fix(54383): Declare method quick fix not returned for #private method (#54400)

Author: a-tarasyuk

src/services/codefixes/fixAddMissingMember.ts

@@ -538,11 +538,6 @@ function getActionsForMissingMethodDeclaration(context: CodeFixContext, info: Ty
         return undefined;
     }
 
-    // Private methods are not implemented yet.
-    if (isPrivateIdentifier(token)) {
-        return undefined;
-    }
-
     const methodName = token.text;
     const addMethodDeclarationChanges = (modifierFlags: ModifierFlags) => textChanges.ChangeTracker.with(context, t => addMethodDeclaration(context, t, call, token, modifierFlags, parentDeclaration, declSourceFile));
     const actions = [createCodeFixAction(fixMissingMember, addMethodDeclarationChanges(modifierFlags & ModifierFlags.Static), [modifierFlags & ModifierFlags.Static ? Diagnostics.Declare_static_method_0 : Diagnostics.Declare_method_0, methodName], fixMissingMember, Diagnostics.Add_all_missing_members)];
@@ -556,7 +551,7 @@ function addMethodDeclaration(
     context: CodeFixContextBase,
     changes: textChanges.ChangeTracker,
     callExpression: CallExpression,
-    name: Identifier,
+    name: Identifier | PrivateIdentifier,
     modifierFlags: ModifierFlags,
     parentDeclaration: ClassLikeDeclaration | InterfaceDeclaration | TypeLiteralNode,
     sourceFile: SourceFile,

src/services/codefixes/helpers.ts

@@ -69,6 +69,7 @@ import {
     ObjectLiteralExpression,
     ObjectType,
     ParameterDeclaration,
+    PrivateIdentifier,
     Program,
     PropertyAssignment,
     PropertyDeclaration,
@@ -464,7 +465,7 @@ export function createSignatureDeclarationFromCallExpression(
     context: CodeFixContextBase,
     importAdder: ImportAdder,
     call: CallExpression,
-    name: Identifier | string,
+    name: Identifier | PrivateIdentifier | string,
     modifierFlags: ModifierFlags,
     contextNode: Node
 ): MethodDeclaration | FunctionDeclaration | MethodSignature {
@@ -517,6 +518,7 @@ export function createSignatureDeclarationFromCallExpression(
                 type === undefined ? factory.createKeywordTypeNode(SyntaxKind.UnknownKeyword) : type
             );
         case SyntaxKind.FunctionDeclaration:
+            Debug.assert(typeof name === "string" || isIdentifier(name), "Unexpected name");
             return factory.createFunctionDeclaration(
                 modifiers,
                 asteriskToken,

tests/cases/fourslash/codeFixAddMissingMember29.ts

@@ -0,0 +1,21 @@
+/// <reference path='fourslash.ts' />
+
+////class C {
+////    constructor() {
+////        this.#foo();
+////    }
+////}
+
+verify.codeFix({
+    description: [ts.Diagnostics.Declare_method_0.message, "#foo"],
+    index: 0,
+    newFileContent:
+`class C {
+    constructor() {
+        this.#foo();
+    }
+    #foo() {
+        throw new Error("Method not implemented.");
+    }
+}`,
+});