mypy, doc fixup

Author: jbrockmendel

doc/source/whatsnew/v3.0.0.rst

@@ -335,6 +335,7 @@ with a :class:`Day` ``freq`` no longer preserves that ``freq`` attribute.
 - Adding or subtracing a :class:`Day` with a :class:`Timedelta` is no longer supported.
 - Adding or subtracting a :class:`Day` offset to a :class:`Timestamp` or datetime-like may lead to an ambiguous or non-existent time, which will raise.
 
+
 .. _whatsnew_300.api_breaking.deps:
 
 Increased minimum version for Python

pandas/core/resample.py

@@ -2650,7 +2650,13 @@ def _get_timestamp_range_edges(
                 origin = origin.tz_localize(None)
 
         first, last = _adjust_dates_anchored(
-            first, last, freq, closed=closed, origin=origin, offset=offset, unit=unit
+            first,
+            last,
+            cast("Day | Tick", freq),
+            closed=closed,
+            origin=origin,
+            offset=offset,
+            unit=unit,
         )
         if isinstance(freq, Day):
             first = first.tz_localize(index_tz)