c++: wrong targs in satisfaction diagnostic context line [PR99214]

In the three-parameter version of satisfy_declaration_constraints, when
't' isn't the most general template, then 't' won't correspond with
'args' after we augment the latter via add_outermost_template_args, and
so the instantiation context that we push via push_tinst_level isn't
quite correct: 'args' is a complete set of template arguments, but 't'
is not necessarily the most general template.  This manifests as
misleading diagnostic context lines when issuing a satisfaction failure
error, e.g.  the below testcase without this patch we emit:
  In substitution of '... void A<int>::f<U>() ... [with U = int]'
and with this patch we emit:
  In substitution of '... void A<int>::f<U>() ... [with U = char]'.

This patch fixes this by passing the original 'args' to push_tinst_level,
which ought to properly correspond to 't'.

	PR c++/99214

gcc/cp/ChangeLog:

	* constraint.cc (satisfy_declaration_constraints): Pass the
	original ARGS to push_tinst_level.

gcc/testsuite/ChangeLog:

	* g++.dg/concepts/diagnostic20.C: New test.

Reviewed-by: Jason Merrill <jason@redhat.com>

0 files changed, 0 insertions, 0 deletions