This is the context state available during incr. comp. hashing. It contains enough information to transform DefIds and HirIds into stable DefPaths (i.e., a reference to the TyCtxt) and it holds a few caches for speeding up various things (e.g., each DefId/DefPath is only hashed once).


The BodyResolver allows mapping a BodyId to the corresponding hir::Body. We could also just store a plain reference to the hir::Crate but we want to avoid that the crate is used to get untracked access to all of the HIR.