Unbreak a use case for #1110 / fix for #1121

"Function" is builtin, but anything prefixed or suffixed for whatever
reason shouldn't be handled the same way. So check if the final result
is in builtin list, not the original unmodified name

integration/test-1110/test-1110-test.ts

@@ -1,8 +1,13 @@
-import { UserRule } from "./test-1110";
+import { UserRule, Nested_Function } from "./test-1110";
 
 describe("test-1110", () => {
   it("Able to create a partial user rule with reserved word messages", () => {
     const simple: UserRule = UserRule.fromPartial({ UUID: "foo" });
     expect(simple).toBeTruthy();
   });
+
+  it("built in handling should only be done to top level", () => {
+    const nestedFunction: Nested_Function = Nested_Function.fromPartial({});
+    expect(nestedFunction).toBeTruthy();
+  });
 });

integration/test-1110/test-1110.proto

@@ -25,5 +25,12 @@ message Function {
     string name = 2;
 }
 
+message Nested {
+  message Function {
+      string namespace = 1;
+      string name = 2;
+  }
+}
+
 service APIService {
 }

src/visit.ts

@@ -39,7 +39,7 @@ export function visit(
     const protoFullName = protoPrefix + enumDesc.name;
     // I.e. FooBar_ZazInner
     const tsFullName = tsPrefix + maybeSnakeToCamel(enumDesc.name, options);
-    const tsFullNameWithAffixes = `${options.typePrefix}${tsFullName}${options.typeSuffix}`;
+    const tsFullNameWithAffixes = messageName(`${options.typePrefix}${tsFullName}${options.typeSuffix}`);
     const nestedSourceInfo = sourceInfo.open(childEnumType, index);
     enumFn(tsFullNameWithAffixes, enumDesc, nestedSourceInfo, protoFullName);
   });
@@ -51,8 +51,8 @@ export function visit(
     // I.e. Foo_Bar.Zaz_Inner
     const protoFullName = protoPrefix + message.name;
     // I.e. FooBar_ZazInner
-    const tsFullName = tsPrefix + maybeSnakeToCamel(messageName(message), options);
-    const tsFullNameWithAffixes = `${options.typePrefix}${tsFullName}${options.typeSuffix}`;
+    const tsFullName = tsPrefix + maybeSnakeToCamel(message.name, options);
+    const tsFullNameWithAffixes = messageName(`${options.typePrefix}${tsFullName}${options.typeSuffix}`);
     const nestedSourceInfo = sourceInfo.open(childType, index);
     messageFn(tsFullNameWithAffixes, message, nestedSourceInfo, protoFullName);
     const delim = options.useSnakeTypeName ? "_" : "";
@@ -63,8 +63,7 @@ export function visit(
 const builtInNames = ["Date", "Function"];
 
 /** Potentially suffixes `Message` to names to avoid conflicts, i.e. with `Date`. */
-function messageName(message: DescriptorProto): string {
-  const { name } = message;
+function messageName(name: string): string {
   return builtInNames.includes(name) ? `${name}Message` : name;
 }