function <,>() {}", "<stdin>: ERROR: Expected identifier but found \",\"\n")
	expectParseErrorTS(t, "export default function <T><T>() {}", "<stdin>: ERROR: Expected \"(\" but found \"<\"\n")

	expectPrintedTS(t, `
		export default function foo();
		export default function foo(x);
		export default function foo(x?, y?) {}
	`, "export default function foo(x, y) {\n}\n")
}

func TestTSDecl(t *testing.T) {
	expectPrintedTS(t, "var a!: string, b!: boolean", "var a, b;\n")
	expectPrintedTS(t, "let a!: string, b!: boolean", "let a, b;\n")
	expectPrintedTS(t, "const a!: string = '', b!: boolean = false", "const a = \"\", b = false;\n")
	expectPrintedTS(t, "var a\n!b", "var a;\n!b;\n")
	expectPrintedTS(t, "let a\n!b", "let a;\n!b;\n")
	expectParseErrorTS(t, "var a!", "<stdin>: ERROR: Expected \":\" but found end of file\n")
	expectParseErrorTS(t, "var a! = ", "<stdin>: ERROR: Expected \":\" but found \"=\"\n")
	expectParseErrorTS(t, "var a!, b", "<stdin>: ERROR: Expected \":\" but found \",\"\n")

	expectPrinted(t, "a ? ({b}) => {} : c", "a ? ({ b }) => {\n} : c;\n")
	expectPrinted(t, "a ? (({b}) => {}) : c", "a ? ({ b }) => {\n} : c;\n")
	expectPrinted(t, "a ? (({b})) : c", "a ? { b } : c;\n")
	expectParseError(t, "a ? (({b})) => {} : c", "<stdin>: ERROR: Invalid binding pattern\n")
	expectPrintedTS(t, "a ? ({b}) => {} : c", "a ? ({ b }) => {\n} : c;\n")
	expectPrintedTS(t, "a ? (({b}) => {}) : c", "a ? ({ b }) => {\n} : c;\n")
	expectPrintedTS(t, "a ? (({b})) : c", "a ? { b } : c;\n")
	expectParseErrorTS(t, "a ? (({b})) => {} : c", "<stdin>: ERROR: Invalid binding pattern\n")
}

func TestTSDeclare(t *testing.T) {
	expectPrintedTS(t, "declare var x: number", "")
	expectPrintedTS(t, "declare let x: number", "")
	expectPrintedTS(t, "declare const x: number", "")
	expectPrintedTS(t, "declare function fn(); function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare function fn()\n function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare function fn() {} function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare enum X {} function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare class X {} function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare interface X {} function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare namespace X {} function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare module X {} function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare module 'X' {} function scope() {}", "function scope() {\n}\n")
	expectPrintedTS(t, "declare module 'X'; let foo", "let foo;\n")
	expectPrintedTS(t, "declare module 'X'\nlet foo", "let foo;\n")
	expectPrintedTS(t, "declare module 'X' { let foo }", "")
	expectPrintedTS(t, "declare module 'X'\n{ let foo }", "")
	expectPrintedTS(t, "declare global { interface Foo {} let foo: any } let bar", "let bar;\n")
	expectPrintedTS(t, "declare module M { const x }", "")
	expectPrintedTS(t, "declare module M { global { const x } }", "")
	expectPrintedTS(t, "declare module M { global { const x } function foo() {} }", "")
	expectPrintedTS(t, "declare module M { global \n { const x } }", "")
	expectPrintedTS(t, "declare module M { import 'path' }", "")
	expectPrintedTS(t, "declare module M { import x from 'path' }", "")
	expectPrintedTS(t, "declare module M { import {x} from 'path' }", "")
	expectPrintedTS(t, "declare module M { import * as ns from 'path' }", "")
	expectPrintedTS(t, "declare module M { import foo = bar }", "")
	expectPrintedTS(t, "declare module M { export import foo = bar }", "")
	expectPrintedTS(t, "declare module M { export {x} from 'path' }", "")
	expectPrintedTS(t, "declare module M { export default 123 }", "")
	expectPrintedTS(t, "declare module M { export default function x() {} }", "")
	expectPrintedTS(t, "declare module M { export default class X {} }", "")
	expectPrintedTS(t, "declare module M { export * as ns from 'path' }", "")
	expectPrintedTS(t, "declare module M { export * from 'path' }", "")
	expectPrintedTS(t, "declare module M { export = foo }", "")
	expectPrintedTS(t, "declare module M { export as namespace ns }", "")
	expectPrintedTS(t, "declare module M { export as namespace ns; }", "")
	expectParseErrorTS(t, "declare module M { export as namespace ns.foo }", "<stdin>: ERROR: Expected \";\" but found \".\"\n")
	expectParseErrorTS(t, "declare module M { export as namespace ns function foo() {} }", "<stdin>: ERROR: Expected \";\" but found \"function\"\n")
	expectParseErrorTS(t, "module M { const x }", "<stdin>: ERROR: The constant \"x\" must be initialized\n")
	expectParseErrorTS(t, "module M { const [] }", "<stdin>: ERROR: This constant must be initialized\n")
	expectParseErrorTS(t, "module M { const {} }", "<stdin>: ERROR: This constant must be initialized\n")

	// This is a weird case where "," after a rest parameter is allowed
	expectPrintedTS(t, "declare function fn(x: any, ...y, )", "")
	expectPrintedTS(t, "declare function fn(x: any, ...y: any, )", "")
	expectParseErrorTS(t, "function fn(x: any, ...y, )", "<stdin>: ERROR: Expected \")\" but found \",\"\n")
	expectParseErrorTS(t, "function fn(x: any, ...y, ) {}", "<stdin>: ERROR: Expected \")\" but found \",\"\n")
	expectParseErrorTS(t, "function fn(x: any, ...y: any, )", "<stdin>: ERROR: Expected \")\" but found \",\"\n")
	expectParseErrorTS(t, "function fn(x: any, ...y: any, ) {}", "<stdin>: ERROR: Expected \")\" but found \",\"\n")

	// This declares a global module
	expectPrintedTS(t, "export as namespace ns", "")
	expectParseErrorTS(t, "export as namespace ns.foo", "<stdin>: ERROR: Expected \";\" but found \".\"\n")
}

func TestTSDecorator(t *testing.T) {
	// Tests of "declare class"
	expectPrintedTS(t, "@dec(() => 0) declare class Foo {} {let foo}", "{\n  let foo;\n}\n")
	expectPrintedTS(t, "@dec(() => 0) declare abstract class Foo {} {let foo}", "{\n  let foo;\n}\n")
	expectPrintedTS(t, "@dec(() => 0) export declare class Foo {} {let foo}", "{\n  let foo;\n}\n")
	expectPrintedTS(t, "@dec(() => 0) export declare abstract class Foo {} {let foo}", "{\n  let foo;\n}\n")
	expectPrintedTS(t, "declare class Foo { @dec(() => 0) foo } {let foo}", "{\n  let foo;\n}\n")
	expectPrintedTS(t, "declare class Foo { @dec(() => 0) foo() } {let foo}", "{\n  let foo;\n}\n")
	expectPrintedTS(t, "declare class Foo { foo(@dec(() => 0) x) } {let foo}", "{\n  let foo;\n}\n")

	// Decorators must only work on class statements
	notes := "<stdin>: NOTE: The preceding TypeScript decorator is here:\n" +
		"NOTE: Decorators can only be used with class declarations in TypeScript.\n"
	expectParseErrorTS(t, "@dec enum foo {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"enum\"\n"+notes)
	expectParseErrorTS(t, "@dec namespace foo {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"namespace\"\n"+notes)
	expectParseErrorTS(t, "@dec function foo() {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"function\"\n"+notes)
	expectParseErrorTS(t, "@dec abstract", "<stdin>: ERROR: Expected \"class\" but found end of file\n")
	expectParseErrorTS(t, "@dec declare: x", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \":\"\n"+notes)
	expectParseErrorTS(t, "@dec declare enum foo {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"enum\"\n"+notes)
	expectParseErrorTS(t, "@dec declare namespace foo {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"namespace\"\n"+notes)
	expectParseErrorTS(t, "@dec declare function foo()", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"function\"\n"+notes)
	expectParseErrorTS(t, "@dec export {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"{\"\n"+notes)
	expectParseErrorTS(t, "@dec export enum foo {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"enum\"\n"+notes)
	expectParseErrorTS(t, "@dec export namespace foo {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"namespace\"\n"+notes)
	expectParseErrorTS(t, "@dec export function foo() {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"function\"\n"+notes)
	expectParseErrorTS(t, "@dec export default abstract", "<stdin>: ERROR: Expected \"class\" but found end of file\n")
	expectParseErrorTS(t, "@dec export declare enum foo {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"enum\"\n"+notes)
	expectParseErrorTS(t, "@dec export declare namespace foo {}", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"namespace\"\n"+notes)
	expectParseErrorTS(t, "@dec export declare function foo()", "<stdin>: ERROR: Expected \"class\" after TypeScript decorator but found \"function\"\n"+notes)

	// Decorators must be forbidden outside class statements
	note := "<stdin>: NOTE: This is a class expression, not a class declaration:\n"
	expectParseErrorTS(t, "(class { @dec foo })", "<stdin>: ERROR: Decorators can only be used with class declarations in TypeScript\n"+note)
	expectParseErrorTS(t, "(class { @dec foo() {} })", "<stdin>: ERROR: Decorators can only be used with class declarations in TypeScript\n"+note)
	expectParseErrorTS(t, "(class { foo(@dec x) {} })", "<stdin>: ERROR: Decorators can only be used with class declarations in TypeScript\n"+note)
	expectParseErrorTS(t, "({ @dec foo })", "<stdin>: ERROR: Expected identifier but found \"@\"\n")
	expectParseErrorTS(t, "({ @dec foo() {} })", "<stdin>: ERROR: Expected identifier but found \"@\"\n")
	expectParseErrorTS(t, "({ foo(@dec x) {} })", "<stdin>: ERROR: Expected identifier but found \"@\"\n")

	// Decorators aren't allowed with private names
	expectParseErrorTS(t, "class Foo { @dec #foo }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec #foo = 1 }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec #foo() {} }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec *#foo() {} }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec async #foo() {} }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec async* #foo() {} }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec static #foo }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec static #foo = 1 }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec static #foo() {} }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec static *#foo() {} }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec static async #foo() {} }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")
	expectParseErrorTS(t, "class Foo { @dec static async* #foo() {} }", "<stdin>: ERROR: Expected identifier but found \"#foo\"\n")

	// Decorators aren't allowed on class constructors
	expectParseErrorTS(t, "class Foo { @dec constructor() {} }", "<stdin>: ERROR: TypeScript does not allow decorators on class constructors\n")
	expectParseErrorTS(t, "class Foo { @dec public constructor() {} }", "<stdin>: ERROR: TypeScript does not allow decorators on class constructors\n")
}

func TestTSTry(t *testing.T) {
	expectPrintedTS(t, "try {} catch (x: any) {}", "try {\n} catch (x) {\n}\n")
	expectPrintedTS(t, "try {} catch (x: unknown) {}", "try {\n} catch (x) {\n}\n")
	expectPrintedTS(t, "try {} catch (x: number) {}", "try {\n} catch (x) {\n}\n")

	expectPrintedTS(t, "try {} catch ({x}: any) {}", "try {\n} catch ({ x }) {\n}\n")
	expectPrintedTS(t, "try {} catch ({x}: unknown) {}", "try {\n} catch ({ x }) {\n}\n")
	expectPrintedTS(t, "try {} catch ({x}: number) {}", "try {\n} catch ({ x }) {\n}\n")

	expectPrintedTS(t, "try {} catch ([x]: any) {}", "try {\n} catch ([x]) {\n}\n")
	expectPrintedTS(t, "try {} catch ([x]: unknown) {}", "try {\n} catch ([x]) {\n}\n")
	expectPrintedTS(t, "try {} catch ([x]: number) {}", "try {\n} catch ([x]) {\n}\n")

	expectParseErrorTS(t, "try {} catch (x!) {}", "<stdin>: ERROR: Expected \")\" but found \"!\"\n")
	expectParseErrorTS(t, "try {} catch (x!: any) {}", "<stdin>: ERROR: Expected \")\" but found \"!\"\n")
	expectParseErrorTS(t, "try {} catch (x!: unknown) {}", "<stdin>: ERROR: Expected \")\" but found \"!\"\n")
}

func TestTSArrow(t *testing.T) {
	expectPrintedTS(t, "(a?) => {}", "(a) => {\n};\n")
	expectPrintedTS(t, "(a?: number) => {}", "(a) => {\n};\n")
	expectPrintedTS(t, "(a?: number = 0) => {}", "(a = 0) => {\n};\n")
	expectParseErrorTS(t, "(a? = 0) => {}", "<stdin>: ERROR: Unexpected \"=\"\n")

	expectPrintedTS(t, "(a?, b) => {}", "(a, b) => {\n};\n")
	expectPrintedTS(t, "(a?: number, b) => {}", "(a, b) => {\n};\n")
	expectPrintedTS(t, "(a?: number = 0, b) => {}", "(a = 0, b) => {\n};\n")
	expectParseErrorTS(t, "(a? = 0, b) => {}", "<stdin>: ERROR: Unexpected \"=\"\n")

	expectPrintedTS(t, "(a: number) => {}", "(a) => {\n};\n")
	expectPrintedTS(t, "(a: number = 0) => {}", "(a = 0) => {\n};\n")
	expectPrintedTS(t, "(a: number, b) => {}", "(a, b) => {\n};\n")

	expectPrintedTS(t, "(): void => {}", "() => {\n};\n")
	expectPrintedTS(t, "(a): void => {}", "(a) => {\n};\n")
	expectParseErrorTS(t, "x: void => {}", "<stdin>: ERROR: Unexpected \"=>\"\n")
	expectPrintedTS(t, "a ? (1 + 2) : (3 + 4)", "a ? 1 + 2 : 3 + 4;\n")
	expectPrintedTS(t, "(foo) ? (foo as Bar) : null;", "foo ? foo : null;\n")
	expectPrintedTS(t, "((foo) ? (foo as Bar) : null)", "foo ? foo : null;\n")
	expectPrintedTS(t, "let x = a ? (b, c) : (d, e)", "let x = a ? (b, c) : (d, e);\n")

	expectPrintedTS(t, "let x: () => void = () => {}", "let x = () => {\n};\n")
	expectPrintedTS(t, "let x: (y) => void = () => {}", "let x = () => {\n};\n")
	expectPrintedTS(t, "let x: (this) => void = () => {}", "let x = () => {\n};\n")
	expectPrintedTS(t, "let x: (this: any) => void = () => {}", "let x = () => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): (() => {}) => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): () => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): (y) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ([,[b]]) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ([a,[b]]) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ([a,[b],]) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ({a}) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ({a,}) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ({a:{b}}) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ({0:{b}}) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ({'a':{b}}) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ({if:{b}}) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ({...a}) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): ({a,...b}) => {} => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): (y[]) => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "let x = (y: any): (a | b) => {};", "let x = (y) => {\n};\n")
	expectPrintedTS(t, "type x = ({...fi}) => {};", "")
	expectParseErrorTS(t, "let x = (y: any): (y) => {};", "<stdin>: ERROR: Unexpected \":\"\n")
	expectParseErrorTS(t, "let x = (y: any): (y) => {return 0};", "<stdin>: ERROR: Unexpected \":\"\n")
	expectParseErrorTS(t, "let x = (y: any): asserts y is (y) => {};", "<stdin>: ERROR: Unexpected \":\"\n")
	expectParseErrorTS(t, "type x = ({...if}) => {};", "<stdin>: ERROR: Unexpected \"...\"\n")

	expectPrintedTS(t, "async (): void => {}", "async () => {\n};\n")
	expectPrintedTS(t, "async (a): void => {}", "async (a) => {\n};\n")
	expectParseErrorTS(t, "async x: void => {}", "<stdin>: ERROR: Expected \"=>\" but found \":\"\n")

	expectPrintedTS(t, "function foo(x: boolean): asserts x", "")
	expectPrintedTS(t, "function foo(x: boolean): asserts<T>", "")
	expectPrintedTS(t, "function foo(x: boolean): asserts\nx", "x;\n")
	expectPrintedTS(t, "function foo(x: boolean): asserts<T>\nx", "x;\n")
	expectParseErrorTS(t, "function foo(x: boolean): asserts<T> x", "<stdin>: ERROR: Expected \";\" but found \"x\"\n")
	expectPrintedTS(t, "(x: boolean): asserts x => {}", "(x) => {\n};\n")
	expectPrintedTS(t, "(x: boolean): asserts this is object => {}", "(x) => {\n};\n")
	expectPrintedTS(t, "(x: T): asserts x is NonNullable<T> => {}", "(x) => {\n};\n")
	expectPrintedTS(t, "(x: any): x is number => {}", "(x) => {\n};\n")
	expectPrintedTS(t, "(x: any): this is object => {}", "(x) => {\n};\n")
	expectPrintedTS(t, "(x: any): (() => void) => {}", "(x) => {\n};\n")
	expectPrintedTS(t, "(x: any): ((y: any) => void) => {}", "(x) => {\n};\n")
	expectPrintedTS(t, "function foo(this: any): this is number {}", "function foo() {\n}\n")
	expectPrintedTS(t, "function foo(this: any): asserts this is number {}", "function foo() {\n}\n")
	expectPrintedTS(t, "(symbol: any): symbol is number => {}", "(symbol) => {\n};\n")

	expectPrintedTS(t, "let x: () => {} | ({y: z});", "let x;\n")
	expectPrintedTS(t, "function x(): ({y: z}) {}", "function x() {\n}\n")

	expectParseErrorTargetTS(t, 5, "return check ? (hover = 2, bar) : baz()", "")
	expectParseErrorTargetTS(t, 5, "return check ? (hover = 2, bar) => 0 : baz()",
		"<stdin>: ERROR: Transforming default arguments to the configured target environment is not supported yet\n")
}

func TestTSCall(t *testing.T) {
	expectPrintedTS(t, "foo()", "foo();\n")
	expectPrintedTS(t, "foo<number>()", "foo();\n")
	expectPrintedTS(t, "foo<number, boolean>()", "foo();\n")
}

func TestTSNew(t *testing.T) {
	expectPrintedTS(t, "new Foo()", "new Foo();\n")
	expectPrintedTS(t, "new Foo<number>()", "new Foo();\n")
	expectPrintedTS(t, "new Foo<number, boolean>()", "new Foo();\n")
	expectPrintedTS(t, "new Foo<number>", "new Foo();\n")
	expectPrintedTS(t, "new Foo<number, boolean>", "new Foo();\n")

	expectPrintedTS(t, "new Foo!()", "new Foo();\n")
	expectPrintedTS(t, "new Foo!<number>()", "new Foo();\n")
	expectPrintedTS(t, "new Foo!.Bar()", "new Foo.Bar();\n")
	expectPrintedTS(t, "new Foo!.Bar<number>()", "new Foo.Bar();\n")
	expectPrintedTS(t, "new Foo!['Bar']()", "new Foo[\"Bar\"]();\n")
	expectPrintedTS(t, "new Foo\n!(x)", "new Foo();\n!x;\n")
	expectPrintedTS(t, "new Foo<number>!(x)", "new Foo() < number > !x;\n")
	expectParseErrorTS(t, "new Foo<number>!()", "<stdin>: ERROR: Unexpected \")\"\n")
	expectParseErrorTS(t, "new Foo\n!.Bar()", "<stdin>: ERROR: Unexpected \".\"\n")
	expectParseError(t, "new Foo!()", "<stdin>: ERROR: Unexpected \"!\"\n")
}

func TestTSInstantiationExpression(t *testing.T) {
	expectPrintedTS(t, "f<number>", "f;\n")
	expectPrintedTS(t, "f<number, boolean>", "f;\n")
	expectPrintedTS(t, "f.g<number>", "f.g;\n")
	expectPrintedTS(t, "f<number>.g", "f.g;\n")
	expectPrintedTS(t, "f<number>.g<number>", "f.g;\n")
	expectPrintedTS(t, "f['g']<number>", "f[\"g\"];\n")
	expectPrintedTS(t, "(f<number>)<number>", "f;\n")

	// function call
	expectPrintedTS(t, "const x1 = f<true>\n(true);", "const x1 = f(true);\n")
	// relational expression
	expectPrintedTS(t, "const x1 = f<true>\ntrue;", "const x1 = f < true > true;\n")
	// instantiation expression
	expectPrintedTS(t, "const x1 = f<true>;\n(true);", "const x1 = f;\ntrue;\n")

	expectPrintedTS(t, "f<number>?.();", "f?.();\n")
	expectPrintedTS(t, "f?.<number>();", "f?.();\n")

	expectPrintedTS(t, "f<number>['g'];", "f < number > [\"g\"];\n")

	expectPrintedTS(t, "type T21 = typeof Array<string>; f();", "f();\n")
	expectPrintedTS(t, "type T22 = typeof Array<string, number>; f();", "f();\n")

	expectPrintedTS(t, "f<x>, g<y>;", "f, g;\n")
	expectPrintedTS(t, "[f<x>];", "[f];\n")
	expectPrintedTS(t, "f<x> ? g<y> : h<z>;", "f ? g : h;\n")
	expectPrintedTS(t, "f<x> ^ g<y>;", "f ^ g;\n")
	expectPrintedTS(t, "f<x> & g<y>;", "f & g;\n")
	expectPrintedTS(t, "f<x> | g<y>;", "f | g;\n")
	expectPrintedTS(t, "f<x> && g<y>;", "f && g;\n")
	expectPrintedTS(t, "f<x> || g<y>;", "f || g;\n")
	expectPrintedTS(t, "f<x> ?? g<y>;", "f ?? g;\n")
	expectPrintedTS(t, "{ f<x> }", "{\n  f;\n}\n")
	expectPrintedTS(t, "f<x> == g<y>;", "f == g;\n")
	expectPrintedTS(t, "f<x> === g<y>;", "f === g;\n")
	expectPrintedTS(t, "f<x> != g<y>;", "f != g;\n")
	expectPrintedTS(t, "f<x> !== g<y>;", "f !== g;\n")

	expectParseErrorTS(t, "const a8 = f<number><number>;", "<stdin>: ERROR: Unexpected \";\"\n")
	expectParseErrorTS(t, "const b1 = f?.<number>;", "<stdin>: ERROR: Expected \"(\" but found \";\"\n")
}

func TestTSExponentiation(t *testing.T) {
	// More info: https://github.com/microsoft/TypeScript/issues/41755
	expectParseErrorTS(t, "await x! ** 2", "<stdin>: ERROR: Unexpected \"**\"\n")
	expectPrintedTS(t, "await x as any ** 2", "(await x) ** 2;\n")
}

func TestTSImport(t *testing.T) {
	expectPrintedTS(t, "import {x} from 'foo'", "")
	expectPrintedTS(t, "import {x} from 'foo'; log(x)", "import { x } from \"foo\";\nlog(x);\n")
	expectPrintedTS(t, "import {x, y as z} from 'foo'; log(z)", "import { y as z } from \"foo\";\nlog(z);\n")

	expectPrintedTS(t, "import x from 'foo'", "")
	expectPrintedTS(t, "import x from 'foo'; log(x)", "import x from \"foo\";\nlog(x);\n")

	expectPrintedTS(t, "import * as ns from 'foo'", "")
	expectPrintedTS(t, "import * as ns from 'foo'; log(ns)", "import * as ns from \"foo\";\nlog(ns);\n")

	// Dead control flow must not affect usage tracking
	expectPrintedTS(t, "import {x} from 'foo'; if (false) log(x)", "import \"foo\";\nif (false)\n  log(x);\n")
	expectPrintedTS(t, "import x from 'foo'; if (false) log(x)", "import \"foo\";\nif (false)\n  log(x);\n")
	expectPrintedTS(t, "import * as ns from 'foo'; if (false) log(ns)", "import \"foo\";\nif (false)\n  log(ns);\n")
}

// This is TypeScript-specific export syntax
func TestTSExportEquals(t *testing.T) {
	// This use of the "export" keyword should not trigger strict mode because
	// this syntax works in CommonJS modules, not in ECMAScript modules
	expectPrintedTS(t, "export = []", "module.exports = [];\n")
	expectPrintedTS(t, "export = []; with ({}) ;", "with ({})\n  ;\nmodule.exports = [];\n")
}

// This is TypeScript-specific import syntax
func TestTSImportEquals(t *testing.T) {
	// This use of the "export" keyword should not trigger strict mode because
	// this syntax works in CommonJS modules, not in ECMAScript modules
	expectPrintedTS(t, "import x = require('y')", "const x = require(\"y\");\n")
	expectPrintedTS(t, "import x = require('y'); with ({}) ;", "const x = require(\"y\");\nwith ({})\n  ;\n")

	expectPrintedTS(t, "import x = require('foo'); x()", "const x = require(\"foo\");\nx();\n")
	expectPrintedTS(t, "import x = require('foo')\nx()", "const x = require(\"foo\");\nx();\n")
	expectPrintedTS(t, "import x = require\nx()", "const x = require;\nx();\n")
	expectPrintedTS(t, "import x = foo.bar; x()", "const x = foo.bar;\nx();\n")
	expectPrintedTS(t, "import x = foo.bar\nx()", "const x = foo.bar;\nx();\n")
	expectParseErrorTS(t, "import x = foo()", "<stdin>: ERROR: Expected \";\" but found \"(\"\n")
	expectParseErrorTS(t, "import x = foo<T>.bar", "<stdin>: ERROR: Expected \";\" but found \"<\"\n")
	expectParseErrorTS(t, "{ import x = foo.bar }", "<stdin>: ERROR: Unexpected \"x\"\n")

	expectPrintedTS(t, "export import x = require('foo'); x()", "export const x = require(\"foo\");\nx();\n")
	expectPrintedTS(t, "export import x = require('foo')\nx()", "export const x = require(\"foo\");\nx();\n")
	expectPrintedTS(t, "export import x = foo.bar; x()", "export const x = foo.bar;\nx();\n")
	expectPrintedTS(t, "export import x = foo.bar\nx()", "export const x = foo.bar;\nx();\n")

	expectParseError(t, "export import foo = bar", "<stdin>: ERROR: Unexpected \"import\"\n")
	expectParseErrorTS(t, "export import {foo} from 'bar'", "<stdin>: ERROR: Expected identifier but found \"{\"\n")
	expectParseErrorTS(t, "export import foo from 'bar'", "<stdin>: ERROR: Expected \"=\" but found \"from\"\n")
	expectParseErrorTS(t, "export import foo = bar; var x; export {x as foo}",
		`<stdin>: ERROR: Multiple exports with the same name "foo"
<stdin>: NOTE: The name "foo" was originally exported here:
`)
	expectParseErrorTS(t, "{ export import foo = bar }", "<stdin>: ERROR: Unexpected \"export\"\n")

	errorText := `<stdin>: WARNING: This assignment will throw because "x" is a constant
<stdin>: NOTE: The symbol "x" was declared a constant here:
`
	expectParseErrorTS(t, "import x = require('y'); x = require('z')", errorText)
	expectParseErrorTS(t, "import x = y.z; x = z.y", errorText)
}

func TestTSImportEqualsInNamespace(t *testing.T) {
	expectPrintedTS(t, "namespace ns { import foo = bar }", "")
	expectPrintedTS(t, "namespace ns { import foo = bar; type x = foo.x }", "")
	expectPrintedTS(t, "namespace ns { import foo = bar.x; foo }", `var ns;
((ns) => {
  const foo = bar.x;
  foo;
})(ns || (ns = {}));
`)
	expectPrintedTS(t, "namespace ns { export import foo = bar }", `var ns;
((ns) => {
  ns.foo = bar;
})(ns || (ns = {}));
`)
	expectPrintedTS(t, "namespace ns { export import foo = bar.x; foo }", `var ns;
((ns) => {
  ns.foo = bar.x;
  ns.foo;
})(ns || (ns = {}));
`)
	expectParseErrorTS(t, "namespace ns { import {foo} from 'bar' }", "<stdin>: ERROR: Expected identifier but found \"{\"\n")
	expectParseErrorTS(t, "namespace ns { import foo from 'bar' }", "<stdin>: ERROR: Expected \"=\" but found \"from\"\n")
	expectParseErrorTS(t, "namespace ns { export import {foo} from 'bar' }", "<stdin>: ERROR: Expected identifier but found \"{\"\n")
	expectParseErrorTS(t, "namespace ns { export import foo from 'bar' }", "<stdin>: ERROR: Expected \"=\" but found \"from\"\n")
	expectParseErrorTS(t, "namespace ns { { import foo = bar } }", "<stdin>: ERROR: Unexpected \"foo\"\n")
	expectParseErrorTS(t, "namespace ns { { export import foo = bar } }", "<stdin>: ERROR: Unexpected \"export\"\n")
}

func TestTSTypeOnlyImport(t *testing.T) {
	expectPrintedTS(t, "import type foo from 'bar'; x", "x;\n")
	expectPrintedTS(t, "import type foo from 'bar'\nx", "x;\n")
	expectPrintedTS(t, "import type * as foo from 'bar'; x", "x;\n")
	expectPrintedTS(t, "import type * as foo from 'bar'\nx", "x;\n")
	expectPrintedTS(t, "import type {foo, bar as baz} from 'bar'; x", "x;\n")
	expectPrintedTS(t, "import type {'foo' as bar} from 'bar'\nx", "x;\n")
	expectPrintedTS(t, "import type foo = require('bar'); x", "x;\n")
	expectPrintedTS(t, "import type foo = bar.baz; x", "x;\n")

	expectPrintedTS(t, "import type = bar; type", "const type = bar;\ntype;\n")
	expectPrintedTS(t, "import type = foo.bar; type", "const type = foo.bar;\ntype;\n")
	expectPrintedTS(t, "import type = require('type'); type", "const type = require(\"type\");\ntype;\n")
	expectPrintedTS(t, "import type from 'bar'; type", "import type from \"bar\";\ntype;\n")

	expectPrintedTS(t, "import { type } from 'mod'; type", "import { type } from \"mod\";\ntype;\n")
	expectPrintedTS(t, "import { x, type foo } from 'mod'; x", "import { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "import { x, type as } from 'mod'; x", "import { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "import { x, type foo as bar } from 'mod'; x", "import { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "import { x, type foo as as } from 'mod'; x", "import { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "import { type as as } from 'mod'; as", "import { type as as } from \"mod\";\nas;\n")
	expectPrintedTS(t, "import { type as foo } from 'mod'; foo", "import { type as foo } from \"mod\";\nfoo;\n")
	expectPrintedTS(t, "import { type as type } from 'mod'; type", "import { type } from \"mod\";\ntype;\n")
	expectPrintedTS(t, "import { x, type as as foo } from 'mod'; x", "import { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "import { x, type as as as } from 'mod'; x", "import { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "import { x, type type as as } from 'mod'; x", "import { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "import { x, \\u0074ype y } from 'mod'; x, y", "import { x } from \"mod\";\nx, y;\n")
	expectPrintedTS(t, "import { x, type if as y } from 'mod'; x, y", "import { x } from \"mod\";\nx, y;\n")

	expectPrintedTS(t, "import a = b; import c = a.c", "")
	expectPrintedTS(t, "import c = a.c; import a = b", "")
	expectPrintedTS(t, "import a = b; import c = a.c; c()", "const a = b;\nconst c = a.c;\nc();\n")
	expectPrintedTS(t, "import c = a.c; import a = b; c()", "const c = a.c;\nconst a = b;\nc();\n")

	expectParseErrorTS(t, "import type", "<stdin>: ERROR: Expected \"from\" but found end of file\n")
	expectParseErrorTS(t, "import type * foo", "<stdin>: ERROR: Expected \"as\" but found \"foo\"\n")
	expectParseErrorTS(t, "import type * as 'bar'", "<stdin>: ERROR: Expected identifier but found \"'bar'\"\n")
	expectParseErrorTS(t, "import type { 'bar' }", "<stdin>: ERROR: Expected \"as\" but found \"}\"\n")

	expectParseErrorTS(t, "import type foo, * as foo from 'bar'", "<stdin>: ERROR: Expected \"from\" but found \",\"\n")
	expectParseErrorTS(t, "import type foo, {foo} from 'bar'", "<stdin>: ERROR: Expected \"from\" but found \",\"\n")
	expectParseErrorTS(t, "import type * as foo = require('bar')", "<stdin>: ERROR: Expected \"from\" but found \"=\"\n")
	expectParseErrorTS(t, "import type {foo} = require('bar')", "<stdin>: ERROR: Expected \"from\" but found \"=\"\n")

	expectParseErrorTS(t, "import { type as export } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"export\"\n")
	expectParseErrorTS(t, "import { type as as export } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"export\"\n")
	expectParseErrorTS(t, "import { type import } from 'mod'", "<stdin>: ERROR: Expected \"as\" but found \"}\"\n")
	expectParseErrorTS(t, "import { type foo bar } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"bar\"\n")
	expectParseErrorTS(t, "import { type foo as } from 'mod'", "<stdin>: ERROR: Expected identifier but found \"}\"\n")
	expectParseErrorTS(t, "import { type foo as bar baz } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"baz\"\n")
	expectParseErrorTS(t, "import { type as as as as } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"as\"\n")
	expectParseErrorTS(t, "import { type \\u0061s x } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"x\"\n")
	expectParseErrorTS(t, "import { type x \\u0061s y } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"\\\\u0061s\"\n")
	expectParseErrorTS(t, "import { type x as if } from 'mod'", "<stdin>: ERROR: Expected identifier but found \"if\"\n")
	expectParseErrorTS(t, "import { type as if } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"if\"\n")

	// Forbidden names
	expectParseErrorTS(t, "import { type as eval } from 'mod'", "<stdin>: ERROR: Cannot use \"eval\" as an identifier here:\n")
	expectParseErrorTS(t, "import { type as arguments } from 'mod'", "<stdin>: ERROR: Cannot use \"arguments\" as an identifier here:\n")

	// Arbitrary module namespace identifier names
	expectPrintedTS(t, "import { x, type 'y' as z } from 'mod'; x, z", "import { x } from \"mod\";\nx, z;\n")
	expectParseErrorTS(t, "import { x, type 'y' } from 'mod'", "<stdin>: ERROR: Expected \"as\" but found \"}\"\n")
	expectParseErrorTS(t, "import { x, type 'y' as } from 'mod'", "<stdin>: ERROR: Expected identifier but found \"}\"\n")
	expectParseErrorTS(t, "import { x, type 'y' as 'z' } from 'mod'", "<stdin>: ERROR: Expected identifier but found \"'z'\"\n")
	expectParseErrorTS(t, "import { x, type as 'y' } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"'y'\"\n")
	expectParseErrorTS(t, "import { x, type y as 'z' } from 'mod'", "<stdin>: ERROR: Expected identifier but found \"'z'\"\n")
}

func TestTSTypeOnlyExport(t *testing.T) {
	expectPrintedTS(t, "export type {foo, bar as baz} from 'bar'", "")
	expectPrintedTS(t, "export type {foo, bar as baz}", "")
	expectPrintedTS(t, "export type {foo} from 'bar'; x", "x;\n")
	expectPrintedTS(t, "export type {foo} from 'bar'\nx", "x;\n")
	expectPrintedTS(t, "export type {default} from 'bar'", "")
	expectParseErrorTS(t, "export type {default}", "<stdin>: ERROR: Expected identifier but found \"default\"\n")

	expectPrintedTS(t, "export { type } from 'mod'; type", "export { type } from \"mod\";\ntype;\n")
	expectPrintedTS(t, "export { type, as } from 'mod'", "export { type, as } from \"mod\";\n")
	expectPrintedTS(t, "export { x, type foo } from 'mod'; x", "export { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "export { x, type as } from 'mod'; x", "export { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "export { x, type foo as bar } from 'mod'; x", "export { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "export { x, type foo as as } from 'mod'; x", "export { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "export { type as as } from 'mod'; as", "export { type as as } from \"mod\";\nas;\n")
	expectPrintedTS(t, "export { type as foo } from 'mod'; foo", "export { type as foo } from \"mod\";\nfoo;\n")
	expectPrintedTS(t, "export { type as type } from 'mod'; type", "export { type } from \"mod\";\ntype;\n")
	expectPrintedTS(t, "export { x, type as as foo } from 'mod'; x", "export { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "export { x, type as as as } from 'mod'; x", "export { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "export { x, type type as as } from 'mod'; x", "export { x } from \"mod\";\nx;\n")
	expectPrintedTS(t, "export { x, \\u0074ype y }; let x, y", "export { x };\nlet x, y;\n")
	expectPrintedTS(t, "export { x, \\u0074ype y } from 'mod'", "export { x } from \"mod\";\n")
	expectPrintedTS(t, "export { x, type if } from 'mod'", "export { x } from \"mod\";\n")
	expectPrintedTS(t, "export { x, type y as if }; let x", "export { x };\nlet x;\n")

	expectParseErrorTS(t, "export { type foo bar } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"bar\"\n")
	expectParseErrorTS(t, "export { type foo as } from 'mod'", "<stdin>: ERROR: Expected identifier but found \"}\"\n")
	expectParseErrorTS(t, "export { type foo as bar baz } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"baz\"\n")
	expectParseErrorTS(t, "export { type as as as as } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"as\"\n")
	expectParseErrorTS(t, "export { type \\u0061s x } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"x\"\n")
	expectParseErrorTS(t, "export { type x \\u0061s y } from 'mod'", "<stdin>: ERROR: Expected \"}\" but found \"\\\\u0061s\"\n")
	expectParseErrorTS(t, "export { x, type if }", "<stdin>: ERROR: Expected identifier but found \"if\"\n")

	// Arbitrary module namespace identifier names
	expectPrintedTS(t, "export { type as \"\" } from 'mod'", "export { type as \"\" } from \"mod\";\n")
	expectPrintedTS(t, "export { type as as \"\" } from 'mod'", "export {} from \"mod\";\n")
	expectPrintedTS(t, "export { type x as \"\" } from 'mod'", "export {} from \"mod\";\n")
	expectPrintedTS(t, "export { type \"\" as x } from 'mod'", "export {} from \"mod\";\n")
	expectPrintedTS(t, "export { type \"\" as \" \" } from 'mod'", "export {} from \"mod\";\n")
	expectPrintedTS(t, "export { type \"\" } from 'mod'", "export {} from \"mod\";\n")
	expectParseErrorTS(t, "export { type \"\" }", "<stdin>: ERROR: Expected identifier but found \"\\\"\\\"\"\n")
	expectParseErrorTS(t, "export { type \"\" as x }", "<stdin>: ERROR: Expected identifier but found \"\\\"\\\"\"\n")
	expectParseErrorTS(t, "export { type \"\" as \" \" }", "<stdin>: ERROR: Expected identifier but found \"\\\"\\\"\"\n")

	// Named exports should be removed if they don't refer to a local symbol
	expectPrintedTS(t, "const Foo = {}; export {Foo}", "const Foo = {};\nexport { Foo };\n")
	expectPrintedTS(t, "type Foo = {}; export {Foo}", "export {};\n")
	expectPrintedTS(t, "const Foo = {}; export {Foo as Bar}", "const Foo = {};\nexport { Foo as Bar };\n")
	expectPrintedTS(t, "type Foo = {}; export {Foo as Bar}", "export {};\n")
	expectPrintedTS(t, "import Foo from 'foo'; export {Foo}", "import Foo from \"foo\";\nexport { Foo };\n")
	expectPrintedTS(t, "import {Foo} from 'foo'; export {Foo}", "import { Foo } from \"foo\";\nexport { Foo };\n")
	expectPrintedTS(t, "import * as Foo from 'foo'; export {Foo}", "import * as Foo from \"foo\";\nexport { Foo };\n")
	expectPrintedTS(t, "{ var Foo; } export {Foo}", "{\n  var Foo;\n}\nexport { Foo };\n")
	expectPrintedTS(t, "{ let Foo; } export {Foo}", "{\n  let Foo;\n}\nexport {};\n")
	expectPrintedTS(t, "export {Foo}", "export {};\n")
	expectParseError(t, "export {Foo}", "<stdin>: ERROR: \"Foo\" is not declared in this file\n")
}

func TestTSOptionalChain(t *testing.T) {
	expectParseError(t, "a?.<T>()", "<stdin>: ERROR: Expected identifier but found \"<\"\n")
	expectPrintedTS(t, "a?.<T>()", "a?.();\n")
	expectParseErrorTS(t, "a?.<T>b", "<stdin>: ERROR: Expected \"(\" but found \"b\"\n")
	expectParseErrorTS(t, "a?.<T>[b]", "<stdin>: ERROR: Expected \"(\" but found \"[\"\n")

	expectPrintedTS(t, "a?.b.c", "a?.b.c;\n")
	expectPrintedTS(t, "(a?.b).c", "(a?.b).c;\n")
	expectPrintedTS(t, "a?.b!.c", "a?.b.c;\n")

	expectPrintedTS(t, "a?.b[c]", "a?.b[c];\n")
	expectPrintedTS(t, "(a?.b)[c]", "(a?.b)[c];\n")
	expectPrintedTS(t, "a?.b![c]", "a?.b[c];\n")

	expectPrintedTS(t, "a?.b(c)", "a?.b(c);\n")
	expectPrintedTS(t, "(a?.b)(c)", "(a?.b)(c);\n")
	expectPrintedTS(t, "a?.b!(c)", "a?.b(c);\n")
	expectPrintedTS(t, "a?.b<T>(c)", "a?.b(c);\n")
}

func TestTSJSX(t *testing.T) {
	expectParseErrorTSX(t, "<div>></div>",
		"<stdin>: ERROR: The character \">\" is not valid inside a JSX element\n"+
			"NOTE: Did you mean to escape it as \"{'>'}\" instead?\n")
	expectParseErrorTSX(t, "<div>{1}}</div>",
		"<stdin>: ERROR: The character \"}\" is not valid inside a JSX element\n"+
			"NOTE: Did you mean to escape it as \"{'}'}\" instead?\n")

	expectPrintedTS(t, "const x = <number>1", "const x = 1;\n")
	expectPrintedTSX(t, "const x = <number>1</number>", "const x = /* @__PURE__ */ React.createElement(\"number\", null, \"1\");\n")
	expectParseErrorTSX(t, "const x = <number>1", "<stdin>: ERROR: Unexpected end of file\n")

	expectPrintedTSX(t, "<x>a{}c</x>", "/* @__PURE__ */ React.createElement(\"x\", null, \"a\", \"c\");\n")
	expectPrintedTSX(t, "<x>a{b}c</x>", "/* @__PURE__ */ React.createElement(\"x\", null, \"a\", b, \"c\");\n")
	expectPrintedTSX(t, "<x>a{...b}c</x>", "/* @__PURE__ */ React.createElement(\"x\", null, \"a\", b, \"c\");\n")

	expectPrintedTSX(t, "const x = <Foo<T>></Foo>", "const x = /* @__PURE__ */ React.createElement(Foo, null);\n")
	expectPrintedTSX(t, "const x = <Foo<T> data-foo></Foo>", "const x = /* @__PURE__ */ React.createElement(Foo, {\n  \"data-foo\": true\n});\n")
	expectParseErrorTSX(t, "const x = <Foo<T>=>", "<stdin>: ERROR: Expected \">\" but found \"=>\"\n")

	expectPrintedTS(t, "const x = <T>() => {}", "const x = () => {\n};\n")
	expectPrintedTS(t, "const x = <T>(y)", "const x = y;\n")
	expectPrintedTS(t, "const x = <T>(y, z)", "const x = (y, z);\n")
	expectPrintedTS(t, "const x = <T>(y: T) => {}", "const x = (y) => {\n};\n")
	expectPrintedTS(t, "const x = <T>(y, z) => {}", "const x = (y, z) => {\n};\n")
	expectPrintedTS(t, "const x = <T = X>(y: T) => {}", "const x = (y) => {\n};\n")
	expectPrintedTS(t, "const x = <T = X>(y, z) => {}", "const x = (y, z) => {\n};\n")
	expectPrintedTS(t, "const x = <T extends X>(y: T) => {}", "const x = (y) => {\n};\n")
	expectPrintedTS(t, "const x = <T extends X>(y, z) => {}", "const x = (y, z) => {\n};\n")
	expectPrintedTS(t, "const x = <T extends X = Y>(y: T) => {}", "const x = (y) => {\n};\n")
	expectPrintedTS(t, "const x = <T extends X = Y>(y, z) => {}", "const x = (y, z) => {\n};\n")

	expectPrintedTS(t, "const x = async <T>() => {}", "const x = async () => {\n};\n")
	expectPrintedTS(t, "const x = async <T>(y)", "const x = async(y);\n")
	expectPrintedTS(t, "const x = async\n<T>(y)", "const x = async(y);\n")
	expectPrintedTS(t, "const x = async <T>(y, z)", "const x = async(y, z);\n")
	expectPrintedTS(t, "const x = async <T>(y: T) => {}", "const x = async (y) => {\n};\n")
	expectPrintedTS(t, "const x = async <T>(y, z) => {}", "const x = async (y, z) => {\n};\n")
	expectPrintedTS(t, "const x = async <T = X>(y: T) => {}", "const x = async (y) => {\n};\n")
	expectPrintedTS(t, "const x = async <T = X>(y, z) => {}", "const x = async (y, z) => {\n};\n")
	expectPrintedTS(t, "const x = async <T extends X>(y: T) => {}", "const x = async (y) => {\n};\n")
	expectPrintedTS(t, "const x = async <T extends X>(y, z) => {}", "const x = async (y, z) => {\n};\n")
	expectPrintedTS(t, "const x = async <T extends X = Y>(y: T) => {}", "const x = async (y) => {\n};\n")
	expectPrintedTS(t, "const x = async <T extends X = Y>(y, z) => {}", "const x = async (y, z) => {\n};\n")
	expectParseErrorTS(t, "const x = async <T>(y: T)", "<stdin>: ERROR: Unexpected \":\"\n")
	expectParseErrorTS(t, "const x = async\n<T>() => {}", "<stdin>: ERROR: Expected \";\" but found \"=>\"\n")
	expectParseErrorTS(t, "const x = async\n<T>(x) => {}", "<stdin>: ERROR: Expected \";\" but found \"=>\"\n")

	expectPrintedTS(t, "const x = <{}>() => {}", "const x = () => {\n};\n")
	expectPrintedTS(t, "const x = <{}>(y)", "const x = y;\n")
	expectPrintedTS(t, "const x = <{}>(y, z)", "const x = (y, z);\n")
	expectPrintedTS(t, "const x = <{}>(y, z) => {}", "const x = (y, z) => {\n};\n")

	expectPrintedTS(t, "const x = <[]>() => {}", "const x = () => {\n};\n")
	expectPrintedTS(t, "const x = <[]>(y)", "const x = y;\n")
	expectPrintedTS(t, "const x = <[]>(y, z)", "const x = (y, z);\n")
	expectPrintedTS(t, "const x = <[]>(y, z) => {}", "const x = (y, z) => {\n};\n")

	invalid := "<stdin>: ERROR: The character \">\" is not valid inside a JSX element\nNOTE: Did you mean to escape it as \"{'>'}\" instead?\n"
	expectParseErrorTSX(t, "(<T>(y) => {}</T>)", invalid)
	expectParseErrorTSX(t, "(<T extends>(y) => {}</T>)", invalid)
	expectParseErrorTSX(t, "(<T extends={false}>(y) => {}</T>)", invalid)
	expectPrintedTSX(t, "(<T extends X>(y) => {})", "(y) => {\n};\n")
	expectPrintedTSX(t, "(<T extends X = Y>(y) => {})", "(y) => {\n};\n")
	expectPrintedTSX(t, "(<T,>() => {})", "() => {\n};\n")
	expectPrintedTSX(t, "(<T, X>(y) => {})", "(y) => {\n};\n")
	expectPrintedTSX(t, "(<T, X>(y): (() => {}) => {})", "(y) => {\n};\n")
	expectParseErrorTSX(t, "(<T>() => {})", invalid+"<stdin>: ERROR: Unexpected end of file\n")
	expectParseErrorTSX(t, "(<[]>(y))", "<stdin>: ERROR: Expected identifier but found \"[\"\n")
	expectParseErrorTSX(t, "(<T[]>(y))", "<stdin>: ERROR: Expected \">\" but found \"[\"\n")
	expectParseErrorTSX(t, "(<T = X>(y))", "<stdin>: ERROR: Expected \">\" but found \"=\"\n")
	expectParseErrorTSX(t, "(<T, X>(y))", "<stdin>: ERROR: Expected \"=>\" but found \")\"\n")
	expectParseErrorTSX(t, "(<T, X>y => {})", "<stdin>: ERROR: Expected \"(\" but found \"y\"\n")
}

func TestTSNoAmbiguousLessThan(t *testing.T) {
	expectPrintedTSNoAmbiguousLessThan(t, "(<T,>() => {})", "() => {\n};\n")
	expectPrintedTSNoAmbiguousLessThan(t, "(<T, X>() => {})", "() => {\n};\n")
	expectPrintedTSNoAmbiguousLessThan(t, "(<T extends X>() => {})", "() => {\n};\n")
	expectParseErrorTSNoAmbiguousLessThan(t, "(<T>x)",
		"<stdin>: ERROR: This syntax is not allowed in files with the \".mts\" or \".cts\" extension\n")
	expectParseErrorTSNoAmbiguousLessThan(t, "(<T>() => {})",
		"<stdin>: ERROR: This syntax is not allowed in files with the \".mts\" or \".cts\" extension\n")
	expectParseErrorTSNoAmbiguousLessThan(t, "(<T>(x) => {})",
		"<stdin>: ERROR: This syntax is not allowed in files with the \".mts\" or \".cts\" extension\n")
	expectParseErrorTSNoAmbiguousLessThan(t, "<x>y</x>",
		"<stdin>: ERROR: This syntax is not allowed in files with the \".mts\" or \".cts\" extension\n"+
			"<stdin>: ERROR: Unexpected end of file\n")
	expectParseErrorTSNoAmbiguousLessThan(t, "<x extends></x>",
		"<stdin>: ERROR: This syntax is not allowed in files with the \".mts\" or \".cts\" extension\n"+
			"<stdin>: ERROR: Unexpected \">\"\n")
	expectParseErrorTSNoAmbiguousLessThan(t, "<x extends={y}></x>",
		"<stdin>: ERROR: This syntax is not allowed in files with the \".mts\" or \".cts\" extension\n"+
			"<stdin>: ERROR: Unexpected \"=\"\n")
}

func TestClassSideEffectOrder(t *testing.T) {
	// The order of computed property side effects must not change
	expectPrintedTS(t, `class Foo {
	[a()]() {}
	[b()];
	[c()] = 1;
	[d()]() {}
	static [e()];
	static [f()] = 1;
	static [g()]() {}
	[h()];
}
`, `var _a, _b;
class Foo {
  constructor() {
    this[_a] = 1;
  }
  [a()]() {
  }
  [(b(), _a = c(), d())]() {
  }
  static [(e(), _b = f(), g())]() {
  }
}
h();
Foo[_b] = 1;
`)
}

func TestMangleTSStringEnumLength(t *testing.T) {
	expectPrintedTS(t, "enum x { y = '' } z = x.y.length",
		"var x = /* @__PURE__ */ ((x) => {\n  x[\"y\"] = \"\";\n  return x;\n})(x || {});\nz = \"\" /* y */.length;\n")

	expectPrintedMangleTS(t, "enum x { y = '' } x.y.length++",
		"var x = /* @__PURE__ */ ((x) => (x.y = \"\", x))(x || {});\n\"\" /* y */.length++;\n")

	expectPrintedMangleTS(t, "enum x { y = '' } x.y.length = z",
		"var x = /* @__PURE__ */ ((x) => (x.y = \"\", x))(x || {});\n\"\" /* y */.length = z;\n")

	expectPrintedMangleTS(t, "enum x { y = '' } z = x.y.length",
		"var x = /* @__PURE__ */ ((x) => (x.y = \"\", x))(x || {});\nz = 0;\n")

	expectPrintedMangleTS(t, "enum x { y = 'abc' } z = x.y.length",
		"var x = /* @__PURE__ */ ((x) => (x.y = \"abc\", x))(x || {});\nz = 3;\n")

	expectPrintedMangleTS(t, "enum x { y = 'ȧḃċ' } z = x.y.length",
		"var x = /* @__PURE__ */ ((x) => (x.y = \"ȧḃċ\", x))(x || {});\nz = 3;\n")

	expectPrintedMangleTS(t, "enum x { y = '👯‍♂️' } z = x.y.length",
		"var x = /* @__PURE__ */ ((x) => (x.y = \"👯‍♂️\", x))(x || {});\nz = 5;\n")
}