https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123790
--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-15 branch has been updated by Jakub Jelinek <[email protected]>: https://gcc.gnu.org/g:6b76bcb2673b323127fb1b1d9260bde2f595593d commit r15-10891-g6b76bcb2673b323127fb1b1d9260bde2f595593d Author: Jakub Jelinek <[email protected]> Date: Fri Jan 30 11:40:17 2026 +0100 fold-const: Fix implicit cast to nullptr_t typedef [PR123790] The following testcase is incorrectly rejected, because since r15-6744 it adds build_nop to preserve the exact typedef type and cxx_eval_constant_expression can't fold NOP_EXPR from integer_zerop of one NULLPTR_TYPE to another NULLPTR_TYPE, while cxx_eval_constant_expression relies on fold to do such folding. I see 3 options to fix that, one is deal with this in the r15-6744 spot and special case NULLPTR_TYPE there and build_zero_cst instead of build_nop (with similar condition like in the patch below), another possibility is special case this in cxx_eval_constant_expression, and another one (done in this patch) is to handle this in fold-const.cc - fold_convert_loc and also in fold_convert_const. 2026-01-30 Jakub Jelinek <[email protected]> PR c++/123790 * fold-const.cc (fold_convert_const): Handle conversion of integer_zerop to NULLPTR_TYPE. (fold_convert_loc): Likewise. * g++.dg/cpp0x/nullptr47.C: New test. (cherry picked from commit cffe5fd7c98babd85acf86f3e7f8d02b04416ec2)
