keep the slice.step field as NULL if no step expression is given
diff --git a/Lib/test/test_ast.py b/Lib/test/test_ast.py
index 1674b97..eac42d3 100644
--- a/Lib/test/test_ast.py
+++ b/Lib/test/test_ast.py
@@ -146,6 +146,12 @@
self.assertEquals(to_tuple(ast_tree), o)
self._assert_order(ast_tree, (0, 0))
+ def test_slice(self):
+ slc = ast.parse("x[::]").body[0].value.slice
+ self.assertIsNone(slc.upper)
+ self.assertIsNone(slc.lower)
+ self.assertIsNone(slc.step)
+
def test_nodeclasses(self):
x = ast.BinOp(1, 2, 3, lineno=0)
self.assertEquals(x.left, 1)
diff --git a/Misc/NEWS b/Misc/NEWS
index 3a4e1ac..1192618 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
Core and Builtins
-----------------
+- In the slice AST type, the step field will always be None if a step expression
+ is not specified.
+
- Issue #4547: When debugging a very large function, it was not always
possible to update the lineno attribute of the current frame.
diff --git a/Python/ast.c b/Python/ast.c
index b3f4fcb..772047f 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1468,14 +1468,7 @@
ch = CHILD(n, NCH(n) - 1);
if (TYPE(ch) == sliceop) {
- if (NCH(ch) == 1) {
- /* No expression, so step is None */
- ch = CHILD(ch, 0);
- step = Name(new_identifier("None", c->c_arena), Load,
- LINENO(ch), ch->n_col_offset, c->c_arena);
- if (!step)
- return NULL;
- } else {
+ if (NCH(ch) != 1) {
ch = CHILD(ch, 1);
if (TYPE(ch) == test) {
step = ast_for_expr(c, ch);