[PATCH] Make std::scoped_allocator_adaptor's OUTERMOST recursive

[Jonathan Wakely <jwakely at redhat dot com>]

This fixes a TODO in <scoped_allocator> which is one of our remaining
C++11 conformance gaps.

I also found that the constructors need to be constrained, otherwise
is_constructible gives false positives, and then that causes
uses_allocator to give false positives, which makes uses-allocator
take a branch that doesn't compile. I'll report that as a defect.

	* doc/xml/manual/status_cxx2011.xml: Update status.
	* include/std/scoped_allocator (__outer_allocator_t, __outermost_type):
	New helpers for recursive OUTERMOST.
	(__outermost): Use __outermost_type::_S_outermost.
	(__do_outermost, scoped_allocator_adaptor::__outermost_type): Remove.
	(scoped_allocator_adaptor::__outermost_alloc_traits): Use new
	__outermost_type helper.
	* testsuite/20_util/scoped_allocator/outermost.cc: New test.

Tested x86_64-linux, committed to trunk.

Attachment: patch.txt
Description: Text document