r374202 - [ObjC generics] Fix not inheriting type bounds in categories/extensions.

[Volodymyr Sapsai via cfe-commits]

Author: vsapsai
Date: Wed Oct  9 12:29:13 2019
New Revision: 374202

URL: http://llvm.org/viewvc/llvm-project?rev=374202&view=rev
Log:
[ObjC generics] Fix not inheriting type bounds in categories/extensions.

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

Reviewers: erik.pilkington, ahatanak

Reviewed By: erik.pilkington

Subscribers: jkorous, dexonsmith, ributzka, cfe-commits

Differential Revision: https://reviews.llvm.org/D66696

Modified:
    cfe/trunk/include/clang/AST/Type.h
    cfe/trunk/lib/AST/Type.cpp
    cfe/trunk/test/SemaObjC/parameterized_classes_subst.m

Modified: cfe/trunk/include/clang/AST/Type.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Type.h?rev=374202&r1=374201&r2=374202&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/Type.h (original)
+++ cfe/trunk/include/clang/AST/Type.h Wed Oct  9 12:29:13 2019
@@ -5569,7 +5569,7 @@ class ObjCTypeParamType : public Type,
 
 public:
   bool isSugared() const { return true; }
-  QualType desugar() const { return getCanonicalTypeInternal(); }
+  QualType desugar() const;
 
   static bool classof(const Type *T) {
     return T->getTypeClass() == ObjCTypeParam;

Modified: cfe/trunk/lib/AST/Type.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/Type.cpp?rev=374202&r1=374201&r2=374202&view=diff
==============================================================================
--- cfe/trunk/lib/AST/Type.cpp (original)
+++ cfe/trunk/lib/AST/Type.cpp Wed Oct  9 12:29:13 2019
@@ -663,6 +663,10 @@ ObjCTypeParamType::ObjCTypeParamType(con
   initialize(protocols);
 }
 
+QualType ObjCTypeParamType::desugar() const {
+  return getDecl()->getUnderlyingType();
+}
+
 ObjCObjectType::ObjCObjectType(QualType Canonical, QualType Base,
                                ArrayRef<QualType> typeArgs,
                                ArrayRef<ObjCProtocolDecl *> protocols,

Modified: cfe/trunk/test/SemaObjC/parameterized_classes_subst.m
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjC/parameterized_classes_subst.m?rev=374202&r1=374201&r2=374202&view=diff
==============================================================================
--- cfe/trunk/test/SemaObjC/parameterized_classes_subst.m (original)
+++ cfe/trunk/test/SemaObjC/parameterized_classes_subst.m Wed Oct  9 12:29:13 2019
@@ -467,3 +467,17 @@ void bar(MyMutableDictionary<NSString *,
 - (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