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JukkaLJukkaL
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Revert "Fixes to union simplification, isinstance and more (#3025)"
I found a major bug when experimenting with real-world codebases. This reverts commit 67cda6e.
1 parent 7b41e53 commit f24089b

20 files changed

+126
-696
lines changed

‎mypy/checker.py

+38-39
Original file line numberDiff line numberDiff line change
@@ -28,7 +28,7 @@
2828
Type, AnyType, CallableType, FunctionLike, Overloaded, TupleType, TypedDictType,
2929
Instance, NoneTyp, ErrorType, strip_type, TypeType,
3030
UnionType, TypeVarId, TypeVarType, PartialType, DeletedType, UninhabitedType, TypeVarDef,
31-
true_only, false_only, function_type, is_named_instance, union_items
31+
true_only, false_only, function_type, is_named_instance
3232
)
3333
from mypy.sametypes import is_same_type, is_same_types
3434
from mypy.messages import MessageBuilder
@@ -812,45 +812,44 @@ def check_overlapping_op_methods(self,
812812
# of x in __radd__ would not be A, the methods could be
813813
# non-overlapping.
814814

815-
for forward_item in union_items(forward_type):
816-
if isinstance(forward_item, CallableType):
817-
# TODO check argument kinds
818-
if len(forward_item.arg_types) < 1:
819-
# Not a valid operator method -- can't succeed anyway.
820-
return
815+
if isinstance(forward_type, CallableType):
816+
# TODO check argument kinds
817+
if len(forward_type.arg_types) < 1:
818+
# Not a valid operator method -- can't succeed anyway.
819+
return
821820

822-
# Construct normalized function signatures corresponding to the
823-
# operator methods. The first argument is the left operand and the
824-
# second operand is the right argument -- we switch the order of
825-
# the arguments of the reverse method.
826-
forward_tweaked = CallableType(
827-
[forward_base, forward_item.arg_types[0]],
828-
[nodes.ARG_POS] * 2,
829-
[None] * 2,
830-
forward_item.ret_type,
831-
forward_item.fallback,
832-
name=forward_item.name)
833-
reverse_args = reverse_type.arg_types
834-
reverse_tweaked = CallableType(
835-
[reverse_args[1], reverse_args[0]],
836-
[nodes.ARG_POS] * 2,
837-
[None] * 2,
838-
reverse_type.ret_type,
839-
fallback=self.named_type('builtins.function'),
840-
name=reverse_type.name)
841-
842-
if is_unsafe_overlapping_signatures(forward_tweaked,
843-
reverse_tweaked):
844-
self.msg.operator_method_signatures_overlap(
845-
reverse_class.name(), reverse_name,
846-
forward_base.type.name(), forward_name, context)
847-
elif isinstance(forward_item, Overloaded):
848-
for item in forward_item.items():
849-
self.check_overlapping_op_methods(
850-
reverse_type, reverse_name, reverse_class,
851-
item, forward_name, forward_base, context)
852-
elif not isinstance(forward_item, AnyType):
853-
self.msg.forward_operator_not_callable(forward_name, context)
821+
# Construct normalized function signatures corresponding to the
822+
# operator methods. The first argument is the left operand and the
823+
# second operand is the right argument -- we switch the order of
824+
# the arguments of the reverse method.
825+
forward_tweaked = CallableType(
826+
[forward_base, forward_type.arg_types[0]],
827+
[nodes.ARG_POS] * 2,
828+
[None] * 2,
829+
forward_type.ret_type,
830+
forward_type.fallback,
831+
name=forward_type.name)
832+
reverse_args = reverse_type.arg_types
833+
reverse_tweaked = CallableType(
834+
[reverse_args[1], reverse_args[0]],
835+
[nodes.ARG_POS] * 2,
836+
[None] * 2,
837+
reverse_type.ret_type,
838+
fallback=self.named_type('builtins.function'),
839+
name=reverse_type.name)
840+
841+
if is_unsafe_overlapping_signatures(forward_tweaked,
842+
reverse_tweaked):
843+
self.msg.operator_method_signatures_overlap(
844+
reverse_class.name(), reverse_name,
845+
forward_base.type.name(), forward_name, context)
846+
elif isinstance(forward_type, Overloaded):
847+
for item in forward_type.items():
848+
self.check_overlapping_op_methods(
849+
reverse_type, reverse_name, reverse_class,
850+
item, forward_name, forward_base, context)
851+
elif not isinstance(forward_type, AnyType):
852+
self.msg.forward_operator_not_callable(forward_name, context)
854853

855854
def check_inplace_operator_method(self, defn: FuncBase) -> None:
856855
"""Check an inplace operator method such as __iadd__.

‎mypy/checkexpr.py

+2-2
Original file line numberDiff line numberDiff line change
@@ -32,7 +32,7 @@
3232
from mypy import messages
3333
from mypy.infer import infer_type_arguments, infer_function_type_arguments
3434
from mypy import join
35-
from mypy.meet import narrow_declared_type
35+
from mypy.meet import meet_simple
3636
from mypy.maptype import map_instance_to_supertype
3737
from mypy.subtypes import is_subtype, is_equivalent
3838
from mypy import applytype
@@ -2221,7 +2221,7 @@ def narrow_type_from_binder(self, expr: Expression, known_type: Type) -> Type:
22212221
if expr.literal >= LITERAL_TYPE:
22222222
restriction = self.chk.binder.get(expr)
22232223
if restriction:
2224-
ans = narrow_declared_type(known_type, restriction)
2224+
ans = meet_simple(known_type, restriction)
22252225
return ans
22262226
return known_type
22272227

‎mypy/erasetype.py

+1-2
Original file line numberDiff line numberDiff line change
@@ -76,8 +76,7 @@ def visit_typeddict_type(self, t: TypedDictType) -> Type:
7676
return t.fallback.accept(self)
7777

7878
def visit_union_type(self, t: UnionType) -> Type:
79-
erased_items = [erase_type(item) for item in t.items]
80-
return UnionType.make_simplified_union(erased_items)
79+
return AnyType() # XXX: return underlying type if only one?
8180

8281
def visit_type_type(self, t: TypeType) -> Type:
8382
return TypeType(t.item.accept(self), line=t.line)

‎mypy/join.py

+3-3
Original file line numberDiff line numberDiff line change
@@ -10,7 +10,7 @@
1010
UninhabitedType, TypeType, true_or_false
1111
)
1212
from mypy.maptype import map_instance_to_supertype
13-
from mypy.subtypes import is_subtype, is_equivalent, is_subtype_ignoring_tvars, is_proper_subtype
13+
from mypy.subtypes import is_subtype, is_equivalent, is_subtype_ignoring_tvars
1414

1515
from mypy import experiments
1616

@@ -29,10 +29,10 @@ def join_simple(declaration: Type, s: Type, t: Type) -> Type:
2929
if isinstance(s, ErasedType):
3030
return t
3131

32-
if is_proper_subtype(s, t):
32+
if is_subtype(s, t):
3333
return t
3434

35-
if is_proper_subtype(t, s):
35+
if is_subtype(t, s):
3636
return s
3737

3838
if isinstance(declaration, UnionType):

‎mypy/meet.py

+11-20
Original file line numberDiff line numberDiff line change
@@ -25,26 +25,21 @@ def meet_types(s: Type, t: Type) -> Type:
2525
return t.accept(TypeMeetVisitor(s))
2626

2727

28-
def narrow_declared_type(declared: Type, narrowed: Type) -> Type:
29-
"""Return the declared type narrowed down to another type."""
30-
if declared == narrowed:
31-
return declared
32-
if isinstance(declared, UnionType):
33-
return UnionType.make_simplified_union([narrow_declared_type(x, narrowed)
34-
for x in declared.items])
35-
elif not is_overlapping_types(declared, narrowed, use_promotions=True):
28+
def meet_simple(s: Type, t: Type, default_right: bool = True) -> Type:
29+
if s == t:
30+
return s
31+
if isinstance(s, UnionType):
32+
return UnionType.make_simplified_union([meet_types(x, t) for x in s.items])
33+
elif not is_overlapping_types(s, t, use_promotions=True):
3634
if experiments.STRICT_OPTIONAL:
3735
return UninhabitedType()
3836
else:
3937
return NoneTyp()
40-
elif isinstance(narrowed, UnionType):
41-
return UnionType.make_simplified_union([narrow_declared_type(declared, x)
42-
for x in narrowed.items])
43-
elif isinstance(narrowed, AnyType):
44-
return narrowed
45-
elif isinstance(declared, (Instance, TupleType)):
46-
return meet_types(declared, narrowed)
47-
return narrowed
38+
else:
39+
if default_right:
40+
return t
41+
else:
42+
return s
4843

4944

5045
def is_overlapping_types(t: Type, s: Type, use_promotions: bool = False) -> bool:
@@ -254,10 +249,6 @@ def visit_tuple_type(self, t: TupleType) -> Type:
254249
elif (isinstance(self.s, Instance) and
255250
self.s.type.fullname() == 'builtins.tuple' and self.s.args):
256251
return t.copy_modified(items=[meet_types(it, self.s.args[0]) for it in t.items])
257-
elif (isinstance(self.s, Instance) and t.fallback.type == self.s.type):
258-
# Uh oh, a broken named tuple type (https://github.com/python/mypy/issues/3016).
259-
# Do something reasonable until that bug is fixed.
260-
return t
261252
else:
262253
return self.default(self.s)
263254

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