[clang] [clang] Improve diagnostics around constexpr limits (PR #212091)

[via cfe-commits]

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@@ -170,7 +170,7 @@ def note_constexpr_depth_limit_exceeded : Note<
 def note_constexpr_call_limit_exceeded : Note<
   "constexpr evaluation hit maximum call limit">;
 def note_constexpr_step_limit_exceeded : Note<
-  "constexpr evaluation hit maximum step limit; possible infinite loop?">;
+  "constexpr evaluation hit maximum step limit of %0; possible infinite loop?">;
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Sirraide wrote:

Maybe there’s some heuristics, but in the general case, that runs into the halting problem; I think always including that in the note is fine

https://github.com/llvm/llvm-project/pull/212091