r273442 - in /trunk/libstdc++-v3: ChangeLog inc...

[redi@gcc.gnu.org]

Author: redi
Date: Fri Jul 12 11:43:22 2019
New Revision: 273442

URL: https://gcc.gnu.org/viewcvs?rev=273442&root=gcc&view=rev
Log:
Define __type_identity_t alias and use for string_view

This defines the equivalent of C++2a's std::type_identity_t alias but
for use in C++11 and later. This can be used to replace __detail::__idt
in the string_view headers, which previously used common_type_t because
the one argument specialization of common_type_t was simply the identity
transform (which is no longer true).

	* include/experimental/string_view (__detail::__idt): Remove.
	(operator==, operator!=, operator<, operator>, operator<=, operator>=):
	Use __type_identity_t instead of __detail::__idt;
	* include/std/string_view (__detail::__idt): Remove.
	(operator==, operator!=, operator<, operator>, operator<=, operator>=):
	Use __type_identity_t instead of __detail::__idt;
	* include/std/type_traits (__type_identity_t): New alias template.

Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/include/experimental/string_view
    trunk/libstdc++-v3/include/std/string_view
    trunk/libstdc++-v3/include/std/type_traits