Change the analyzer to recognize (but ignore) assignments to isa.  Fixes PR 6302.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@99904 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Checker/GRExprEngine.cpp b/lib/Checker/GRExprEngine.cpp
index ae4c5fe..1afe091 100644
--- a/lib/Checker/GRExprEngine.cpp
+++ b/lib/Checker/GRExprEngine.cpp
@@ -897,6 +897,11 @@
       return;
     }
 
+    case Stmt::ObjCIsaExprClass:
+      // FIXME: Do something more intelligent with 'x->isa = ...'.
+      //  For now, just ignore the assignment.
+      return;
+
     case Stmt::ObjCPropertyRefExprClass:
     case Stmt::ObjCImplicitSetterGetterRefExprClass:
       // FIXME: Property assignments are lvalues, but not really "locations".