[clang] [clang-tools-extra] [clang] Implement CWG2398 provisional TTP matching to class templates (PR #94981)

[Matheus Izvekov via cfe-commits]

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@@ -9219,7 +9222,8 @@ class Sema final : public SemaBase {
   /// \returns true if an error occurred, false otherwise.
   bool CheckTemplateArgumentList(
       TemplateDecl *Template, SourceLocation TemplateLoc,
-      TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
+      TemplateArgumentListInfo &TemplateArgs,
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mizvekov wrote:

Yeah. One issue I have often had with these functions with large amount of both defaulted and non-defaulted parameters, is that you would want to extend it by changing the signature, then arguments would match parameters incorrectly, but this would not cause a hard error on all of the call sites.

I could have easily added DefaultArgs as defaulted empty here, but chose not to due to this reason.

Besides that, overloading functions with such huge numbers of parameters creates some confusion as well.
I'd slightly prefer if we avoided that, but don't have strong enough feelings to go on a crusade against it.

https://github.com/llvm/llvm-project/pull/94981