<!-- Thank you for finding an Internal Compiler Error! 🧊 If possible, try to provide a minimal verifiable example. You can read "Rust Bug Minimization Patterns" for how to create smaller examples. http://blog.pnkfx.org/blog/2019/11/18/rust-bug-minimization-patterns/ --> The following throws a 'Free regions in optimized MIR' ICE on master: ### Code ```Rust #![feature(adt_const_params)] #![feature(generic_const_exprs)] fn foo<const B: &'static bool>(arg: &'static bool) -> bool { B == arg } fn main() { foo::<{&true}>(&false); } ``` [backtrace.txt](https://github.com/rust-lang/rust/files/9298157/backtrace.txt)