Honestly, if there's a warning you've accepted as a known issue or inapplicable ...

Pxtl on July 5, 2017 | parent | context | favorite | on: How we made compiler warnings fatal in Firefox

Honestly, if there's a warning you've accepted as a known issue or inapplicable to your code, just suppress it. Maybe document it as a low priority bug in the tracker so it has a place on the to-do list, but get it out of the compiler results.