diff --git a/Lib/test/test_index.py b/Lib/test/test_index.py
index 69aae298f..a215b1c83 100644
--- a/Lib/test/test_index.py
+++ b/Lib/test/test_index.py
@@ -22,8 +22,6 @@ class BaseTestCase(unittest.TestCase):
         self.assertEqual(operator.index(self.o), -2)
         self.assertEqual(operator.index(self.n), 2)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_slice(self):
         self.o.ind = 1
         self.n.ind = 2
diff --git a/Lib/test/test_slice.py b/Lib/test/test_slice.py
index 5a9116365..ecdd92b6c 100644
--- a/Lib/test/test_slice.py
+++ b/Lib/test/test_slice.py
@@ -155,8 +155,6 @@ class SliceTest(unittest.TestCase):
             expected = range(length)[slice]
             self.assertEqual(actual, expected)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_indices(self):
         self.assertEqual(slice(None           ).indices(10), (0, 10,  1))
         self.assertEqual(slice(None,  None,  2).indices(10), (0, 10,  2))
diff --git a/vm/src/builtins/slice.rs b/vm/src/builtins/slice.rs
index 59f293ad4..0f09b4a92 100644
--- a/vm/src/builtins/slice.rs
+++ b/vm/src/builtins/slice.rs
@@ -1,6 +1,6 @@
 // sliceobject.{h,c} in CPython
 
-use super::int::PyInt;
+use super::int::{PyInt, PyIntRef};
 use super::pytype::PyTypeRef;
 use crate::function::{FuncArgs, OptionalArg};
 use crate::pyobject::{
@@ -205,16 +205,17 @@ impl PySlice {
     }
 
     #[pymethod(name = "indices")]
-    fn indices(&self, length: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        if let Some(length) = length.payload::<PyInt>() {
-            let (start, stop, step) = self.inner_indices(length.borrow_value(), vm)?;
+    fn indices(&self, length: PyIntRef, vm: &VirtualMachine) -> PyResult {
+        let length = length.borrow_value();
+        if length.is_negative() {
+            Err(vm.new_value_error("length should not be negative.".to_owned()))
+        } else {
+            let (start, stop, step) = self.inner_indices(length, vm)?;
             Ok(vm.ctx.new_tuple(vec![
                 vm.ctx.new_int(start),
                 vm.ctx.new_int(stop),
                 vm.ctx.new_int(step),
             ]))
-        } else {
-            Ok(vm.ctx.not_implemented())
         }
     }
 }