This patch changes the implementation of operator[], to follow similar
pattern as at, where we normalize argument types and forward to single
overload. The conversion now uses __mdspan::__index_type_cast, instead
of static_assert. This introduces asserts assuring that conversion is
is value preserving.
Finally, __is_multi_index is implemented as local lambda, avoiding
the need to create a local array with copies of the arguments.
libstdc++-v3/ChangeLog:
* include/std/mdspan (__mdspan::__is_multi_index): Removed,
replaced with local lambda in mdspan::operator[].
(__mdspan::operator[]): Implement in terms of single overload
accepting index_type. Use __mdspan::__index_type_cast for type
conversion.
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Signed-off-by: Tomasz Kamiński <tkaminsk@redhat.com>
66e60479e9