1 files changed, 11 insertions, 1 deletions
diff --git a/clang/lib/Sema/SemaCast.cpp b/clang/lib/Sema/SemaCast.cpp
index d6c378e3d48..eb11a577cb0 100644
--- a/clang/lib/Sema/SemaCast.cpp
+++ b/clang/lib/Sema/SemaCast.cpp
@@ -1452,7 +1452,7 @@ static TryCastResult TryConstCast(Sema &Self, Expr *SrcExpr, QualType DestType,
   DestType = Self.Context.getCanonicalType(DestType);
   QualType SrcType = SrcExpr->getType();
   if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) {
-    if (DestTypeTmp->isLValueReferenceType() && !SrcExpr->isLValue()) {
+    if (isa<LValueReferenceType>(DestTypeTmp) && !SrcExpr->isLValue()) {
       // Cannot const_cast non-lvalue to lvalue reference type. But if this
       // is C-style, static_cast might find a way, so we simply suggest a
       // message and tell the parent to keep searching.
@@ -1460,6 +1460,16 @@ static TryCastResult TryConstCast(Sema &Self, Expr *SrcExpr, QualType DestType,
       return TC_NotApplicable;
     }
 
+    // It's not completely clear under the standard whether we can
+    // const_cast bit-field gl-values.  Doing so would not be
+    // intrinsically complicated, but for now, we say no for
+    // consistency with other compilers and await the word of the
+    // committee.
+    if (SrcExpr->refersToBitField()) {
+      msg = diag::err_bad_cxx_cast_bitfield;
+      return TC_NotApplicable;
+    }
+
     // C++ 5.2.11p4: An lvalue of type T1 can be [cast] to an lvalue of type T2
     //   [...] if a pointer to T1 can be [cast] to the type pointer to T2.
     DestType = Self.Context.getPointerType(DestTypeTmp->getPointeeType());