https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87704
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- Author: redi Date: Tue Oct 23 15:55:05 2018 New Revision: 265429 URL: https://gcc.gnu.org/viewcvs?rev=265429&root=gcc&view=rev Log: PR libstdc++/87704 fix unique_ptr(nullptr_t) constructors Using a delegating constructor to implement these constructors means that they instantiate the destructor, which requires the element_type to be complete. In C++11 and C++14 they were specified to be delegating, but that was changed as part of LWG 2801 so in C++17 they don't require a complete type (as was intended all along). PR libstdc++/87704 * include/bits/unique_ptr.h (unique_ptr::unique_ptr(nullptr_t)): Do not delegate to default constructor. (unique_ptr<T[], D>::unique_ptr(nullptr_t)): Likewise. * testsuite/20_util/unique_ptr/cons/incomplete.cc: New test. Added: branches/gcc-7-branch/libstdc++-v3/testsuite/20_util/unique_ptr/cons/incomplete.cc Modified: branches/gcc-7-branch/libstdc++-v3/ChangeLog branches/gcc-7-branch/libstdc++-v3/include/bits/unique_ptr.h
