[ffigen] Struct Member Renamed Due to Top-Level Function Collision #2850

ffigen renames struct members with a $1 suffix if they share a name with a top-level function in the generated bindings, even if the struct member is scoped within a class and shouldn't conflict.

Minimal Reproducible Example

C Header (example.h)

typedef struct {
    void (*FindClass)(void);
} JniEnv;

void FindClass(void);

2. Reproduction Script (repro.dart)

import 'package:ffigen/ffigen.dart';
import 'dart:io';

void main() {
  final generator = FfiGenerator(
    output: Output(dartFile: Uri.file('bindings.dart')),
    headers: Headers(entryPoints: [Platform.script.resolve('example.h')]),
    structs: Structs.includeAll,
    functions: Functions.includeAll,
  );
  
  generator.generate();
}

3. Generated Dart (bindings.dart)

// ...
@ffi.Native<ffi.Void Function()>()
external void FindClass();

final class JniEnv extends ffi.Struct {
  external ffi.Pointer<ffi.NativeFunction<ffi.Void Function()>> FindClass$1;
}

Expected Behavior

The struct member FindClass should retain its name, as it is a member of the JniEnv class/struct and does not conflict with the top-level FindClass function in Dart.

Actual Behavior

The struct member is renamed to FindClass$1.