[c++2a] Allow comparison functions to be explicitly defaulted.

This adds some initial syntactic checking that only the appropriate
function signatures can be defaulted. No implicit definitions are
generated yet.

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/Parse/ParseDeclCXX.cpp b/clang/lib/Parse/ParseDeclCXX.cpp
index b98ce3e6629..6d4a1a4a4e8 100644
--- a/clang/lib/Parse/ParseDeclCXX.cpp
+++ b/clang/lib/Parse/ParseDeclCXX.cpp
@@ -2978,7 +2978,8 @@ ExprResult Parser::ParseCXXMemberInitializer(Decl *D, bool IsFunction,
         Diag(Tok, diag::err_default_delete_in_multiple_declaration)
           << 0 /* default */;
       else
-        Diag(ConsumeToken(), diag::err_default_special_members);
+        Diag(ConsumeToken(), diag::err_default_special_members)
+            << getLangOpts().CPlusPlus2a;
       return ExprError();
     }
   }