[clang] [Clang] Treat address-of template substitution as SFINAE (PR #208062)

[Erich Keane via cfe-commits]

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@@ -4852,6 +4821,11 @@ TemplateDeductionResult Sema::DeduceTemplateArguments(
         /*OriginalCallArgs=*/nullptr, /*PartialOverloading=*/false,
         /*PartialOrdering=*/true, IsAddressOfFunction);
   });
+  if (Trap.hasErrorOccurred()) {
+    if (Specialization)
+      Specialization->setInvalidDecl(true);
+    return TemplateDeductionResult::SubstitutionFailure;
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erichkeane wrote:

Are we sure about SubstitutionFailure here?  Do we have standardeeze you can put in a comment above here to justify this? 

https://github.com/llvm/llvm-project/pull/208062