Rewrite pre_postconditions to use walk instead of fold

Author: catamorphism

src/comp/middle/tstate/ck.rs

@@ -62,7 +62,7 @@ import bitvectors::promises;
 
 import annotate::annotate_crate;
 import collect_locals::mk_f_to_fn_info;
-import pre_post_conditions::check_item_fn;
+import pre_post_conditions::fn_pre_post;
 import states::find_pre_post_state_fn;
 
 fn check_states_expr(&fn_ctxt fcx, @expr e) -> () {
@@ -199,19 +199,18 @@ fn check_crate(ty::node_type_table nt, ty::ctxt cx, @crate crate) -> @crate {
     annotate_crate(ccx, *crate);
 
     /* Compute the pre and postcondition for every subexpression */
-    
-    auto fld = new_identity_fold[crate_ctxt]();
-    fld = @rec(fold_item_fn = bind check_item_fn(_,_,_,_,_,_,_) with *fld);
-    auto with_pre_postconditions =
-           fold_crate[crate_ctxt](ccx, fld, crate);
+    auto do_pre_post = walk::default_visitor();
+    do_pre_post = rec(visit_fn_pre = bind fn_pre_post(ccx, _, _, _)
+                      with do_pre_post);
+    walk::walk_crate(do_pre_post, *crate);
 
     auto fld1 = new_identity_fold[crate_ctxt]();
 
     fld1 = @rec(fold_item_fn = bind check_item_fn_state(_,_,_,_,_,_,_),
                 fold_obj     = bind check_obj_state(_,_,_,_)
                 with *fld1);
 
-    ret fold_crate[crate_ctxt](ccx, fld1, with_pre_postconditions);
+    ret fold_crate[crate_ctxt](ccx, fld1, crate);
 }
 
 //

src/comp/middle/tstate/pre_post_conditions.rs

@@ -679,18 +679,11 @@ fn find_pre_post_fn(&fn_ctxt fcx, &_fn f) -> () {
     find_pre_post_block(fcx, f.body);
 }
 
-fn check_item_fn(&crate_ctxt ccx, &span sp, &ident i, &_fn f,
-                 &vec[ty_param] ty_params,
-                 &def_id id, &ann a) -> @item {
-    log("check_item_fn:");
-    log_fn(f, i, ty_params);
-
+fn fn_pre_post(crate_ctxt ccx, &_fn f, &ident i, &def_id id) -> () {
     assert (ccx.fm.contains_key(id));
     auto fcx = rec(enclosing=ccx.fm.get(id),
                    id=id, name=i, ccx=ccx);
     find_pre_post_fn(fcx, f);  
-
-    ret @respan(sp, item_fn(i, f, ty_params, id, a));
 }
 
 //