Add basic translation of monomorphisation to the new type checker

1 files changed, 976 insertions, 0 deletions

diff --git a/src/monomorphise_new.ml b/src/monomorphise_new.ml
new file mode 100644
index 00000000..f73ecb13
--- /dev/null
+++ b/src/monomorphise_new.ml
@@ -0,0 +1,976 @@
+open Parse_ast
+open Ast
+open Ast_util
+open Type_check_new
+
+let disable_const_propagation = ref false
+
+(* TODO: some places will need Type_check_new.expand_synonyms *)
+
+(* TODO: put this somewhere common *)
+
+let id_to_string (Id_aux(id,l)) =
+  match id with
+    | Id(s) -> s
+    | DeIid(s) -> s
+
+(* TODO: check for temporary failwiths *)
+
+let optmap v f =
+  match v with
+  | None -> None
+  | Some v -> Some (f v)
+
+module KSubst = Map.Make(Kid)
+module ISubst = Map.Make(Id)
+let ksubst_from_list = List.fold_left (fun s (v,i) -> KSubst.add v i s) KSubst.empty
+let isubst_from_list = List.fold_left (fun s (v,i) -> ISubst.add v i s) ISubst.empty
+
+let subst_src_typ substs t =
+  let rec s_snexp (Nexp_aux (ne,l) as nexp) =
+    let re ne = Nexp_aux (ne,l) in
+    match ne with
+    | Nexp_var (Kid_aux (_,l) as kid) ->
+       (try KSubst.find kid substs
+       with Not_found -> nexp)
+    | Nexp_id _
+    | Nexp_constant _ -> nexp
+    | Nexp_times (n1,n2) -> re (Nexp_times (s_snexp n1, s_snexp n2))
+    | Nexp_sum (n1,n2)   -> re (Nexp_sum   (s_snexp n1, s_snexp n2))
+    | Nexp_minus (n1,n2) -> re (Nexp_minus (s_snexp n1, s_snexp n2))
+    | Nexp_exp ne -> re (Nexp_exp (s_snexp ne))
+    | Nexp_neg ne -> re (Nexp_neg (s_snexp ne))
+  in
+  let rec s_styp ((Typ_aux (t,l)) as ty) =
+    let re t = Typ_aux (t,l) in
+    match t with
+    | Typ_wild
+    | Typ_id _
+    | Typ_var _
+      -> ty
+    | Typ_fn (t1,t2,e) -> re (Typ_fn (s_styp t1, s_styp t2,e))
+    | Typ_tup ts -> re (Typ_tup (List.map s_styp ts))
+    | Typ_app (id,tas) -> re (Typ_app (id,List.map s_starg tas))
+  and s_starg (Typ_arg_aux (ta,l) as targ) =
+    match ta with
+    | Typ_arg_nexp ne -> Typ_arg_aux (Typ_arg_nexp (s_snexp ne),l)
+    | Typ_arg_typ t -> Typ_arg_aux (Typ_arg_typ (s_styp t),l)
+    | Typ_arg_order _
+    | Typ_arg_effect _ -> targ
+  in s_styp t
+
+
+
+
+(* Based on current type checker's behaviour *)
+let pat_id_is_variable env id =
+  match Env.lookup_id id env with
+  | Register _
+  | Local _
+    -> true
+  | Enum _
+  | Union _
+    -> false
+  | Unbound -> failwith "unbound var"
+
+let rec is_value (E_aux (e,(l,annot))) =
+  match e with
+  | E_id id ->
+     (match annot with
+     | None -> false (* Be conservative if we have no info *)
+     | Some (env,_,_) -> not (pat_id_is_variable env id))
+  | E_lit _ -> true
+  | E_tuple es -> List.for_all is_value es
+(* TODO: more? *)
+  | _ -> false
+
+let is_pure (Effect_opt_aux (e,_)) =
+  match e with
+  | Effect_opt_pure -> true
+  | Effect_opt_effect (Effect_aux (Effect_set [],_)) -> true
+  | _ -> false
+
+let rec list_extract f = function
+  | [] -> None
+  | h::t -> match f h with None -> list_extract f t | Some v -> Some v
+
+let rec cross = function
+  | [] -> failwith "cross"
+  | [(x,l)] -> List.map (fun y -> [(x,y)]) l
+  | (x,l)::t -> 
+     let t' = cross t in
+     List.concat (List.map (fun y -> List.map (fun l' -> (x,y)::l') t') l)
+
+(* Given a type for a constructor, work out which refinements we ought to produce *)
+(* TODO collision avoidance *)
+let split_src_type i ty (TypQ_aux (q,ql)) =
+  let rec size_nvars_nexp (Nexp_aux (ne,_)) =
+    match ne with
+    | Nexp_var v -> [v]
+    | Nexp_id _
+    | Nexp_constant _
+      -> []
+    | Nexp_times (n1,n2)
+    | Nexp_sum (n1,n2)
+    | Nexp_minus (n1,n2)
+      -> size_nvars_nexp n1 @ size_nvars_nexp n2
+    | Nexp_exp n
+    | Nexp_neg n
+      -> size_nvars_nexp n
+  in
+  let rec size_nvars_ty (Typ_aux (ty,l)) =
+    match ty with
+    | Typ_wild
+    | Typ_id _
+    | Typ_var _
+      -> []
+    | Typ_fn _ ->
+       raise (Reporting_basic.err_general l ("Function type in constructor " ^ i))
+    | Typ_tup ts -> List.concat (List.map size_nvars_ty ts)
+    | Typ_app (Id_aux (Id "vector",_),
+               [_;Typ_arg_aux (Typ_arg_nexp sz,_);
+                _;Typ_arg_aux (Typ_arg_typ (Typ_aux (Typ_id (Id_aux (Id "bit",_)),_)),_)]) ->
+       size_nvars_nexp sz
+    | Typ_app (_, tas) ->
+       []  (* We only support sizes for bitvectors mentioned explicitly, not any buried
+              inside another type *)
+  in
+  let nvars = List.sort_uniq Kid.compare (size_nvars_ty ty) in
+  match nvars with
+  | [] -> None
+  | sample::__ ->
+     (* Only check for constraints if we found a size to constrain *)
+     let qs =
+       match q with
+       | TypQ_no_forall -> 
+          raise (Reporting_basic.err_general ql
+                   ("No set constraint for variable " ^ string_of_kid sample ^ " in constructor " ^ i))
+       | TypQ_tq qs -> qs
+     in
+     let find_set (Kid_aux (Var nvar,_) as kid) =
+       match list_extract (function
+       | QI_aux (QI_const (NC_aux (NC_nat_set_bounded (Kid_aux (Var nvar',_),vals),_)),_)
+         -> if nvar = nvar' then Some vals else None
+       | _ -> None) qs with
+       | None ->
+          raise (Reporting_basic.err_general ql
+                   ("No set constraint for variable " ^ nvar ^ " in constructor " ^ i))
+       | Some vals -> (kid,vals)
+     in
+     let nvar_sets = List.map find_set nvars in
+     let total_variants = List.fold_left ( * ) 1 (List.map (fun (_,l) -> List.length l) nvar_sets) in
+     let limit = 8 in
+     let () = if total_variants > limit then
+         raise (Reporting_basic.err_general ql
+                  (string_of_int total_variants ^ "variants for constructor " ^ i ^
+                     "bigger than limit " ^ string_of_int limit)) else ()
+     in
+     let variants = cross nvar_sets in
+     let name l = String.concat "_" (i::(List.map (fun (v,i) -> string_of_kid v ^ string_of_int i) l)) in
+     Some (List.map (fun l -> (l, name l)) variants)
+
+(* TODO: maybe fold this into subst_src_typ? *)
+let inst_src_type insts ty =
+  let insts = List.map (fun (v,i) -> (v,Nexp_aux (Nexp_constant i,Generated Unknown))) insts in
+  let subst = ksubst_from_list insts in
+  subst_src_typ subst ty
+
+let reduce_nexp subst ne =
+  let rec eval (Nexp_aux (ne,_) as nexp) =
+    match ne with
+    | Nexp_constant i -> i
+    | Nexp_sum (n1,n2) -> (eval n1) + (eval n2)
+    | Nexp_minus (n1,n2) -> (eval n1) - (eval n2)
+    | Nexp_times (n1,n2) -> (eval n1) * (eval n2)
+    | Nexp_exp n -> 1 lsl (eval n)
+    | Nexp_neg n -> - (eval n)
+    | _ ->
+       raise (Reporting_basic.err_general Unknown ("Couldn't turn nexp " ^
+                                                      string_of_nexp nexp ^ " into concrete value"))
+  in eval ne
+
+(* Check to see if we need to monomorphise a use of a constructor.  Currently
+   assumes that bitvector sizes are always given as a variable; don't yet handle
+   more general cases (e.g., 8 * var) *)
+
+(* TODO: use type checker's instantiation instead *)
+let refine_constructor refinements i substs (E_aux (_,(l,_)) as arg) t =
+  let rec derive_vars (Typ_aux (t,_)) (E_aux (e,(l,tannot))) =
+    match t with
+    | Typ_app (Id_aux (Id "vector",_), [_;Typ_arg_aux (Typ_arg_nexp (Nexp_aux (Nexp_var v,_)),_);_;Typ_arg_aux (Typ_arg_typ (Typ_aux (Typ_id (Id_aux (Id "bit",_)),_)),_)]) ->
+       (match tannot with
+       | Some (_,Typ_aux (Typ_app (Id_aux (Id "vector",_), [_;Typ_arg_aux (Typ_arg_nexp ne,_);_;Typ_arg_aux (Typ_arg_typ (Typ_aux (Typ_id (Id_aux (Id "bit",_)),_)),_)]),_),_) ->
+          [(v,reduce_nexp substs ne)]
+       | _ -> [])
+    | Typ_wild
+    | Typ_var _
+    | Typ_id _
+    | Typ_fn _
+    | Typ_app _
+      -> []
+    | Typ_tup ts ->
+       match e with
+       | E_tuple es -> List.concat (List.map2 derive_vars ts es)
+       | _ -> [] (* TODO? *)
+  in
+  try
+    let irefinements = List.assoc i refinements in
+    let vars = List.sort_uniq (fun x y -> Kid.compare (fst x) (fst y)) (derive_vars t arg) in
+    try
+      Some (List.assoc vars irefinements)
+    with Not_found ->
+      (Reporting_basic.print_err false true l "Monomorphisation"
+         ("Failed to find a monomorphic constructor for " ^ i ^ " instance " ^
+             match vars with [] -> "<empty>"
+             | _ -> String.concat "," (List.map (fun (x,y) -> string_of_kid x ^ "=" ^ string_of_int y) vars)); None)
+  with Not_found -> None
+
+
+(* Substitute found nexps for variables in an expression, and rename constructors to reflect
+   specialisation *)
+
+let nexp_subst_fns substs refinements =
+(*
+  let s_t t = typ_subst substs true t in
+(*  let s_typschm (TypSchm_aux (TypSchm_ts (q,t),l)) = TypSchm_aux (TypSchm_ts (q,s_t t),l) in
+   hopefully don't need this anyway *)
+  let s_typschm tsh = tsh in
+  let s_tannot = function
+    | Base ((params,t),tag,ranges,effl,effc,bounds) ->
+       (* TODO: do other fields need mapped? *)
+       Base ((params,s_t t),tag,ranges,effl,effc,bounds)
+    | tannot -> tannot
+  in
+  let rec s_pat (P_aux (p,(l,annot))) =
+    let re p = P_aux (p,(l,s_tannot annot)) in
+    match p with
+    | P_lit _ | P_wild | P_id _ -> re p
+    | P_as (p',id) -> re (P_as (s_pat p', id))
+    | P_typ (ty,p') -> re (P_typ (ty,s_pat p'))
+    | P_app (id,ps) -> re (P_app (id, List.map s_pat ps))
+    | P_record (fps,flag) -> re (P_record (List.map s_fpat fps, flag))
+    | P_vector ps -> re (P_vector (List.map s_pat ps))
+    | P_vector_indexed ips -> re (P_vector_indexed (List.map (fun (i,p) -> (i,s_pat p)) ips))
+    | P_vector_concat ps -> re (P_vector_concat (List.map s_pat ps))
+    | P_tup ps -> re (P_tup (List.map s_pat ps))
+    | P_list ps -> re (P_list (List.map s_pat ps))
+  and s_fpat (FP_aux (FP_Fpat (id, p), (l,annot))) =
+    FP_aux (FP_Fpat (id, s_pat p), (l,s_tannot annot))
+  in*)
+  let rec s_exp (E_aux (e,(l,annot))) =
+    let re e = E_aux (e,(l,(*s_tannot*) annot)) in
+      match e with
+      | E_block es -> re (E_block (List.map s_exp es))
+      | E_nondet es -> re (E_nondet (List.map s_exp es))
+      | E_id _
+      | E_lit _
+      | E_comment _ -> re e
+      | E_sizeof ne -> re (E_sizeof ne) (* TODO: do this need done?  does it appear in type checked code? *)
+      | E_internal_exp (l,annot) -> re (E_internal_exp (l, (*s_tannot*) annot))
+      | E_sizeof_internal (l,annot) -> re (E_sizeof_internal (l, (*s_tannot*) annot))
+      | E_internal_exp_user ((l1,annot1),(l2,annot2)) ->
+         re (E_internal_exp_user ((l1, (*s_tannot*) annot1),(l2, (*s_tannot*) annot2)))
+      | E_cast (t,e') -> re (E_cast (t, s_exp e'))
+      | E_app (id,es) ->
+         let es' = List.map s_exp es in
+         let arg =
+           match es' with
+           | [] -> E_aux (E_lit (L_aux (L_unit,Unknown)),(l,None))
+           | [e] -> e
+           | _ -> E_aux (E_tuple es',(l,None))
+         in
+         let i = id_to_string id in
+         let id' = 
+           let env = match annot with Some (e,_,_) -> e | None -> failwith "env" in
+           match Env.lookup_id id env with
+           | Union (qs,Typ_aux (Typ_fn(inty,outty,_),_)) ->
+              (match refine_constructor refinements i substs arg inty with
+              | None -> id
+              | Some i -> Id_aux (Id i,Generated l))
+           | _ -> id
+         in re (E_app (id',es'))
+      | E_app_infix (e1,id,e2) -> re (E_app_infix (s_exp e1,id,s_exp e2))
+      | E_tuple es -> re (E_tuple (List.map s_exp es))
+      | E_if (e1,e2,e3) -> re (E_if (s_exp e1, s_exp e2, s_exp e3))
+      | E_for (id,e1,e2,e3,ord,e4) -> re (E_for (id,s_exp e1,s_exp e2,s_exp e3,ord,s_exp e4))
+      | E_vector es -> re (E_vector (List.map s_exp es))
+      | E_vector_indexed (ies,ed) -> re (E_vector_indexed (List.map (fun (i,e) -> (i,s_exp e)) ies,
+                                                           s_opt_default ed))
+      | E_vector_access (e1,e2) -> re (E_vector_access (s_exp e1,s_exp e2))
+      | E_vector_subrange (e1,e2,e3) -> re (E_vector_subrange (s_exp e1,s_exp e2,s_exp e3))
+      | E_vector_update (e1,e2,e3) -> re (E_vector_update (s_exp e1,s_exp e2,s_exp e3))
+      | E_vector_update_subrange (e1,e2,e3,e4) -> re (E_vector_update_subrange (s_exp e1,s_exp e2,s_exp e3,s_exp e4))
+      | E_vector_append (e1,e2) -> re (E_vector_append (s_exp e1,s_exp e2))
+      | E_list es -> re (E_list (List.map s_exp es))
+      | E_cons (e1,e2) -> re (E_cons (s_exp e1,s_exp e2))
+      | E_record fes -> re (E_record (s_fexps fes))
+      | E_record_update (e,fes) -> re (E_record_update (s_exp e, s_fexps fes))
+      | E_field (e,id) -> re (E_field (s_exp e,id))
+      | E_case (e,cases) -> re (E_case (s_exp e, List.map s_pexp cases))
+      | E_let (lb,e) -> re (E_let (s_letbind lb, s_exp e))
+      | E_assign (le,e) -> re (E_assign (s_lexp le, s_exp e))
+      | E_exit e -> re (E_exit (s_exp e))
+      | E_return e -> re (E_return (s_exp e))
+      | E_assert (e1,e2) -> re (E_assert (s_exp e1,s_exp e2))
+      | E_internal_cast ((l,ann),e) -> re (E_internal_cast ((l,(*s_tannot*) ann),s_exp e))
+      | E_comment_struc e -> re (E_comment_struc e)
+      | E_internal_let (le,e1,e2) -> re (E_internal_let (s_lexp le, s_exp e1, s_exp e2))
+      | E_internal_plet (p,e1,e2) -> re (E_internal_plet ((*s_pat*) p, s_exp e1, s_exp e2))
+      | E_internal_return e -> re (E_internal_return (s_exp e))
+    and s_opt_default (Def_val_aux (ed,(l,annot))) =
+      match ed with
+      | Def_val_empty -> Def_val_aux (Def_val_empty,(l,(*s_tannot*) annot))
+      | Def_val_dec e -> Def_val_aux (Def_val_dec (s_exp e),(l,(*s_tannot*) annot))
+    and s_fexps (FES_aux (FES_Fexps (fes,flag), (l,annot))) =
+      FES_aux (FES_Fexps (List.map s_fexp fes, flag), (l,(*s_tannot*) annot))
+    and s_fexp (FE_aux (FE_Fexp (id,e), (l,annot))) =
+      FE_aux (FE_Fexp (id,s_exp e),(l,(*s_tannot*) annot))
+    and s_pexp (Pat_aux (Pat_exp (p,e),(l,annot))) =
+      Pat_aux (Pat_exp ((*s_pat*) p, s_exp e),(l,(*s_tannot*) annot))
+    and s_letbind (LB_aux (lb,(l,annot))) =
+      match lb with
+      | LB_val_explicit (tysch,p,e) ->
+         LB_aux (LB_val_explicit ((*s_typschm*) tysch,(*s_pat*) p,s_exp e), (l,(*s_tannot*) annot))
+      | LB_val_implicit (p,e) -> LB_aux (LB_val_implicit ((*s_pat*) p,s_exp e), (l,(*s_tannot*) annot))
+    and s_lexp (LEXP_aux (e,(l,annot))) =
+      let re e = LEXP_aux (e,(l,(*s_tannot*) annot)) in
+      match e with
+      | LEXP_id _
+      | LEXP_cast _
+        -> re e
+      | LEXP_memory (id,es) -> re (LEXP_memory (id,List.map s_exp es))
+      | LEXP_tup les -> re (LEXP_tup (List.map s_lexp les))
+      | LEXP_vector (le,e) -> re (LEXP_vector (s_lexp le, s_exp e))
+      | LEXP_vector_range (le,e1,e2) -> re (LEXP_vector_range (s_lexp le, s_exp e1, s_exp e2))
+      | LEXP_field (le,id) -> re (LEXP_field (s_lexp le, id))
+  in ((fun x -> x (*s_pat*)),s_exp)
+let nexp_subst_pat substs refinements = fst (nexp_subst_fns substs refinements)
+let nexp_subst_exp substs refinements = snd (nexp_subst_fns substs refinements)
+
+let bindings_from_pat p =
+  let rec aux_pat (P_aux (p,(l,annot))) =
+    let env = match annot with Some (e,_,_) -> e | None -> failwith "env" in
+    match p with
+    | P_lit _
+    | P_wild
+      -> []
+    | P_as (p,id) -> id::(aux_pat p)
+    | P_typ (_,p) -> aux_pat p
+    | P_id id ->
+       if pat_id_is_variable env id then [id] else []
+    | P_vector ps
+    | P_vector_concat ps
+    | P_app (_,ps)
+    | P_tup ps
+    | P_list ps
+      -> List.concat (List.map aux_pat ps)
+    | P_record (fps,_) -> List.concat (List.map aux_fpat fps)
+    | P_vector_indexed ips -> List.concat (List.map (fun (_,p) -> aux_pat p) ips)
+  and aux_fpat (FP_aux (FP_Fpat (_,p), _)) = aux_pat p
+  in aux_pat p
+
+let remove_bound env pat =
+  let bound = bindings_from_pat pat in
+  List.fold_left (fun sub v -> ISubst.remove v env) env bound
+
+(* We may need to split up a pattern match if (1) we've been told to case split
+   on a variable by the user, or (2) we monomorphised a constructor that's used
+   in the pattern. *)
+type split =
+  | NoSplit
+  | VarSplit of (tannot pat * (id * tannot Ast.exp)) list
+  | ConstrSplit of (tannot pat * nexp KSubst.t) list
+
+let split_defs splits (Type_check.Env (d_env,t_env,b_env,tp_env)) defs =
+  let split_constructors (Defs defs) =
+    let sc_type_union q (Tu_aux (tu,l) as tua) =
+      match tu with
+      | Tu_id id -> [],[tua]
+      | Tu_ty_id (ty,id) ->
+         let i = id_to_string id in
+         (match split_src_type i ty q with
+         | None -> ([],[Tu_aux (Tu_ty_id (ty,id),l)])
+         | Some variants ->
+            ([(i,variants)],
+             List.map (fun (insts, i') -> Tu_aux (Tu_ty_id (inst_src_type insts ty,Id_aux (Id i',Generated l)),Generated l)) variants))
+    in
+    let sc_type_def ((TD_aux (tda,annot)) as td) =
+      match tda with
+      | TD_variant (id,nscm,quant,tus,flag) ->
+         let (refinements, tus') = List.split (List.map (sc_type_union quant) tus) in
+         (List.concat refinements, TD_aux (TD_variant (id,nscm,quant,List.concat tus',flag),annot))
+      | _ -> ([],td)
+    in
+    let sc_def d =
+      match d with
+    | DEF_type td -> let (refinements,td') = sc_type_def td in (refinements, DEF_type td')
+    | _ -> ([], d)
+    in
+    let (refinements, defs') = List.split (List.map sc_def defs)
+    in (List.concat refinements, Defs defs')
+  in
+
+  let (refinements, defs') = split_constructors defs in
+
+  (* Attempt simple pattern matches *)
+  let can_match (E_aux (e,(l,annot)) as exp0) cases =
+    let (env,ty) = match annot with Some (env,ty,_) -> env,ty | None -> failwith "env" in
+    match e with
+    | E_id id ->
+       let i = id_to_string id in
+       (match Env.lookup_id id env with
+       | Enum _ ->
+          let rec findpat cases =
+            match cases with
+            | [] -> (Reporting_basic.print_err false true l "Monomorphisation"
+                       ("Failed to find a case for " ^ i); None)
+            | [Pat_aux (Pat_exp (P_aux (P_wild,_),exp),_)] -> Some (exp,[])
+            | (Pat_aux (Pat_exp (P_aux (P_typ (_,p),_),exp),ann))::tl ->
+               findpat ((Pat_aux (Pat_exp (p,exp),ann))::tl)
+            | (Pat_aux (Pat_exp (P_aux (P_id id',_),exp),_))::tl
+                when pat_id_is_variable env id' ->
+               Some (exp, [(id', exp0)])
+            | (Pat_aux (Pat_exp (P_aux (P_id id',_),exp),_))::tl
+            | (Pat_aux (Pat_exp (P_aux (P_app (id',[]),_),exp),_))::tl ->
+               if i = id_to_string id' then Some (exp,[]) else findpat tl
+            | (Pat_aux (Pat_exp (P_aux (_,(l',_)),_),_))::_ ->
+               (Reporting_basic.print_err false true l' "Monomorphisation"
+                  "Unexpected kind of pattern for enumeration"; None)
+          in findpat cases
+       | _ -> None)
+    (* TODO: could generalise Lit matching *)
+    | E_lit (L_aux ((L_zero | L_one | L_true | L_false) as bit, _)) ->
+       let rec findpat cases =
+         match cases with
+         | [] -> (Reporting_basic.print_err false true l "Monomorphisation"
+                    ("Failed to find a case for bit"); None)
+         | [Pat_aux (Pat_exp (P_aux (P_wild,_),exp),_)] -> Some (exp,[])
+         | (Pat_aux (Pat_exp (P_aux (P_typ (_,p),_),exp),ann))::tl ->
+            findpat ((Pat_aux (Pat_exp (p,exp),ann))::tl)
+         | (Pat_aux (Pat_exp (P_aux (P_id id',_),exp),_))::tl
+             when pat_id_is_variable env id' ->
+            Some (exp, [(id', exp0)])
+         | (Pat_aux (Pat_exp (P_aux (P_lit (L_aux (lit, _)),_),exp),_))::tl ->
+            (match bit,lit with
+            | (L_zero | L_false), (L_zero | L_false) -> Some (exp,[])
+            | (L_one  | L_true ), (L_one  | L_true ) -> Some (exp,[])
+            | _ -> findpat tl)
+         | (Pat_aux (Pat_exp (P_aux (_,(l',_)),_),_))::_ ->
+            (Reporting_basic.print_err false true l' "Monomorphisation"
+               "Unexpected kind of pattern for bit"; None)
+       in findpat cases
+    | _ -> None
+  in
+
+  (* Similarly, simple conditionals *)
+  (* TODO: doublecheck *)
+  let lit_eq (L_aux (l1,_)) (L_aux (l2,_)) =
+    match l1,l2 with
+    | (L_zero|L_false), (L_zero|L_false)
+    | (L_one |L_true ), (L_one |L_true)
+      -> Some true
+    | L_undef, _ | _, L_undef -> None
+    | _ -> Some (l1 = l2)
+  in
+
+  (* TODO: any useful type information revealed? (probably not) *)
+  let try_app_infix (l,ann) (E_aux (e1,ann1)) id (E_aux (e2,ann2)) =
+    let new_l = Generated l in
+    match e1, id, e2 with
+    | E_lit l1, ("=="|"!="), E_lit l2 ->
+       let lit b = if b then L_true else L_false in
+       let lit b = lit (if id = "==" then b else not b) in
+       (match lit_eq l1 l2 with
+       | Some b -> Some (E_aux (E_lit (L_aux (lit b,new_l)), (l,ann)))
+       | None -> None)
+    | _ -> None
+  in
+
+  (* Extract nvar substitution by comparing two types *)
+  let build_nexp_subst l t1 t2 = [] (*
+    let rec from_types t1 t2 =
+      let t1 = match t1.t with Tabbrev(_,t) -> t | _ -> t1 in
+      let t2 = match t2.t with Tabbrev(_,t) -> t | _ -> t2 in
+      if t1 = t2 then [] else
+        match t1.t,t2.t with
+        | Tapp (s1,args1), Tapp (s2,args2) ->
+           if s1 = s2 then
+             List.concat (List.map2 from_args args1 args2)
+           else (Reporting_basic.print_err false true l "Monomorphisation"
+                   "Unexpected type mismatch"; [])
+        | Ttup ts1, Ttup ts2 ->
+           if List.length ts1 = List.length ts2 then
+             List.concat (List.map2 from_types ts1 ts2)
+           else (Reporting_basic.print_err false true l "Monomorphisation"
+                   "Unexpected type mismatch"; [])
+        | _ -> []
+    and from_args arg1 arg2 =
+    match arg1,arg2 with
+    | TA_typ t1, TA_typ t2 -> from_types t1 t2
+    | TA_nexp n1, TA_nexp n2 -> from_nexps n1 n2
+    | _ -> []
+    and from_nexps n1 n2 =
+      match n1.nexp, n2.nexp with
+      | Nvar s, Nvar s' when s = s' -> []
+      | Nvar s, _ -> [(s,n2)]
+      | Nadd (n3,n4), Nadd (n5,n6)
+      | Nsub (n3,n4), Nsub (n5,n6)
+      | Nmult (n3,n4), Nmult (n5,n6)
+        -> from_nexps n3 n5 @ from_nexps n4 n6
+      | N2n (n3,p1), N2n (n4,p2) when p1 = p2 -> from_nexps n3 n4
+      | Npow (n3,p1), Npow (n4,p2) when p1 = p2 -> from_nexps n3 n4
+      | Nneg n3, Nneg n4 -> from_nexps n3 n4
+      | _ -> []
+    in match t1,t2 with
+    | Base ((_,t1),_,_,_,_,_),Base ((_,t2),_,_,_,_,_) -> from_types t1 t2
+    | _ -> []*)
+  in
+
+  let nexp_substs = ref [] in
+
+  (* Constant propogation *)
+  let rec const_prop_exp substs ((E_aux (e,(l,annot))) as exp) =
+    let re e = E_aux (e,(l,annot)) in
+    match e with
+      (* TODO: are there more circumstances in which we should get rid of these? *)
+    | E_block [e] -> const_prop_exp substs e
+    | E_block es -> re (E_block (List.map (const_prop_exp substs) es))
+    | E_nondet es -> re (E_nondet (List.map (const_prop_exp substs) es))
+       
+    | E_id id ->
+       (try ISubst.find id substs
+        with Not_found -> exp)
+    | E_lit _
+    | E_sizeof _
+    | E_internal_exp _
+    | E_sizeof_internal _
+    | E_internal_exp_user _
+    | E_comment _
+      -> exp
+    | E_cast (t,e') -> re (E_cast (t, const_prop_exp substs e'))
+    | E_app (id,es) ->
+       let es' = List.map (const_prop_exp substs) es in
+       (match const_prop_try_fn (id,es') with
+       | None -> re (E_app (id,es'))
+       | Some r -> r)
+    | E_app_infix (e1,id,e2) ->
+       let e1',e2' = const_prop_exp substs e1,const_prop_exp substs e2 in
+       (match try_app_infix (l,annot) e1' (id_to_string id) e2' with
+       | Some exp -> exp
+       | None -> re (E_app_infix (e1',id,e2')))
+    | E_tuple es -> re (E_tuple (List.map (const_prop_exp substs) es))
+    | E_if (e1,e2,e3) ->
+       let e1' = const_prop_exp substs e1 in
+       let e2',e3' = const_prop_exp substs e2, const_prop_exp substs e3 in
+       (match e1' with
+       | E_aux (E_lit (L_aux ((L_true|L_false) as lit ,_)),_) ->
+          let e' = match lit with L_true -> e2' | _ -> e3' in
+          (match e' with E_aux (_,(_,annot')) ->
+            nexp_substs := build_nexp_subst l annot annot' @ !nexp_substs;
+            e')
+       | _ -> re (E_if (e1',e2',e3')))
+    | E_for (id,e1,e2,e3,ord,e4) -> re (E_for (id,const_prop_exp substs e1,const_prop_exp substs e2,const_prop_exp substs e3,ord,const_prop_exp (ISubst.remove id substs) e4))
+    | E_vector es -> re (E_vector (List.map (const_prop_exp substs) es))
+    | E_vector_indexed (ies,ed) -> re (E_vector_indexed (List.map (fun (i,e) -> (i,const_prop_exp substs e)) ies,
+                                                         const_prop_opt_default substs ed))
+    | E_vector_access (e1,e2) -> re (E_vector_access (const_prop_exp substs e1,const_prop_exp substs e2))
+    | E_vector_subrange (e1,e2,e3) -> re (E_vector_subrange (const_prop_exp substs e1,const_prop_exp substs e2,const_prop_exp substs e3))
+    | E_vector_update (e1,e2,e3) -> re (E_vector_update (const_prop_exp substs e1,const_prop_exp substs e2,const_prop_exp substs e3))
+    | E_vector_update_subrange (e1,e2,e3,e4) -> re (E_vector_update_subrange (const_prop_exp substs e1,const_prop_exp substs e2,const_prop_exp substs e3,const_prop_exp substs e4))
+    | E_vector_append (e1,e2) -> re (E_vector_append (const_prop_exp substs e1,const_prop_exp substs e2))
+    | E_list es -> re (E_list (List.map (const_prop_exp substs) es))
+    | E_cons (e1,e2) -> re (E_cons (const_prop_exp substs e1,const_prop_exp substs e2))
+    | E_record fes -> re (E_record (const_prop_fexps substs fes))
+    | E_record_update (e,fes) -> re (E_record_update (const_prop_exp substs e, const_prop_fexps substs fes))
+    | E_field (e,id) -> re (E_field (const_prop_exp substs e,id))
+    | E_case (e,cases) ->
+       let e' = const_prop_exp substs e in
+       (match can_match e' cases with
+       | None -> re (E_case (e', List.map (const_prop_pexp substs) cases))
+       | Some (E_aux (_,(_,annot')) as exp,newbindings) ->
+          let newbindings_env = isubst_from_list newbindings in
+          let substs' = ISubst.union (fun _ _ s -> Some s) substs newbindings_env in
+          nexp_substs := build_nexp_subst l annot annot' @ !nexp_substs;
+          const_prop_exp substs' exp)
+    | E_let (lb,e) ->
+       let (lb',substs') = const_prop_letbind substs lb in
+       re (E_let (lb', const_prop_exp substs' e))
+    | E_assign (le,e) -> re (E_assign (const_prop_lexp substs le, const_prop_exp substs e))
+    | E_exit e -> re (E_exit (const_prop_exp substs e))
+    | E_return e -> re (E_return (const_prop_exp substs e))
+    | E_assert (e1,e2) -> re (E_assert (const_prop_exp substs e1,const_prop_exp substs e2))
+    | E_internal_cast (ann,e) -> re (E_internal_cast (ann,const_prop_exp substs e))
+    | E_comment_struc e -> re (E_comment_struc e)
+    | E_internal_let _
+    | E_internal_plet _
+    | E_internal_return _
+      -> raise (Reporting_basic.err_unreachable l
+                  "Unexpected internal expression encountered in monomorphisation")
+    and const_prop_opt_default substs ((Def_val_aux (ed,annot)) as eda) =
+    match ed with
+    | Def_val_empty -> eda
+    | Def_val_dec e -> Def_val_aux (Def_val_dec (const_prop_exp substs e),annot)
+  and const_prop_fexps substs (FES_aux (FES_Fexps (fes,flag), annot)) =
+    FES_aux (FES_Fexps (List.map (const_prop_fexp substs) fes, flag), annot)
+  and const_prop_fexp substs (FE_aux (FE_Fexp (id,e), annot)) =
+    FE_aux (FE_Fexp (id,const_prop_exp substs e),annot)
+  and const_prop_pexp substs (Pat_aux (Pat_exp (p,e),l)) =
+    Pat_aux (Pat_exp (p,const_prop_exp (remove_bound substs p) e),l)
+  and const_prop_letbind substs (LB_aux (lb,annot)) =
+    match lb with
+    | LB_val_explicit (tysch,p,e) ->
+       (LB_aux (LB_val_explicit (tysch,p,const_prop_exp substs e), annot),
+        remove_bound substs p)
+    | LB_val_implicit (p,e) ->
+       (LB_aux (LB_val_implicit (p,const_prop_exp substs e), annot),
+        remove_bound substs p)
+  and const_prop_lexp substs ((LEXP_aux (e,annot)) as le) =
+    let re e = LEXP_aux (e,annot) in
+    match e with
+    | LEXP_id _ (* shouldn't end up substituting here *)
+    | LEXP_cast _
+      -> le
+    | LEXP_memory (id,es) -> re (LEXP_memory (id,List.map (const_prop_exp substs) es)) (* or here *)
+    | LEXP_tup les -> re (LEXP_tup (List.map (const_prop_lexp substs) les))
+    | LEXP_vector (le,e) -> re (LEXP_vector (const_prop_lexp substs le, const_prop_exp substs e))
+    | LEXP_vector_range (le,e1,e2) -> re (LEXP_vector_range (const_prop_lexp substs le, const_prop_exp substs e1, const_prop_exp substs e2))
+    | LEXP_field (le,id) -> re (LEXP_field (const_prop_lexp substs le, id))
+  (* Reduce a function when
+     1. all arguments are values,
+     2. the function is pure,
+     3. the result is a value
+     (and 4. the function is not scattered, but that's not terribly important)
+     to try and keep execution time and the results managable.
+  *)
+  and const_prop_try_fn (id,args) =
+    if not (List.for_all is_value args) then
+      None
+    else
+      let i = id_to_string id in
+      let Defs ds = defs in
+      match list_extract (function
+      | (DEF_fundef (FD_aux (FD_function (_,_,eff,((FCL_aux (FCL_Funcl (id',_,_),_))::_ as fcls)),_)))
+        -> if i = id_to_string id' then Some (eff,fcls) else None
+      | _ -> None) ds with
+      | None -> None
+      | Some (eff,_) when not (is_pure eff) -> None
+      | Some (_,fcls) ->
+         let arg = match args with
+           | [] -> E_aux (E_lit (L_aux (L_unit,Unknown)),(Unknown,None))
+           | [e] -> e
+           | _ -> E_aux (E_tuple args,(Unknown,None)) in
+         let cases = List.map (function
+           | FCL_aux (FCL_Funcl (_,pat,exp), ann) -> Pat_aux (Pat_exp (pat,exp),ann))
+           fcls in
+         match can_match arg cases with
+         | Some (exp,bindings) ->
+            let substs = isubst_from_list bindings in
+            let result = const_prop_exp substs exp in
+            if is_value result then Some result else None
+         | None -> None
+  in
+
+  let subst_exp subst exp =
+    if !disable_const_propagation then
+    (* TODO: This just sticks a let in - we really need propogation *)
+      let (subi,(E_aux (_,subannot) as sube)) = subst in
+      let E_aux (e,(l,annot)) = exp in
+      let lg = Generated l in
+      let id = match subi with Id_aux (i,l) -> Id_aux (i,lg) in
+      let p = P_aux (P_id id, subannot) in
+      E_aux (E_let (LB_aux (LB_val_implicit (p,sube),(lg,annot)), exp),(lg,annot))
+    else 
+      let substs = isubst_from_list [subst] in
+      let () = nexp_substs := [] in
+      let exp' = const_prop_exp substs exp in
+      (* Substitute what we've learned about nvars into the term *)
+      let nsubsts = isubst_from_list !nexp_substs in
+      let () = nexp_substs := [] in
+      nexp_subst_exp nsubsts refinements exp'
+  in
+    
+let env_some_enum_lookup _ _ = None in
+  (* Split a variable pattern into every possible value *)
+
+  let split var env (Typ_aux (ty,l) as typ) =
+    let new_l = Generated l in
+    let new_id i = Id_aux (Id i, new_l) in
+    let v = string_of_id var in
+    let cannot () =
+      raise (Reporting_basic.err_general l
+               ("Cannot split type " ^ string_of_typ typ ^ " for variable " ^ v))
+    in
+    match ty with
+    | Typ_id id ->
+       (match env_some_enum_lookup id env with
+          (* enumerations *)
+       | Some ns -> List.map (fun n -> (P_aux (P_id (new_id n),(l,None)),
+                                        (var,E_aux (E_id (new_id n),(new_l,None))))) ns
+       | None ->
+          if id_to_string id = "bit" then
+            List.map (fun b ->
+              P_aux (P_lit (L_aux (b,new_l)),(l,None)),
+              (var,E_aux (E_lit (L_aux (b,new_l)),(new_l, None))))
+              [L_zero; L_one]
+          else cannot ())
+       (*|  vectors TODO *)
+       (*|  numbers TODO *)
+    | _ -> cannot ()
+  in
+  
+  (* Split variable patterns at the given locations *)
+
+  let map_locs ls (Defs defs) =
+    let rec match_l = function
+      | Unknown
+      | Int _ -> []
+      | Generated l -> [] (* Could do match_l l, but only want to split user-written patterns *)
+      | Range (p,q) ->
+         List.filter (fun ((filename,line),_) ->
+           Filename.basename p.Lexing.pos_fname = filename &&
+             p.Lexing.pos_lnum <= line && line <= q.Lexing.pos_lnum) ls
+    in 
+
+    let split_pat var p =
+      let rec list f = function
+        | [] -> None
+        | h::t ->
+           match f h with
+           | None -> (match list f t with None -> None | Some (l,ps,r) -> Some (h::l,ps,r))
+           | Some ps -> Some ([],ps,t)
+      in
+      let rec spl (P_aux (p,(l,annot))) =
+        let relist f ctx ps =
+          optmap (list f ps) 
+            (fun (left,ps,right) ->
+              List.map (fun (p,sub) -> P_aux (ctx (left@p::right),(l,annot)),sub) ps)
+        in
+        let re f p =
+          optmap (spl p)
+            (fun ps -> List.map (fun (p,sub) -> (P_aux (f p,(l,annot)), sub)) ps)
+        in
+        let fpat (FP_aux ((FP_Fpat (id,p),annot))) =
+          optmap (spl p)
+            (fun ps -> List.map (fun (p,sub) -> FP_aux (FP_Fpat (id,p), annot), sub) ps)
+        in
+        let ipat (i,p) = optmap (spl p) (List.map (fun (p,sub) -> (i,p),sub))
+        in
+        match p with
+        | P_lit _
+        | P_wild
+          -> None
+        | P_as (p',id) ->
+           let i = id_to_string id in
+           if i = var
+           then raise (Reporting_basic.err_general l
+                         ("Cannot split " ^ var ^ " on 'as' pattern"))
+           else re (fun p -> P_as (p,id)) p'
+        | P_typ (t,p') -> re (fun p -> P_typ (t,p)) p'
+        | P_id id ->
+           let i = id_to_string id in
+           if i = var
+           then
+             match annot with
+             | Some (env,ty,_) -> Some (split id env ty)
+             | None -> raise (Reporting_basic.err_general l
+                                ("Missing type environment when splitting " ^ var))
+           else None
+        | P_app (id,ps) ->
+           relist spl (fun ps -> P_app (id,ps)) ps
+        | P_record (fps,flag) ->
+           relist fpat (fun fps -> P_record (fps,flag)) fps
+        | P_vector ps ->
+           relist spl (fun ps -> P_vector ps) ps
+        | P_vector_indexed ips ->
+           relist ipat (fun ips -> P_vector_indexed ips) ips
+        | P_vector_concat ps ->
+           relist spl (fun ps -> P_vector_concat ps) ps
+        | P_tup ps ->
+           relist spl (fun ps -> P_tup ps) ps
+        | P_list ps ->
+           relist spl (fun ps -> P_list ps) ps
+      in spl p
+    in
+
+    let map_pat_by_loc (P_aux (p,(l,_)) as pat) =
+      match match_l l with
+      | [] -> None
+      | [(_,var)] -> split_pat var pat
+      | lvs -> raise (Reporting_basic.err_general l
+                        ("Multiple variables to split on: " ^ String.concat ", " (List.map snd lvs)))
+    in
+    let map_pat (P_aux (p,(l,tannot)) as pat) =
+      match map_pat_by_loc pat with
+      | Some l -> VarSplit l
+      | None ->
+         match p with
+         | P_app (id,args) ->
+            (try
+              let i = id_to_string id in
+              let variants = List.assoc i refinements in
+              let env = match tannot with Some (env,_,_) -> env | None -> failwith "env" in
+              let constr_out_typ =
+                match Env.lookup_id id env with
+                | Union (qs,Typ_aux (Typ_fn(_,outt,_),_)) -> outt
+                | _ -> raise (Reporting_basic.err_general l
+                                ("Constructor " ^ i ^ " is not a construtor!"))
+              in
+              let varmap = build_nexp_subst l constr_out_typ tannot in
+              let map_inst (insts,i') =
+                let insts = List.map (fun (v,i) ->
+                  ((match List.assoc (string_of_kid v) varmap with
+                  | Nexp_aux (Nexp_var s, _) -> s
+                  | _ -> raise (Reporting_basic.err_general l
+                                  ("Constructor parameter not a variable: " ^ string_of_kid v))),
+                   Nexp_aux (Nexp_constant i,Generated l)))
+                  insts in
+                P_aux (P_app (Id_aux (Id i',Generated l),args),(Generated l,tannot)),
+                ksubst_from_list insts
+              in
+              ConstrSplit (List.map map_inst variants)
+            with Not_found -> NoSplit)
+         | _ -> NoSplit
+    in
+
+    let check_single_pat (P_aux (_,(l,annot)) as p) =
+      match match_l l with
+      | [] -> p
+      | lvs ->
+         let pvs = bindings_from_pat p in
+         let pvs = List.map string_of_id pvs in
+         let overlap = List.exists (fun (_,v) -> List.mem v pvs) lvs in
+         let () =
+           if overlap then
+             Reporting_basic.print_err false true l "Monomorphisation"
+               "Splitting a singleton pattern is not possible"
+         in p
+    in
+
+    let rec map_exp ((E_aux (e,annot)) as ea) =
+      let re e = E_aux (e,annot) in
+      match e with
+      | E_block es -> re (E_block (List.map map_exp es))
+      | E_nondet es -> re (E_nondet (List.map map_exp es))
+      | E_id _
+      | E_lit _
+      | E_sizeof _
+      | E_internal_exp _
+      | E_sizeof_internal _
+      | E_internal_exp_user _
+      | E_comment _
+        -> ea
+      | E_cast (t,e') -> re (E_cast (t, map_exp e'))
+      | E_app (id,es) -> re (E_app (id,List.map map_exp es))
+      | E_app_infix (e1,id,e2) -> re (E_app_infix (map_exp e1,id,map_exp e2))
+      | E_tuple es -> re (E_tuple (List.map map_exp es))
+      | E_if (e1,e2,e3) -> re (E_if (map_exp e1, map_exp e2, map_exp e3))
+      | E_for (id,e1,e2,e3,ord,e4) -> re (E_for (id,map_exp e1,map_exp e2,map_exp e3,ord,map_exp e4))
+      | E_vector es -> re (E_vector (List.map map_exp es))
+      | E_vector_indexed (ies,ed) -> re (E_vector_indexed (List.map (fun (i,e) -> (i,map_exp e)) ies,
+                                                           map_opt_default ed))
+      | E_vector_access (e1,e2) -> re (E_vector_access (map_exp e1,map_exp e2))
+      | E_vector_subrange (e1,e2,e3) -> re (E_vector_subrange (map_exp e1,map_exp e2,map_exp e3))
+      | E_vector_update (e1,e2,e3) -> re (E_vector_update (map_exp e1,map_exp e2,map_exp e3))
+      | E_vector_update_subrange (e1,e2,e3,e4) -> re (E_vector_update_subrange (map_exp e1,map_exp e2,map_exp e3,map_exp e4))
+      | E_vector_append (e1,e2) -> re (E_vector_append (map_exp e1,map_exp e2))
+      | E_list es -> re (E_list (List.map map_exp es))
+      | E_cons (e1,e2) -> re (E_cons (map_exp e1,map_exp e2))
+      | E_record fes -> re (E_record (map_fexps fes))
+      | E_record_update (e,fes) -> re (E_record_update (map_exp e, map_fexps fes))
+      | E_field (e,id) -> re (E_field (map_exp e,id))
+      | E_case (e,cases) -> re (E_case (map_exp e, List.concat (List.map map_pexp cases)))
+      | E_let (lb,e) -> re (E_let (map_letbind lb, map_exp e))
+      | E_assign (le,e) -> re (E_assign (map_lexp le, map_exp e))
+      | E_exit e -> re (E_exit (map_exp e))
+      | E_return e -> re (E_return (map_exp e))
+      | E_assert (e1,e2) -> re (E_assert (map_exp e1,map_exp e2))
+      | E_internal_cast (ann,e) -> re (E_internal_cast (ann,map_exp e))
+      | E_comment_struc e -> re (E_comment_struc e)
+      | E_internal_let (le,e1,e2) -> re (E_internal_let (map_lexp le, map_exp e1, map_exp e2))
+      | E_internal_plet (p,e1,e2) -> re (E_internal_plet (check_single_pat p, map_exp e1, map_exp e2))
+      | E_internal_return e -> re (E_internal_return (map_exp e))
+    and map_opt_default ((Def_val_aux (ed,annot)) as eda) =
+      match ed with
+      | Def_val_empty -> eda
+      | Def_val_dec e -> Def_val_aux (Def_val_dec (map_exp e),annot)
+    and map_fexps (FES_aux (FES_Fexps (fes,flag), annot)) =
+      FES_aux (FES_Fexps (List.map map_fexp fes, flag), annot)
+    and map_fexp (FE_aux (FE_Fexp (id,e), annot)) =
+      FE_aux (FE_Fexp (id,map_exp e),annot)
+    and map_pexp (Pat_aux (Pat_exp (p,e),l)) =
+      match map_pat p with
+      | NoSplit -> [Pat_aux (Pat_exp (p,map_exp e),l)]
+      | VarSplit patsubsts ->
+         List.map (fun (pat',subst) ->
+           let exp' = subst_exp subst e in
+           Pat_aux (Pat_exp (pat', map_exp exp'),l))
+           patsubsts
+      | ConstrSplit patnsubsts ->
+         List.map (fun (pat',nsubst) ->
+           (* Leave refinements to later *)
+           let pat' = nexp_subst_pat nsubst [] pat' in
+           let exp' = nexp_subst_exp nsubst [] e in
+           Pat_aux (Pat_exp (pat', map_exp exp'),l)
+         ) patnsubsts
+    and map_letbind (LB_aux (lb,annot)) =
+      match lb with
+      | LB_val_explicit (tysch,p,e) -> LB_aux (LB_val_explicit (tysch,check_single_pat p,map_exp e), annot)
+      | LB_val_implicit (p,e) -> LB_aux (LB_val_implicit (check_single_pat p,map_exp e), annot)
+    and map_lexp ((LEXP_aux (e,annot)) as le) =
+      let re e = LEXP_aux (e,annot) in
+      match e with
+      | LEXP_id _
+      | LEXP_cast _
+        -> le
+      | LEXP_memory (id,es) -> re (LEXP_memory (id,List.map map_exp es))
+      | LEXP_tup les -> re (LEXP_tup (List.map map_lexp les))
+      | LEXP_vector (le,e) -> re (LEXP_vector (map_lexp le, map_exp e))
+      | LEXP_vector_range (le,e1,e2) -> re (LEXP_vector_range (map_lexp le, map_exp e1, map_exp e2))
+      | LEXP_field (le,id) -> re (LEXP_field (map_lexp le, id))
+    in
+
+    let map_funcl (FCL_aux (FCL_Funcl (id,pat,exp),annot)) =
+      match map_pat pat with
+      | NoSplit -> [FCL_aux (FCL_Funcl (id, pat, map_exp exp), annot)]
+      | VarSplit patsubsts ->
+         List.map (fun (pat',subst) ->
+           let exp' = subst_exp subst exp in
+           FCL_aux (FCL_Funcl (id, pat', map_exp exp'), annot))
+           patsubsts
+      | ConstrSplit patnsubsts ->
+         List.map (fun (pat',nsubst) ->
+           (* Leave refinements to later *)
+           let pat' = nexp_subst_pat nsubst [] pat' in
+           let exp' = nexp_subst_exp nsubst [] exp in
+           FCL_aux (FCL_Funcl (id, pat', map_exp exp'), annot)
+         ) patnsubsts
+    in
+
+    let map_fundef (FD_aux (FD_function (r,t,e,fcls),annot)) =
+      FD_aux (FD_function (r,t,e,List.concat (List.map map_funcl fcls)),annot)
+    in
+    let map_scattered_def sd =
+      match sd with
+      | SD_aux (SD_scattered_funcl fcl, annot) ->
+         List.map (fun fcl' -> SD_aux (SD_scattered_funcl fcl', annot)) (map_funcl fcl)
+      | _ -> [sd]
+    in
+    let map_def d =
+      match d with
+      | DEF_kind _
+      | DEF_type _
+      | DEF_spec _
+      | DEF_default _
+      | DEF_reg_dec _
+      | DEF_comm _
+      | DEF_overload _
+        -> [d]
+      | DEF_fundef fd -> [DEF_fundef (map_fundef fd)]
+      | DEF_val lb -> [DEF_val (map_letbind lb)]
+      | DEF_scattered sd -> List.map (fun x -> DEF_scattered x) (map_scattered_def sd)
+
+    in
+    Defs (List.concat (List.map map_def defs))
+  in
+  map_locs splits defs'
+