Further enhance comment for property in continuation class.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149639 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/SemaObjCProperty.cpp b/lib/Sema/SemaObjCProperty.cpp
index 42a5c9d0e870c76137034e7c1a44b5e3d638630b..9d849ff74fdfc7ec1eab2c6d23acfe14b4d3aab2 100644 (file)
--- a/lib/Sema/SemaObjCProperty.cpp
+++ b/lib/Sema/SemaObjCProperty.cpp
@@ -281,7 +281,10 @@ Sema::HandlePropertyInClassExtension(Scope *S,
     QualType ConvertedType;
     // Relax the strict type matching for property type in continuation class.
     // Allow property object type of continuation class to be different as long
-    // as it narrows the object type in its primary class property.
+    // as it narrows the object type in its primary class property. Note that
+    // this conversion is safe only because the wider type is for a 'readonly'
+    // property in primary class and 'narrowed' type for a 'readwrite' property
+    // in continuation class.
     if (!isa<ObjCObjectPointerType>(PIDecl->getType()) ||
         !isa<ObjCObjectPointerType>(PDecl->getType()) ||
         (!isObjCPointerConversion(PDecl->getType(), PIDecl->getType(),