[ffigen] Fix a naming conflict in function internal variables (#2787)

Author: liamappelbe

pkgs/ffigen/CHANGELOG.md

@@ -9,6 +9,8 @@
   `Declarations.includeMemberSet`, `Declarations.useOriginalName`,
   `Declarations.renameWithMap`, `Declarations.useMemberOriginalName`, and
   `Declarations.renameMemberWithMap`.
+- Fix [a bug](https://github.com/dart-lang/native/issues/2760) in the internal
+  variables generated by function bindings.
 
 ## 20.0.0
 

pkgs/ffigen/lib/src/code_generator/func.dart

@@ -110,7 +110,7 @@ class Func extends LookUpBinding with HasLocalScope {
         functionType.getFfiDartType(context, writeArgumentNames: false);
     final needsWrapper = !functionType.sameDartAndFfiDartType && !isInternal;
 
-    final funcVarName = localScope.addPrivate('_$name');
+    final funcVarName = context.rootScope.addPrivate('_$name');
     final ffiReturnType = functionType.returnType.getFfiDartType(context);
     final ffiArgDeclString = functionType.dartTypeParameters
         .map((p) => '${p.type.getFfiDartType(context)} ${p.name},\n')
@@ -182,7 +182,7 @@ $dartReturnType $enclosingFuncName($dartArgDeclString) => $funcImplCall;
         );
       }
     } else {
-      final funcPointerName = localScope.addPrivate('_${name}Ptr');
+      final funcPointerName = context.rootScope.addPrivate('_${name}Ptr');
       final isLeafString = isLeaf ? 'isLeaf:true' : '';
 
       // Write enclosing function.

pkgs/ffigen/test/native_objc_test/method_test.dart

@@ -37,10 +37,10 @@ void main() {
           'objc_test.dylib',
         ),
       );
-      // verifySetupFile(dylib);
+      verifySetupFile(dylib);
       DynamicLibrary.open(dylib.absolute.path);
       testInstance = MethodInterface();
-      // generateBindingsForCoverage('method');
+      generateBindingsForCoverage('method');
     });
 
     group('Instance methods', () {

pkgs/ffigen/test/native_objc_test/static_func_config.yaml

@@ -5,6 +5,8 @@ output: 'static_func_bindings.dart'
 exclude-all-by-default: true
 functions:
   include:
+    - foo
+    - fooPtr
     - staticFuncOfObject
     - staticFuncOfNullableObject
     - staticFuncOfBlock

pkgs/ffigen/test/native_objc_test/static_func_native_config.yaml

@@ -6,6 +6,8 @@ exclude-all-by-default: true
 ffi-native:
 functions:
   include:
+    - foo
+    - fooPtr
     - staticFuncOfObject
     - staticFuncOfNullableObject
     - staticFuncOfBlock

pkgs/ffigen/test/native_objc_test/static_func_native_test.dart

@@ -192,5 +192,11 @@ void main() {
       expect(counter.value, 0);
       calloc.free(counter);
     }, skip: !canDoGC);
+
+    test('Internal variable conflict resolution', () {
+      // Regression test for https://github.com/dart-lang/native/issues/2760
+      expect(foo(123), 1230);
+      expect(fooPtr(123), 12300);
+    });
   });
 }

pkgs/ffigen/test/native_objc_test/static_func_test.dart

@@ -194,5 +194,11 @@ void main() {
       expect(counter.value, 0);
       calloc.free(counter);
     }, skip: !canDoGC);
+
+    test('Internal variable conflict resolution', () {
+      // Regression test for https://github.com/dart-lang/native/issues/2760
+      expect(lib.foo(123), 1230);
+      expect(lib.fooPtr(123), 12300);
+    });
   });
 }

pkgs/ffigen/test/native_objc_test/static_func_test.m

@@ -58,3 +58,6 @@ - (void)dealloc {
   if (counter != nil) --*counter;
 }
 @end
+
+int foo(int x) { return 10 * x; }
+int fooPtr(int x) { return 100 * x; }