re PR c++/61636 (generic lambda: segfault / "cannot call member function without object")

	PR c++/61636
	* cp-tree.h (maybe_generic_this_capture): Declare.
	* lambda.c (resolvable_dummy_lambda): New, broken out of ...
	(maybe_resolve_dummy): ... here.  Call it.
	(maybe_generic_this_capture): New.
	* parser.c (cp_parser_postfix_expression): Speculatively capture
	this in generic lambda in unresolved member function call.
	* pt.c (tsubst_copy_and_build): Force hard error from failed
	member function lookup in generic lambda.

	PR c++/61636
	* g++.dg/cpp1y/pr61636-1.C: New.
	* g++.dg/cpp1y/pr61636-2.C: New.
	* g++.dg/cpp1y/pr61636-3.C: New.

From-SVN: r244544