https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103049
--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:93810fd673654db9ff16170624a6d36449eab241 commit r12-5386-g93810fd673654db9ff16170624a6d36449eab241 Author: Marek Polacek <pola...@redhat.com> Date: Wed Nov 3 11:04:22 2021 -0400 c++: Implement C++23 P0849R8 - auto(x) [PR103049] This patch implements P0849R8 which allows auto in a functional cast, the result of which is a prvalue. [expr.type.conv]/1 says that the type is determined by placeholder type deduction. We only accept 'auto', not 'decltype(auto)' -- that the type shall be auto comes from [dcl.type.auto.deduct]. Therefore the rules are like for [temp.deduct.call], deducing template arguments from a function call, so the result type will never be a reference, and we decay arrays/functions. PR c++/103049 gcc/cp/ChangeLog: * semantics.c (finish_compound_literal): Accept C++23 auto{x}. * typeck2.c (build_functional_cast_1): Accept C++23 auto(x). gcc/testsuite/ChangeLog: * g++.dg/cpp0x/auto25.C: Adjust dg-error. * g++.dg/cpp0x/auto9.C: Likewise. * g++.dg/cpp2a/concepts-pr84979-2.C: Likewise. * g++.dg/cpp2a/concepts-pr84979-3.C: Likewise. * g++.dg/cpp23/auto-fncast1.C: New test. * g++.dg/cpp23/auto-fncast2.C: New test. * g++.dg/cpp23/auto-fncast3.C: New test. * g++.dg/cpp23/auto-fncast4.C: New test. * g++.dg/cpp23/auto-fncast5.C: New test. * g++.dg/cpp23/auto-fncast6.C: New test.
