… checks;

Also add the instruction format name in format predicates, since they're
going to be used when generating encodings.

This is a map with facilities to insert a default value when the
searched key has no entry yet.

The latter helps deduplicating predicates during encodings and recipes
construction.

Co-authored-by: Benjamin Bouvier <public@benj.me>
Co-authored-by: bjorn3 <bjorn3@users.noreply.github.com>

Co-authored-by: Benjamin Bouvier <public@benj.me>
Co-authored-by: bjorn3 <bjorn3@users.noreply.github.com>

KILL THE SNAKE WITH FIRE.

…no shuffle yet)

This assert was added when porting legalization from Python to Rust and
doesn't hold when we have derived type variables.

… constraints;

…ases;