Fix two more diagnostics

Author: Sirraide

clang/docs/ReleaseNotes.rst

@@ -505,9 +505,8 @@ Improvements to Clang's diagnostics
 - ``-Wreserved-identifier`` now fires on reserved parameter names in a function
   declaration which is not a definition.
 
-- The compatibility diagnostic for implicit ``typename`` before a dependent type
-  name is now correctly part of ``-Wpre-c++20-compat`` rather than
-  ``-Wc++20-compat``. (#GH138775)
+- Several compatibility diagnostics that were incorrectly being grouped under
+  ``-Wpre-c++20-compat`` are now part of ``-Wc++20-compat``. (#GH138775)
 
 Improvements to Clang's time-trace
 ----------------------------------

clang/include/clang/Basic/DiagnosticCommonKinds.td

@@ -132,7 +132,7 @@ def err_enum_template : Error<"enumeration cannot be a template">;
 
 def warn_cxx20_compat_consteval : Warning<
   "'consteval' specifier is incompatible with C++ standards before C++20">,
-  InGroup<CXX20Compat>, DefaultIgnore;
+  InGroup<CXXPre20Compat>, DefaultIgnore;
 def warn_missing_type_specifier : Warning<
   "type specifier missing, defaults to 'int'">,
   InGroup<ImplicitInt>, DefaultIgnore;

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -9568,7 +9568,7 @@ def err_incomplete_type_used_in_type_trait_expr : Error<
 // C++20 constinit and require_constant_initialization attribute
 def warn_cxx20_compat_constinit : Warning<
   "'constinit' specifier is incompatible with C++ standards before C++20">,
-  InGroup<CXX20Compat>, DefaultIgnore;
+  InGroup<CXXPre20Compat>, DefaultIgnore;
 def err_constinit_local_variable : Error<
   "local variable cannot be declared 'constinit'">;
 def err_require_constant_init_failed : Error<

clang/test/SemaCXX/gh138775.cpp

@@ -1,7 +1,14 @@
 // RUN: %clang_cc1 -std=c++17 -fsyntax-only -verify=cxx17 %s
-// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify=cxx20 -Wpre-c++20-compat %s
+// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify=pre-cxx20-compat -Wpre-c++20-compat %s
+// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify=cxx20-compat -Wc++20-compat %s
+// cxx20-compat-no-diagnostics
 
-// cxx17-error@+3 {{unknown type name 'consteval'; did you mean 'constexpr'}}
-// cxx17-warning@+2 {{missing 'typename' prior to dependent type name 'T::type' is a C++20 extension}}
-// cxx20-warning@+1 {{missing 'typename' prior to dependent type name 'T::type' is incompatible with C++ standards before C++20}}
+// cxx17-error@+4 {{unknown type name 'consteval'; did you mean 'constexpr'}}
+// cxx17-warning@+3 {{missing 'typename' prior to dependent type name 'T::type' is a C++20 extension}}
+// pre-cxx20-compat-warning@+2 {{'consteval' specifier is incompatible with C++ standards before C++20}}
+// pre-cxx20-compat-warning@+1 {{missing 'typename' prior to dependent type name 'T::type' is incompatible with C++ standards before C++20}}
 template<typename T> consteval T::type f();
+
+// cxx17-error@+2 {{unknown type name 'constinit'}}
+// pre-cxx20-compat-warning@+1 {{'constinit' specifier is incompatible with C++ standards before C++20}}
+constinit int x = 4;