[clang] [clang-tools-extra] [Clang] support friend declarations with a dependent nested-name-specifier (PR #191268)

[Matheus Izvekov via cfe-commits]

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@@ -18069,6 +18069,34 @@ Decl *Sema::BuildStaticAssertDeclaration(SourceLocation StaticAssertLoc,
   return Decl;
 }
 
+bool Sema::CheckDependentFriend(SourceLocation Loc, NestedNameSpecifier NNS,
+                                TemplateParameterList *FPL) {
+  if (!NNS || !FPL || FPL->size() == 0)
+    return false;
+
+  if (NNS.isDependent()) {
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mizvekov wrote:

Nit: Maybe just throw !NNS.isDependent() into the if above, flattening this function? That can replace the `!NNS` check.

https://github.com/llvm/llvm-project/pull/191268