Hi: was working through p2680r1 example with the code as follows. --- auto f (int i) -> int { return i + 100; } int g (int j) [[pre: f (j) < j ]] { int r { j - f (j)}; return 2 * r; } auto test () -> void { g (5); } --- Environment - Linux 6.1.0-3-amd64 x86_64 GNU/Linux - Debian GLIBC 2.36-8) 2.36 - gcc version 13.0.1 20230215 (experimental) (GCC) What is not clear to me is the following. This works. :: g++ -std=c++23 -fcontracts contract_01.cc :: ./a.out contract violation in function g at contract_01.cc:8: f (j) < j terminate called without an active exception Aborted :: But this doesn't work ! :: g++ -std=c++23 -O3 -g2 -fcontracts contract_01.cc during RTL pass: final contract_01.cc: In function ‘int g(int)’: contract_01.cc:13:1: internal compiler error: in gen_inlined_subroutine_die, at dwarf2out.cc:25002 13 | } | ^ 0x7d40a5 gen_inlined_subroutine_die /opt/gcc/src/gcc/dwarf2out.cc:25002 0x7d40a5 gen_block_die /opt/gcc/src/gcc/dwarf2out.cc:26487 0xe3b3ca decls_for_scope /opt/gcc/src/gcc/dwarf2out.cc:26612 0xe18c93 gen_subprogram_die /opt/gcc/src/gcc/dwarf2out.cc:24086 0xe1d82f gen_decl_die /opt/gcc/src/gcc/dwarf2out.cc:27020 0xe1e60a dwarf2out_decl /opt/gcc/src/gcc/dwarf2out.cc:27598 0xe1ea62 dwarf2out_function_decl /opt/gcc/src/gcc/dwarf2out.cc:27613 0xea23e7 rest_of_handle_final /opt/gcc/src/gcc/final.cc:4274 0xea23e7 execute /opt/gcc/src/gcc/final.cc:4318 Please submit a full bug report, with preprocessed source (by using -freport-bug). Please include the complete backtrace with any bug report. Is there any impact of the choice of '-O0', '-O1', '-O2' or '-O3' ? If yes, what is the recommended optimization level ? warm regards Saifi