diff --git a/arraycontext/container/traversal.py b/arraycontext/container/traversal.py
index 5a4dcf745282a0a1e07304a2ddcbebc5d9dac8f6..940f5ea7fd7b9c526f0054472600693329619456 100644
--- a/arraycontext/container/traversal.py
+++ b/arraycontext/container/traversal.py
@@ -754,7 +754,7 @@ def flatten(
 
 
 def unflatten(
-        template: ArrayOrContainerT, ary: Any,
+        template: ArrayOrContainerT, ary: Array,
         actx: ArrayContext, *,
         strict: bool = True) -> ArrayOrContainerT:
     """Unflatten an array *ary* produced by :func:`flatten` back into an
@@ -822,17 +822,17 @@ def unflatten(
 
             # {{{ check strides
 
-            if strict and hasattr(template_subary, "strides"):
+            if strict and hasattr(template_subary_c, "strides"):
                 # Checking strides for 0 sized arrays is ill-defined
                 # since they cannot be indexed
                 if (
                     # Mypy has a point: nobody promised a .strides attribute.
-                    template_subary_c.strides != subary.strides  # type: ignore[attr-defined]  # noqa: E501
+                    template_subary_c.strides != subary.strides
                     and template_subary_c.size != 0
                 ):
                     raise ValueError(
                             # Mypy has a point: nobody promised a .strides attribute.
-                            f"strides do not match template: got {subary.strides}, "   # type: ignore[attr-defined]  # noqa: E501
+                            f"strides do not match template: got {subary.strides}, "
                             f"expected {template_subary_c.strides}")
 
             # }}}
@@ -849,7 +849,7 @@ def unflatten(
                 f"array context: got '{type(ary).__name__}', expected one of "
                 f"{actx.array_types}")
 
-    if ary.ndim != 1:
+    if len(ary.shape) != 1:
         raise ValueError(
                 "only one dimensional arrays can be unflattened: "
                 f"'ary' has shape {ary.shape}")