Roc crashed with `Cannot load no data into general registers`

[lukewilliamboswell]

This issue was caught in #6990 CI for start-nix-linux-x86-64-tests using the dev backend

$ cargo nextest-gen-dev gen_list::list_sort_asc_by
    Starting 1 test across 2 binaries (1080 skipped; run ID: ed49984b-8660-441b-8234-cc1ddfd2244e, nextest profile: default)
        FAIL [   0.315s] test_gen::test_gen gen_list::list_sort_asc_by

--- STDOUT:              test_gen::test_gen gen_list::list_sort_asc_by ---

running 1 test
--- STDERR:              test_gen::test_gen gen_list::list_sort_asc_by ---
An internal compiler expectation was broken.
This is definitely a compiler bug.
Please file an issue here: <https://github.com/roc-lang/roc/issues/new/choose>
Cannot load no data into general registers: `#UserApp.IdentId(65)`
Location: crates/compiler/gen_dev/src/generic64/storage.rs:544:17

[lukewilliamboswell]

I spent a while tinkering with this but didn't make any progress.

[shua]

was this discovered as part of #6990 ? Since that's closed, is this still relevant?