+
+ | _, NCic.Meta (n, _) when is_locked n subst ->
+ (let (metasenv, subst), i =
+ match NCicReduction.whd ~subst context t1 with
+ | NCic.Appl (NCic.Meta (i,l)::args) ->
+ let metasenv, subst, lambda_Mj =
+ lambda_intros rdb metasenv subst context t1 args
+ in
+ unify rdb test_eq_only metasenv subst context
+ (C.Meta (i,l)) lambda_Mj,
+ i
+ | NCic.Meta (i,_) -> (metasenv, subst), i
+ | _ ->
+ raise (UnificationFailure (lazy "Locked term vs non
+ flexible term; probably not saturated enough yet!"))
+ in
+ let t1 = NCicReduction.whd ~subst context t1 in
+ let j, lj =
+ match t1 with NCic.Meta (j,l) -> j, l | _ -> assert false
+ in
+ let metasenv, subst =
+ instantiate rdb test_eq_only metasenv subst context j lj t2 true
+ in
+ (* We need to remove the out_scope_tags to avoid propagation of
+ them that triggers again the ad-hoc case *)
+ let subst =
+ List.map (fun (i,(tag,ctx,bo,ty)) ->
+ let tag =
+ match tag with
+ Some tag when
+ tag = NCicMetaSubst.in_scope_tag
+ || NCicMetaSubst.is_out_scope_tag tag -> None
+ | _ -> tag
+ in
+ i,(tag,ctx,bo,ty)
+ ) subst
+ in
+ (try
+ let name, ctx, term, ty = NCicUtils.lookup_subst i subst in
+ let term = eta_reduce subst term in
+ let subst = List.filter (fun (j,_) -> j <> i) subst in
+ metasenv, ((i, (name, ctx, term, ty)) :: subst)
+ with Not_found -> assert false))