r178095 - <rdar://problem/13278115> Improve diagnostic when failing to bind an rvalue reference to an lvalue of compatible type.

[Douglas Gregor]

Author: dgregor
Date: Tue Mar 26 18:59:23 2013
New Revision: 178095

URL: http://llvm.org/viewvc/llvm-project?rev=178095&view=rev
Log:
<rdar://problem/13278115> Improve diagnostic when failing to bind an rvalue reference to an lvalue of compatible type.

Modified:
    cfe/trunk/lib/Sema/SemaInit.cpp
    cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5-0x.cpp

Modified: cfe/trunk/lib/Sema/SemaInit.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaInit.cpp?rev=178095&r1=178094&r2=178095&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaInit.cpp (original)
+++ cfe/trunk/lib/Sema/SemaInit.cpp Tue Mar 26 18:59:23 2013
@@ -3518,6 +3518,14 @@ static void TryReferenceInitializationCo
       return;
     }
 
+    if ((RefRelationship == Sema::Ref_Compatible ||
+         RefRelationship == Sema::Ref_Compatible_With_Added_Qualification) &&
+        isRValueRef && InitCategory.isLValue()) {
+      Sequence.SetFailed(
+        InitializationSequence::FK_RValueReferenceBindingToLValue);
+      return;
+    }
+
     Sequence.SetFailed(InitializationSequence::FK_ReferenceInitDropsQualifiers);
     return;
   }

Modified: cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5-0x.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5-0x.cpp?rev=178095&r1=178094&r2=178095&view=diff
==============================================================================
--- cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5-0x.cpp (original)
+++ cfe/trunk/test/CXX/dcl.decl/dcl.init/dcl.init.ref/p5-0x.cpp Tue Mar 26 18:59:23 2013
@@ -192,3 +192,11 @@ namespace PR11003 {
     Value y(Move(0));
   }
 }
+
+namespace rdar13278115 {
+  struct X { };
+  struct Y : X { };
+  X &&f0(X &x) { return x; } // expected-error{{rvalue reference to type 'rdar13278115::X' cannot bind to lvalue of type 'rdar13278115::X'}}
+  X &&f1(Y &y) { return y; } // expected-error{{rvalue reference to type 'rdar13278115::X' cannot bind to lvalue of type 'rdar13278115::Y'}}
+  const X &&f2(Y &y) { return y; } // expected-error{{rvalue reference to type 'const rdar13278115::X' cannot bind to lvalue of type 'rdar13278115::Y'}}
+}