[clang] [clang-tools-extra] [Clang] Warning as error Array Comparisons from C++26 (PR #118872)

[Yanzuo Liu via cfe-commits]

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@@ -10274,6 +10274,11 @@ def warn_array_comparison : Warning<
   "to compare array addresses, use unary '+' to decay operands to pointers">,
   InGroup<DiagGroup<"array-compare">>;
 
+def warn_array_comparison_cxx26 : Warning<
+  "comparison between two arrays compare their addresses not their contents; "
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zwuis wrote:

I would prefer "not allowed" instead of "ill-formed".

Example:
 https://github.com/llvm/llvm-project/blob/02ad623bb560afa1a789b49f715c9a0e48ea9b16/clang/include/clang/Basic/DiagnosticSemaKinds.td#L665-L667

https://github.com/llvm/llvm-project/pull/118872