Type entity

[emhane]

Impl cranelift_entity::EntityRef for Type. This enables using cranelift_entity::SecondaryMap for error stack in verifier.

[Y-Nak]

We shouldn't implement EntityRef for Type just because Type is not a reference(rather, it's an entity itself).
Also, I'm not sure why we want to use entity pattern for Type because we don't need to distinguish instances of type when they are the "same" type(e,g,. do we want to distinguish two Type::i8 and Type::i8?).
I think we should use HashMap or FxHashMap in this case if you don't have a special reason.

[emhane]

We shouldn't implement EntityRef for Type just because Type is not a reference(rather, it's an entity itself). Also, I'm not sure why we want to use entity pattern for Type because we don't need to distinguish instances of type when they are the "same" type(e,g,. do we want to distinguish two Type::i8 and Type::i8?).

this impl doesn't distinguish between between instances of same type variant. as the test shows, a SecondaryMap would be indexed by type variant.

I think we should use HashMap or FxHashMap in this case if you don't have a special reason.

sgtm