Type Definition rustc_mir::borrow_check::type_check::free_region_relations::RegionBoundPairs

type RegionBoundPairs<'tcx> = Vec<(Region<'tcx>, GenericKind<'tcx>)>;

Each RBP ('a, GK) indicates that GK: 'a can be assumed to be true. These encode relationships like T: 'a that are added via implicit bounds.

Each region here is guaranteed to be a key in the indices map. We use the "original" regions (i.e., the keys from the map, and not the values) because the code in process_registered_region_obligations has some special-cased logic expecting to see (e.g.) ReStatic, and if we supplied our special inference variable there, we would mess that up.