Fix signatureToSignatureDeclarationHelper

Even if `SuppressAnyReturnType` is on, don't supress it if it's a function.

Fixes #35508.

src/compiler/checker.ts

@@ -4532,7 +4532,8 @@ namespace ts {
                     const returnType = getReturnTypeOfSignature(signature);
                     returnTypeNode = returnType && typeToTypeNodeHelper(returnType, context);
                 }
-                if (context.flags & NodeBuilderFlags.SuppressAnyReturnType) {
+                if (context.flags & NodeBuilderFlags.SuppressAnyReturnType
+                    && kind !== SyntaxKind.FunctionType && kind !== SyntaxKind.ConstructorType) {
                     if (returnTypeNode && returnTypeNode.kind === SyntaxKind.AnyKeyword) {
                         returnTypeNode = undefined;
                     }

tests/cases/fourslash/codeFixClassImplementInterfaceCallback.ts

@@ -0,0 +1,75 @@
+/// <reference path='fourslash.ts' />
+
+// #35508
+
+////interface IFoo1 {
+////    parse(reviver: () => any): void;
+////}
+////
+////class Foo1 implements IFoo1 {
+////}
+////
+////interface IFoo2 {
+////    parse(reviver: { (): any }): void;
+////}
+////
+////class Foo2 implements IFoo2 {
+////}
+////
+////interface IFoo3 {
+////    parse(reviver: new () => any): void;
+////}
+////
+////class Foo3 implements IFoo3 {
+////}
+////
+////interface IFoo4 {
+////    parse(reviver: { new (): any }): void;
+////}
+////
+////class Foo4 implements IFoo4 {
+////}
+
+verify.codeFixAll({
+  fixAllDescription: ts.Diagnostics.Implement_all_unimplemented_interfaces.message,
+  fixId: "fixClassIncorrectlyImplementsInterface",
+  newFileContent:
+`interface IFoo1 {
+    parse(reviver: () => any): void;
+}
+
+class Foo1 implements IFoo1 {
+    parse(reviver: () => any): void {
+        throw new Error("Method not implemented.");
+    }
+}
+
+interface IFoo2 {
+    parse(reviver: { (): any }): void;
+}
+
+class Foo2 implements IFoo2 {
+    parse(reviver: () => any): void {
+        throw new Error("Method not implemented.");
+    }
+}
+
+interface IFoo3 {
+    parse(reviver: new () => any): void;
+}
+
+class Foo3 implements IFoo3 {
+    parse(reviver: new () => any): void {
+        throw new Error("Method not implemented.");
+    }
+}
+
+interface IFoo4 {
+    parse(reviver: { new (): any }): void;
+}
+
+class Foo4 implements IFoo4 {
+    parse(reviver: new () => any): void {
+        throw new Error("Method not implemented.");
+    }
+}`});