fix missing subst in clippy utils

Author: kylematsuda

src/tools/clippy/clippy_utils/src/ty.rs

@@ -647,8 +647,8 @@ pub fn ty_sig<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<ExprFnSig<'t
             Some(ExprFnSig::Closure(decl, subs.as_closure().sig()))
         },
         ty::FnDef(id, subs) => Some(ExprFnSig::Sig(cx.tcx.bound_fn_sig(id).subst(cx.tcx, subs), Some(id))),
-        ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) => {
-            sig_from_bounds(cx, ty, cx.tcx.item_bounds(def_id).subst_identity(), cx.tcx.opt_parent(def_id))
+        ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
+            sig_from_bounds(cx, ty, cx.tcx.item_bounds(def_id).subst(cx.tcx, substs), cx.tcx.opt_parent(def_id))
         },
         ty::FnPtr(sig) => Some(ExprFnSig::Sig(sig, None)),
         ty::Dynamic(bounds, _, _) => {