Better error message for OOB result

Closes pandas-dev#31774

Author: TomAugspurger

doc/source/whatsnew/v1.0.2.rst

@@ -64,6 +64,7 @@ Bug fixes
 
 - Bug in :meth:`DataFrame.reindex` and :meth:`Series.reindex` when reindexing with a tz-aware index (:issue:`26683`)
 - Bug where :func:`to_datetime` would raise when passed ``pd.NA`` (:issue:`32213`)
+- Improved error message when subtracting two :class:`Timestamp` that result in an invalide :class:`Timedelta` (:issue:`31774`)
 
 **Categorical**
 

pandas/_libs/tslibs/c_timestamp.pyx

@@ -299,9 +299,15 @@ cdef class _Timestamp(datetime):
             # scalar Timestamp/datetime - Timestamp/datetime -> yields a
             # Timedelta
             from pandas._libs.tslibs.timedeltas import Timedelta
+            from pandas._libs.tslibs.timestamps import Timestamp
             try:
                 return Timedelta(self.value - other.value)
-            except (OverflowError, OutOfBoundsDatetime):
+            except (OverflowError, OutOfBoundsDatetime) as e:
+                if isinstance(other, Timestamp):
+                    raise OverflowError(
+                        "Result is too large for pandas.Timestamp. Convert inputs "
+                        "to datetime.datetime before subtracting."
+                    ) from e
                 pass
         elif is_datetime64_object(self):
             # GH#28286 cython semantics for __rsub__, `other` is actually

pandas/tests/scalar/timestamp/test_arithmetic.py

@@ -60,6 +60,15 @@ def test_overflow_offset_raises(self):
         with pytest.raises(OverflowError, match=msg):
             stamp - offset_overflow
 
+    def test_overflow_timestamp_raises(self):
+        # https://github.com/pandas-dev/pandas/issues/31774
+        msg = "Result is too large"
+        a = Timestamp("2101-01-01 00:00:00")
+        b = Timestamp("1688-01-01 00:00:00")
+
+        with pytest.raises(OverflowError, match=msg):
+            a - b
+
     def test_delta_preserve_nanos(self):
         val = Timestamp(1337299200000000123)
         result = val + timedelta(1)