[clang] fix DependentNameType -> UnresolvedUsingType transforms (llvm#153862)

Author: mizvekov

clang/lib/Sema/TreeTransform.h

@@ -7668,8 +7668,11 @@ QualType TreeTransform<Derived>::TransformDependentNameType(
   } else if (isa<TypedefType>(Result)) {
     TLB.push<TypedefTypeLoc>(Result).set(TL.getElaboratedKeywordLoc(),
                                          QualifierLoc, TL.getNameLoc());
+  } else if (isa<UnresolvedUsingType>(Result)) {
+    auto NewTL = TLB.push<UnresolvedUsingTypeLoc>(Result);
+    NewTL.set(TL.getElaboratedKeywordLoc(), QualifierLoc, TL.getNameLoc());
   } else {
-    DependentNameTypeLoc NewTL = TLB.push<DependentNameTypeLoc>(Result);
+    auto NewTL = TLB.push<DependentNameTypeLoc>(Result);
     NewTL.setElaboratedKeywordLoc(TL.getElaboratedKeywordLoc());
     NewTL.setQualifierLoc(QualifierLoc);
     NewTL.setNameLoc(TL.getNameLoc());

clang/test/SemaCXX/using-decl-templates.cpp

@@ -153,3 +153,11 @@ T foo(T t) { // OK
 }
 } // namespace sss
 } // namespace func_templ
+
+namespace DependentName {
+  template <typename T> struct S {
+    using typename T::Ty;
+    static Ty Val;
+  };
+  template <typename T> typename S<T>::Ty S<T>::Val;
+} // DependentName