[clang] [clang] CTAD: implement the missing IsDeducible constraint for alias templates (PR #89358)

[Haojian Wu via cfe-commits]

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@@ -3239,6 +3239,40 @@ static TemplateDeductionResult FinishTemplateArgumentDeduction(
 
   return TemplateDeductionResult::Success;
 }
+/// Complete template argument deduction for DeduceTemplateArgumentsFromType.
+/// FIXME: this is mostly duplicated with the above two versions. Deduplicate
+/// the three implementations.
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hokein wrote:

It is in my TODO list, but its priority is currently low, so I don't anticipate addressing it in the near future. This seems like a good candidate for a "GoodFirst" issue, so I'm thinking we can file an issue in case someone wants to contribute.

https://github.com/llvm/llvm-project/pull/89358