Index: Python/ast.c
===================================================================
--- Python/ast.c	(revision 46757)
+++ Python/ast.c	(working copy)
@@ -1431,6 +1431,20 @@
     }
     else {
         REQ(CHILD(n, 0), LSQB);
+        if (NCH(n) == 2) {
+                /* Return a subscript with an empty Tuple */
+                asdl_seq *elts;
+                expr_ty e;
+                REQ(CHILD(n, 1), RSQB);
+                elts = asdl_seq_new(0, c->c_arena);
+                if (!elts)
+                        return NULL;
+                e = Tuple(elts, Load, LINENO(n), n->n_col_offset, c->c_arena);
+                if (!e)
+                        return NULL;
+                return Subscript(left_expr, Index(e, c->c_arena),
+                                Load, LINENO(n), n->n_col_offset, c->c_arena);
+        }
         REQ(CHILD(n, 2), RSQB);
         n = CHILD(n, 1);
         if (NCH(n) == 1) {
Index: Grammar/Grammar
===================================================================
--- Grammar/Grammar	(revision 46757)
+++ Grammar/Grammar	(working copy)
@@ -119,7 +119,7 @@
 listmaker: test ( list_for | (',' test)* [','] )
 testlist_gexp: test ( gen_for | (',' test)* [','] )
 lambdef: 'lambda' [varargslist] ':' test
-trailer: '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
+trailer: '(' [arglist] ')' | '[' [subscriptlist] ']' | '.' NAME
 subscriptlist: subscript (',' subscript)* [',']
 subscript: '.' '.' '.' | test | [test] ':' [test] [sliceop]
 sliceop: ':' [test]
Index: Modules/parsermodule.c
===================================================================
--- Modules/parsermodule.c	(revision 46757)
+++ Modules/parsermodule.c	(working copy)
@@ -2713,7 +2713,7 @@
 
 /*  trailer:
  *
- *  '(' [arglist] ')' | '[' subscriptlist ']' | '.' NAME
+ *  '(' [arglist] ')' | '[' [subscriptlist] ']' | '.' NAME
  */
 static int
 validate_trailer(node *tree)
@@ -2729,9 +2729,9 @@
                 res = validate_arglist(CHILD(tree, 1));
             break;
           case LSQB:
-            res = (validate_numnodes(tree, 3, "trailer")
-                   && validate_subscriptlist(CHILD(tree, 1))
-                   && validate_ntype(CHILD(tree, 2), RSQB));
+            res = validate_ntype(CHILD(tree, nch - 1), RSQB);
+            if (res && (nch == 3))
+                res = validate_subscriptlist(CHILD(tree, 1));
             break;
           case DOT:
             res = (validate_numnodes(tree, 2, "trailer")