3 files changed, 38 insertions, 23 deletions
diff --git a/lib/Sema/SemaCXXCast.cpp b/lib/Sema/SemaCXXCast.cpp
index d053d5a9e9..0721814c18 100644
--- a/lib/Sema/SemaCXXCast.cpp
+++ b/lib/Sema/SemaCXXCast.cpp
@@ -1717,7 +1717,8 @@ Sema::CXXCheckCStyleCast(SourceRange R, QualType CastTy, ExprValueKind &VK,
     Kind = CK_Dependent;
     return Owned(CastExpr);
   }
-
+  
+  QualType origCastExprType = CastExpr->getType();
   if (VK == VK_RValue && !CastTy->isRecordType()) {
     ExprResult CastExprRes = DefaultFunctionArrayLvalueConversion(CastExpr);
     if (CastExprRes.isInvalid())
@@ -1773,8 +1774,15 @@ Sema::CXXCheckCStyleCast(SourceRange R, QualType CastTy, ExprValueKind &VK,
     }
   }
 
-  if (getLangOptions().ObjCAutoRefCount && tcr == TC_Success)
+  if (getLangOptions().ObjCAutoRefCount && tcr == TC_Success) {
     CheckObjCARCConversion(R, CastTy, CastExpr, CCK);
+    if (!CheckObjCARCUnavailableWeakConversion(CastTy, 
+                                               origCastExprType))
+      Diag(CastExpr->getLocStart(), 
+           diag::err_arc_cast_of_weak_unavailable)
+      << origCastExprType << CastTy 
+      << CastExpr->getSourceRange();
+  }
 
   if (tcr != TC_Success && msg != 0) {
     if (CastExpr->getType() == Context.OverloadTy) {
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index cf03684c67..fea31aa046 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -4066,22 +4066,12 @@ ExprResult Sema::CheckCastTypes(SourceLocation CastStartLoc, SourceRange TyR,
         }
       }
     } 
-    else {
-      QualType canCastType = 
-        Context.getCanonicalType(castType).getUnqualifiedType();
-        if (isa<ObjCObjectPointerType>(canCastType) &&
-            castType.getObjCLifetime() == Qualifiers::OCL_Weak &&
-            castExprType->isObjCObjectPointerType()) {
-          if (const ObjCObjectPointerType *ObjT =
-              castExprType->getAs<ObjCObjectPointerType>())
-            if (ObjT->getInterfaceDecl()->isArcWeakrefUnavailable()) {
-              Diag(castExpr->getLocStart(), 
-                   diag::err_arc_cast_of_weak_unavailable)
+    else if (!CheckObjCARCUnavailableWeakConversion(castType, castExprType)) {
+           Diag(castExpr->getLocStart(), 
+                diag::err_arc_cast_of_weak_unavailable)
                 << castExprType << castType 
                 << castExpr->getSourceRange();
-              return ExprError();
-            }
-        }
+          return ExprError();
     }
   }
   
@@ -5300,12 +5290,8 @@ Sema::CheckAssignmentConstraints(QualType lhsType, ExprResult &rhs,
         checkObjCPointerTypesForAssignment(*this, lhsType, rhsType);
       if (getLangOptions().ObjCAutoRefCount &&
           result == Compatible && 
-          origLhsType.getObjCLifetime() == Qualifiers::OCL_Weak) {
-        if (const ObjCObjectPointerType *ObjT = 
-              rhsType->getAs<ObjCObjectPointerType>())
-          if (ObjT->getInterfaceDecl()->isArcWeakrefUnavailable())
-            result = IncompatibleObjCWeakRef;
-      }
+          !CheckObjCARCUnavailableWeakConversion(origLhsType, rhsType))
+        result = IncompatibleObjCWeakRef;
       return result;
     }
 
@@ -5474,8 +5460,12 @@ Sema::CheckSingleAssignmentConstraints(QualType lhsType, ExprResult &rExpr) {
                                                  AA_Assigning);
       if (Res.isInvalid())
         return Incompatible;
+      Sema::AssignConvertType result = Compatible;
+      if (getLangOptions().ObjCAutoRefCount &&
+          !CheckObjCARCUnavailableWeakConversion(lhsType, rExpr.get()->getType()))
+        result = IncompatibleObjCWeakRef;
       rExpr = move(Res);
-      return Compatible;
+      return result;
     }
 
     // FIXME: Currently, we fall through and treat C++ classes like C
diff --git a/lib/Sema/SemaExprObjC.cpp b/lib/Sema/SemaExprObjC.cpp
index fa51098f1a..22953da97b 100644
--- a/lib/Sema/SemaExprObjC.cpp
+++ b/lib/Sema/SemaExprObjC.cpp
@@ -1771,6 +1771,23 @@ Sema::CheckObjCARCConversion(SourceRange castRange, QualType castType,
     << castRange << castExpr->getSourceRange();
 }
 
+bool Sema::CheckObjCARCUnavailableWeakConversion(QualType castType,
+                                                 QualType exprType) {
+  QualType canCastType = 
+    Context.getCanonicalType(castType).getUnqualifiedType();
+  QualType canExprType = 
+    Context.getCanonicalType(exprType).getUnqualifiedType();
+  if (isa<ObjCObjectPointerType>(canCastType) &&
+      castType.getObjCLifetime() == Qualifiers::OCL_Weak &&
+      canExprType->isObjCObjectPointerType()) {
+    if (const ObjCObjectPointerType *ObjT =
+        canExprType->getAs<ObjCObjectPointerType>())
+      if (ObjT->getInterfaceDecl()->isArcWeakrefUnavailable())
+        return false;
+  }
+  return true;
+}
+
 /// Look for an ObjCReclaimReturnedObject cast and destroy it.
 static Expr *maybeUndoReclaimObject(Expr *e) {
   // For now, we just undo operands that are *immediately* reclaim