[ObjC] Diagnose implicit type coercion from ObjC 'Class' to object

pointer types.

For example, in Objective-C mode, the initialization of 'x' in:
```
  @implementation MyType
  + (void)someClassMethod {
    MyType *x = self;
  }
  @end
```
is correctly diagnosed with an incompatible-pointer-types warning, but
in Objective-C++ mode, it is not diagnosed at all -- even though
incompatible pointer conversions generally become an error in C++.

This patch fixes that oversight, allowing implicit conversions
involving Class only to/from unqualified-id, and between qualified and
unqualified Class, where the protocols are compatible.

Note that this does change some behaviors in Objective-C, as well, as
shown by the modified tests.

Of particular note is that assignment from from 'Class<MyProtocol>' to
'id<MyProtocol>' now warns. (Despite appearances, those are not
compatible types. 'Class<MyProtocol>' is not expected to have instance
methods defined by 'MyProtocol', while 'id<MyProtocol>' is.)

Differential Revision: https://reviews.llvm.org/D67983

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@375125 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 2 insertions, 2 deletions

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index 6e3980275a..333983a430 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -10068,8 +10068,8 @@ static bool convertPointersToCompositeType(Sema &S, SourceLocation Loc,
 
   QualType T = S.FindCompositePointerType(Loc, LHS, RHS);
   if (T.isNull()) {
-    if ((LHSType->isPointerType() || LHSType->isMemberPointerType()) &&
-        (RHSType->isPointerType() || RHSType->isMemberPointerType()))
+    if ((LHSType->isAnyPointerType() || LHSType->isMemberPointerType()) &&
+        (RHSType->isAnyPointerType() || RHSType->isMemberPointerType()))
       diagnoseDistinctPointerComparison(S, Loc, LHS, RHS, /*isError*/true);
     else
       S.InvalidOperands(Loc, LHS, RHS);