Grab-bag of bit-field fixes:
- References to ObjC bit-field ivars are bit-field lvalues;
fixes rdar://13794269, which got me started down this.
- Introduce Expr::refersToBitField, switch a couple users to
it where semantically important, and comment the difference
between this and the existing API.
- Discourage Expr::getBitField by making it a bit longer and
less general-sounding.
- Lock down on const_casts of bit-field gl-values until we
hear back from the committee as to whether they're allowed.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@181252 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaCast.cpp b/lib/Sema/SemaCast.cpp
index d6c378e..eb11a57 100644
--- a/lib/Sema/SemaCast.cpp
+++ b/lib/Sema/SemaCast.cpp
@@ -1452,7 +1452,7 @@
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 @@
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());