[Concepts] Deprecate -fconcepts-ts, enable Concepts under -std=c++2a

Now with concepts support merged and mostly complete, we do not need -fconcepts-ts
(which was also misleading as we were not implementing the TS) and can enable
concepts features under C++2a. A warning will be generated if users still attempt
to use -fconcepts-ts.

1 files changed, 2 insertions, 1 deletions

diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 398f960..44abcc3 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -2858,9 +2858,10 @@ static void ParseLangArgs(LangOptions &Opts, ArgList &Args, InputKind IK,
                                                  << A->getValue();
     Opts.NewAlignOverride = 0;
   }
-  Opts.ConceptsTS = Args.hasArg(OPT_fconcepts_ts);
   Opts.ConceptSatisfactionCaching =
       !Args.hasArg(OPT_fno_concept_satisfaction_caching);
+  if (Args.hasArg(OPT_fconcepts_ts))
+    Diags.Report(diag::warn_fe_concepts_ts_flag);
   Opts.HeinousExtensions = Args.hasArg(OPT_fheinous_gnu_extensions);
   Opts.AccessControl = !Args.hasArg(OPT_fno_access_control);
   Opts.ElideConstructors = !Args.hasArg(OPT_fno_elide_constructors);