[clang] [Clang] Fix synthesis of alias CTAD constraints (PR #223340)

[Younan Zhang via cfe-commits]

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@@ -998,33 +998,42 @@ buildAssociatedConstraints(Sema &SemaRef, FunctionTemplateDecl *F,
           AliasTemplate->getInstantiatedFromMemberTemplate())
     AdjustDepth = PrimaryTemplate->getTemplateDepth();
 
+  // FIXME: We're rebuilding the synthesized template parameter list again
+  // Consider reuse the template parameter from its caller.
+
   // We rebuild all template parameters with the uninstantiated depth, and
   // build template arguments refer to them.
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zyn0217 wrote:

I think it's possible we could rewrite the depth from the built template parameter list, anyway FIXME removed

https://github.com/llvm/llvm-project/pull/223340