[NFC][Clang] Fix enumerated mismatch warning

[jsji]

This is one of the many PRs to fix errors with LLVM_ENABLE_WERROR=on. Built by GCC 11.

Fix warning:
llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:3153:14: error: enumerated mismatch in conditional expression: ‘clang::diag::<unnamed enum>’ vs ‘clang::diag::<unnamed enum>’ [-Werror=enum-compare]
 3152 |          DS.isFriendSpecified() || NextToken().is(tok::kw_friend)
      |          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 3153 |              ? diag::err_friend_concept
      |              ^~~~~~~~~~~~~~~~~~~~~~~~~~
 3154 |              : diag::
      |              ~~~~~~~~
 3155 |                    err_concept_decls_may_only_appear_in_global_namespace_scope);

[llvmbot]

@llvm/pr-subscribers-clang

Author: Jinsong Ji (jsji)

Changes

This is one of the many PRs to fix errors with LLVM_ENABLE_WERROR=on. Built by GCC 11.

Fix warning:
llvm-project/clang/lib/Parse/ParseDeclCXX.cpp:3153:14: error: enumerated mismatch in conditional expression: ‘clang::diag::<unnamed enum>’ vs ‘clang::diag::<unnamed enum>’ [-Werror=enum-compare]
3152 | DS.isFriendSpecified() || NextToken().is(tok::kw_friend)
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3153 | ? diag::err_friend_concept
| ^~~~~~~~~~~~~~~~~~~~~~~~~~
3154 | : diag::
| ~~~~~~~~
3155 | err_concept_decls_may_only_appear_in_global_namespace_scope);

---

Full diff: https://github.com/llvm/llvm-project/pull/112816.diff

2 Files Affected:

• (modified) clang/include/clang/Basic/DiagnosticParseKinds.td (-3)
• (modified) clang/include/clang/Basic/DiagnosticSemaKinds.td (+2)

diff --git a/clang/include/clang/Basic/DiagnosticParseKinds.td b/clang/include/clang/Basic/DiagnosticParseKinds.td
index 78510e61a639fa..cb52629f9c61c7 100644
--- a/clang/include/clang/Basic/DiagnosticParseKinds.td
+++ b/clang/include/clang/Basic/DiagnosticParseKinds.td
@@ -983,9 +983,6 @@ def warn_cxx23_variadic_friends : Warning<
   "variadic 'friend' declarations are incompatible with C++ standards before C++2c">,
   DefaultIgnore, InGroup<CXXPre26Compat>;
 
-def err_friend_concept : Error<
-  "friend declaration cannot be a concept">;
-
 // C++11 default member initialization
 def ext_nonstatic_member_init : ExtWarn<
   "default member initializer for non-static data member is a C++11 "
diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 883db838ca0147..d102a45f8c1ed2 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3020,6 +3020,8 @@ def err_c23_constexpr_pointer_not_null : Error<
   "constexpr pointer initializer is not null">;
 
 // C++ Concepts
+def err_friend_concept : Error<
+  "friend declaration cannot be a concept">;
 def err_concept_decls_may_only_appear_in_global_namespace_scope : Error<
   "concept declarations may only appear in global or namespace scope">;
 def err_concept_no_parameters : Error<

[Sirraide]

This doesn’t seem right: that diagnostic is only used in the parser, which is why it is in DiagnosticParseKinds.td. Instead, it’d be better to cast the two diagnostic IDs that are causing the problem to unsigned where they’re used.

[jsji]

@Sirraide @cor3ntin Updated, can you please have another look? Thanks.

[Sirraide]

LGTM