27dada7d06
This patch simplifies the constraints on the constructors from arrays by removing the redundant checks that element_type and value_type are convertible to element_type. The incorrect uses of __adl_data in those constructors are removed as well (they should use std::data not std::ranges::data, and the former doesn't use ADL). The range/container constructors are now constrained to exclude all specializations of std::span, not just the current instantiation. The range constructor now also checks s subset of the contiguous_range requirements. All relevant constructor constraints now use the _Require helper in order to short circuit and avoid unnecessary instantiations after the first failed constraint. A new constructor supports initialization from different specializations of std::span<OtherType, OtherExtent>, as specified in the C++20 draft. * include/bits/range_access.h (__adl_to_address): Remove. * include/std/span (__is_base_derived_safe_convertible_v): Replace with span::__is_compatible. (__is_std_array_v): Replace with __is_std_array class template and partial specializations. (__is_std_array, __is_std_span): New class templates and partial specializations. (span::__is_compatible): New alias template for SFINAE constraints. (span::span(element_type (&)[N])): Remove redundant constraints. Do not use __adl_data to obtain a pointer. (span::span(array<value_type, N>&)): Likewise. (span::span(const array<value_type, N>&)): Likewise. [_GLIBCXX_P1394] (span::iter_reference_t, span::iterator_t) (span::iter_value_t, span::derived_from): New alias templates for SFINAE constraints, until the equivalents are supported in <concepts> and <iterator>. [_GLIBCXX_P1394] (span::__is_compatible_iterator): New alias template for SFINAE constraints. [_GLIBCXX_P1394] (span::is_compatible_range): New class template for SFINAE constraints. [_GLIBCXX_P1394] (span::span(Range&&)): Improve constraints. [_GLIBCXX_P1394] (span::span(ContiguousIterator, Sentinel)): Likewise. Use std::to_address instead of __adl_to_address. [_GLIBCXX_P1394] (span::span(ContiguousIterator, size_type)): Likewise. [!_GLIBCXX_P1394] (span::__is_compatible_container): New alias template for SFINAE constraints. [!_GLIBCXX_P1394] (span::span(Container&)) (span::span(const Container&)): Improve constraints. [!_GLIBCXX_P1394] (span::span(pointer, size_type)) (span::span(pointer, pointer)): Remove redundant cast of pointer. (span(const span<OType, OExtent>&)): New constructor. From-SVN: r275513 |
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| include | ||
| libsupc++ | ||
| po | ||
| python | ||
| scripts | ||
| src | ||
| testsuite | ||
| acinclude.m4 | ||
| aclocal.m4 | ||
| ChangeLog | ||
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| ChangeLog-2018 | ||
| config.h.in | ||
| configure | ||
| configure.ac | ||
| configure.host | ||
| crossconfig.m4 | ||
| fragment.am | ||
| linkage.m4 | ||
| Makefile.am | ||
| Makefile.in | ||
| README | ||
file: libstdc++-v3/README New users may wish to point their web browsers to the file index.html in the 'doc/html' subdirectory. It contains brief building instructions and notes on how to configure the library in interesting ways.