[Bug c++/125904] New: contracts: assertion not evaluated if only statement in loop body

[ivan.lazaric.gcc at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125904

            Bug ID: 125904
           Summary: contracts: assertion not evaluated if only statement
                    in loop body
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ivan.lazaric.gcc at gmail dot com
  Target Milestone: ---

```cpp
int main() {
  for (int i = 0; i < 10; ++i) {
    contract_assert(false);
  }
}
```

Compiler flags: "-std=c++26 -fcontracts"

Expected this to raise a contract violation on execution, but nothing happens
Godbolt: https://godbolt.org/z/hsfbW77Gc

If we just add a meaningless `0;` statement to the loop body, it suddenly works
https://godbolt.org/z/ac86Yjh35