diff --git a/python_modules/dagster/dagster/_core/definitions/partition_mapping.py b/python_modules/dagster/dagster/_core/definitions/partition_mapping.py
index 66cc6092a7a56..492448e9cce27 100644
--- a/python_modules/dagster/dagster/_core/definitions/partition_mapping.py
+++ b/python_modules/dagster/dagster/_core/definitions/partition_mapping.py
@@ -122,7 +122,7 @@ def get_upstream_mapped_partitions_result_for_partitions(
         if downstream_partitions_subset is None:
             check.failed("downstream asset is not partitioned")
 
-        if downstream_partitions_subset.partitions_def == upstream_partitions_def:
+        if downstream_partitions_def == upstream_partitions_def:
             return UpstreamPartitionsResult(downstream_partitions_subset, [])
 
         upstream_partition_keys = set(
@@ -150,7 +150,7 @@ def get_downstream_partitions_for_partitions(
         if upstream_partitions_subset is None:
             check.failed("upstream asset is not partitioned")
 
-        if upstream_partitions_subset.partitions_def == downstream_partitions_def:
+        if upstream_partitions_def == downstream_partitions_def:
             return upstream_partitions_subset
 
         upstream_partition_keys = set(upstream_partitions_subset.get_partition_keys())