[clang] [clang][Serialization] Outline LangOptions mismatch diagnostics (PR #202843)

[David Zbarsky via cfe-commits]

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@@ -333,8 +346,8 @@ static bool checkLanguageOptions(const LangOptions &LangOpts,
          !AllowCompatibleDifferences)) {                                       \
       if (ExistingLangOpts.get##Name() != LangOpts.get##Name()) {              \
         if (Diags)                                                             \
-          Diags->Report(diag::err_ast_file_langopt_value_mismatch)             \
-              << Description << ModuleFilename;                                \
+          diagnoseLanguageOptionValueMismatch(*Diags, Description,             \
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dzbarsky wrote:

good idea, i'll tweak that

https://github.com/llvm/llvm-project/pull/202843