https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101532
--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-9 branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>: https://gcc.gnu.org/g:4df77364f7fd9ce88c012843fff124346e4d3c06 commit r9-10155-g4df77364f7fd9ce88c012843fff124346e4d3c06 Author: Patrick Palka <ppa...@redhat.com> Date: Tue Jan 25 15:04:49 2022 -0500 c++: deleted fn and noexcept inst [PR101532, PR104225] Here when attempting to use B's implicitly deleted default constructor, mark_used rightfully returns false, but for the wrong reason: it tries to instantiate the synthesized noexcept specifier which then only silently fails because get_defaulted_eh_spec suppresses diagnostics for deleted functions. This lack of diagnostics causes us to crash on the first testcase below (thanks to the assert in finish_expr_stmt), and silently accept the second testcase. To fix this, this patch makes mark_used avoid attempting to instantiate the noexcept specifier of a deleted function, so that we'll instead directly reject (and diagnose) the function due to its deletedness. PR c++/101532 PR c++/104225 gcc/cp/ChangeLog: * decl2.c (mark_used): Don't consider maybe_instantiate_noexcept on a deleted function. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/nsdmi-template21.C: New test. * g++.dg/cpp0x/nsdmi-template21a.C: New test. (cherry picked from commit bc90dd0ecf02e11d47d1af7f627e2e2acaa40106)
