> I thought "contracts" were dropped out of C++20.[1] You're right, but (I'm not an authority, someone from /r/cpp would be better to speak here probably) I th

> I thought "contracts" were dropped out of C++20.[1] You're right, but (I'm not an authority, someone from /r/cpp would be better to speak here probably) I think after the Kona meeting recently they were back on the charter for next iteration Specifically, GCC 13 has had support for Contracts in main since November: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ea63396f6b08f88f1cde827e6cab94cd488f7fa7 https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ea63396f6b08f8... > A big issue is, when does control enter and exit the object? What if you call a public member function from inside the object? Did you re-enter? If you check the generated code from the end of the blogpost (see the bit that shows the Ghidra dissasembly) or the notes section, the pattern used in the plugin is: T function() { check_invariants(); // unless we're in constructor result = function_body(); check_invariants(); // unless we're in a destructor return result; } This does mean that a single member call can cause multiple cascading calls to check_invariants() If "this.foo()" calls "this.bar()" which calls "this.baz()", etc. But it's not avoidable, because in this open-world assumption we assume any member call can potentially mutate the state of the member.