Use self._reason as error position instead

Author: sterliakov

mypy/plugins/dataclasses.py

@@ -472,7 +472,7 @@ def _add_dunder_hash(self, is_hashable: bool) -> None:
                 self._api.fail(
                     "Incompatible override of '__hash__': dataclasses without"
                     " 'frozen' or 'unsafe_hash' have '__hash__' set to None",
-                    self._cls,
+                    self._reason,
                 )
             add_attribute_to_class(
                 self._api, self._cls, "__hash__", typ=NoneType(), is_classvar=True

test-data/unit/check-dataclasses.test

@@ -259,9 +259,8 @@ from dataclasses import dataclass
 class FrozenBase:
     pass
 
-@dataclass
-class BadNormalDerived(FrozenBase):  # E: Incompatible override of '__hash__': dataclasses without 'frozen' or 'unsafe_hash' have '__hash__' set to None \
-                                     # E: Non-frozen dataclass cannot inherit from a frozen dataclass
+@dataclass  # E: Incompatible override of '__hash__': dataclasses without 'frozen' or 'unsafe_hash' have '__hash__' set to None
+class BadNormalDerived(FrozenBase):  # E: Non-frozen dataclass cannot inherit from a frozen dataclass
     pass
 
 @dataclass
@@ -277,6 +276,12 @@ class BadFrozenDerived(NormalBase):  # E: Signature of "__hash__" incompatible w
                                      # E: Frozen dataclass cannot inherit from a non-frozen dataclass
     pass
 
+
+
+
+
+
+
 [builtins fixtures/dataclasses.pyi]
 
 [case testDataclassesFields]
@@ -2634,8 +2639,8 @@ class Good(Hashable):
 class AlsoGood(Hashable):
     a: int
 
-@dataclasses.dataclass()
-class Bad(Hashable):  # E: Incompatible override of '__hash__': dataclasses without 'frozen' or 'unsafe_hash' have '__hash__' set to None
+@dataclasses.dataclass()  # E: Incompatible override of '__hash__': dataclasses without 'frozen' or 'unsafe_hash' have '__hash__' set to None
+class Bad(Hashable):
     a: int
 
 Good(4)