The tracking issue for this feature is: #85512.

This feature allows you to cause any lint to produce a warning even if the lint has a different level by default or another level is set somewhere else. For instance, the force-warn option can be used to make a lint (e.g., dead_code) produce a warning even if that lint is allowed in code with #![allow(dead_code)].



fn dead_function() {}
// This would normally not produce a warning even though the
// function is not used, because dead code is being allowed

fn main() {}

We can force a warning to be produced by providing --force-warn dead_code to rustc.