Implement the special template argument deduction rule for T&& in a

call (C++0x [temp.deduct.call]p3).

As part of this, start improving the reference-binding implementation
used in the computation of implicit conversion sequences (for overload
resolution) to reflect C++0x semantics. It still needs more work and
testing, of course.

llvm-svn: 123966

1 files changed, 12 insertions, 0 deletions

diff --git a/clang/lib/Sema/SemaTemplateDeduction.cpp b/clang/lib/Sema/SemaTemplateDeduction.cpp
index fc480391ea1..333eb32293a 100644
--- a/clang/lib/Sema/SemaTemplateDeduction.cpp
+++ b/clang/lib/Sema/SemaTemplateDeduction.cpp
@@ -2399,6 +2399,18 @@ static bool AdjustFunctionParmAndArgTypesForDeduction(Sema &S,
     ParamType = ParamType.getLocalUnqualifiedType();
   const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>();
   if (ParamRefType) {
+    //   [C++0x] If P is an rvalue reference to a cv-unqualified
+    //   template parameter and the argument is an lvalue, the type
+    //   "lvalue reference to A" is used in place of A for type
+    //   deduction.
+    if (const RValueReferenceType *RValueRef
+                                   = dyn_cast<RValueReferenceType>(ParamType)) {
+      if (!RValueRef->getPointeeType().getQualifiers() &&
+          isa<TemplateTypeParmType>(RValueRef->getPointeeType()) &&
+          Arg->Classify(S.Context).isLValue())
+        ArgType = S.Context.getLValueReferenceType(ArgType);
+    }
+
     //   [...] If P is a reference type, the type referred to by P is used
     //   for type deduction.
     ParamType = ParamRefType->getPointeeType();