From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2181) id 7429438515F2; Fri, 18 Jun 2021 15:55:16 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 7429438515F2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Jonathan Wakely To: gcc-cvs@gcc.gnu.org, libstdc++-cvs@gcc.gnu.org Subject: [gcc r11-8621] libstdc++: Replace incorrect static assertion in std::reduce [PR95833] X-Act-Checkin: gcc X-Git-Author: Jonathan Wakely X-Git-Refname: refs/heads/releases/gcc-11 X-Git-Oldrev: 85f85b7e62aacc6abae475932cf483a4c80176ce X-Git-Newrev: fe918041ce9809755a7e1b2f62071c2b27829610 Message-Id: <20210618155516.7429438515F2@sourceware.org> Date: Fri, 18 Jun 2021 15:55:16 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Jun 2021 15:55:16 -0000 https://gcc.gnu.org/g:fe918041ce9809755a7e1b2f62071c2b27829610 commit r11-8621-gfe918041ce9809755a7e1b2f62071c2b27829610 Author: Jonathan Wakely Date: Fri Jun 18 14:46:58 2021 +0100 libstdc++: Replace incorrect static assertion in std::reduce [PR95833] The standard does not require the iterator's value type to be convertible to the result type, it only requires that the result of dereferencing the iterator can be passed to the binary function. libstdc++-v3/ChangeLog: PR libstdc++/95833 * include/std/numeric (reduce(Iter, Iter, T, BinaryOp)): Replace incorrect static_assert with ones matching the 'Mandates' conditions in the standard. * testsuite/26_numerics/reduce/95833.cc: New test. (cherry picked from commit 0532452dcd17910dfd3d2b0df50dfe3ef1194bf7) Diff: --- libstdc++-v3/include/std/numeric | 6 ++++-- libstdc++-v3/testsuite/26_numerics/reduce/95833.cc | 16 ++++++++++++++++ 2 files changed, 20 insertions(+), 2 deletions(-) diff --git a/libstdc++-v3/include/std/numeric b/libstdc++-v3/include/std/numeric index f36c1f96b2e..2ab337a0f3a 100644 --- a/libstdc++-v3/include/std/numeric +++ b/libstdc++-v3/include/std/numeric @@ -278,9 +278,11 @@ namespace __detail reduce(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOperation __binary_op) { - using value_type = typename iterator_traits<_InputIterator>::value_type; + using __ref = typename iterator_traits<_InputIterator>::reference; + static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, _Tp&, __ref>); + static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, __ref, _Tp&>); static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, _Tp&, _Tp&>); - static_assert(is_convertible_v); + static_assert(is_invocable_r_v<_Tp, _BinaryOperation&, __ref, __ref>); if constexpr (__is_random_access_iter<_InputIterator>::value) { while ((__last - __first) >= 4) diff --git a/libstdc++-v3/testsuite/26_numerics/reduce/95833.cc b/libstdc++-v3/testsuite/26_numerics/reduce/95833.cc new file mode 100644 index 00000000000..cf4644f53c9 --- /dev/null +++ b/libstdc++-v3/testsuite/26_numerics/reduce/95833.cc @@ -0,0 +1,16 @@ +// { dg-do compile { target c++17 } } +// PR libstdc++/95833 - Incorrect static_assert in std::reduce overload + +#include + +struct A { }; +struct B { }; + +struct binop +{ + template + A operator()(T&&, U&&) const { return A{}; } +}; + +B b; +A a = std::reduce(&b, &b + 1, A{}, binop{});