[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:

Do we need to keep all implementation details in a single file?
Shouldn't we try to avoid growing huge files so they're easier to read, maintain etc.?
If it's useful somewhere else, someone would just move it and use it I guess.

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