[ObjC++] Conversions from specialized to non-specialized Objective-C generic
object types should be preferred over conversions to other object pointers
This change ensures that Clang will select the correct overload for the
following code sample:
void overload(Base *b);
void overload(Derived *d);
void test(Base<Base *> b) {
overload(b); // Select overload(Base *), not overload(Derived *)
}
rdar://20124827
Differential Revision: https://reviews.llvm.org/D31597
llvm-svn: 299648
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index 477e04d..c556fb7 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -4047,7 +4047,7 @@
= S.Context.canAssignObjCInterfaces(ToPtr1, ToPtr2);
bool ToAssignRight
= S.Context.canAssignObjCInterfaces(ToPtr2, ToPtr1);
-
+
// A conversion to an a non-id object pointer type or qualified 'id'
// type is better than a conversion to 'id'.
if (ToPtr1->isObjCIdType() &&
@@ -4081,11 +4081,25 @@
return ImplicitConversionSequence::Better;
// -- "conversion of C* to B* is better than conversion of C* to A*,"
- if (S.Context.hasSameType(FromType1, FromType2) &&
+ if (S.Context.hasSameType(FromType1, FromType2) &&
!FromPtr1->isObjCIdType() && !FromPtr1->isObjCClassType() &&
- (ToAssignLeft != ToAssignRight))
+ (ToAssignLeft != ToAssignRight)) {
+ if (FromPtr1->isSpecialized()) {
+ // "conversion of B<A> * to B * is better than conversion of B * to
+ // C *.
+ bool IsFirstSame =
+ FromPtr1->getInterfaceDecl() == ToPtr1->getInterfaceDecl();
+ bool IsSecondSame =
+ FromPtr1->getInterfaceDecl() == ToPtr2->getInterfaceDecl();
+ if (IsFirstSame) {
+ if (!IsSecondSame)
+ return ImplicitConversionSequence::Better;
+ } else if (IsSecondSame)
+ return ImplicitConversionSequence::Worse;
+ }
return ToAssignLeft? ImplicitConversionSequence::Worse
: ImplicitConversionSequence::Better;
+ }
// -- "conversion of B* to A* is better than conversion of C* to A*,"
if (S.Context.hasSameUnqualifiedType(ToType1, ToType2) &&