Debian 11 ships with LDC 1.24.0 (FE 2.094.1), mir-core breaks because the noreturn type didn't exist back then. It's also not possible to manually alias to typeof(*null) with that version yet.
Currently mir-core uses noreturn in a bunch of places, so not sure if it's worth supporting it.
I would definitely like to have it be supported, it being a "relatively recent" DMD FE and mir-core being used in many projects, also older ones like asdf.