BUG: Don't ignore errors when casting dtype in Series constructor

doc/source/whatsnew/v3.0.0.rst

@@ -793,6 +793,7 @@ Styler
 Other
 ^^^^^
 - Bug in :class:`DataFrame` when passing a ``dict`` with a NA scalar and ``columns`` that would always return ``np.nan`` (:issue:`57205`)
+- Bug in :class:`Series` ignoring errors when trying to convert :class:`Series` input data to the given ``dtype`` (:issue:`60728`)
 - Bug in :func:`eval` on :class:`ExtensionArray` on including division ``/`` failed with a ``TypeError``. (:issue:`58748`)
 - Bug in :func:`eval` where the names of the :class:`Series` were not preserved when using ``engine="numexpr"``. (:issue:`10239`)
 - Bug in :func:`eval` with ``engine="numexpr"`` returning unexpected result for float division. (:issue:`59736`)

pandas/core/series.py

@@ -500,7 +500,7 @@ def __init__(
         # create/copy the manager
         if isinstance(data, SingleBlockManager):
             if dtype is not None:
-                data = data.astype(dtype=dtype, errors="ignore")
+                data = data.astype(dtype=dtype)
             elif copy:
                 data = data.copy()
         else:

pandas/tests/series/test_constructors.py

@@ -90,6 +90,13 @@ def test_unparsable_strings_with_dt64_dtype(self):
         with pytest.raises(ValueError, match=msg):
             Series(np.array(vals, dtype=object), dtype="datetime64[ns]")
 
+    def test_invalid_dtype_conversion_datetime_to_timedelta(self):
+        # GH#60728
+        vals = Series([NaT, Timestamp(2025, 1, 1)], dtype="datetime64[ns]")
+        msg = r"^Cannot cast DatetimeArray to dtype timedelta64\[ns\]$"
+        with pytest.raises(TypeError, match=msg):
+            Series(vals, dtype="timedelta64[ns]")
+
     @pytest.mark.parametrize(
         "constructor",
         [