[clang] [clang-tools-extra] [clang][diagnostics] Stable IDs for Clang diagnostics (PR #168153)

[Aaron Ballman via cfe-commits]

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@@ -434,6 +478,30 @@ StringRef DiagnosticIDs::getDescription(unsigned DiagID) const {
   return CustomDiagInfo->getDescription(DiagID).GetDescription();
 }
 
+/// getStableID - Given a diagnostic ID, return the stable ID of the diagnostic.
+std::string DiagnosticIDs::getStableID(unsigned DiagID) const {
+  if (const StaticDiagInfoRec *Info = GetDiagInfo(DiagID))
+    return Info->getStableID().str();
+  assert(CustomDiagInfo && "Invalid CustomDiagInfo");
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AaronBallman wrote:

Isn't this assert going to trigger on all custom diagnostics? (Same below.)

https://github.com/llvm/llvm-project/pull/168153