[NDArray] Fix bug with tuple indexing (#1357)

Fixes #1310

magma/array.py

@@ -774,7 +774,8 @@ def _ndarray_getitem(self, key: tuple):
         if len(key) == 1:
             return self[key[0]]
         if not isinstance(key[0], slice):
-            return self[key[0]][key[1:]]
+            next_key = next_key = key[1:] if len(key) > 2 else key[1]
+            return self[key[0]][next_key]
         if not self._is_whole_slice(key[0]):
             # If it's not a slice of the whole array, first slice the
             # current array (self), then replace with a slice of the whole

tests/test_type/test_ndarray.py

@@ -116,3 +116,9 @@ class Main(m.Circuit):
     m.compile("build/test_ndarray_get_slice", Main, inline=True)
     assert check_files_equal(__file__, f"build/test_ndarray_get_slice.v",
                              f"gold/test_ndarray_get_slice.v")
+
+
+def test_ndarray_constant():
+    class Foo(m.Circuit):
+        arr_m = m.Array[(3, 2), m.Bits[4]]([[1] * 2] * 3)
+        assert arr_m[0, 0] == 1