https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106838
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:30c811f2bac73e63e0b461ba7ed3805b77898798 commit r13-2550-g30c811f2bac73e63e0b461ba7ed3805b77898798 Author: Jonathan Wakely <jwak...@redhat.com> Date: Tue Sep 6 13:21:09 2022 +0100 c++: Fix type completeness checks for type traits [PR106838] The check_trait_type function is used for a number of different type traits that have different requirements on their arguments. For example, __is_constructible allows arrays of unknown bound even if the array element is an incomplete type, but __is_aggregate does not, it always requires the array element type to be complete. Other traits have different requirements again, e.g. __is_empty allows incomplete unions, and arrays (of known or unknown bound) of incomplete types. This alters the check_trait_type function to take an additional KIND parameter which indicates which set of type trait requirements to check. As noted in a comment, the requirements for __is_aggregate deviate from the ones for std::is_aggregate in the standard. It's not necessary for the elements of an array to be complete types, because arrays are always aggregates. The type_has_virtual_destructor change is needed to avoid an ICE. Previously it could never be called for incomplete union types as they were (incorrectly) rejected by check_trait_type. This change causes some additional diagnostics in some libstdc++ tests, where the front end was not previously complaining about invalid types that the library assertions diagnosed. We should consider removing the library assertions from traits where the front end implements the correct checks now. PR c++/106838 gcc/cp/ChangeLog: * class.cc (type_has_virtual_destructor): Return false for union types. * semantics.cc (check_trait_type): Add KIND parameter to support different sets of requirements. (finish_trait_expr): Pass KIND argument for relevant traits. gcc/ChangeLog: * doc/extend.texi (Type Traits): Fix requirements. Document __is_aggregate and __is_final. gcc/testsuite/ChangeLog: * g++.dg/ext/array4.C: Fix invalid use of __is_constructible. * g++.dg/ext/unary_trait_incomplete.C: Fix tests for traits with different requirements. libstdc++-v3/ChangeLog: * testsuite/20_util/is_complete_or_unbounded/memoization_neg.cc: Prune additional errors from front-end. * testsuite/20_util/is_move_constructible/incomplete_neg.cc: Likewise. * testsuite/20_util/is_nothrow_swappable/incomplete_neg.cc: Likewise. * testsuite/20_util/is_nothrow_swappable_with/incomplete_neg.cc: Likewise. * testsuite/20_util/is_swappable_with/incomplete_neg.cc: Likewise.
