[PATCH] D66696: [ObjC generics] Fix not inheriting type bounds in categories/extensions.

[Volodymyr Sapsai via Phabricator via cfe-commits]

vsapsai created this revision.
vsapsai added reviewers: erik.pilkington, ahatanak.
Herald added subscribers: ributzka, dexonsmith, jkorous.

When a category/extension doesn't repeat a type bound, corresponding
type parameter is substituted with `id` when used as a type argument. As
a result, in the added test case it was causing errors like

> type argument 'T' (aka 'id') does not satisfy the bound ('id<NSCopying>') of type parameter 'T'

We are already checking that type parameters should be consistent
everywhere (see `checkTypeParamListConsistency`) and update
`ObjCTypeParamDecl` to have correct underlying type. And when we use the
type parameter as a method return type or a method parameter type, it is
substituted to the bounded type. But when we use the type parameter as a
type argument, we check `ObjCTypeParamType` that ignores the updated
underlying type and remains `id`.

Fix by desugaring `ObjCTypeParamType` to the underlying type, the same
way we are doing with `TypedefType`.

rdar://problem/54329242


https://reviews.llvm.org/D66696

Files:
  clang/include/clang/AST/Type.h
  clang/lib/AST/Type.cpp
  clang/test/SemaObjC/parameterized_classes_subst.m


Index: clang/test/SemaObjC/parameterized_classes_subst.m
===================================================================
--- clang/test/SemaObjC/parameterized_classes_subst.m
+++ clang/test/SemaObjC/parameterized_classes_subst.m
@@ -467,3 +467,17 @@
 - (void)mapUsingBlock2:(id)block { // expected-warning{{conflicting parameter types in implementation}}
 }
 @end
+
+// --------------------------------------------------------------------------
+// Use a type parameter as a type argument.
+// --------------------------------------------------------------------------
+// Type bounds in a category/extension are omitted. rdar://problem/54329242
+ at interface ParameterizedContainer<T : id<NSCopying>>
+- (ParameterizedContainer<T> *)inInterface;
+ at end
+ at interface ParameterizedContainer<T> (Cat)
+- (ParameterizedContainer<T> *)inCategory;
+ at end
+ at interface ParameterizedContainer<U> ()
+- (ParameterizedContainer<U> *)inExtension;
+ at end
Index: clang/lib/AST/Type.cpp
===================================================================
--- clang/lib/AST/Type.cpp
+++ clang/lib/AST/Type.cpp
@@ -611,6 +611,10 @@
   initialize(protocols);
 }
 
+QualType ObjCTypeParamType::desugar() const {
+  return getDecl()->getUnderlyingType();
+}
+
 ObjCObjectType::ObjCObjectType(QualType Canonical, QualType Base,
                                ArrayRef<QualType> typeArgs,
                                ArrayRef<ObjCProtocolDecl *> protocols,
Index: clang/include/clang/AST/Type.h
===================================================================
--- clang/include/clang/AST/Type.h
+++ clang/include/clang/AST/Type.h
@@ -5554,7 +5554,7 @@
 
 public:
   bool isSugared() const { return true; }
-  QualType desugar() const { return getCanonicalTypeInternal(); }
+  QualType desugar() const;
 
   static bool classof(const Type *T) {
     return T->getTypeClass() == ObjCTypeParam;


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D66696.216993.patch
Type: text/x-patch
Size: 1877 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20190824/d4e34c8a/attachment-0001.bin>