diff --git a/amaranth/lib/wiring.py b/amaranth/lib/wiring.py
index 75eac1c..27b28f9 100644
--- a/amaranth/lib/wiring.py
+++ b/amaranth/lib/wiring.py
@@ -394,7 +394,7 @@ class Signature(metaclass=SignatureMeta):
                     dimension, *rest_of_dimensions = dimensions
                     for index in range(dimension):
                         yield from iter_dimensions(value[index], rest_of_dimensions,
-                                                   path=(path, index))
+                                                   path=(*path, index))
 
             yield from iter_dimensions(value, dimensions=member.dimensions, path=path)
 
diff --git a/tests/test_lib_wiring.py b/tests/test_lib_wiring.py
index 75a0583..f5af0f2 100644
--- a/tests/test_lib_wiring.py
+++ b/tests/test_lib_wiring.py
@@ -385,8 +385,8 @@ class SignatureTestCase(unittest.TestCase):
         intf = sig.create()
         self.assertFlattenedSignature(sig.flatten(intf), [
             (("a",), In(1), intf.a),
-            ((("b",), 0), Out(2), intf.b[0]),
-            ((("b",), 1), Out(2), intf.b[1])
+            (("b", 0), Out(2), intf.b[0]),
+            (("b", 1), Out(2), intf.b[1])
         ])
 
     def test_flatten_sig(self):