[swift2objc] Fix nesting bugs (#3173)

Author: liamappelbe

pkgs/swift2objc/lib/src/ast/_core/interfaces/declaration.dart

@@ -7,6 +7,7 @@ import '../../ast_node.dart';
 import '../../declarations/built_in/built_in_declaration.dart';
 import '../shared/referred_type.dart';
 import 'availability.dart';
+import 'nestable_declaration.dart';
 
 /// A common interface for all Swift entities declarations.
 abstract interface class Declaration implements AstNode, Availability {
@@ -20,7 +21,14 @@ extension AsDeclaredType<T extends Declaration> on T {
   DeclaredType<T> get asDeclaredType => DeclaredType(id: id, declaration: this);
 }
 
-extension DeclarationIsBuiltIn on Declaration {
+extension DeclarationExtensions on Declaration {
   bool get isBuiltIn =>
       this is BuiltInDeclaration || source == builtInInputConfig;
+
+  String get fullName {
+    final parent = this is InnerNestableDeclaration
+        ? (this as InnerNestableDeclaration).nestingParent
+        : null;
+    return parent != null ? '${parent.fullName}.$name' : name;
+  }
 }

pkgs/swift2objc/lib/src/transformer/_core/utils.dart

@@ -84,7 +84,7 @@ import 'unique_namer.dart';
     );
 
     return (
-      '${transformedTypeDeclaration.name}($value)',
+      '${transformedTypeDeclaration.fullName}($value)',
       transformedTypeDeclaration.asDeclaredType,
     );
   } else if (type is OptionalType) {

pkgs/swift2objc/lib/src/transformer/transform.dart

@@ -31,6 +31,8 @@ class TransformationState {
 
   // Bindings that will be generated as stubs.
   final stubs = <Declaration>{};
+
+  late final UniqueNamer globalNamer;
 }
 
 /// Transforms the given declarations into the desired ObjC wrapped declarations
@@ -61,7 +63,7 @@ List<Declaration> transform(
   state.stubs.addAll(listDecls.stubDecls);
   state.bindings.addAll(listDecls.stubDecls);
 
-  final globalNamer = UniqueNamer(
+  state.globalNamer = UniqueNamer(
     state.bindings.map((declaration) => declaration.name),
   );
 
@@ -72,9 +74,9 @@ List<Declaration> transform(
 
   final transformedDeclarations = [
     ...topLevelDecls.map(
-      (d) => maybeTransformDeclaration(d, globalNamer, state),
+      (d) => maybeTransformDeclaration(d, state.globalNamer, state),
     ),
-    transformGlobals(globals, globalNamer, state),
+    transformGlobals(globals, state.globalNamer, state),
   ].nonNulls.toList();
 
   return [
@@ -112,10 +114,20 @@ Declaration? maybeTransformDeclaration(
   }
 
   if (declaration is InnerNestableDeclaration &&
-      declaration.nestingParent != null) {
+      declaration.nestingParent != null &&
+      !nested) {
     // It's important that nested declarations are only transformed in the
-    // context of their parent, so that their parentNamer is correct.
-    assert(nested);
+    // context of their parent, so that their parentNamer is correct. So find
+    // the top level declaration this is nested in, and transform that first.
+    maybeTransformDeclaration(
+      _topLevelNestingParent(declaration),
+      state.globalNamer,
+      state,
+    );
+
+    // Now that the parents are transformed, this declaration should haven been
+    // transformed, and will be in the cache.
+    return state.map[declaration]!;
   }
 
   return switch (declaration) {
@@ -136,3 +148,8 @@ List<Declaration> _getPrimitiveWrapperClasses(TransformationState state) =>
         .map((entry) => entry.value)
         .nonNulls
         .toList();
+
+Declaration _topLevelNestingParent(Declaration declaration) =>
+    declaration is InnerNestableDeclaration && declaration.nestingParent != null
+    ? _topLevelNestingParent(declaration.nestingParent!)
+    : declaration;

pkgs/swift2objc/test/integration/nested_types_input.swift

@@ -12,6 +12,10 @@ public class OuterClass {
     public static func makeOuter() -> OuterClass { return OuterClass(); }
     public static func makeInner() -> InnerStruct { return InnerStruct(); }
   }
+
+  public func makeOther() -> OuterStruct.InnerClass {
+    return OuterStruct.InnerClass();
+  }
 }
 
 public struct OuterStruct {
@@ -28,4 +32,8 @@ public struct OuterStruct {
     public static func makeOuter() -> OuterStruct { return OuterStruct(); }
     public static func makeInner() -> InnerStruct { return InnerStruct(); }
   }
+
+  public func makeOther() -> OuterClass.InnerClass {
+    return OuterClass.InnerClass();
+  }
 }

pkgs/swift2objc/test/integration/nested_types_output.swift

@@ -16,12 +16,17 @@ import Foundation
 
   @objc static public func makeInnerClass() -> OuterClassWrapper.InnerClassWrapper {
     let result = OuterClass.makeInnerClass()
-    return InnerClassWrapper(result)
+    return OuterClassWrapper.InnerClassWrapper(result)
   }
 
   @objc static public func makeInnerStruct() -> OuterClassWrapper.InnerStructWrapper {
     let result = OuterClass.makeInnerStruct()
-    return InnerStructWrapper(result)
+    return OuterClassWrapper.InnerStructWrapper(result)
+  }
+
+  @objc public func makeOther() -> OuterStructWrapper.InnerClassWrapper {
+    let result = wrappedInstance.makeOther()
+    return OuterStructWrapper.InnerClassWrapper(result)
   }
 
   @objc public class InnerClassWrapper: NSObject {
@@ -78,12 +83,17 @@ import Foundation
 
   @objc static public func makeInnerStruct() -> OuterStructWrapper.InnerStructWrapper {
     let result = OuterStruct.makeInnerStruct()
-    return InnerStructWrapper(result)
+    return OuterStructWrapper.InnerStructWrapper(result)
   }
 
   @objc static public func makeInnerClass() -> OuterStructWrapper.InnerClassWrapper {
     let result = OuterStruct.makeInnerClass()
-    return InnerClassWrapper(result)
+    return OuterStructWrapper.InnerClassWrapper(result)
+  }
+
+  @objc public func makeOther() -> OuterClassWrapper.InnerClassWrapper {
+    let result = wrappedInstance.makeOther()
+    return OuterClassWrapper.InnerClassWrapper(result)
   }
 
   @objc public class InnerStructWrapper: NSObject {