[clang] [clang][Sema] Improve template argument deduction diagnostic (PR #122754)

[Justin Fargnoli via cfe-commits]

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@@ -3575,7 +3575,15 @@ TemplateDeductionResult Sema::SubstituteExplicitTemplateArguments(
     unsigned Index = SugaredBuilder.size();
     if (Index >= TemplateParams->size())
       return TemplateDeductionResult::SubstitutionFailure;
+
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justinfargnoli wrote:

```suggestion
```

https://github.com/llvm/llvm-project/pull/122754