use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin};
use rustc_middle::middle::stability::AllowUnstable;
use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef};
use rustc_hir::{GenericArg, GenericArgs, OpaqueTyOrigin};
use rustc_middle::middle::stability::AllowUnstable;
use rustc_middle::ty::subst::{self, GenericArgKind, InternalSubsts, SubstsRef};