[Sema] Improve diagnostics for const- and ref-qualified member functions

(Re-submission of D39937 with fixed tests.)

Adjust wording for const-qualification mismatch to be a little more clear.

Also add another diagnostic for a ref qualifier mismatch, which previously produced a useless error (this error path is simply very old; see rL119336):

Before:
  error: cannot initialize object parameter of type 'X0' with an expression of type 'X0'

After:
  error: 'this' argument to member function 'rvalue' is an lvalue, but function has rvalue ref-qualifier

Reviewers: aaron.ballman

Reviewed By: aaron.ballman

Subscribers: lebedev.ri, cfe-commits

Differential Revision: https://reviews.llvm.org/D41646

llvm-svn: 321609

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/test/SemaCXX/copy-initialization.cpp b/clang/test/SemaCXX/copy-initialization.cpp
index 4f6c65cf550..cd7e5f07e14 100644
--- a/clang/test/SemaCXX/copy-initialization.cpp
+++ b/clang/test/SemaCXX/copy-initialization.cpp
@@ -26,7 +26,7 @@ struct foo {
 };
 
 // PR3600
-void test(const foo *P) { P->bar(); } // expected-error{{'bar' not viable: 'this' argument has type 'const foo', but function is not marked const}}
+void test(const foo *P) { P->bar(); } // expected-error{{'this' argument to member function 'bar' has type 'const foo', but function is not marked const}}
 
 namespace PR6757 {
   struct Foo {