2015-03-20 Andrew Sutton <andrew.n.sutton@gmail.com>

2015-03-20  Andrew Sutton  <andrew.n.sutton@gmail.com>

	Fix grammar error type requirements and improve diagnostics
	for mis-defined function concepts and errors involving pack
	expansions.
	* gcc/cp/pt.c (determine_specialization). Remove dead code.
	(lookup_template_class_1): Return an error if constraints
	aren't satisfied.
	* gcc/cp/constraint.cc (lift_function_definition): Don't
	re-check for empty/erroneous concept definitions.
	(lift_pack_expansion): Removed. Don't inline patterns so
	that we can preserve the syntax beneath them.
	(lift_expression): Don't do anything with pack expansions.
	(check_function_concept): Specifically check for empty
	concept definitions.
	(diagnose_pack_expansion): Diagnose errors in expansions
	more thoughtfully by determining which arguments are failing
	their expanded requirements.
	gcc/cp/parser.c (cp_parser_type_requirement): Accept an
	optional template keyword before a template-id and
	parse that as a special case of required type name.
	gcc/testsuite/g++.dg/concepts/template-parm11.C: Update test
	for fixed grammar, diagnostics.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/c++-concepts@221540 138bc75d-0d04-0410-961f-82ee72b054a4