use rustc::ty::{GenericParamDef, GenericParamDefKind};
use rustc::ty::subst::{self, Subst, InternalSubsts, SubstsRef};
use rustc::ty::wf::object_region_bounds;
use rustc::ty::{GenericParamDef, GenericParamDefKind};
use rustc::ty::subst::{self, Subst, InternalSubsts, SubstsRef};
use rustc::ty::wf::object_region_bounds;