c++: alias template with dependent attributes [PR115897]
Here we're prematurely stripping the dependent alias template-id A<T> to
its defining-type-id T when used as a template argument, which in turn
causes us to essentially ignore A's vector_size attribute in the outer
template-id.
This has always been a problem for class template-ids it seems, and after
r14-2170 variable template-ids are affected as well.
This patch marks alias templates that have a dependent attribute as
complex (as with e.g. constrained alias templates) so that we don't look
through them prematurely.
PR c++/115897
gcc/cp/ChangeLog:
* pt.cc (complex_alias_template_p): Return true for an alias
template with attributes.
(get_underlying_template): Don't look through an alias template
with attributes.