Index: clang/lib/Sema/TreeTransform.h
===================================================================
--- clang/lib/Sema/TreeTransform.h
+++ clang/lib/Sema/TreeTransform.h
@@ -6992,7 +6992,8 @@
     // type sugar, and therefore cannot be diagnosed in any other way.
     if (auto nullability = oldType->getImmediateNullability()) {
       if (!modifiedType->canHaveNullability()) {
-        SemaRef.Diag(TL.getAttr()->getLocation(),
+        SemaRef.Diag((TL.getAttr() ? TL.getAttr()->getLocation()
+                                   : TL.getModifiedLoc().getBeginLoc()),
                      diag::err_nullability_nonpointer)
             << DiagNullabilityKind(*nullability, false) << modifiedType;
         return QualType();
Index: clang/test/SemaCXX/nullability.cpp
===================================================================
--- clang/test/SemaCXX/nullability.cpp
+++ clang/test/SemaCXX/nullability.cpp
@@ -136,3 +136,9 @@
 void testNullabilityCompletenessWithTemplate() {
   Template<int*> tip;
 }
+
+namespace GH60344 {
+class a;
+template <typename b> using c = b _Nullable; // expected-error {{'_Nullable' cannot be applied to non-pointer type 'GH60344::a'}}
+c<a>;  // expected-note {{in instantiation of template type alias 'c' requested here}}
+}