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Now we can override attributes with methods, refs #10134 #11561

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Merged
97littleleaf11 merged 5 commits into from
Nov 18, 2021
Merged

Now we can override attributes with methods, refs #10134 #11561

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03dc44a
Now we can override attributes with methods, refs #10134
sobolevn Nov 16, 2021
f55324a
Fixes CI
sobolevn Nov 16, 2021
2255919
Update test-data/unit/check-classes.test
sobolevn Nov 17, 2021
c9e99ec
Update test-data/unit/check-classes.test
sobolevn Nov 17, 2021
42411b4
Update test-data/unit/check-classes.test
sobolevn Nov 17, 2021
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10 changes: 10 additions & 0 deletions mypy/checker.py
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Original file line number Diff line number Diff line change
Expand Up @@ -1536,6 +1536,16 @@ def check_method_override_for_base_with_name(
original_type = self.function_type(original_node)
elif isinstance(original_node, Decorator):
original_type = self.function_type(original_node.func)
elif isinstance(original_node, Var):
# Super type can define method as an attribute.
# See https://github.com/python/mypy/issues/10134

# We also check that sometimes `original_node.type` is None.
# This is the case when we use something like `__hash__ = None`.
if original_node.type is not None:
original_type = get_proper_type(original_node.type)
else:
original_type = NoneType()
else:
assert False, str(base_attr.node)
if isinstance(original_node, (FuncDef, OverloadedFuncDef)):
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37 changes: 37 additions & 0 deletions test-data/unit/check-classes.test
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Expand Up @@ -114,6 +114,43 @@ class A:
A().f = None # E: Cannot assign to a method


[case testOverrideAttributeWithMethod]
# This was crashing:
# https://github.com/python/mypy/issues/10134
from typing import Protocol

class Base:
__hash__ = None

class Derived(Base):
def __hash__(self) -> int: # E: Signature of "__hash__" incompatible with supertype "Base"
pass

# Correct:

class CallableProtocol(Protocol):
def __call__(self, arg: int) -> int:
pass

class CorrectBase:
attr: CallableProtocol

class CorrectDerived(CorrectBase):
def attr(self, arg: int) -> int:
pass

[case testOverrideMethodWithAttribute]
# The reverse should not crash as well:
from typing import Callable

class Base:
def __hash__(self) -> int:
pass

class Derived(Base):
__hash__ = 1 # E: Incompatible types in assignment (expression has type "int", base class "Base" defined the type as "Callable[[Base], int]")


-- Attributes
-- ----------

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