[clang] [clang-tools-extra] [llvm] [clang] Introduce diagnostics suppression mappings (PR #112517)

[Boaz Brickner via cfe-commits]

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@@ -477,6 +485,100 @@ void DiagnosticsEngine::setSeverityForAll(diag::Flavor Flavor,
       setSeverity(Diag, Map, Loc);
 }
 
+namespace {
+class WarningsSpecialCaseList : public llvm::SpecialCaseList {
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bricknerb wrote:

Yes, I think the current state is pretty bad so if you're willing to refactor (in a separate PR, could also be a followup), this would be great. I think WarningsSpecialCaseList::createOrDie() would be surprising and I assume future changes could be harder to make and/or make the API much less clear.

https://github.com/llvm/llvm-project/pull/112517