fix(54694): Class incorrectly implements interface generated with template string literal mapped type (#54715)

src/compiler/checker.ts

@@ -335,6 +335,7 @@ import {
     getParseTreeNode,
     getPropertyAssignmentAliasLikeExpression,
     getPropertyNameForPropertyNameNode,
+    getPropertyNameFromType,
     getResolutionDiagnostic,
     getResolutionModeOverrideForClause,
     getResolvedExternalModuleName,
@@ -729,6 +730,7 @@ import {
     isTypeQueryNode,
     isTypeReferenceNode,
     isTypeReferenceType,
+    isTypeUsableAsPropertyName,
     isUMDExportSymbol,
     isValidBigIntString,
     isValidESSymbolDeclaration,
@@ -12286,13 +12288,6 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         return type as InterfaceTypeWithDeclaredMembers;
     }
 
-    /**
-     * Indicates whether a type can be used as a property name.
-     */
-    function isTypeUsableAsPropertyName(type: Type): type is StringLiteralType | NumberLiteralType | UniqueESSymbolType {
-        return !!(type.flags & TypeFlags.StringOrNumberLiteralOrUnique);
-    }
-
     /**
      * Indicates whether a declaration name is definitely late-bindable.
      * A declaration name is only late-bindable if:
@@ -12338,19 +12333,6 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         return isDynamicName(node) && !isLateBindableName(node);
     }
 
-    /**
-     * Gets the symbolic name for a member from its type.
-     */
-    function getPropertyNameFromType(type: StringLiteralType | NumberLiteralType | UniqueESSymbolType): __String {
-        if (type.flags & TypeFlags.UniqueESSymbol) {
-            return (type as UniqueESSymbolType).escapedName;
-        }
-        if (type.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
-            return escapeLeadingUnderscores("" + (type as StringLiteralType | NumberLiteralType).value);
-        }
-        return Debug.fail();
-    }
-
     /**
      * Adds a declaration to a late-bound dynamic member. This performs the same function for
      * late-bound members that `addDeclarationToSymbol` in binder.ts performs for early-bound

src/compiler/utilities.ts

@@ -416,6 +416,7 @@ import {
     noop,
     normalizePath,
     NoSubstitutionTemplateLiteral,
+    NumberLiteralType,
     NumericLiteral,
     ObjectFlags,
     ObjectFlagsType,
@@ -494,6 +495,7 @@ import {
     stringContains,
     StringLiteral,
     StringLiteralLike,
+    StringLiteralType,
     stringToToken,
     SuperCall,
     SuperExpression,
@@ -544,6 +546,7 @@ import {
     TypeReferenceNode,
     unescapeLeadingUnderscores,
     UnionOrIntersectionTypeNode,
+    UniqueESSymbolType,
     UserPreferences,
     ValidImportTypeNode,
     VariableDeclaration,
@@ -10313,3 +10316,25 @@ export function getTextOfJsxNamespacedName(node: JsxNamespacedName) {
 export function intrinsicTagNameToString(node: Identifier | JsxNamespacedName) {
     return isIdentifier(node) ? idText(node) : getTextOfJsxNamespacedName(node);
 }
+
+/**
+ * Indicates whether a type can be used as a property name.
+ * @internal
+ */
+export function isTypeUsableAsPropertyName(type: Type): type is StringLiteralType | NumberLiteralType | UniqueESSymbolType {
+    return !!(type.flags & TypeFlags.StringOrNumberLiteralOrUnique);
+}
+
+/**
+ * Gets the symbolic name for a member from its type.
+ * @internal
+ */
+export function getPropertyNameFromType(type: StringLiteralType | NumberLiteralType | UniqueESSymbolType): __String {
+    if (type.flags & TypeFlags.UniqueESSymbol) {
+        return (type as UniqueESSymbolType).escapedName;
+    }
+    if (type.flags & (TypeFlags.StringLiteral | TypeFlags.NumberLiteral)) {
+        return escapeLeadingUnderscores("" + (type as StringLiteralType | NumberLiteralType).value);
+    }
+    return Debug.fail();
+}

src/services/codefixes/helpers.ts

@@ -6,27 +6,32 @@ import {
     Block,
     CallExpression,
     CharacterCodes,
+    CheckFlags,
     ClassLikeDeclaration,
     CodeFixContextBase,
     combine,
     Debug,
+    Declaration,
     Diagnostics,
     emptyArray,
     EntityName,
     Expression,
     factory,
     find,
+    firstOrUndefined,
     flatMap,
     FunctionDeclaration,
     FunctionExpression,
     GetAccessorDeclaration,
     getAllAccessorDeclarations,
+    getCheckFlags,
     getEffectiveModifierFlags,
     getEmitScriptTarget,
     getFirstIdentifier,
     getModuleSpecifierResolverHost,
     getNameForExportedSymbol,
     getNameOfDeclaration,
+    getPropertyNameFromType,
     getQuotePreference,
     getSetAccessorValueParameter,
     getSynthesizedDeepClone,
@@ -52,6 +57,7 @@ import {
     isSetAccessorDeclaration,
     isStringLiteral,
     isTypeNode,
+    isTypeUsableAsPropertyName,
     isYieldExpression,
     LanguageServiceHost,
     length,
@@ -91,6 +97,7 @@ import {
     textChanges,
     TextSpan,
     textSpanEnd,
+    TransientSymbol,
     tryCast,
     TsConfigSourceFile,
     Type,
@@ -98,6 +105,7 @@ import {
     TypeFlags,
     TypeNode,
     TypeParameterDeclaration,
+    unescapeLeadingUnderscores,
     UnionType,
     UserPreferences,
     visitEachChild,
@@ -174,7 +182,7 @@ export function addNewNodeForMemberSymbol(
     isAmbient = false,
 ): void {
     const declarations = symbol.getDeclarations();
-    const declaration = declarations?.[0];
+    const declaration = firstOrUndefined(declarations);
     const checker = context.program.getTypeChecker();
     const scriptTarget = getEmitScriptTarget(context.program.getCompilerOptions());
 
@@ -193,7 +201,7 @@ export function addNewNodeForMemberSymbol(
      * In such cases, we assume the declaration to be a `PropertySignature`.
      */
     const kind = declaration?.kind ?? SyntaxKind.PropertySignature;
-    const declarationName = getSynthesizedDeepClone(getNameOfDeclaration(declaration), /*includeTrivia*/ false) as PropertyName;
+    const declarationName = createDeclarationName(symbol, declaration);
     const effectiveModifierFlags = declaration ? getEffectiveModifierFlags(declaration) : ModifierFlags.None;
     let modifierFlags = effectiveModifierFlags & ModifierFlags.Static;
     modifierFlags |=
@@ -310,7 +318,6 @@ export function addNewNodeForMemberSymbol(
         if (method) addClassElement(method);
     }
 
-
     function createModifiers(): NodeArray<Modifier> | undefined {
         let modifiers: Modifier[] | undefined;
 
@@ -344,6 +351,16 @@ export function addNewNodeForMemberSymbol(
     function createTypeNode(typeNode: TypeNode | undefined) {
         return getSynthesizedDeepClone(typeNode, /*includeTrivia*/ false);
     }
+
+    function createDeclarationName(symbol: Symbol, declaration: Declaration | undefined): PropertyName {
+        if (getCheckFlags(symbol) & CheckFlags.Mapped) {
+            const nameType = (symbol as TransientSymbol).links.nameType;
+            if (nameType && isTypeUsableAsPropertyName(nameType)) {
+                return factory.createIdentifier(unescapeLeadingUnderscores(getPropertyNameFromType(nameType)));
+            }
+        }
+        return getSynthesizedDeepClone(getNameOfDeclaration(declaration), /*includeTrivia*/ false) as PropertyName;
+    }
 }
 
 /** @internal */

tests/cases/fourslash/codeFixClassImplementInterfaceMappedType2.ts

@@ -0,0 +1,20 @@
+/// <reference path="fourslash.ts" />
+
+////type ListenerTemplate<T, S extends string, I extends string = "${1}"> = {
+////    [K in keyof T as K extends string
+////        ? S extends `${infer F}${I}${infer R}` ? `${F}${K}${R}` : K : K]
+////        : (listener: (payload: T[K]) => void) => void;
+////};
+////type ListenActionable<E> = ListenerTemplate<E, "add*Listener" | "remove*Listener", "*">;
+////type ClickEventSupport = ListenActionable<{ Click: 'some-click-event-payload' }>;
+////
+////[|class C implements ClickEventSupport { }|]
+
+verify.codeFix({
+    description: "Implement interface 'ClickEventSupport'",
+    newRangeContent:
+`class C implements ClickEventSupport {
+    addClickListener: (listener: (payload: "some-click-event-payload") => void) => void;
+    removeClickListener: (listener: (payload: "some-click-event-payload") => void) => void;
+}`,
+});