c++: imported templates and alias-template changes [PR 99283]

During development of modules, I had difficulty deciding whether the
module flags of a template should live on the decl_template_result,
the template_decl, or both.  I chose the latter, and require them to
be consistent.  This and a few other defects show how hard that
consistency is.  Hence this patch move to holding the flags on the
template-decl-result decl.  That's the entity various bits of the
parser have at the appropriate time.   Once needs STRIP_TEMPLATE in a
bunch of places, which this patch adds.  Also a check that we never
give a TEMPLATE_DECL to the module flag accessors.

This left a problem with how I was handling template aliases.  These
were in two parts -- separating the TEMPLATE_DECL from the TYPE_DECL.
That seemed somewhat funky, but development showed it necessary.  Of
course, that causes problems if the TEMPLATE_DECL cannot contain 'am
imported' information.  Investigating now shows that we do not need to
treat them separately.  By reverting a bit of template instantiation
machinery that caused the problem, we're back on course.  I think what
has happened is that between then and now, other typedef fixes have
corrected the underlying problem this separation was working around.
It allows a bunch of cleanup in the decl streamer, as we no longer
have to handle a null TEMPLATE_DECL_RESULT.

	PR c++/99283
	gcc/cp/
	* cp-tree.h (DECL_MODULE_CHECK): Ban TEMPLATE_DECL.
	(SET_TYPE_TEMPLATE_INFO): Restore Alias template setting.
	* decl.c (duplicate_decls): Remove template_decl module flag
	propagation.
	* module.cc (merge_kind_name): Add alias tmpl spec as a thing.
	(dumper::impl::nested_name): Adjust for template-decl module flag
	change.
	(trees_in::assert_definition): Likewise.
	(trees_in::install_entity): Likewise.
	(trees_out::decl_value): Likewise.  Remove alias template
	separation of template and type_decl.
	(trees_in::decl_value): Likewise.
	(trees_out::key_mergeable): Likewise,
	(trees_in::key_mergeable): Likewise.
	(trees_out::decl_node): Adjust for template-decl module flag
	change.
	(depset::hash::make_dependency): Likewise.
	(get_originating_module, module_may_redeclare): Likewise.
	(set_instantiating_module, set_defining_module): Likewise.
	* name-lookup.c (name_lookup::search_adl): Likewise.
	(do_pushdecl): Likewise.
	* pt.c (build_template_decl): Likewise.
	(lookup_template_class_1): Remove special alias_template handling
	of DECL_TI_TEMPLATE.
	(tsubst_template_decl): Likewise.
	gcc/testsuite/
	* g++.dg/modules/pr99283-2_a.H: New.
	* g++.dg/modules/pr99283-2_b.H: New.
	* g++.dg/modules/pr99283-2_c.H: New.
	* g++.dg/modules/pr99283-3_a.H: New.
	* g++.dg/modules/pr99283-3_b.H: New.
	* g++.dg/modules/pr99283-4.H: New.
	* g++.dg/modules/tpl-alias-1_a.H: Adjust scans.
	* g++.dg/modules/tpl-alias-1_b.C: Adjust scans.

0 files changed, 0 insertions, 0 deletions