[Bug c++/118139] Broken diagnostic: 'decltype_type' not supported by pp_cxx_unqualified_id

[mpolacek at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118139

--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
pp_cxx_nested_name_specifier shouldn't be calling pp_cxx_unqualified_id for
DECLTYPE_TYPE; it should handle a computed-type-specifier specifically.

With the following patch we print

118139.C:6:15: error: ‘static void CW<T>::operator=(int) requires
requires(typename decltype(T())::type x) {x;}’ must be a non-static member
function [-Wtemplate-body]
    6 |   static void operator=(int) requires requires(V x) { x; } {}
      |               ^~~~~~~~


--- a/gcc/cp/cxx-pretty-print.cc
+++ b/gcc/cp/cxx-pretty-print.cc
@@ -234,8 +234,12 @@ pp_cxx_template_keyword_if_needed (cxx_pretty_printer *pp,
tree scope, tree t)
 }

 /* nested-name-specifier:
-      class-or-namespace-name :: nested-name-specifier(opt)
-      class-or-namespace-name :: template nested-name-specifier   */
+      ::
+      type-name ::
+      namespace-name ::
+      computed-type-specifier ::
+      nested-name-specifier identifier ::
+      nested-name-specifier templateopt simple-template-id ::  */

 static void
 pp_cxx_nested_name_specifier (cxx_pretty_printer *pp, tree t)
@@ -252,7 +256,11 @@ pp_cxx_nested_name_specifier (cxx_pretty_printer *pp, tree
t)
       tree scope = get_containing_scope (t);
       pp_cxx_nested_name_specifier (pp, scope);
       pp_cxx_template_keyword_if_needed (pp, scope, t);
-      pp_cxx_unqualified_id (pp, t);
+      /* This is a computed-type-specifier.  */
+      if (TREE_CODE (t) == PACK_INDEX_TYPE || TREE_CODE (t) == DECLTYPE_TYPE)
+   pp->type_id (t);
+      else
+   pp_cxx_unqualified_id (pp, t);
       pp_cxx_colon_colon (pp);
     }
 }