def analyze_type_callable_member_access(name: str, typ: FunctionLike,
mx: MemberContext) -> Type:
# Class attribute.
# TODO super?
ret_type = typ.items()[0].ret_type
assert isinstance(ret_type, ProperType)
if isinstance(ret_type, TupleType):
ret_type = tuple_fallback(ret_type)
if isinstance(ret_type, Instance):
if not mx.is_operator:
# When Python sees an operator (eg `3 == 4`), it automatically translates that
# into something like `int.__eq__(3, 4)` instead of `(3).__eq__(4)` as an
# optimization.
#
# While it normally it doesn't matter which of the two versions are used, it
# does cause inconsistencies when working with classes. For example, translating
# `int == int` to `int.__eq__(int)` would not work since `int.__eq__` is meant to
# compare two int _instances_. What we really want is `type(int).__eq__`, which
# is meant to compare two types or classes.
#
# This check makes sure that when we encounter an operator, we skip looking up
# the corresponding method in the current instance to avoid this edge case.
# See https://github.com/python/mypy/pull/1787 for more info.
# TODO: do not rely on same type variables being present in all constructor overloads.
result = analyze_class_attribute_access(
ret_type, name, mx, original_vars=typ.items()[0].variables)
if result:
return result
# Look up from the 'type' type.
return _analyze_member_access(name, typ.fallback, mx)
else:
assert False, 'Unexpected type {}'.format(repr(ret_type))
def type_object_type_from_function(signature: FunctionLike, info: TypeInfo,
def_info: TypeInfo, fallback: Instance,
is_new: bool) -> FunctionLike:
# We first need to record all non-trivial (explicit) self types in __init__,
# since they will not be available after we bind them. Note, we use explicit
# self-types only in the defining class, similar to __new__ (but not exactly the same,
# see comment in class_callable below). This is mostly useful for annotating library
# classes such as subprocess.Popen.
default_self = fill_typevars(info)
if not is_new and not info.is_newtype:
orig_self_types = [(it.arg_types[0]
if it.arg_types and it.arg_types[0] != default_self
and it.arg_kinds[0] == ARG_POS else None)
for it in signature.items()]
else:
orig_self_types = [None] * len(signature.items())
# The __init__ method might come from a generic superclass 'def_info'
# with type variables that do not map identically to the type variables of
# the class 'info' being constructed. For example:
#
# class A(Generic[T]):
# def __init__(self, x: T) -> None: ...
# class B(A[List[T]]):
# ...
#
# We need to map B's __init__ to the type (List[T]) -> None.
signature = bind_self(signature,
original_type=default_self,
is_classmethod=is_new)
signature = cast(FunctionLike,
map_type_from_supertype(signature, info, def_info))
special_sig = None # type: Optional[str]
if def_info.fullname == 'builtins.dict':
# Special signature!
special_sig = 'dict'
if isinstance(signature, CallableType):
return class_callable(signature, info, fallback, special_sig, is_new,
orig_self_types[0])
else:
# Overloaded __init__/__new__.
assert isinstance(signature, Overloaded)
items = [] # type: List[CallableType]
for item, orig_self in zip(signature.items(), orig_self_types):
items.append(
class_callable(item, info, fallback, special_sig, is_new,
orig_self))
return Overloaded(items)
def check_self_arg(functype: FunctionLike, dispatched_arg_type: Type,
is_classmethod: bool, context: Context, name: str,
msg: MessageBuilder) -> None:
"""For x.f where A.f: A1 -> T, check that meet(type(x), A) <: A1 for each overload.
dispatched_arg_type is meet(B, A) in the following example
def g(x: B): x.f
class A:
f: Callable[[A1], None]
"""
# TODO: this is too strict. We can return filtered overloads for matching definitions
for item in functype.items():
if not item.arg_types or item.arg_kinds[0] not in (ARG_POS, ARG_STAR):
# No positional first (self) argument (*args is okay).
msg.no_formal_self(name, item, context)
else:
selfarg = item.arg_types[0]
if is_classmethod:
dispatched_arg_type = TypeType.make_normalized(
dispatched_arg_type)
if not subtypes.is_subtype(dispatched_arg_type,
erase_to_bound(selfarg)):
msg.incompatible_self_argument(name, dispatched_arg_type, item,
is_classmethod, context)
def check_method_type(functype: FunctionLike, itype: Instance,
is_classmethod: bool, context: Context,
msg: MessageBuilder) -> None:
for item in functype.items():
if not item.arg_types or item.arg_kinds[0] not in (ARG_POS, ARG_STAR):
# No positional first (self) argument (*args is okay).
msg.invalid_method_type(item, context)
elif not is_classmethod:
# Check that self argument has type 'Any' or valid instance type.
selfarg = item.arg_types[0]
# If this is a method of a tuple class, correct for the fact that
# we passed to typ.fallback in analyze_member_access. See #1432.
if isinstance(selfarg, TupleType):
selfarg = selfarg.fallback
if not subtypes.is_subtype(selfarg, itype):
msg.invalid_method_type(item, context)
else:
# Check that cls argument has type 'Any' or valid class type.
# (This is sufficient for the current treatment of @classmethod,
# but probably needs to be revisited when we implement Type[C]
# or advanced variants of it like Type[<args>, C].)
clsarg = item.arg_types[0]
if isinstance(clsarg, CallableType) and clsarg.is_type_obj():
if not subtypes.is_equivalent(clsarg.ret_type, itype):
msg.invalid_class_method_type(item, context)
else:
if not subtypes.is_equivalent(clsarg, AnyType()):
msg.invalid_class_method_type(item, context)
def check_method_type(
functype: FunctionLike, itype: Instance, is_classmethod: bool, context: Context, msg: MessageBuilder
) -> None:
for item in functype.items():
if not item.arg_types or item.arg_kinds[0] not in (ARG_POS, ARG_STAR):
# No positional first (self) argument (*args is okay).
msg.invalid_method_type(item, context)
elif not is_classmethod:
# Check that self argument has type 'Any' or valid instance type.
selfarg = item.arg_types[0]
# If this is a method of a tuple class, correct for the fact that
# we passed to typ.fallback in analyze_member_access. See #1432.
if isinstance(selfarg, TupleType):
selfarg = selfarg.fallback
if not subtypes.is_equivalent(selfarg, itype):
msg.invalid_method_type(item, context)
else:
# Check that cls argument has type 'Any' or valid class type.
# (This is sufficient for the current treatment of @classmethod,
# but probably needs to be revisited when we implement Type[C]
# or advanced variants of it like Type[<args>, C].)
clsarg = item.arg_types[0]
if isinstance(clsarg, CallableType) and clsarg.is_type_obj():
if not subtypes.is_equivalent(clsarg.ret_type, itype):
msg.invalid_class_method_type(item, context)
else:
if not subtypes.is_equivalent(clsarg, AnyType()):
msg.invalid_class_method_type(item, context)
def check_self_arg(functype: FunctionLike,
dispatched_arg_type: Type,
is_classmethod: bool,
context: Context, name: str,
msg: MessageBuilder) -> None:
"""For x.f where A.f: A1 -> T, check that meet(type(x), A) <: A1 for each overload.
dispatched_arg_type is meet(B, A) in the following example
def g(x: B): x.f
class A:
f: Callable[[A1], None]
"""
# TODO: this is too strict. We can return filtered overloads for matching definitions
for item in functype.items():
if not item.arg_types or item.arg_kinds[0] not in (ARG_POS, ARG_STAR):
# No positional first (self) argument (*args is okay).
msg.no_formal_self(name, item, context)
else:
selfarg = item.arg_types[0]
if is_classmethod:
dispatched_arg_type = TypeType.make_normalized(dispatched_arg_type)
if not subtypes.is_subtype(dispatched_arg_type, erase_to_bound(selfarg)):
msg.incompatible_self_argument(name, dispatched_arg_type, item,
is_classmethod, context)
def analyze_type_callable_member_access(name: str,
typ: FunctionLike,
mx: MemberContext) -> Type:
# Class attribute.
# TODO super?
ret_type = typ.items()[0].ret_type
if isinstance(ret_type, TupleType):
ret_type = tuple_fallback(ret_type)
if isinstance(ret_type, Instance):
if not mx.is_operator:
# When Python sees an operator (eg `3 == 4`), it automatically translates that
# into something like `int.__eq__(3, 4)` instead of `(3).__eq__(4)` as an
# optimization.
#
# While it normally it doesn't matter which of the two versions are used, it
# does cause inconsistencies when working with classes. For example, translating
# `int == int` to `int.__eq__(int)` would not work since `int.__eq__` is meant to
# compare two int _instances_. What we really want is `type(int).__eq__`, which
# is meant to compare two types or classes.
#
# This check makes sure that when we encounter an operator, we skip looking up
# the corresponding method in the current instance to avoid this edge case.
# See https://github.com/python/mypy/pull/1787 for more info.
result = analyze_class_attribute_access(ret_type, name, mx)
if result:
return result
# Look up from the 'type' type.
return _analyze_member_access(name, typ.fallback, mx)
else:
assert False, 'Unexpected type {}'.format(repr(ret_type))
def type_object_type_from_function(signature: FunctionLike, info: TypeInfo,
def_info: TypeInfo,
fallback: Instance) -> FunctionLike:
# The __init__ method might come from a generic superclass
# (init_or_new.info) with type variables that do not map
# identically to the type variables of the class being constructed
# (info). For example
#
# class A(Generic[T]): def __init__(self, x: T) -> None: pass
# class B(A[List[T]], Generic[T]): pass
#
# We need to first map B's __init__ to the type (List[T]) -> None.
signature = bind_self(signature)
signature = cast(FunctionLike,
map_type_from_supertype(signature, info, def_info))
special_sig = None # type: Optional[str]
if def_info.fullname() == 'builtins.dict':
# Special signature!
special_sig = 'dict'
if isinstance(signature, CallableType):
return class_callable(signature, info, fallback, special_sig)
else:
# Overloaded __init__/__new__.
assert isinstance(signature, Overloaded)
items = [] # type: List[CallableType]
for item in signature.items():
items.append(class_callable(item, info, fallback, special_sig))
return Overloaded(items)
def _unify_type(
function: FunctionLike,
fetch_type: Callable[[CallableType], MypyType],
) -> MypyType:
return UnionType.make_union([
fetch_type(case)
for case in function.items()
])
def check_method_type(functype: FunctionLike, itype: Instance, context: Context, msg: MessageBuilder) -> None:
for item in functype.items():
if not item.arg_types or item.arg_kinds[0] != ARG_POS:
# No positional first (self) argument.
msg.invalid_method_type(item, context)
else:
# Check that self argument has type 'Any' or valid instance type.
selfarg = item.arg_types[0]
if not subtypes.is_equivalent(selfarg, itype):
msg.invalid_method_type(item, context)
def check_method_type(functype: FunctionLike, itype: Instance,
context: Context, msg: MessageBuilder) -> None:
for item in functype.items():
if not item.arg_types or item.arg_kinds[0] != ARG_POS:
# No positional first (self) argument.
msg.invalid_method_type(item, context)
else:
# Check that self argument has type 'Any' or valid instance type.
selfarg = item.arg_types[0]
if not subtypes.is_equivalent(selfarg, itype):
msg.invalid_method_type(item, context)
def check_self_arg(functype: FunctionLike,
dispatched_arg_type: Type,
is_classmethod: bool,
context: Context, name: str,
msg: MessageBuilder) -> FunctionLike:
"""Check that an instance has a valid type for a method with annotated 'self'.
For example if the method is defined as:
class A:
def f(self: S) -> T: ...
then for 'x.f' we check that meet(type(x), A) <: S. If the method is overloaded, we
select only overloads items that satisfy this requirement. If there are no matching
overloads, an error is generated.
Note: dispatched_arg_type uses a meet to select a relevant item in case if the
original type of 'x' is a union. This is done because several special methods
treat union types in ad-hoc manner, so we can't use MemberContext.self_type yet.
"""
items = functype.items()
if not items:
return functype
new_items = []
if is_classmethod:
dispatched_arg_type = TypeType.make_normalized(dispatched_arg_type)
for item in items:
if not item.arg_types or item.arg_kinds[0] not in (ARG_POS, ARG_STAR):
# No positional first (self) argument (*args is okay).
msg.no_formal_self(name, item, context)
# This is pretty bad, so just return the original signature if
# there is at least one such error.
return functype
else:
selfarg = item.arg_types[0]
if subtypes.is_subtype(dispatched_arg_type, erase_typevars(erase_to_bound(selfarg))):
new_items.append(item)
if not new_items:
# Choose first item for the message (it may be not very helpful for overloads).
msg.incompatible_self_argument(name, dispatched_arg_type, items[0],
is_classmethod, context)
return functype
if len(new_items) == 1:
return new_items[0]
return Overloaded(new_items)