[clang] [clang] Implement CTAD for type alias template. (PR #77890)

[Erich Keane via cfe-commits]

================
@@ -2612,44 +2669,312 @@ struct ConvertConstructorToDeductionGuideTransform {
     SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
     return NewParam;
   }
+};
 
-  FunctionTemplateDecl *buildDeductionGuide(
-      TemplateParameterList *TemplateParams, CXXConstructorDecl *Ctor,
-      ExplicitSpecifier ES, TypeSourceInfo *TInfo, SourceLocation LocStart,
-      SourceLocation Loc, SourceLocation LocEnd,
-      llvm::ArrayRef<TypedefNameDecl *> MaterializedTypedefs = {}) {
-    DeclarationNameInfo Name(DeductionGuideName, Loc);
-    ArrayRef<ParmVarDecl *> Params =
-        TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
+// Find all template parameters that appear in the given DeducedArgs.
+// Return the indices of the template parameters in the TemplateParams.
+SmallVector<unsigned> TemplateParamsReferencedInTemplateArgumentList(
+    ArrayRef<NamedDecl *> TemplateParams,
+    ArrayRef<TemplateArgument> DeducedArgs) {
+  struct FindAppearedTemplateParams
----------------
erichkeane wrote:

> I missed this one when renaming the function. What do you think about the current one `ReferenceFinder`?

ReferenceFinder is a little overloaded of a name :)  Perhaps `TypeReferencedFinder`? Note the 'd' which I think prevents it from being mistaken with a "finds all things with an L or R value reference".

https://github.com/llvm/llvm-project/pull/77890