Tighten pattern parsing on 0-ary constructors.

Author: graydon

src/boot/fe/item.ml

@@ -281,7 +281,11 @@ and parse_stmts (ps:pstate) : Ast.stmt array =
                   let parse_pat ps = either_get_left (parse_pat ps) in
                   let args =
                     match peek ps with
-                        LPAREN -> paren_comma_list parse_pat ps
+                        LPAREN ->
+                          let args = paren_comma_list parse_pat ps in
+                            if Array.length args = 0
+                            then raise (err "empty pattern argument list" ps)
+                            else args
                       | _ -> [| |]
                   in
                     Left (Ast.PAT_tag (lv, args))

src/lib/map.rs

@@ -113,10 +113,10 @@ fn mk_hashmap[K, V](&hashfn[K] hasher, &eqfn[K] eqer) -> hashmap[K, V] {
             ret util.some[V](v);
           }
         }
-        case (nil[K, V]()) {
+        case (nil[K, V]) {
           ret util.none[V];
         }
-        case (deleted[K, V]()) { }
+        case (deleted[K, V]) { }
       }
       i += 1u;
     }