[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, 1 insertions, 6 deletions

diff --git a/clang/lib/Frontend/InitPreprocessor.cpp b/clang/lib/Frontend/InitPreprocessor.cpp
index 42e6fd88515..8a0ff55e44f 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -385,9 +385,6 @@ static void InitializeStandardPredefinedMacros(const TargetInfo &TI,
     else
       Builder.defineMacro("__cplusplus", "199711L");
 
-    if (LangOpts.ConceptsTS)
-      Builder.defineMacro("__cpp_concepts", "201707L");
-
     // C++1z [cpp.predefined]p1:
     //   An integer literal of type std::size_t whose value is the alignment
     //   guaranteed by a call to operator new(std::size_t)
@@ -551,7 +548,7 @@ static void InitializeCPlusPlusFeatureTestMacros(const LangOptions &LangOpts,
   // C++20 features.
   if (LangOpts.CPlusPlus2a) {
     //Builder.defineMacro("__cpp_aggregate_paren_init", "201902L");
-    //Builder.defineMacro("__cpp_concepts", "201907L");
+    Builder.defineMacro("__cpp_concepts", "201907L");
     Builder.defineMacro("__cpp_conditional_explicit", "201806L");
     //Builder.defineMacro("__cpp_consteval", "201811L");
     Builder.defineMacro("__cpp_constexpr_dynamic_alloc", "201907L");
@@ -567,8 +564,6 @@ static void InitializeCPlusPlusFeatureTestMacros(const LangOptions &LangOpts,
   Builder.defineMacro("__cpp_impl_destroying_delete", "201806L");
 
   // TS features.
-  if (LangOpts.ConceptsTS)
-    Builder.defineMacro("__cpp_experimental_concepts", "1L");
   if (LangOpts.Coroutines)
     Builder.defineMacro("__cpp_coroutines", "201703L");
 }