https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109787
Bug ID: 109787
Summary: Warn about contract violations that can be detected at
compile time
Product: gcc
Version: 13.1.0
Status: UNCONFIRMED
Keywords: diagnostic
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: redi at gcc dot gnu.org
Blocks: 87403
Target Milestone: ---
struct array {
int operator[](unsigned n) [[pre: n < 1]] { return 0; }
};
int main() {
array a;
return a[1];
}
When this C++ program is compiled with -fcontracts it will fail at runtime:
contract violation in function array<int, 1>::operator[] at contract.cc:7: n <
N
terminate called without an active exception
Aborted (core dumped)
The front-end inserts a call to this handler when the precondition check fails:
extern "C++" {
void handle_contract_violation (const std::experimental::contract_violation &);
}
It would be nice if the middle-end could notice that the contract handler is
reached on all paths, and so warn. If we can prove we're going to call the
contract violation handler, then we can prove the program is wrong, and we
should warn.
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87403
[Bug 87403] [Meta-bug] Issues that suggest a new warning
