Fixed declaration emit for expando properties on function declarations declared using element access expressions

src/compiler/checker.ts

@@ -506,6 +506,7 @@ import {
     isEnumDeclaration,
     isEnumMember,
     isExclusivelyTypeOnlyImportOrExport,
+    isExpandoPropertyDeclaration,
     isExportAssignment,
     isExportDeclaration,
     isExportsIdentifier,
@@ -8165,6 +8166,10 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                 const type = checkExpression(name.expression);
                 return !!(type.flags & TypeFlags.StringLike);
             }
+            if (isElementAccessExpression(name)) {
+                const type = checkExpression(name.argumentExpression);
+                return !!(type.flags & TypeFlags.StringLike);
+            }
             return isStringLiteral(name);
         }
 
@@ -47091,7 +47096,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         if (!symbol || !(symbol.flags & SymbolFlags.Function)) {
             return false;
         }
-        return !!forEachEntry(getExportsOfSymbol(symbol), p => p.flags & SymbolFlags.Value && p.valueDeclaration && isPropertyAccessExpression(p.valueDeclaration));
+        return !!forEachEntry(getExportsOfSymbol(symbol), p => p.flags & SymbolFlags.Value && isExpandoPropertyDeclaration(p.valueDeclaration));
     }
 
     function getPropertiesOfContainerFunction(node: Declaration): Symbol[] {

src/compiler/transformers/declarations.ts

@@ -95,15 +95,14 @@ import {
     isAnyImportSyntax,
     isArray,
     isArrayBindingElement,
-    isBinaryExpression,
     isBindingElement,
     isBindingPattern,
     isClassDeclaration,
     isClassElement,
     isDeclaration,
-    isElementAccessExpression,
     isEntityName,
     isEntityNameExpression,
+    isExpandoPropertyDeclaration,
     isExportAssignment,
     isExportDeclaration,
     isExpressionWithTypeArguments,
@@ -133,7 +132,6 @@ import {
     isNightly,
     isOmittedExpression,
     isPrivateIdentifier,
-    isPropertyAccessExpression,
     isPropertySignature,
     isSemicolonClassElement,
     isSetAccessorDeclaration,
@@ -1537,7 +1535,7 @@ export function transformDeclarations(context: TransformationContext) {
                     fakespace.symbol = props[0].parent!;
                     const exportMappings: [Identifier, string][] = [];
                     let declarations: (VariableStatement | ExportDeclaration)[] = mapDefined(props, p => {
-                        if (!p.valueDeclaration || !(isPropertyAccessExpression(p.valueDeclaration) || isElementAccessExpression(p.valueDeclaration) || isBinaryExpression(p.valueDeclaration))) {
+                        if (!isExpandoPropertyDeclaration(p.valueDeclaration)) {
                             return undefined;
                         }
                         const nameStr = unescapeLeadingUnderscores(p.escapedName);

src/compiler/utilities.ts

@@ -10434,3 +10434,8 @@ export function getPropertyNameFromType(type: StringLiteralType | NumberLiteralT
     }
     return Debug.fail();
 }
+
+/** @internal */
+export function isExpandoPropertyDeclaration(declaration: Declaration | undefined): declaration is PropertyAccessExpression | ElementAccessExpression | BinaryExpression {
+    return !!declaration && (isPropertyAccessExpression(declaration) || isElementAccessExpression(declaration) || isBinaryExpression(declaration));
+}

tests/baselines/reference/declarationEmitLateBoundAssignments2.js

@@ -0,0 +1,186 @@
+//// [tests/cases/compiler/declarationEmitLateBoundAssignments2.ts] ////
+
+//// [declarationEmitLateBoundAssignments2.ts]
+// https://github.com/microsoft/TypeScript/issues/54811
+
+const c = "C"
+const num = 1
+const numStr = "10"
+const withWhitespace = "foo bar"
+const emoji = "🤷‍♂️"
+
+export function decl() {}
+decl["B"] = 'foo'
+
+export function decl2() {}
+decl2[c] = 0
+
+export function decl3() {}
+decl3[77] = 0
+
+export function decl4() {}
+decl4[num] = 0
+
+export function decl5() {}
+decl5["101"] = 0
+
+export function decl6() {}
+decl6[numStr] = 0
+
+export function decl7() {}
+decl7["qwe rty"] = 0
+
+export function decl8() {}
+decl8[withWhitespace] = 0
+
+export function decl9() {}
+decl9["🤪"] = 0
+
+export function decl10() {}
+decl10[emoji] = 0
+
+export const arrow = () => {}
+arrow["B"] = 'bar'
+
+export const arrow2 = () => {}
+arrow2[c] = 100
+
+export const arrow3 = () => {}
+arrow3[77] = 0
+
+export const arrow4 = () => {}
+arrow4[num] = 0
+
+export const arrow5 = () => {}
+arrow5["101"] = 0
+
+export const arrow6 = () => {}
+arrow6[numStr] = 0
+
+export const arrow7 = () => {}
+arrow7["qwe rty"] = 0
+
+export const arrow8 = () => {}
+arrow8[withWhitespace] = 0
+
+export const arrow9 = () => {}
+arrow9["🤪"] = 0
+
+export const arrow10 = () => {}
+arrow10[emoji] = 0
+
+
+//// [declarationEmitLateBoundAssignments2.js]
+// https://github.com/microsoft/TypeScript/issues/54811
+const c = "C";
+const num = 1;
+const numStr = "10";
+const withWhitespace = "foo bar";
+const emoji = "🤷‍♂️";
+export function decl() { }
+decl["B"] = 'foo';
+export function decl2() { }
+decl2[c] = 0;
+export function decl3() { }
+decl3[77] = 0;
+export function decl4() { }
+decl4[num] = 0;
+export function decl5() { }
+decl5["101"] = 0;
+export function decl6() { }
+decl6[numStr] = 0;
+export function decl7() { }
+decl7["qwe rty"] = 0;
+export function decl8() { }
+decl8[withWhitespace] = 0;
+export function decl9() { }
+decl9["🤪"] = 0;
+export function decl10() { }
+decl10[emoji] = 0;
+export const arrow = () => { };
+arrow["B"] = 'bar';
+export const arrow2 = () => { };
+arrow2[c] = 100;
+export const arrow3 = () => { };
+arrow3[77] = 0;
+export const arrow4 = () => { };
+arrow4[num] = 0;
+export const arrow5 = () => { };
+arrow5["101"] = 0;
+export const arrow6 = () => { };
+arrow6[numStr] = 0;
+export const arrow7 = () => { };
+arrow7["qwe rty"] = 0;
+export const arrow8 = () => { };
+arrow8[withWhitespace] = 0;
+export const arrow9 = () => { };
+arrow9["🤪"] = 0;
+export const arrow10 = () => { };
+arrow10[emoji] = 0;
+
+
+//// [declarationEmitLateBoundAssignments2.d.ts]
+export declare function decl(): void;
+export declare namespace decl {
+    var B: string;
+}
+export declare function decl2(): void;
+export declare namespace decl2 {
+    var C: number;
+}
+export declare function decl3(): void;
+export declare namespace decl3 { }
+export declare function decl4(): void;
+export declare namespace decl4 { }
+export declare function decl5(): void;
+export declare namespace decl5 { }
+export declare function decl6(): void;
+export declare namespace decl6 { }
+export declare function decl7(): void;
+export declare namespace decl7 { }
+export declare function decl8(): void;
+export declare namespace decl8 { }
+export declare function decl9(): void;
+export declare namespace decl9 { }
+export declare function decl10(): void;
+export declare namespace decl10 { }
+export declare const arrow: {
+    (): void;
+    B: string;
+};
+export declare const arrow2: {
+    (): void;
+    C: number;
+};
+export declare const arrow3: {
+    (): void;
+    77: number;
+};
+export declare const arrow4: {
+    (): void;
+    1: number;
+};
+export declare const arrow5: {
+    (): void;
+    "101": number;
+};
+export declare const arrow6: {
+    (): void;
+    "10": number;
+};
+export declare const arrow7: {
+    (): void;
+    "qwe rty": number;
+};
+export declare const arrow8: {
+    (): void;
+    "foo bar": number;
+};
+export declare const arrow9: {
+    (): void;
+    "\uD83E\uDD2A": number;
+};
+export declare const arrow10: {
+    (): void;
+    "\uD83E\uDD37\u200D\u2642\uFE0F": number;
+};