This implements the resolution of LWG 1203 so that the constraints for
rvalue stream insertion/extraction are simpler, and the return type is
the original rvalue stream type not its base class.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/std/istream (operator>>(Istream&&, x&)): Simplify, as
per LWG 1203.
* include/std/ostream (operator<<(Ostream&&, const x&)):
Likewise.
* testsuite/27_io/basic_istream/extractors_character/char/lwg2499_neg.cc:
Adjust dg-error pattern.
* testsuite/27_io/basic_istream/extractors_character/wchar_t/lwg2499_neg.cc:
Likewise.
* testsuite/27_io/basic_istream/extractors_other/char/4.cc: Define
is_extractable trait to replace std::__is_extractable. Make it
work with rvalue streams as well as lvalues, to replace f() and
g() helper functions.
* testsuite/27_io/basic_istream/extractors_other/wchar_t/4.cc:
Likewise.
* testsuite/27_io/basic_ostream/inserters_other/char/6.cc:
Define is_insertable trait to replace std::__is_insertable. Make
it work with rvalue streams as well as lvalues, to replace f()
and g() helper functions.
* testsuite/27_io/basic_ostream/inserters_other/wchar_t/6.cc:
Likewise.
* testsuite/27_io/filesystem/path/io/dr2989.cc: Prune additional
errors from new constraints.
* testsuite/27_io/rvalue_streams-2.cc: Remove PR 80675 checks,
which are no longer expected to compile.
* testsuite/27_io/rvalue_streams.cc: Adjust existing test.
Verify LWG 1203 changes.
aa475c4ac8