RustPython
diff --git a/Lib/test/test_enumerate.py b/Lib/test/test_enumerate.py
@@ -2,6 +2,7 @@
 import operator
 import sys
 import pickle
+import gc
 
 from test import support
 
@@ -127,13 +128,37 @@ def test_argumentcheck(self):
         self.assertRaises(TypeError, self.enum, 'abc', 'a') # wrong type
         self.assertRaises(TypeError, self.enum, 'abc', 2, 3) # too many arguments
 
+    def test_kwargs(self):
+        self.assertEqual(list(self.enum(iterable=Ig(self.seq))), self.res)
+        expected = list(self.enum(Ig(self.seq), 0))
+        self.assertEqual(list(self.enum(iterable=Ig(self.seq), start=0)),
+                         expected)
+        self.assertEqual(list(self.enum(start=0, iterable=Ig(self.seq))),
+                         expected)
+        self.assertRaises(TypeError, self.enum, iterable=[], x=3)
+        self.assertRaises(TypeError, self.enum, start=0, x=3)
+        self.assertRaises(TypeError, self.enum, x=0, y=3)
+        self.assertRaises(TypeError, self.enum, x=0)
+
     @support.cpython_only
     def test_tuple_reuse(self):
         # Tests an implementation detail where tuple is reused
         # whenever nothing else holds a reference to it
         self.assertEqual(len(set(map(id, list(enumerate(self.seq))))), len(self.seq))
         self.assertEqual(len(set(map(id, enumerate(self.seq)))), min(1,len(self.seq)))
 
+    @support.cpython_only
+    def test_enumerate_result_gc(self):
+        # bpo-42536: enumerate's tuple-reuse speed trick breaks the GC's
+        # assumptions about what can be untracked. Make sure we re-track result
+        # tuples whenever we reuse them.
+        it = self.enum([[]])
+        gc.collect()
+        # That GC collection probably untracked the recycled internal result
+        # tuple, which is initialized to (None, None). Make sure it's re-tracked
+        # when it's mutated and returned from __next__:
+        self.assertTrue(gc.is_tracked(next(it)))
+
 class MyEnum(enumerate):
     pass
 
@@ -253,14 +278,16 @@ def test_basicfunction(self):
 
 
 class TestStart(EnumerateStartTestCase):
+    def enum(self, iterable, start=11):
+        return enumerate(iterable, start=start)
 
-    enum = lambda self, i: enumerate(i, start=11)
     seq, res = 'abc', [(11, 'a'), (12, 'b'), (13, 'c')]
 
 
 class TestLongStart(EnumerateStartTestCase):
+    def enum(self, iterable, start=sys.maxsize + 1):
+        return enumerate(iterable, start=start)
 
-    enum = lambda self, i: enumerate(i, start=sys.maxsize+1)
     seq, res = 'abc', [(sys.maxsize+1,'a'), (sys.maxsize+2,'b'),
                        (sys.maxsize+3,'c')]
 

diff --git a/vm/src/builtins/enumerate.rs b/vm/src/builtins/enumerate.rs
@@ -19,7 +19,7 @@ use num_traits::Zero;
 pub struct PyEnumerate {
     #[pytraverse(skip)]
     counter: PyRwLock<BigInt>,
-    iterator: PyIter,
+    iterable: PyIter,
 }
 
 impl PyPayload for PyEnumerate {
@@ -31,7 +31,8 @@ impl PyPayload for PyEnumerate {
 
 #[derive(FromArgs)]
 pub struct EnumerateArgs {
-    iterator: PyIter,
+    #[pyarg(any)]
+    iterable: PyIter,
     #[pyarg(any, optional)]
     start: OptionalArg<PyIntRef>,
 }
@@ -41,13 +42,13 @@ impl Constructor for PyEnumerate {
 
     fn py_new(
         cls: PyTypeRef,
-        Self::Args { iterator, start }: Self::Args,
+        Self::Args { iterable, start }: Self::Args,
         vm: &VirtualMachine,
     ) -> PyResult {
         let counter = start.map_or_else(BigInt::zero, |start| start.as_bigint().clone());
         Self {
             counter: PyRwLock::new(counter),
-            iterator,
+            iterable,
         }
         .into_ref_with_type(vm, cls)
         .map(Into::into)
@@ -68,7 +69,7 @@ impl Py<PyEnumerate> {
     fn __reduce__(&self) -> (PyTypeRef, (PyIter, BigInt)) {
         (
             self.class().to_owned(),
-            (self.iterator.clone(), self.counter.read().clone()),
+            (self.iterable.clone(), self.counter.read().clone()),
         )
     }
 }
@@ -77,7 +78,7 @@ impl SelfIter for PyEnumerate {}
 
 impl IterNext for PyEnumerate {
     fn next(zelf: &Py<Self>, vm: &VirtualMachine) -> PyResult<PyIterReturn> {
-        let next_obj = raise_if_stop!(zelf.iterator.next(vm)?);
+        let next_obj = raise_if_stop!(zelf.iterable.next(vm)?);
         let mut counter = zelf.counter.write();
         let position = counter.clone();
         *counter += 1;