[clang] [Clang] Added explanation why a is constructible evaluated to false. (PR #143309)

[Erich Keane via cfe-commits]

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@@ -1981,8 +1982,14 @@ static ExtractedTypeTraitInfo ExtractTypeTraitFromExpression(const Expr *E) {
     Trait = StdNameToTypeTrait(Name);
     if (!Trait)
       return std::nullopt;
-    for (const auto &Arg : VD->getTemplateArgs().asArray())
-      Args.push_back(Arg.getAsType());
+    for (const auto &Arg : VD->getTemplateArgs().asArray()) {
+      if (Arg.getKind() == TemplateArgument::ArgKind::Pack) {
+        for (const auto &InnerArg : Arg.pack_elements())
+          Args.push_back(InnerArg.getAsType());
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erichkeane wrote:

IS this a valid assumption here (that this is a type?).  Presumably this could be an NTTP pack as well...

Though `getAsType` would assert for us?

https://github.com/llvm/llvm-project/pull/143309