diff --git a/cylc/flow/network/schema.py b/cylc/flow/network/schema.py
index 3a8626e2c95..70e40232c1d 100644
--- a/cylc/flow/network/schema.py
+++ b/cylc/flow/network/schema.py
@@ -502,7 +502,7 @@ async def get_nodes_edges(root, info: 'ResolveInfo', **args):
 
 
 def resolve_state_totals(root, info, **args):
-    state_totals = {state: 0 for state in TASK_STATUSES_ORDERED}
+    state_totals = dict.fromkeys(TASK_STATUSES_ORDERED, 0)
     # Update with converted protobuf map container
     state_totals.update(
         dict(getattr(root, to_snake_case(info.field_name), {})))
diff --git a/cylc/flow/task_outputs.py b/cylc/flow/task_outputs.py
index 40b9d991b30..1af37e1554e 100644
--- a/cylc/flow/task_outputs.py
+++ b/cylc/flow/task_outputs.py
@@ -251,11 +251,7 @@ def get_optional_outputs(
             )
             for output in used_compvars
         },
-        # the outputs that are not used in the expression
-        **{
-            output: None
-            for output in all_compvars - used_compvars
-        },
+        **dict.fromkeys(all_compvars - used_compvars),
     }
 
 
diff --git a/cylc/flow/tui/updater.py b/cylc/flow/tui/updater.py
index 26a8614b1a3..2a28b5d7906 100644
--- a/cylc/flow/tui/updater.py
+++ b/cylc/flow/tui/updater.py
@@ -68,11 +68,8 @@ def get_default_filters():
     These filters show everything.
     """
     return {
-        'tasks': {
-            # filtered task statuses
-            state: True
-            for state in TASK_STATUSES_ORDERED
-        },
+        # filtered task statuses
+        'tasks': dict.fromkeys(TASK_STATUSES_ORDERED, True),
         'workflows': {
             # filtered workflow statuses
             **{