resolve element access property names

a-tarasyuk · a-tarasyuk · commit 90a1027c47a8 · 2025-10-09T17:03:11.000+03:00
diff --git a/internal/binder/referenceresolver.go b/internal/binder/referenceresolver.go
@@ -11,6 +11,7 @@ type ReferenceResolver interface {
 	GetReferencedImportDeclaration(node *ast.IdentifierNode) *ast.Declaration
 	GetReferencedValueDeclaration(node *ast.IdentifierNode) *ast.Declaration
 	GetReferencedValueDeclarations(node *ast.IdentifierNode) []*ast.Declaration
+	GetElementAccessExpressionName(expression *ast.ElementAccessExpression) string
 }
 
 type ReferenceResolverHooks struct {
@@ -21,6 +22,7 @@ type ReferenceResolverHooks struct {
 	GetSymbolOfDeclaration                 func(*ast.Declaration) *ast.Symbol
 	GetTypeOnlyAliasDeclaration            func(symbol *ast.Symbol, include ast.SymbolFlags) *ast.Declaration
 	GetExportSymbolOfValueSymbolIfExported func(*ast.Symbol) *ast.Symbol
+	GetElementAccessExpressionName         func(*ast.ElementAccessExpression) (string, bool)
 }
 
 var _ ReferenceResolver = &referenceResolver{}
@@ -236,3 +238,14 @@ func (r *referenceResolver) GetReferencedValueDeclarations(node *ast.IdentifierN
 	}
 	return declarations
 }
+
+func (r *referenceResolver) GetElementAccessExpressionName(expression *ast.ElementAccessExpression) string {
+	if expression != nil {
+		if r.hooks.GetElementAccessExpressionName != nil {
+			if name, ok := r.hooks.GetElementAccessExpressionName(expression); ok {
+				return name
+			}
+		}
+	}
+	return ""
+}
diff --git a/internal/checker/emitresolver.go b/internal/checker/emitresolver.go
@@ -825,6 +825,7 @@ func (r *emitResolver) getReferenceResolver() binder.ReferenceResolver {
 			GetSymbolOfDeclaration:                 r.checker.getSymbolOfDeclaration,
 			GetTypeOnlyAliasDeclaration:            r.checker.getTypeOnlyAliasDeclarationEx,
 			GetExportSymbolOfValueSymbolIfExported: r.checker.getExportSymbolOfValueSymbolIfExported,
+			GetElementAccessExpressionName:         r.checker.tryGetElementAccessExpressionName,
 		})
 	}
 	return r.referenceResolver
@@ -879,6 +880,17 @@ func (r *emitResolver) GetReferencedValueDeclarations(node *ast.IdentifierNode)
 	return r.getReferenceResolver().GetReferencedValueDeclarations(node)
 }
 
+func (r *emitResolver) GetElementAccessExpressionName(expression *ast.ElementAccessExpression) string {
+	if !ast.IsParseTreeNode(expression.AsNode()) {
+		return ""
+	}
+
+	r.checkerMu.Lock()
+	defer r.checkerMu.Unlock()
+
+	return r.getReferenceResolver().GetElementAccessExpressionName(expression)
+}
+
 // TODO: the emit resolver being responsible for some amount of node construction is a very leaky abstraction,
 // and requires giving it access to a lot of context it's otherwise not required to have, which also further complicates the API
 // and likely reduces performance. There's probably some refactoring that could be done here to simplify this.
diff --git a/internal/transformers/declarations/transform.go b/internal/transformers/declarations/transform.go
@@ -1826,18 +1826,13 @@ func (tx *DeclarationTransformer) visitExpressionStatement(node *ast.ExpressionS
 
 func (tx *DeclarationTransformer) transformExpandoAssignment(node *ast.BinaryExpression) *ast.Node {
 	left := node.Left
-
-	if ast.IsElementAccessExpression(left) {
-		return nil
-	}
-
 	symbol := node.Symbol
 	if symbol == nil || symbol.Flags&ast.SymbolFlagsAssignment == 0 {
 		return nil
 	}
 
-	ns := ast.GetFirstIdentifier(left)
-	if ns == nil {
+	ns := ast.GetLeftmostAccessExpression(left)
+	if ns == nil || ns.Kind != ast.KindIdentifier {
 		return nil
 	}
 
@@ -1852,7 +1847,14 @@ func (tx *DeclarationTransformer) transformExpandoAssignment(node *ast.BinaryExp
 	}
 
 	name := tx.Factory().NewIdentifier(ns.Text())
+	property := tx.tryGetPropertyName(left)
+	if property == "" || !scanner.IsIdentifierText(property, core.LanguageVariantStandard) {
+		return nil
+	}
+
 	tx.transformExpandoHost(name, declaration)
+	isNonContextualKeywordName := ast.IsNonContextualKeyword(scanner.StringToToken(property))
+	exportName := core.IfElse(isNonContextualKeywordName, tx.Factory().NewGeneratedNameForNode(left), tx.Factory().NewIdentifier(property))
 
 	synthesizedNamespace := tx.Factory().NewModuleDeclaration(nil /*modifiers*/, ast.KindNamespaceKeyword, name, tx.Factory().NewModuleBlock(tx.Factory().NewNodeList([]*ast.Node{})))
 	synthesizedNamespace.Parent = tx.enclosingDeclaration
@@ -1868,10 +1870,6 @@ func (tx *DeclarationTransformer) transformExpandoAssignment(node *ast.BinaryExp
 	t := tx.resolver.CreateTypeOfExpression(tx.EmitContext(), left, synthesizedNamespace, declarationEmitNodeBuilderFlags, declarationEmitInternalNodeBuilderFlags|nodebuilder.InternalFlagsNoSyntacticPrinter, tx.tracker)
 	tx.state.getSymbolAccessibilityDiagnostic = saveDiag
 
-	nameToken := scanner.StringToToken(left.Name().Text())
-	isNonContextualKeywordName := ast.IsNonContextualKeyword(nameToken)
-
-	exportName := core.IfElse(isNonContextualKeywordName, tx.Factory().NewGeneratedNameForNode(left), tx.Factory().NewIdentifier(left.Name().Text()))
 	statements := []*ast.Statement{
 		tx.Factory().NewVariableStatement(
 			nil, /*modifiers*/
@@ -1964,3 +1962,13 @@ func extractExpandoHostParams(node *ast.Node) (typeParameters *ast.TypeParameter
 		return fn.TypeParameters, fn.Parameters, fn.AsteriskToken
 	}
 }
+
+func (tx *DeclarationTransformer) tryGetPropertyName(node *ast.Node) string {
+	if ast.IsElementAccessExpression(node) {
+		return tx.resolver.GetElementAccessExpressionName(node.AsElementAccessExpression())
+	}
+	if ast.IsPropertyAccessExpression(node) {
+		return node.Name().Text()
+	}
+	return ""
+}
diff --git a/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundAssignments.js b/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundAssignments.js
@@ -39,3 +39,6 @@ export declare function foo(): void;
 export declare namespace foo {
     const bar: number;
 }
+export declare namespace foo {
+    const strMemName: string;
+}
diff --git a/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundAssignments.js.diff b/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundAssignments.js.diff
@@ -7,4 +7,7 @@
 -    var bar: number;
 -    var strMemName: string;
 +    const bar: number;
++}
++export declare namespace foo {
++    const strMemName: string;
  }
diff --git a/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundAssignments2.js b/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundAssignments2.js
@@ -121,7 +121,13 @@ arrow10[emoji] = 0;
 
 //// [declarationEmitLateBoundAssignments2.d.ts]
 export declare function decl(): void;
+export declare namespace decl {
+    const B: string;
+}
 export declare function decl2(): void;
+export declare namespace decl2 {
+    const C: number;
+}
 export declare function decl3(): void;
 export declare function decl4(): void;
 export declare function decl5(): void;
@@ -130,14 +136,14 @@ export declare function decl7(): void;
 export declare function decl8(): void;
 export declare function decl9(): void;
 export declare function decl10(): void;
-export declare const arrow: {
-    (): void;
-    B: string;
-};
-export declare const arrow2: {
-    (): void;
-    C: number;
-};
+export declare function arrow(): void;
+export declare namespace arrow {
+    const B: string;
+}
+export declare function arrow2(): void;
+export declare namespace arrow2 {
+    const C: number;
+}
 export declare const arrow3: {
     (): void;
     77: number;
diff --git a/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundAssignments2.js.diff b/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundAssignments2.js.diff
@@ -1,16 +1,17 @@
 --- old.declarationEmitLateBoundAssignments2.js
 +++ new.declarationEmitLateBoundAssignments2.js
-@@= skipped -120, +120 lines =@@
-
+@@= skipped -121, +121 lines =@@
  //// [declarationEmitLateBoundAssignments2.d.ts]
  export declare function decl(): void;
--export declare namespace decl {
+ export declare namespace decl {
 -    var B: string;
--}
++    const B: string;
+ }
  export declare function decl2(): void;
--export declare namespace decl2 {
+ export declare namespace decl2 {
 -    var C: number;
--}
++    const C: number;
+ }
  export declare function decl3(): void;
 -export declare namespace decl3 { }
  export declare function decl4(): void;
@@ -27,6 +28,22 @@
 -export declare namespace decl9 { }
  export declare function decl10(): void;
 -export declare namespace decl10 { }
- export declare const arrow: {
+-export declare const arrow: {
+-    (): void;
+-    B: string;
+-};
+-export declare const arrow2: {
+-    (): void;
+-    C: number;
+-};
++export declare function arrow(): void;
++export declare namespace arrow {
++    const B: string;
++}
++export declare function arrow2(): void;
++export declare namespace arrow2 {
++    const C: number;
++}
+ export declare const arrow3: {
      (): void;
-     B: string;
+     77: number;
diff --git a/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundJSAssignments.js b/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundJSAssignments.js
@@ -29,3 +29,6 @@ export declare function foo(): void;
 export declare namespace foo {
     const bar: number;
 }
+export declare namespace foo {
+    const strMemName: string;
+}
diff --git a/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundJSAssignments.js.diff b/testdata/baselines/reference/submodule/compiler/declarationEmitLateBoundJSAssignments.js.diff
@@ -11,4 +11,7 @@
 +export declare function foo(): void;
 +export declare namespace foo {
 +    const bar: number;
++}
++export declare namespace foo {
++    const strMemName: string;
  }
diff --git a/testdata/baselines/reference/submodule/compiler/expandoFunctionExpressionsWithDynamicNames.js b/testdata/baselines/reference/submodule/compiler/expandoFunctionExpressionsWithDynamicNames.js
@@ -27,11 +27,11 @@ exports.expr2[s] = 0;
 
 
 //// [expandoFunctionExpressionsWithDynamicNames.d.ts]
-export declare const expr: {
-    (): void;
-    X: number;
-};
-export declare const expr2: {
-    (): void;
-    X: number;
-};
+export declare function expr(): void;
+export declare namespace expr {
+    const X: number;
+}
+export declare function expr2(): void;
+export declare namespace expr2 {
+    const X: number;
+}
diff --git a/testdata/baselines/reference/submodule/compiler/expandoFunctionExpressionsWithDynamicNames.js.diff b/testdata/baselines/reference/submodule/compiler/expandoFunctionExpressionsWithDynamicNames.js.diff
@@ -10,4 +10,24 @@
 +// https://github.com/microsoft/TypeScript/issues/54809
  const s = "X";
  const expr = () => { };
- exports.expr = expr;
+ exports.expr = expr;
+@@= skipped -13, +13 lines =@@
+
+
+ //// [expandoFunctionExpressionsWithDynamicNames.d.ts]
+-export declare const expr: {
+-    (): void;
+-    X: number;
+-};
+-export declare const expr2: {
+-    (): void;
+-    X: number;
+-};
++export declare function expr(): void;
++export declare namespace expr {
++    const X: number;
++}
++export declare function expr2(): void;
++export declare namespace expr2 {
++    const X: number;
++}
diff --git a/testdata/baselines/reference/submodule/conformance/typeFromPropertyAssignment39.js b/testdata/baselines/reference/submodule/conformance/typeFromPropertyAssignment39.js
@@ -14,3 +14,42 @@ declare const foo: {
         blah: number;
     };
 };
+declare namespace foo {
+    const baz: {
+        blah: number;
+    };
+}
+declare namespace foo {
+    const blah: number;
+}
+
+
+//// [DtsFileErrors]
+
+
+a.d.ts(1,15): error TS2451: Cannot redeclare block-scoped variable 'foo'.
+a.d.ts(6,19): error TS2451: Cannot redeclare block-scoped variable 'foo'.
+a.d.ts(11,19): error TS2451: Cannot redeclare block-scoped variable 'foo'.
+
+
+==== a.d.ts (3 errors) ====
+    declare const foo: {
+                  ~~~
+!!! error TS2451: Cannot redeclare block-scoped variable 'foo'.
+        baz: {
+            blah: number;
+        };
+    };
+    declare namespace foo {
+                      ~~~
+!!! error TS2451: Cannot redeclare block-scoped variable 'foo'.
+        const baz: {
+            blah: number;
+        };
+    }
+    declare namespace foo {
+                      ~~~
+!!! error TS2451: Cannot redeclare block-scoped variable 'foo'.
+        const blah: number;
+    }
+    
diff --git a/testdata/baselines/reference/submodule/conformance/typeFromPropertyAssignment39.js.diff b/testdata/baselines/reference/submodule/conformance/typeFromPropertyAssignment39.js.diff
@@ -13,4 +13,43 @@
 +    baz: {
 +        blah: number;
 +    };
-+};
++};
++declare namespace foo {
++    const baz: {
++        blah: number;
++    };
++}
++declare namespace foo {
++    const blah: number;
++}
++
++
++//// [DtsFileErrors]
++
++
++a.d.ts(1,15): error TS2451: Cannot redeclare block-scoped variable 'foo'.
++a.d.ts(6,19): error TS2451: Cannot redeclare block-scoped variable 'foo'.
++a.d.ts(11,19): error TS2451: Cannot redeclare block-scoped variable 'foo'.
++
++
++==== a.d.ts (3 errors) ====
++    declare const foo: {
++                  ~~~
++!!! error TS2451: Cannot redeclare block-scoped variable 'foo'.
++        baz: {
++            blah: number;
++        };
++    };
++    declare namespace foo {
++                      ~~~
++!!! error TS2451: Cannot redeclare block-scoped variable 'foo'.
++        const baz: {
++            blah: number;
++        };
++    }
++    declare namespace foo {
++                      ~~~
++!!! error TS2451: Cannot redeclare block-scoped variable 'foo'.
++        const blah: number;
++    }
++    
diff --git a/testdata/baselines/reference/submodule/conformance/typeFromPrototypeAssignment4.js b/testdata/baselines/reference/submodule/conformance/typeFromPrototypeAssignment4.js
@@ -30,4 +30,13 @@ map4.__underscores__();
 
 //// [a.d.ts]
 declare function Multimap4(): void;
+declare namespace Multimap4 {
+    const prototype: {
+        /**
+         * @param {string} key
+         * @returns {number} the value ok
+         */
+        get(key: string): number;
+    };
+}
 declare const map4: any;
diff --git a/testdata/baselines/reference/submodule/conformance/typeFromPrototypeAssignment4.js.diff b/testdata/baselines/reference/submodule/conformance/typeFromPrototypeAssignment4.js.diff

Original file line number	Diff line number	Diff line change
`@@ -39,3 +39,6 @@ export declare function foo(): void;`
`39`	`39`	`export declare namespace foo {`
`40`	`40`	`const bar: number;`
`41`	`41`	`}`
	`42`	`+export declare namespace foo {`
	`43`	`+ const strMemName: string;`
	`44`	`+}`
Original file line number	Diff line number	Diff line change
`@@ -7,4 +7,7 @@`
`7`	`7`	`- var bar: number;`
`8`	`8`	`- var strMemName: string;`
`9`	`9`	`+ const bar: number;`
	`10`	`++}`
	`11`	`++export declare namespace foo {`
	`12`	`++ const strMemName: string;`
`10`	`13`	`}`
Original file line number	Diff line number	Diff line change
`@@ -29,3 +29,6 @@ export declare function foo(): void;`
`29`	`29`	`export declare namespace foo {`
`30`	`30`	`const bar: number;`
`31`	`31`	`}`
	`32`	`+export declare namespace foo {`
	`33`	`+ const strMemName: string;`
	`34`	`+}`
Original file line number	Diff line number	Diff line change
`@@ -11,4 +11,7 @@`
`11`	`11`	`+export declare function foo(): void;`
`12`	`12`	`+export declare namespace foo {`
`13`	`13`	`+ const bar: number;`
	`14`	`++}`
	`15`	`++export declare namespace foo {`
	`16`	`++ const strMemName: string;`
`14`	`17`	`}`