c++: Fix use of local in constexpr if.

extract_local_specs wasn't finding the mention of 'an' as a template
argument because we weren't walking into template arguments.  So here I
changed cp_walk_subtrees to do so--only walking into template arguments in
the spelling of the type or expression, not any hidden behind typedefs.  The
change to use typedef_variant_p avoids looking through typedefs spelled with
'typedef' as well as those spelled with 'using'.  And then I removed some
now-redundant code for walking into template arguments in a couple of
walk_tree callbacks.

	PR c++/92654
	* tree.c (cp_walk_subtrees): Walk into type template arguments.
	* cp-tree.h (TYPE_TEMPLATE_INFO_MAYBE_ALIAS): Use typedef_variant_p
	instead of TYPE_ALIAS_P.
	* pt.c (push_template_decl_real): Likewise.
	(find_parameter_packs_r): Likewise.  Remove dead code.
	* error.c (find_typenames_r): Remove dead code.

1 files changed, 0 insertions, 6 deletions

diff --git a/gcc/cp/error.c b/gcc/cp/error.c
index 973b303..ab8638f 100644
--- a/gcc/cp/error.c
+++ b/gcc/cp/error.c
@@ -1526,12 +1526,6 @@ find_typenames_r (tree *tp, int *walk_subtrees, void *data)
   if (mv && (mv == *tp || !d->p_set->add (mv)))
     vec_safe_push (d->typenames, mv);
 
-  /* Search into class template arguments, which cp_walk_subtrees
-     doesn't do.  */
-  if (CLASS_TYPE_P (*tp) && CLASSTYPE_TEMPLATE_INFO (*tp))
-    cp_walk_tree (&CLASSTYPE_TI_ARGS (*tp), find_typenames_r,
-		  data, d->p_set);
-
   return NULL_TREE;
 }