[PATCH] D40284: [Sema] Improve diagnostics for template arg deduction

[Erik Pilkington via Phabricator via cfe-commits]

erik.pilkington added a comment.

This looks correct, but I definitely agree that RAII would make this a lot nicer. Have you considered adding a `CancelableSaveAndRestore` or something to SaveAndRestore.h? It seems useful and generic enough to make it worthwhile. Otherwise, you could just write your own RAII object special-cased to handle this. A less intrusive way of doing this might be to wrap calls to this function with another that checks if the return value is TDK_Success, and if so restores these fields.



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Comment at: lib/Sema/SemaTemplateDeduction.cpp:1376
       if (const ComplexType *ComplexArg = Arg->getAs<ComplexType>())
         return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
                                     cast<ComplexType>(Param)->getElementType(),
----------------
What if this return TDK_Success?


https://reviews.llvm.org/D40284