From: Douglas Gregor <dgregor@apple.com>
Date: Sat, 22 Jan 2011 00:19:52 +0000 (+0000)
Subject: Update const_cast semantics for rvalue references. Add tests for
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=575d2a30f288ddab2f24a77dfcc71f6f7f808394;p=clang

Update const_cast semantics for rvalue references. Add tests for
reinterpret_cast and const_cast using rvalue references.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@124007 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Sema/SemaCXXCast.cpp b/lib/Sema/SemaCXXCast.cpp
index 7badc7a797..075deda4dd 100644
--- a/lib/Sema/SemaCXXCast.cpp
+++ b/lib/Sema/SemaCXXCast.cpp
@@ -1050,9 +1050,8 @@ static TryCastResult TryConstCast(Sema &Self, Expr *SrcExpr, QualType DestType,
                                   bool CStyle, unsigned &msg) {
   DestType = Self.Context.getCanonicalType(DestType);
   QualType SrcType = SrcExpr->getType();
-  if (const LValueReferenceType *DestTypeTmp =
-        DestType->getAs<LValueReferenceType>()) {
-    if (!SrcExpr->isLValue()) {
+  if (const ReferenceType *DestTypeTmp =DestType->getAs<ReferenceType>()) {
+    if (DestTypeTmp->isLValueReferenceType() && !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.
@@ -1156,8 +1155,8 @@ static TryCastResult TryReinterpretCast(Sema &Self, Expr *SrcExpr,
   if (const ReferenceType *DestTypeTmp = DestType->getAs<ReferenceType>()) {
     bool LValue = DestTypeTmp->isLValueReferenceType();
     if (LValue && !SrcExpr->isLValue()) {
-      // Cannot cast non-lvalue to reference type. See the similar comment in
-      // const_cast.
+      // Cannot cast non-lvalue to lvalue reference type. See the similar 
+      // comment in const_cast.
       msg = diag::err_bad_cxx_cast_rvalue;
       return TC_NotApplicable;
     }
diff --git a/test/CXX/expr/expr.post/expr.const.cast/p1-0x.cpp b/test/CXX/expr/expr.post/expr.const.cast/p1-0x.cpp
new file mode 100644
index 0000000000..d46488107b
--- /dev/null
+++ b/test/CXX/expr/expr.post/expr.const.cast/p1-0x.cpp
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -std=c++0x -fsyntax-only -verify %s
+
+// The result of the expression const_cast<T>(v) is of type T. If T is
+// an lvalue reference to object type, the result is an lvalue; if T
+// is an rvalue reference to object type, the result is an xvalue;.
+
+unsigned int f(int);
+
+template<typename T> T& lvalue();
+template<typename T> T&& xvalue();
+template<typename T> T prvalue();
+
+void test_classification(const int *ptr) {
+  int *ptr0 = const_cast<int *&&>(ptr);
+  int *ptr1 = const_cast<int *&&>(xvalue<const int*>());
+  int *ptr2 = const_cast<int *&&>(prvalue<const int*>());
+}
diff --git a/test/CXX/expr/expr.post/expr.reinterpret.cast/p1-0x.cpp b/test/CXX/expr/expr.post/expr.reinterpret.cast/p1-0x.cpp
new file mode 100644
index 0000000000..e80082a040
--- /dev/null
+++ b/test/CXX/expr/expr.post/expr.reinterpret.cast/p1-0x.cpp
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -std=c++0x -fsyntax-only -verify %s
+
+// If T is an lvalue reference type or an rvalue reference to function
+// type, the result is an lvalue; if T is an rvalue reference to
+// object type, the result is an xvalue;
+
+unsigned int f(int);
+
+template<typename T> T&& xvalue();
+void test_classification(char *ptr) {
+  int (&fr0)(int) = reinterpret_cast<int (&&)(int)>(f);
+  int &&ir0 = reinterpret_cast<int &&>(*ptr);
+  int &&ir1 = reinterpret_cast<int &&>(0);
+  int &&ir2 = reinterpret_cast<int &&>('a');
+  int &&ir3 = reinterpret_cast<int &&>(xvalue<char>());
+}