The 23_containers/span/deduction.cc test was already passing, but only
because I had previously implemented the original proposed resolution of
3255. As pointed out in 3255 that original P/R was incorrect because it
broke construction from array xvalues. This reverts the incorrect part
of 3255 (and adds tests for the case it broke), and implements the
resolution of 3369 instead.
* include/std/span (span(T (&)[N])): Use non-deduced context to
prevent first parameter from interfering with class template argument
deduction (LWG 3369).
* testsuite/23_containers/span/deduction.cc: Add missing 'const'.
* testsuite/23_containers/span/lwg3255.cc: Check for construction from
rvalues.
This includes fixes for first, last, as_bytes and as_writable_bytes
which were missing from the paper.
* include/std/span (__cpp_lib_span): Update value.
(span(It, size_type), span(It, End)): Make conditionally explicit. Add
assertion.
(span(R&&), span(const span<OType, OExtent>&)): Likewise and relax
constraints.
(span::first<Count>(), span::last<Count>()): Use explicit type in
return statement.
(as_bytes, as_writable_bytes): Likewise.
* include/std/version (__cpp_lib_span): Update value.
* testsuite/23_containers/span/1.cc: Check new value.
* testsuite/23_containers/span/2.cc: Check new value.
* testsuite/23_containers/span/explicit.cc: New test.
Following this change it's no longer possible to use std::span with
structured bindings or with the tuple-like API. It will probably come
back for C++23 though.
P2116R0 Remove tuple-like protocol support from fixed-extent span
* include/std/span (get, tuple_size, tuple_element): Remove.
* testsuite/23_containers/span/everything.cc: Remove checks for
tuple-like API.
* testsuite/23_containers/span/get_neg.cc: Remove.
* testsuite/23_containers/span/tuple_element_dynamic_neg.cc: Remove.
* testsuite/23_containers/span/tuple_element_oob_neg.cc: Remove.
* testsuite/23_containers/span/tuple_size_neg.cc: Remove.
The deduction guide from an iterator and sentinel used the wrong alias
template and so didn't work.
PR libstdc++/93426
* include/std/span (span): Fix deduction guide.
* testsuite/23_containers/span/deduction.cc: New test.
As discussed at https://github.com/cplusplus/draft/issues/3534 two
std::span constructors specify incorrect conditions for throwing
exceptions. This patch makes those constructors have correct
noexcept-specifiers that accurately reflect what can actually throw.
(span(ContiguousIterator, Sentinel)): Add conditional noexcept.
* include/std/span (span(ContiguousIterator, size_type)): Change
noexcept to be unconditionally true.
* testsuite/23_containers/span/nothrow_cons.cc: New test.
From-SVN: r279206
The previous commit fixed the std::span constructors from const arrays,
revealing a bug in this test.
* testsuite/23_containers/span/lwg3255.cc: Fix test. Constructing a
span of non-const elements should not be possible from a const array
or an array of const elements.
From-SVN: r279001
This patch implements P0388R4, Permit conversions to arrays of unknown bound,
<http://wg21.link/p0388r4>. CWG 393 allowed references to arrays of unknown
bound and this C++20 feature allows conversions like
void f(int(&)[]);
int arr[1];
void g() { f(arr); }
int(&r)[] = arr;
The proposal seemed fairly straightforward but it turned out to be quite
shifty. I found out that I needed to implement DR 2352 (done), and also
DR 1307 (done in this patch). The latter DR added wording for
list-initialization ranking of references to arrays which this proposal
extends. DR 330 was also implemented in this patch.
PR c++/91364 - P0388R4: Permit conversions to arrays of unknown bound.
PR c++/69531 - DR 1307: Differently bounded array parameters.
PR c++/88128 - DR 330: Qual convs and pointers to arrays of pointers.
* call.c (build_array_conv): Build ck_identity at the beginning
of the conversion.
(standard_conversion): Pass bounds_none to comp_ptr_ttypes_const.
(maybe_warn_array_conv): New.
(convert_like_real): Call it. Add an error message about converting
from arrays of unknown bounds.
(conv_get_original_expr): New.
(nelts_initialized_by_list_init): New.
(conv_binds_to_array_of_unknown_bound): New.
(compare_ics): Implement list-initialization ranking based on
array sizes, as specified in DR 1307 and P0388R.
* cp-tree.h (comp_ptr_ttypes_const): Adjust declaration.
(compare_bounds_t): New enum.
* typeck.c (comp_array_types): New bool and compare_bounds_t
parameters. Use them.
(structural_comptypes): Adjust the call to comp_array_types.
(similar_type_p): Handle ARRAY_TYPE.
(build_const_cast_1): Pass bounds_none to comp_ptr_ttypes_const.
(comp_ptr_ttypes_real): Don't check cv-quals of ARRAY_TYPEs. Use
comp_array_types to compare array types. Look through arrays as per
DR 330.
(comp_ptr_ttypes_const): Use comp_array_types to compare array types.
Look through arrays as per DR 330.
* g++.dg/conversion/qual1.C: New test.
* g++.dg/conversion/qual2.C: New test.
* g++.dg/conversion/qual3.C: New test.
* g++.dg/conversion/ref2.C: New test.
* g++.dg/conversion/ref3.C: New test.
* g++.dg/cpp0x/initlist-array3.C: Remove dg-error.
* g++.dg/cpp0x/initlist-array7.C: New test.
* g++.dg/cpp0x/initlist-array8.C: New test.
* g++.dg/cpp2a/array-conv1.C: New test.
* g++.dg/cpp2a/array-conv10.C: New test.
* g++.dg/cpp2a/array-conv11.C: New test.
* g++.dg/cpp2a/array-conv12.C: New test.
* g++.dg/cpp2a/array-conv13.C: New test.
* g++.dg/cpp2a/array-conv14.C: New test.
* g++.dg/cpp2a/array-conv15.C: New test.
* g++.dg/cpp2a/array-conv16.C: New test.
* g++.dg/cpp2a/array-conv17.C: New test.
* g++.dg/cpp2a/array-conv2.C: New test.
* g++.dg/cpp2a/array-conv3.C: New test.
* g++.dg/cpp2a/array-conv4.C: New test.
* g++.dg/cpp2a/array-conv5.C: New test.
* g++.dg/cpp2a/array-conv6.C: New test.
* g++.dg/cpp2a/array-conv7.C: New test.
* g++.dg/cpp2a/array-conv8.C: New test.
* g++.dg/cpp2a/array-conv9.C: New test.
* g++.old-deja/g++.bugs/900321_01.C: Adjust dg-error.
* testsuite/23_containers/span/lwg3255.cc: Adjust test to match the
post-P0388R4 behavior.
From-SVN: r276771
Also fix the constraints on span(Container&) and span(const Container&)
constructors so that they aren't used for const spans or const arrays.
* include/std/span (span(element_type(&)[N]))
(span(array<value_type, N>&), span(const array<value_type, N>&)):
Deduce array element type to allow safe const conversions (LWG 3255).
[!_GLIBCXX_P1394] (span(Container&), span(const Container&)): Use
remove_cv_t on arguments to __is_std_span and __is_std_array.
* testsuite/23_containers/span/lwg3255.cc: New test.
From-SVN: r276298
