c++: constraint matching, TEMPLATE_ID_EXPR, current inst

Here we're crashing during constraint matching for the instantiated
hidden friends due to two issues with dependent substitution into a
TEMPLATE_ID_EXPR that names a template from the current instantiation
(as for C<1> with T=T from maybe_substitute_reqs_for):

  * tsubst_copy substitutes into such a TEMPLATE_DECL by looking it up
    from the substituted class scope.  But for this lookup to work when
    the args are dependent, we need to substitute the class scope with
    entering_scope=true so that we obtain the primary template type
    A<T> (which has TYPE_BINFO) instead of the implicit instantiation
    A<T> (which doesn't).
  * lookup_and_finish_template_variable shouldn't instantiate a
    TEMPLATE_ID_EXPR that names a TEMPLATE_DECL which has more than
    one level of (unsubstituted) parameters (such as A<T>::C).

gcc/cp/ChangeLog:

	* pt.cc (lookup_and_finish_template_variable): Don't
	instantiate if the template's scope is dependent.
	(tsubst_copy) <case TEMPLATE_DECL>: Pass entering_scope=true
	when substituting the class scope.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp2a/concepts-friend10.C: New test.

0 files changed, 0 insertions, 0 deletions