BUG: revert parts of #40037

pandas/core/dtypes/cast.py

@@ -26,7 +26,6 @@
 )
 import warnings
 
-from dateutil.parser import ParserError
 import numpy as np
 
 from pandas._libs import (
@@ -1588,19 +1587,10 @@ def maybe_cast_to_datetime(
                             value = to_timedelta(value, errors="raise")._values
                     except OutOfBoundsDatetime:
                         raise
-                    except ParserError:
-                        # Note: ParserError subclasses ValueError
-                        # str that we can't parse to datetime
+                    except ValueError:
+                        # TODO(GH#40048): only catch dateutil's ParserError
+                        #  once we can reliably import it in all supported versions
                         pass
-                    except ValueError as err:
-                        if "mixed datetimes and integers in passed array" in str(err):
-                            # array_to_datetime does not allow this;
-                            # when called from _try_cast, this will be followed
-                            #  by a call to construct_1d_ndarray_preserving_na
-                            #  which will convert these
-                            pass
-                        else:
-                            raise
 
         # coerce datetimelike to object
         elif is_datetime64_dtype(

pandas/tests/frame/test_constructors.py

@@ -89,8 +89,6 @@ def test_array_of_dt64_nat_with_td64dtype_raises(self, frame_or_series):
             arr = arr.reshape(1, 1)
 
         msg = "Could not convert object to NumPy timedelta"
-        if frame_or_series is Series:
-            msg = "Invalid type for timedelta scalar: <class 'numpy.datetime64'>"
         with pytest.raises(ValueError, match=msg):
             frame_or_series(arr, dtype="m8[ns]")
 

pandas/tests/series/test_constructors.py

@@ -1332,7 +1332,7 @@ def test_constructor_dtype_timedelta64(self):
             td.astype("int32")
 
         # this is an invalid casting
-        msg = "Could not convert 'foo' to NumPy timedelta"
+        msg = "Could not convert object to NumPy timedelta"
         with pytest.raises(ValueError, match=msg):
             Series([timedelta(days=1), "foo"], dtype="m8[ns]")