Commit 1a7dd827 authored by Andrei Paskevich's avatar Andrei Paskevich

whyml: mutable variables produce a read effect

Otherwise, we would accept (mpv <- ghost v; let x = mpv in ...)
where both x and mpv are non-ghost.
parent b09cd5a4
......@@ -519,6 +519,10 @@ let vta_of_expr e = match e.e_vty with
| VTvalue _ -> Loc.error ?loc:e.e_loc (ArrowExpected e)
| VTarrow vta -> vta
let pv_effect pv = match pv.pv_vtv.vtv_mut with
| Some r -> eff_read ~ghost:pv.pv_vtv.vtv_ghost eff_empty r
| None -> eff_empty
let add_e_vars e m = varmap_union e.e_varm m
let e_pvset pvs e =
......@@ -592,7 +596,7 @@ let mk_expr node vty eff varm = {
let e_value pv =
let varm = add_pv_vars pv Mid.empty in
mk_expr (Evalue pv) (VTvalue pv.pv_vtv) eff_empty varm
mk_expr (Evalue pv) (VTvalue pv.pv_vtv) (pv_effect pv) varm
let e_arrow ps vta =
let varm = add_ps_vars ps Mid.empty in
......@@ -636,6 +640,7 @@ let e_app_real e pv =
let spec,vty = vta_app (vta_of_expr e) pv in
check_postexpr e spec.c_effect (add_pv_vars pv Mid.empty);
let eff = eff_union e.e_effect spec.c_effect in
let eff = eff_union eff (pv_effect pv) in
mk_expr (Eapp (e,pv,spec)) vty eff (add_pv_vars pv e.e_varm)
let rec e_app_flatten e pv = match e.e_node with
......@@ -703,6 +708,7 @@ let e_plapp pls el ity =
| vtv::vtvl, e::argl ->
let apply_to_pv pv =
let t = t_var pv.pv_vs in
let eff = eff_union eff (pv_effect pv) in
let ghost = ghost || (pv.pv_vtv.vtv_ghost && not vtv.vtv_ghost) in
let sbs = ity_match sbs vtv.vtv_ity pv.pv_vtv.vtv_ity in
app (t::tl) (add_pv_vars pv varm) ghost eff sbs vtvl argl
......@@ -783,7 +789,8 @@ let e_assign_real e0 pv =
let varm = add_pv_vars pv Mid.empty in
check_postexpr e0 eff varm;
let varm = add_e_vars e0 varm in
let eff = eff_union e0.e_effect eff in
let eff = eff_union eff e0.e_effect in
let eff = eff_union eff (pv_effect pv) in
let vty = VTvalue (vty_value ~ghost ity_unit) in
let e = mk_expr (Eassign (e0,r,pv)) vty eff varm in
(* FIXME? Ok, this is awkward. We prohibit assignments
......
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