[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.

(cherry picked from commit 67c608a9695496cfc9d3fdf9d0b12b554ac6b4df)

1 files changed, 3 insertions, 4 deletions

diff --git a/clang/lib/Parse/ParseTemplate.cpp b/clang/lib/Parse/ParseTemplate.cpp
index e96baec0780..3bc4e3596f1 100644
--- a/clang/lib/Parse/ParseTemplate.cpp
+++ b/clang/lib/Parse/ParseTemplate.cpp
@@ -678,7 +678,7 @@ bool Parser::isTypeConstraintAnnotation() {
 ///
 /// \returns true if an error occurred, and false otherwise.
 bool Parser::TryAnnotateTypeConstraint() {
-  if (!getLangOpts().ConceptsTS)
+  if (!getLangOpts().CPlusPlus2a)
     return false;
   CXXScopeSpec SS;
   bool WasScopeAnnotation = Tok.is(tok::annot_cxxscope);
@@ -711,9 +711,8 @@ bool Parser::TryAnnotateTypeConstraint() {
                                       /*EnteringContext=*/false,
                                       PossibleConcept,
                                       MemberOfUnknownSpecialization);
-    assert(!MemberOfUnknownSpecialization
-           && "Member when we only allowed namespace scope qualifiers??");
-    if (!PossibleConcept || TNK != TNK_Concept_template) {
+    if (MemberOfUnknownSpecialization || !PossibleConcept ||
+        TNK != TNK_Concept_template) {
       if (SS.isNotEmpty())
         AnnotateScopeToken(SS, !WasScopeAnnotation);
       return false;