Hoist @typedef and @import tags to containing scopes that permit them (#2003)

Author: ahejlsberg

internal/ast/ast.go

@@ -4845,6 +4845,10 @@ func IsImportDeclaration(node *Node) bool {
 	return node.Kind == KindImportDeclaration
 }
 
+func IsJSImportDeclaration(node *Node) bool {
+	return node.Kind == KindJSImportDeclaration
+}
+
 func IsImportDeclarationOrJSImportDeclaration(node *Node) bool {
 	return node.Kind == KindImportDeclaration || node.Kind == KindJSImportDeclaration
 }

internal/parser/parser.go

@@ -498,12 +498,21 @@ func (p *Parser) reparseTopLevelAwait(sourceFile *ast.SourceFile) *ast.Node {
 func (p *Parser) parseListIndex(kind ParsingContext, parseElement func(p *Parser, index int) *ast.Node) []*ast.Node {
 	saveParsingContexts := p.parsingContexts
 	p.parsingContexts |= 1 << kind
+	outerReparseList := p.reparseList
+	p.reparseList = nil
 	list := make([]*ast.Node, 0, 16)
 	for i := 0; !p.isListTerminator(kind); i++ {
 		if p.isListElement(kind, false /*inErrorRecovery*/) {
 			elt := parseElement(p, i)
 			if len(p.reparseList) > 0 {
-				list = append(list, p.reparseList...)
+				for _, e := range p.reparseList {
+					// Propagate @typedef type alias declarations outwards to a context that permits them.
+					if (ast.IsJSTypeAliasDeclaration(e) || ast.IsJSImportDeclaration(e)) && kind != PCSourceElements && kind != PCBlockStatements {
+						outerReparseList = append(outerReparseList, e)
+					} else {
+						list = append(list, e)
+					}
+				}
 				p.reparseList = nil
 			}
 			list = append(list, elt)
@@ -513,6 +522,7 @@ func (p *Parser) parseListIndex(kind ParsingContext, parseElement func(p *Parser
 			break
 		}
 	}
+	p.reparseList = outerReparseList
 	p.parsingContexts = saveParsingContexts
 	return p.nodeSlicePool.Clone(list)
 }

testdata/baselines/reference/compiler/typedefHoisting.errors.txt

@@ -0,0 +1,25 @@
+error TS5055: Cannot write file 'x.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
+error TS5055: Cannot write file 'y.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
+
+
+!!! error TS5055: Cannot write file 'x.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
+!!! error TS5055: Cannot write file 'y.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
+==== x.js (0 errors) ====
+    class C {
+        /** @import {Bar} from "./y" */
+        /** @typedef {Bar[]} Bars */
+        /** @type {Bars} */
+        foo = ["abc", "def"]
+        bar(/** @type {Bar} */ x) {
+            return x
+        }
+    }
+    
+==== y.js (0 errors) ====
+    /** @typedef {string} Bar */
+    export {}
+    

testdata/baselines/reference/compiler/typedefHoisting.js

@@ -0,0 +1,34 @@
+//// [tests/cases/compiler/typedefHoisting.ts] ////
+
+//// [x.js]
+class C {
+    /** @import {Bar} from "./y" */
+    /** @typedef {Bar[]} Bars */
+    /** @type {Bars} */
+    foo = ["abc", "def"]
+    bar(/** @type {Bar} */ x) {
+        return x
+    }
+}
+
+//// [y.js]
+/** @typedef {string} Bar */
+export {}
+
+
+
+
+//// [y.d.ts]
+export type Bar = string;
+/** @typedef {string} Bar */
+export {};
+//// [x.d.ts]
+import type { Bar } from "./y";
+type Bars = Bar[];
+declare class C {
+    /** @import {Bar} from "./y" */
+    /** @typedef {Bar[]} Bars */
+    /** @type {Bars} */
+    foo: Bars;
+    bar(/** @type {Bar} */ x: Bar): string;
+}

testdata/baselines/reference/compiler/typedefHoisting.symbols

@@ -0,0 +1,26 @@
+//// [tests/cases/compiler/typedefHoisting.ts] ////
+
+=== x.js ===
+class C {
+>C : Symbol(C, Decl(x.js, 0, 0))
+
+    /** @import {Bar} from "./y" */
+    /** @typedef {Bar[]} Bars */
+    /** @type {Bars} */
+    foo = ["abc", "def"]
+>foo : Symbol(C.foo, Decl(x.js, 0, 9))
+
+    bar(/** @type {Bar} */ x) {
+>bar : Symbol(C.bar, Decl(x.js, 4, 24))
+>x : Symbol(x, Decl(x.js, 5, 8))
+
+        return x
+>x : Symbol(x, Decl(x.js, 5, 8))
+    }
+}
+
+=== y.js ===
+
+/** @typedef {string} Bar */
+export {}
+

testdata/baselines/reference/compiler/typedefHoisting.types

@@ -0,0 +1,29 @@
+//// [tests/cases/compiler/typedefHoisting.ts] ////
+
+=== x.js ===
+class C {
+>C : C
+
+    /** @import {Bar} from "./y" */
+    /** @typedef {Bar[]} Bars */
+    /** @type {Bars} */
+    foo = ["abc", "def"]
+>foo : Bars
+>["abc", "def"] : string[]
+>"abc" : "abc"
+>"def" : "def"
+
+    bar(/** @type {Bar} */ x) {
+>bar : (x: string) => string
+>x : string
+
+        return x
+>x : string
+    }
+}
+
+=== y.js ===
+
+/** @typedef {string} Bar */
+export {}
+

testdata/baselines/reference/submodule/conformance/callbackOnConstructor.errors.txt

@@ -35,9 +35,9 @@ var ooscope2 = s => s.length > 0;
 
 
 //// [callbackOnConstructor.d.ts]
+export type ValueGetter_2 = (name: string) => boolean | number | string | undefined;
 export declare class Preferences {
     assignability: string;
-    export type ValueGetter_2 = (name: string) => boolean | number | string | undefined;
     /**
      * @callback ValueGetter_2
      * @param {string} name

testdata/baselines/reference/submodule/conformance/callbackOnConstructor.js

@@ -22,9 +22,9 @@
 
  //// [callbackOnConstructor.d.ts]
 -export class Preferences {
++export type ValueGetter_2 = (name: string) => boolean | number | string | undefined;
 +export declare class Preferences {
      assignability: string;
-+    export type ValueGetter_2 = (name: string) => boolean | number | string | undefined;
 +    /**
 +     * @callback ValueGetter_2
 +     * @param {string} name

testdata/baselines/reference/submodule/conformance/callbackOnConstructor.js.diff

@@ -20,5 +20,7 @@ export class Preferences {
 var ooscope2 = s => s.length > 0
 >ooscope2 : Symbol(ooscope2, Decl(callbackOnConstructor.js, 12, 3))
 >s : Symbol(s, Decl(callbackOnConstructor.js, 12, 14))
+>s.length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))
 >s : Symbol(s, Decl(callbackOnConstructor.js, 12, 14))
+>length : Symbol(String.length, Decl(lib.es5.d.ts, --, --))