New AST node to access "implicit" setter/getter using property dor syntax.
Issuing diagnostics when assigning to read-only properties.
This is work in progress.

llvm-svn: 59874
diff --git a/clang/lib/Analysis/CheckObjCDealloc.cpp b/clang/lib/Analysis/CheckObjCDealloc.cpp
index 8628ff1..6fba9ae 100644
--- a/clang/lib/Analysis/CheckObjCDealloc.cpp
+++ b/clang/lib/Analysis/CheckObjCDealloc.cpp
@@ -72,8 +72,7 @@
     if (BO->isAssignmentOp())
       if(ObjCPropertyRefExpr* PRE = 
          dyn_cast<ObjCPropertyRefExpr>(BO->getLHS()->IgnoreParenCasts()))
-          if(PRE->getKind() == ObjCPropertyRefExpr::PropertyRef &&
-             PRE->getProperty() == PD)
+          if(PRE->getProperty() == PD)
             if(BO->getRHS()->isNullPointerConstant(Ctx))
               return true;