def analyze_class_attribute_access(itype: Instance, name: str,
context: Context, is_lvalue: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context],
None],
msg: MessageBuilder,
original_type: Type) -> Optional[Type]:
"""original_type is the type of E in the expression E.var"""
node = itype.type.get(name)
if not node:
if itype.type.fallback_to_any:
return AnyType(TypeOfAny.special_form)
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
if itype.type.is_enum and not (is_lvalue or is_decorated or is_method):
return itype
t = node.type
if t:
if isinstance(t, PartialType):
symnode = node.node
assert symnode is not None
return handle_partial_attribute_type(t, is_lvalue, msg, symnode)
if not is_method and (isinstance(t, TypeVarType) or get_type_vars(t)):
msg.fail(messages.GENERIC_INSTANCE_VAR_CLASS_ACCESS, context)
is_classmethod = is_decorated and cast(Decorator,
node.node).func.is_class
return add_class_tvars(t, itype, is_classmethod, builtin_type,
original_type)
elif isinstance(node.node, Var):
not_ready_callback(name, context)
return AnyType(TypeOfAny.special_form)
if isinstance(node.node, TypeVarExpr):
msg.fail(
'Type variable "{}.{}" cannot be used as an expression'.format(
itype.type.name(), name), context)
return AnyType(TypeOfAny.from_error)
if isinstance(node.node, TypeInfo):
return type_object_type(node.node, builtin_type)
if isinstance(node.node, MypyFile):
# Reference to a module object.
return builtin_type('types.ModuleType')
if is_decorated:
# TODO: Return type of decorated function. This is quick hack to work around #998.
return AnyType(TypeOfAny.special_form)
else:
return function_type(cast(FuncBase, node.node),
builtin_type('builtins.function'))
def analyze_class_attribute_access(itype: Instance, name: str,
context: Context, is_lvalue: bool,
builtin_type: Callable[[str], Instance],
msg: MessageBuilder) -> Type:
node = itype.type.get(name)
if not node:
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
if itype.type.is_enum and not (is_lvalue or is_decorated or is_method):
return itype
t = node.type
if t:
is_classmethod = is_decorated and cast(Decorator,
node.node).func.is_class
return add_class_tvars(t, itype.type, is_classmethod, builtin_type)
if isinstance(node.node, TypeInfo):
return type_object_type(cast(TypeInfo, node.node), builtin_type)
return function_type(cast(FuncBase, node.node),
builtin_type('builtins.function'))
def analyze_class_attribute_access(itype: Instance,
name: str,
context: Context,
is_lvalue: bool,
builtin_type: Callable[[str], Instance],
msg: MessageBuilder) -> Type:
node = itype.type.get(name)
if not node:
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
if itype.type.is_enum and not (is_lvalue or is_decorated or is_method):
return itype
t = node.type
if t:
is_classmethod = is_decorated and cast(Decorator, node.node).func.is_class
return add_class_tvars(t, itype.type, is_classmethod, builtin_type)
if isinstance(node.node, TypeInfo):
return type_object_type(cast(TypeInfo, node.node), builtin_type)
return function_type(cast(FuncBase, node.node), builtin_type('builtins.function'))
def analyse_class_attribute_access(itype: Instance, name: str,
context: Context, is_lvalue: bool,
msg: MessageBuilder) -> Type:
node = itype.type.get(name)
if not node:
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
t = node.type
if t:
is_classmethod = is_decorated and cast(Decorator, node.node).func.is_class
return add_class_tvars(t, itype.type, is_classmethod)
if isinstance(node.node, TypeInfo):
# TODO add second argument
return type_object_type(cast(TypeInfo, node.node), None)
return function_type(cast(FuncBase, node.node))
def analyse_class_attribute_access(itype: Instance, name: str,
context: Context, is_lvalue: bool,
msg: MessageBuilder) -> Type:
node = itype.type.get(name)
if not node:
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
t = node.type
if t:
is_classmethod = is_decorated and cast(Decorator,
node.node).func.is_class
return add_class_tvars(t, itype.type, is_classmethod)
if isinstance(node.node, TypeInfo):
# TODO add second argument
return type_object_type(cast(TypeInfo, node.node), None)
return function_type(cast(FuncBase, node.node))
def analyze_var(name: str, var: Var, itype: Instance, info: TypeInfo,
node: Context, is_lvalue: bool, msg: MessageBuilder,
original_type: Type,
not_ready_callback: Callable[[str, Context], None], *,
chk: 'mypy.checker.TypeChecker') -> Type:
"""Analyze access to an attribute via a Var node.
This is conceptually part of analyze_member_access and the arguments are similar.
original_type is the type of E in the expression E.var
"""
# Found a member variable.
itype = map_instance_to_supertype(itype, var.info)
typ = var.type
if typ:
if isinstance(typ, PartialType):
return handle_partial_attribute_type(typ, is_lvalue, msg, var)
t = expand_type_by_instance(typ, itype)
if is_lvalue and var.is_property and not var.is_settable_property:
# TODO allow setting attributes in subclass (although it is probably an error)
msg.read_only_property(name, info, node)
if is_lvalue and var.is_classvar:
msg.cant_assign_to_classvar(name, node)
result = t
if var.is_initialized_in_class and isinstance(
t, FunctionLike) and not t.is_type_obj():
if is_lvalue:
if var.is_property:
if not var.is_settable_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound
# methods: the former to the instance, the latter to the
# class.
functype = t
check_method_type(functype, itype, var.is_classmethod, node,
msg)
signature = bind_self(functype, original_type,
var.is_classmethod)
if var.is_property:
# A property cannot have an overloaded type => the cast
# is fine.
assert isinstance(signature, CallableType)
result = signature.ret_type
else:
result = signature
else:
if not var.is_ready:
not_ready_callback(var.name(), node)
# Implicit 'Any' type.
result = AnyType(TypeOfAny.special_form)
fullname = '{}.{}'.format(var.info.fullname(), name)
hook = chk.plugin.get_attribute_hook(fullname)
if hook:
result = hook(AttributeContext(original_type, result, node, chk))
return result
def analyse_member_var_access(name: str, itype: Instance, info: TypeInfo,
node: Context, is_lvalue: bool, is_super: bool,
msg: MessageBuilder,
report_type: Type = None) -> Type:
"""Analyse attribute access that does not target a method.
This is logically part of analyse_member_access and the arguments are
similar.
"""
# It was not a method. Try looking up a variable.
v = lookup_member_var_or_accessor(info, name, is_lvalue)
vv = v
if isinstance(vv, Decorator):
# The associated Var node of a decorator contains the type.
v = vv.var
if isinstance(v, Var):
# Found a member variable.
var = v
itype = map_instance_to_supertype(itype, var.info)
if var.type:
t = expand_type_by_instance(var.type, itype)
if var.is_initialized_in_class and isinstance(t, FunctionLike):
if is_lvalue:
if var.is_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound
# methods: the former to the instance, the latter to the
# class.
functype = cast(FunctionLike, t)
check_method_type(functype, itype, node, msg)
signature = method_type(functype)
if var.is_property:
# A property cannot have an overloaded type => the cast
# is fine.
return cast(Callable, signature).ret_type
else:
return signature
return t
else:
if not var.is_ready:
msg.cannot_determine_type(var.name(), node)
# Implicit 'Any' type.
return AnyType()
elif isinstance(v, FuncDef):
assert False, "Did not expect a function"
# Could not find the member.
if is_super:
msg.undefined_in_superclass(name, node)
return AnyType()
else:
return msg.has_no_attr(report_type or itype, name, node)
def analyze_class_attribute_access(itype: Instance,
name: str,
context: Context,
is_lvalue: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
original_type: Type) -> Optional[Type]:
"""original_type is the type of E in the expression E.var"""
node = itype.type.get(name)
if not node:
if itype.type.fallback_to_any:
return AnyType(TypeOfAny.special_form)
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
if itype.type.is_enum and not (is_lvalue or is_decorated or is_method):
return itype
t = node.type
if t:
if isinstance(t, PartialType):
symnode = node.node
assert symnode is not None
return handle_partial_attribute_type(t, is_lvalue, msg, symnode)
if not is_method and (isinstance(t, TypeVarType) or get_type_vars(t)):
msg.fail(messages.GENERIC_INSTANCE_VAR_CLASS_ACCESS, context)
is_classmethod = is_decorated and cast(Decorator, node.node).func.is_class
return add_class_tvars(t, itype, is_classmethod, builtin_type, original_type)
elif isinstance(node.node, Var):
not_ready_callback(name, context)
return AnyType(TypeOfAny.special_form)
if isinstance(node.node, TypeVarExpr):
msg.fail('Type variable "{}.{}" cannot be used as an expression'.format(
itype.type.name(), name), context)
return AnyType(TypeOfAny.from_error)
if isinstance(node.node, TypeInfo):
return type_object_type(node.node, builtin_type)
if isinstance(node.node, MypyFile):
# Reference to a module object.
return builtin_type('types.ModuleType')
if is_decorated:
# TODO: Return type of decorated function. This is quick hack to work around #998.
return AnyType(TypeOfAny.special_form)
else:
return function_type(cast(FuncBase, node.node), builtin_type('builtins.function'))
def analyze_class_attribute_access(itype: Instance, name: str,
context: Context, is_lvalue: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context],
None],
msg: MessageBuilder,
original_type: Type) -> Type:
"""original_type is the type of E in the expression E.var"""
node = itype.type.get(name)
if not node:
if itype.type.fallback_to_any:
return AnyType()
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
if itype.type.is_enum and not (is_lvalue or is_decorated or is_method):
return itype
t = node.type
if t:
if isinstance(t, PartialType):
return handle_partial_attribute_type(t, is_lvalue, msg, node.node)
is_classmethod = is_decorated and cast(Decorator,
node.node).func.is_class
return add_class_tvars(t, itype, is_classmethod, builtin_type,
original_type)
elif isinstance(node.node, Var):
not_ready_callback(name, context)
return AnyType()
if isinstance(node.node, TypeVarExpr):
return TypeVarType(node.tvar_def, node.tvar_def.line,
node.tvar_def.column)
if isinstance(node.node, TypeInfo):
return type_object_type(node.node, builtin_type)
if isinstance(node.node, MypyFile):
# Reference to a module object.
return builtin_type('builtins.module')
if is_decorated:
# TODO: Return type of decorated function. This is quick hack to work around #998.
return AnyType()
else:
return function_type(cast(FuncBase, node.node),
builtin_type('builtins.function'))
def analyze_var(
name: str,
var: Var,
itype: Instance,
info: TypeInfo,
node: Context,
is_lvalue: bool,
msg: MessageBuilder,
not_ready_callback: Callable[[str, Context], None],
) -> Type:
"""Analyze access to an attribute via a Var node.
This is conceptually part of analyze_member_access and the arguments are similar.
"""
# Found a member variable.
itype = map_instance_to_supertype(itype, var.info)
typ = var.type
if typ:
if isinstance(typ, PartialType):
return handle_partial_attribute_type(typ, is_lvalue, msg, var)
t = expand_type_by_instance(typ, itype)
if is_lvalue and var.is_property and not var.is_settable_property:
# TODO allow setting attributes in subclass (although it is probably an error)
msg.read_only_property(name, info, node)
if var.is_initialized_in_class and isinstance(t, FunctionLike):
if is_lvalue:
if var.is_property:
if not var.is_settable_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound
# methods: the former to the instance, the latter to the
# class.
functype = t
check_method_type(functype, itype, var.is_classmethod, node, msg)
signature = method_type(functype)
if var.is_property:
# A property cannot have an overloaded type => the cast
# is fine.
return cast(CallableType, signature).ret_type
else:
return signature
return t
else:
if not var.is_ready:
not_ready_callback(var.name(), node)
# Implicit 'Any' type.
return AnyType()
def analyze_class_attribute_access(itype: Instance,
name: str,
context: Context,
is_lvalue: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
original_type: Type) -> Type:
"""original_type is the type of E in the expression E.var"""
node = itype.type.get(name)
if not node:
if itype.type.fallback_to_any:
return AnyType()
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
if itype.type.is_enum and not (is_lvalue or is_decorated or is_method):
return itype
t = node.type
if t:
if isinstance(t, PartialType):
return handle_partial_attribute_type(t, is_lvalue, msg, node.node)
is_classmethod = is_decorated and cast(Decorator, node.node).func.is_class
return add_class_tvars(t, itype, is_classmethod, builtin_type, original_type)
elif isinstance(node.node, Var):
not_ready_callback(name, context)
return AnyType()
if isinstance(node.node, TypeVarExpr):
return TypeVarType(node.tvar_def, node.tvar_def.line, node.tvar_def.column)
if isinstance(node.node, TypeInfo):
return type_object_type(node.node, builtin_type)
if isinstance(node.node, MypyFile):
# Reference to a module object.
return builtin_type('builtins.module')
if is_decorated:
# TODO: Return type of decorated function. This is quick hack to work around #998.
return AnyType()
else:
return function_type(cast(FuncBase, node.node), builtin_type('builtins.function'))
def analyze_var(name: str, var: Var, itype: Instance, info: TypeInfo,
node: Context, is_lvalue: bool, msg: MessageBuilder,
not_ready_callback: Callable[[str, Context], None]) -> Type:
"""Analyze access to an attribute via a Var node.
This is conceptually part of analyze_member_access and the arguments are similar.
"""
# Found a member variable.
itype = map_instance_to_supertype(itype, var.info)
typ = var.type
if typ:
if isinstance(typ, PartialType):
return handle_partial_attribute_type(typ, is_lvalue, msg, var)
t = expand_type_by_instance(typ, itype)
if is_lvalue and var.is_property and not var.is_settable_property:
# TODO allow setting attributes in subclass (although it is probably an error)
msg.read_only_property(name, info, node)
if var.is_initialized_in_class and isinstance(t, FunctionLike):
if is_lvalue:
if var.is_property:
if not var.is_settable_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound
# methods: the former to the instance, the latter to the
# class.
functype = t
check_method_type(functype, itype, var.is_classmethod, node,
msg)
signature = method_type(functype)
if var.is_property:
# A property cannot have an overloaded type => the cast
# is fine.
return cast(CallableType, signature).ret_type
else:
return signature
return t
else:
if not var.is_ready:
not_ready_callback(var.name(), node)
# Implicit 'Any' type.
return AnyType()
def analyze_class_attribute_access(
itype: Instance,
name: str,
context: Context,
is_lvalue: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
) -> Type:
node = itype.type.get(name)
if not node:
if itype.type.fallback_to_any:
return AnyType()
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncDef)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
if itype.type.is_enum and not (is_lvalue or is_decorated or is_method):
return itype
t = node.type
if t:
is_classmethod = is_decorated and cast(Decorator, node.node).func.is_class
return add_class_tvars(t, itype.type, is_classmethod, builtin_type)
elif isinstance(node.node, Var):
not_ready_callback(name, context)
return AnyType()
if isinstance(node.node, TypeInfo):
return type_object_type(cast(TypeInfo, node.node), builtin_type)
if is_decorated:
# TODO: Return type of decorated function. This is quick hack to work around #998.
return AnyType()
else:
return function_type(cast(FuncBase, node.node), builtin_type("builtins.function"))
def analyze_var(
name: str, var: Var, itype: Instance, info: TypeInfo, node: Context, is_lvalue: bool, msg: MessageBuilder
) -> Type:
"""Analyze access to an attribute via a Var node.
This is conceptually part of analyze_member_access and the arguments are similar.
"""
# Found a member variable.
itype = map_instance_to_supertype(itype, var.info)
if var.type:
t = expand_type_by_instance(var.type, itype)
if var.is_initialized_in_class and isinstance(t, FunctionLike):
if is_lvalue:
if var.is_property:
if not var.is_settable_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound
# methods: the former to the instance, the latter to the
# class.
functype = cast(FunctionLike, t)
check_method_type(functype, itype, node, msg)
signature = method_type(functype)
if var.is_property:
# A property cannot have an overloaded type => the cast
# is fine.
return cast(CallableType, signature).ret_type
else:
return signature
return t
else:
if not var.is_ready:
msg.cannot_determine_type(var.name(), node)
# Implicit 'Any' type.
return AnyType()
def analyze_var(name: str, var: Var, itype: Instance, info: TypeInfo,
node: Context, is_lvalue: bool, msg: MessageBuilder) -> Type:
"""Analyze access to an attribute via a Var node.
This is conceptually part of analyze_member_access and the arguments are similar.
"""
# Found a member variable.
itype = map_instance_to_supertype(itype, var.info)
if var.type:
t = expand_type_by_instance(var.type, itype)
if var.is_initialized_in_class and isinstance(t, FunctionLike):
if is_lvalue:
if var.is_property:
if not var.is_settable_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound
# methods: the former to the instance, the latter to the
# class.
functype = cast(FunctionLike, t)
check_method_type(functype, itype, node, msg)
signature = method_type(functype)
if var.is_property:
# A property cannot have an overloaded type => the cast
# is fine.
return cast(CallableType, signature).ret_type
else:
return signature
return t
else:
if not var.is_ready:
msg.cannot_determine_type(var.name(), node)
# Implicit 'Any' type.
return AnyType()
def analyze_member_access(name: str,
typ: Type,
node: Context,
is_lvalue: bool,
is_super: bool,
is_operator: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder, *,
original_type: Type,
chk: 'mypy.checker.TypeChecker',
override_info: Optional[TypeInfo] = None) -> Type:
"""Return the type of attribute `name` of typ.
This is a general operation that supports various different variations:
1. lvalue or non-lvalue access (i.e. setter or getter access)
2. supertype access (when using super(); is_super == True and
override_info should refer to the supertype)
original_type is the most precise inferred or declared type of the base object
that we have available. typ is generally a supertype of original_type.
When looking for an attribute of typ, we may perform recursive calls targeting
the fallback type, for example.
original_type is always the type used in the initial call.
"""
# TODO: this and following functions share some logic with subtypes.find_member,
# consider refactoring.
if isinstance(typ, Instance):
if name == '__init__' and not is_super:
# Accessing __init__ in statically typed code would compromise
# type safety unless used via super().
msg.fail(messages.CANNOT_ACCESS_INIT, node)
return AnyType(TypeOfAny.from_error)
# The base object has an instance type.
info = typ.type
if override_info:
info = override_info
if (experiments.find_occurrences and
info.name() == experiments.find_occurrences[0] and
name == experiments.find_occurrences[1]):
msg.note("Occurrence of '{}.{}'".format(*experiments.find_occurrences), node)
# Look up the member. First look up the method dictionary.
method = info.get_method(name)
if method:
if method.is_property:
assert isinstance(method, OverloadedFuncDef)
first_item = cast(Decorator, method.items[0])
return analyze_var(name, first_item.var, typ, info, node, is_lvalue, msg,
original_type, not_ready_callback, chk=chk)
if is_lvalue:
msg.cant_assign_to_method(node)
signature = function_type(method, builtin_type('builtins.function'))
signature = freshen_function_type_vars(signature)
if name == '__new__':
# __new__ is special and behaves like a static method -- don't strip
# the first argument.
pass
else:
signature = bind_self(signature, original_type)
typ = map_instance_to_supertype(typ, method.info)
member_type = expand_type_by_instance(signature, typ)
freeze_type_vars(member_type)
return member_type
else:
# Not a method.
return analyze_member_var_access(name, typ, info, node,
is_lvalue, is_super, builtin_type,
not_ready_callback, msg,
original_type=original_type, chk=chk)
elif isinstance(typ, AnyType):
# The base object has dynamic type.
return AnyType(TypeOfAny.from_another_any, source_any=typ)
elif isinstance(typ, NoneTyp):
if chk.should_suppress_optional_error([typ]):
return AnyType(TypeOfAny.from_error)
# The only attribute NoneType has are those it inherits from object
return analyze_member_access(name, builtin_type('builtins.object'), node, is_lvalue,
is_super, is_operator, builtin_type, not_ready_callback, msg,
original_type=original_type, chk=chk)
elif isinstance(typ, UnionType):
# The base object has dynamic type.
msg.disable_type_names += 1
results = [analyze_member_access(name, subtype, node, is_lvalue, is_super,
is_operator, builtin_type, not_ready_callback, msg,
original_type=original_type, chk=chk)
for subtype in typ.relevant_items()]
msg.disable_type_names -= 1
return UnionType.make_simplified_union(results)
elif isinstance(typ, TupleType):
# Actually look up from the fallback instance type.
return analyze_member_access(name, typ.fallback, node, is_lvalue, is_super,
is_operator, builtin_type, not_ready_callback, msg,
original_type=original_type, chk=chk)
elif isinstance(typ, TypedDictType):
# Actually look up from the fallback instance type.
return analyze_member_access(name, typ.fallback, node, is_lvalue, is_super,
is_operator, builtin_type, not_ready_callback, msg,
original_type=original_type, chk=chk)
elif isinstance(typ, FunctionLike) and typ.is_type_obj():
# Class attribute.
# TODO super?
ret_type = typ.items()[0].ret_type
if isinstance(ret_type, TupleType):
ret_type = ret_type.fallback
if isinstance(ret_type, Instance):
if not 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, node, is_lvalue,
builtin_type, not_ready_callback, msg,
original_type=original_type)
if result:
return result
# Look up from the 'type' type.
return analyze_member_access(name, typ.fallback, node, is_lvalue, is_super,
is_operator, builtin_type, not_ready_callback, msg,
original_type=original_type, chk=chk)
else:
assert False, 'Unexpected type {}'.format(repr(ret_type))
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyze_member_access(name, typ.fallback, node, is_lvalue, is_super,
is_operator, builtin_type, not_ready_callback, msg,
original_type=original_type, chk=chk)
elif isinstance(typ, TypeVarType):
return analyze_member_access(name, typ.upper_bound, node, is_lvalue, is_super,
is_operator, builtin_type, not_ready_callback, msg,
original_type=original_type, chk=chk)
elif isinstance(typ, DeletedType):
msg.deleted_as_rvalue(typ, node)
return AnyType(TypeOfAny.from_error)
elif isinstance(typ, TypeType):
# Similar to FunctionLike + is_type_obj() above.
item = None
fallback = builtin_type('builtins.type')
ignore_messages = msg.copy()
ignore_messages.disable_errors()
if isinstance(typ.item, Instance):
item = typ.item
elif isinstance(typ.item, AnyType):
return analyze_member_access(name, fallback, node, is_lvalue, is_super,
is_operator, builtin_type, not_ready_callback,
ignore_messages, original_type=original_type, chk=chk)
elif isinstance(typ.item, TypeVarType):
if isinstance(typ.item.upper_bound, Instance):
item = typ.item.upper_bound
elif isinstance(typ.item, TupleType):
item = typ.item.fallback
elif isinstance(typ.item, FunctionLike) and typ.item.is_type_obj():
item = typ.item.fallback
elif isinstance(typ.item, TypeType):
# Access member on metaclass object via Type[Type[C]]
if isinstance(typ.item.item, Instance):
item = typ.item.item.type.metaclass_type
if item and not is_operator:
# See comment above for why operators are skipped
result = analyze_class_attribute_access(item, name, node, is_lvalue,
builtin_type, not_ready_callback, msg,
original_type=original_type)
if result:
if not (isinstance(result, AnyType) and item.type.fallback_to_any):
return result
else:
# We don't want errors on metaclass lookup for classes with Any fallback
msg = ignore_messages
if item is not None:
fallback = item.type.metaclass_type or fallback
return analyze_member_access(name, fallback, node, is_lvalue, is_super,
is_operator, builtin_type, not_ready_callback, msg,
original_type=original_type, chk=chk)
if chk.should_suppress_optional_error([typ]):
return AnyType(TypeOfAny.from_error)
return msg.has_no_attr(original_type, typ, name, node)
def analyze_member_access(name: str,
typ: Type,
node: Context,
is_lvalue: bool,
is_super: bool,
is_operator: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
*,
original_type: Type,
override_info: TypeInfo = None,
chk: 'mypy.checker.TypeChecker' = None) -> Type:
"""Return the type of attribute `name` of typ.
This is a general operation that supports various different variations:
1. lvalue or non-lvalue access (i.e. setter or getter access)
2. supertype access (when using super(); is_super == True and
override_info should refer to the supertype)
original_type is the most precise inferred or declared type of the base object
that we have available. typ is generally a supertype of original_type.
When looking for an attribute of typ, we may perform recursive calls targeting
the fallback type, for example.
original_type is always the type used in the initial call.
"""
if isinstance(typ, Instance):
if name == '__init__' and not is_super:
# Accessing __init__ in statically typed code would compromise
# type safety unless used via super().
msg.fail(messages.CANNOT_ACCESS_INIT, node)
return AnyType()
# The base object has an instance type.
info = typ.type
if override_info:
info = override_info
if (experiments.find_occurrences
and info.name() == experiments.find_occurrences[0]
and name == experiments.find_occurrences[1]):
msg.note(
"Occurrence of '{}.{}'".format(*experiments.find_occurrences),
node)
# Look up the member. First look up the method dictionary.
method = info.get_method(name)
if method:
if method.is_property:
assert isinstance(method, OverloadedFuncDef)
return analyze_var(name, method.items[0].var, typ, info, node,
is_lvalue, msg, original_type,
not_ready_callback)
if is_lvalue:
msg.cant_assign_to_method(node)
signature = function_type(method,
builtin_type('builtins.function'))
signature = freshen_function_type_vars(signature)
if name == '__new__':
# __new__ is special and behaves like a static method -- don't strip
# the first argument.
pass
else:
signature = bind_self(signature, original_type)
typ = map_instance_to_supertype(typ, method.info)
member_type = expand_type_by_instance(signature, typ)
freeze_type_vars(member_type)
return member_type
else:
# Not a method.
return analyze_member_var_access(name,
typ,
info,
node,
is_lvalue,
is_super,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, AnyType):
# The base object has dynamic type.
return AnyType()
elif isinstance(typ, NoneTyp):
if chk and chk.should_suppress_optional_error([typ]):
return AnyType()
# The only attribute NoneType has are those it inherits from object
return analyze_member_access(name,
builtin_type('builtins.object'),
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, UnionType):
# The base object has dynamic type.
msg.disable_type_names += 1
results = [
analyze_member_access(name,
subtype,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk) for subtype in typ.items
]
msg.disable_type_names -= 1
return UnionType.make_simplified_union(results)
elif isinstance(typ, TupleType):
# Actually look up from the fallback instance type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, TypedDictType):
# Actually look up from the fallback instance type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, FunctionLike) and typ.is_type_obj():
# Class attribute.
# TODO super?
ret_type = typ.items()[0].ret_type
if isinstance(ret_type, TupleType):
ret_type = ret_type.fallback
if isinstance(ret_type, Instance):
if not 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,
node,
is_lvalue,
builtin_type,
not_ready_callback,
msg,
original_type=original_type)
if result:
return result
# Look up from the 'type' type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
else:
assert False, 'Unexpected type {}'.format(repr(ret_type))
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, TypeVarType):
return analyze_member_access(name,
typ.upper_bound,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
elif isinstance(typ, DeletedType):
msg.deleted_as_rvalue(typ, node)
return AnyType()
elif isinstance(typ, TypeType):
# Similar to FunctionLike + is_type_obj() above.
item = None
if isinstance(typ.item, Instance):
item = typ.item
elif isinstance(typ.item, TypeVarType):
if isinstance(typ.item.upper_bound, Instance):
item = typ.item.upper_bound
if item and not is_operator:
# See comment above for why operators are skipped
result = analyze_class_attribute_access(
item,
name,
node,
is_lvalue,
builtin_type,
not_ready_callback,
msg,
original_type=original_type)
if result:
return result
fallback = builtin_type('builtins.type')
if item is not None:
fallback = item.type.metaclass_type or fallback
return analyze_member_access(name,
fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
original_type=original_type,
chk=chk)
if chk and chk.should_suppress_optional_error([typ]):
return AnyType()
return msg.has_no_attr(original_type, name, node)
def analyze_member_access(
name: str,
typ: Type,
node: Context,
is_lvalue: bool,
is_super: bool,
is_operator: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
override_info: TypeInfo = None,
report_type: Type = None,
chk: "mypy.checker.TypeChecker" = None,
) -> Type:
"""Analyse attribute access.
This is a general operation that supports various different variations:
1. lvalue or non-lvalue access (i.e. setter or getter access)
2. supertype access (when using super(); is_super == True and
override_info should refer to the supertype)
"""
report_type = report_type or typ
if isinstance(typ, Instance):
if name == "__init__" and not is_super:
# Accessing __init__ in statically typed code would compromise
# type safety unless used via super().
msg.fail(messages.CANNOT_ACCESS_INIT, node)
return AnyType()
# The base object has an instance type.
info = typ.type
if override_info:
info = override_info
# Look up the member. First look up the method dictionary.
method = info.get_method(name)
if method:
if method.is_property:
assert isinstance(method, OverloadedFuncDef)
return analyze_var(name, method.items[0].var, typ, info, node, is_lvalue, msg, not_ready_callback)
if is_lvalue:
msg.cant_assign_to_method(node)
typ = map_instance_to_supertype(typ, method.info)
if name == "__new__":
# __new__ is special and behaves like a static method -- don't strip
# the first argument.
signature = function_type(method, builtin_type("builtins.function"))
else:
signature = method_type_with_fallback(method, builtin_type("builtins.function"))
return expand_type_by_instance(signature, typ)
else:
# Not a method.
return analyze_member_var_access(
name,
typ,
info,
node,
is_lvalue,
is_super,
builtin_type,
not_ready_callback,
msg,
report_type=report_type,
chk=chk,
)
elif isinstance(typ, AnyType):
# The base object has dynamic type.
return AnyType()
elif isinstance(typ, NoneTyp):
if chk and chk.should_suppress_optional_error([typ]):
return AnyType()
# The only attribute NoneType has are those it inherits from object
return analyze_member_access(
name,
builtin_type("builtins.object"),
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
report_type=report_type,
chk=chk,
)
elif isinstance(typ, UnionType):
# The base object has dynamic type.
msg.disable_type_names += 1
results = [
analyze_member_access(
name, subtype, node, is_lvalue, is_super, is_operator, builtin_type, not_ready_callback, msg, chk=chk
)
for subtype in typ.items
]
msg.disable_type_names -= 1
return UnionType.make_simplified_union(results)
elif isinstance(typ, TupleType):
# Actually look up from the fallback instance type.
return analyze_member_access(
name, typ.fallback, node, is_lvalue, is_super, is_operator, builtin_type, not_ready_callback, msg, chk=chk
)
elif isinstance(typ, FunctionLike) and typ.is_type_obj():
# Class attribute.
# TODO super?
ret_type = typ.items()[0].ret_type
if isinstance(ret_type, TupleType):
ret_type = ret_type.fallback
if isinstance(ret_type, Instance):
if not 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
# optimation.
#
# 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, node, is_lvalue, builtin_type, not_ready_callback, msg
)
if result:
return result
# Look up from the 'type' type.
return analyze_member_access(
name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
report_type=report_type,
chk=chk,
)
else:
assert False, "Unexpected type {}".format(repr(ret_type))
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyze_member_access(
name,
typ.fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
report_type=report_type,
chk=chk,
)
elif isinstance(typ, TypeVarType):
return analyze_member_access(
name,
typ.upper_bound,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
report_type=report_type,
chk=chk,
)
elif isinstance(typ, DeletedType):
msg.deleted_as_rvalue(typ, node)
return AnyType()
elif isinstance(typ, TypeType):
# Similar to FunctionLike + is_type_obj() above.
item = None
if isinstance(typ.item, Instance):
item = typ.item
elif isinstance(typ.item, TypeVarType):
if isinstance(typ.item.upper_bound, Instance):
item = typ.item.upper_bound
if item and not is_operator:
# See comment above for why operators are skipped
result = analyze_class_attribute_access(item, name, node, is_lvalue, builtin_type, not_ready_callback, msg)
if result:
return result
fallback = builtin_type("builtins.type")
return analyze_member_access(
name,
fallback,
node,
is_lvalue,
is_super,
is_operator,
builtin_type,
not_ready_callback,
msg,
report_type=report_type,
chk=chk,
)
if chk and chk.should_suppress_optional_error([typ]):
return AnyType()
return msg.has_no_attr(report_type, name, node)
def analyse_member_var_access(name: str,
itype: Instance,
info: TypeInfo,
node: Context,
is_lvalue: bool,
is_super: bool,
msg: MessageBuilder,
report_type: Type = None) -> Type:
"""Analyse attribute access that does not target a method.
This is logically part of analyse_member_access and the arguments are
similar.
"""
# It was not a method. Try looking up a variable.
v = lookup_member_var_or_accessor(info, name, is_lvalue)
vv = v
if isinstance(vv, Decorator):
# The associated Var node of a decorator contains the type.
v = vv.var
if isinstance(v, Var):
# Found a member variable.
var = v
itype = map_instance_to_supertype(itype, var.info)
if var.type:
t = expand_type_by_instance(var.type, itype)
if var.is_initialized_in_class and isinstance(t, FunctionLike):
if is_lvalue:
if var.is_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound
# methods: the former to the instance, the latter to the
# class.
functype = cast(FunctionLike, t)
check_method_type(functype, itype, node, msg)
signature = method_type(functype)
if var.is_property:
# A property cannot have an overloaded type => the cast
# is fine.
return cast(Callable, signature).ret_type
else:
return signature
return t
else:
if not var.is_ready:
msg.cannot_determine_type(var.name(), node)
# Implicit 'Any' type.
return AnyType()
elif isinstance(v, FuncDef):
assert False, "Did not expect a function"
# Could not find the member.
if is_super:
msg.undefined_in_superclass(name, node)
return AnyType()
else:
return msg.has_no_attr(report_type or itype, name, node)
def analyze_member_access(name: str,
typ: Type,
node: Context,
is_lvalue: bool,
is_super: bool,
builtin_type: Callable[[str], Instance],
msg: MessageBuilder,
override_info: TypeInfo = None,
report_type: Type = None) -> Type:
"""Analyse attribute access.
This is a general operation that supports various different variations:
1. lvalue or non-lvalue access (i.e. setter or getter access)
2. supertype access (when using super(); is_super == True and
override_info should refer to the supertype)
"""
report_type = report_type or typ
if isinstance(typ, Instance):
if name == '__init__' and not is_super:
# Accessing __init__ in statically typed code would compromise
# type safety unless used via super().
msg.fail(messages.CANNOT_ACCESS_INIT, node)
return AnyType()
# The base object has an instance type.
info = typ.type
if override_info:
info = override_info
# Look up the member. First look up the method dictionary.
method = info.get_method(name)
if method:
if method.is_property:
assert isinstance(method, OverloadedFuncDef)
method = cast(OverloadedFuncDef, method)
return analyze_var(name, method.items[0].var, typ, info, node,
is_lvalue, msg)
if is_lvalue:
msg.cant_assign_to_method(node)
typ = map_instance_to_supertype(typ, method.info)
return expand_type_by_instance(
method_type_with_fallback(method,
builtin_type('builtins.function')),
typ)
else:
# Not a method.
return analyze_member_var_access(name,
typ,
info,
node,
is_lvalue,
is_super,
builtin_type,
msg,
report_type=report_type)
elif isinstance(typ, AnyType):
# The base object has dynamic type.
return AnyType()
elif isinstance(typ, UnionType):
# The base object has dynamic type.
msg.disable_type_names += 1
results = [
analyze_member_access(name, subtype, node, is_lvalue, is_super,
builtin_type, msg) for subtype in typ.items
]
msg.disable_type_names -= 1
return UnionType.make_simplified_union(results)
elif isinstance(typ, TupleType):
# Actually look up from the fallback instance type.
return analyze_member_access(name, typ.fallback, node, is_lvalue,
is_super, builtin_type, msg)
elif isinstance(typ, FunctionLike) and typ.is_type_obj():
# Class attribute.
# TODO super?
itype = cast(Instance, typ.items()[0].ret_type)
result = analyze_class_attribute_access(itype, name, node, is_lvalue,
builtin_type, msg)
if result:
return result
# Look up from the 'type' type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
builtin_type,
msg,
report_type=report_type)
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyze_member_access(name,
typ.fallback,
node,
is_lvalue,
is_super,
builtin_type,
msg,
report_type=report_type)
elif isinstance(typ, TypeVarType):
return analyze_member_access(name,
typ.upper_bound,
node,
is_lvalue,
is_super,
builtin_type,
msg,
report_type=report_type)
return msg.has_no_attr(report_type, name, node)
def analyse_member_access(name: str, typ: Type, node: Context, is_lvalue: bool,
is_super: bool,
builtin_type: Function[[str], Instance],
msg: MessageBuilder, override_info: TypeInfo = None,
report_type: Type = None) -> Type:
"""Analyse attribute access.
This is a general operation that supports various different variations:
1. lvalue or non-lvalue access (i.e. setter or getter access)
2. supertype access (when using super(); is_super == True and
override_info should refer to the supertype)
"""
report_type = report_type or typ
if isinstance(typ, Instance):
if name == '__init__' and not is_super:
# Accessing __init__ in statically typed code would compromise
# type safety unless used via super().
msg.fail(messages.CANNOT_ACCESS_INIT, node)
return AnyType()
# The base object has an instance type.
info = typ.type
if override_info:
info = override_info
# Look up the member. First look up the method dictionary.
method = info.get_method(name)
if method:
if is_lvalue:
msg.cant_assign_to_method(node)
typ = map_instance_to_supertype(typ, method.info)
return expand_type_by_instance(
method_type(method, builtin_type('builtins.function')), typ)
else:
# Not a method.
return analyse_member_var_access(name, typ, info, node,
is_lvalue, is_super, msg,
report_type=report_type)
elif isinstance(typ, AnyType):
# The base object has dynamic type.
return AnyType()
elif isinstance(typ, UnionType):
# The base object has dynamic type.
msg.disable_type_names += 1
results = [analyse_member_access(name, subtype, node, is_lvalue,
is_super, builtin_type, msg)
for subtype in typ.items]
msg.disable_type_names -= 1
return UnionType.make_simplified_union(results)
elif isinstance(typ, TupleType):
# Actually look up from the fallback instance type.
return analyse_member_access(name, typ.fallback, node, is_lvalue,
is_super, builtin_type, msg)
elif (isinstance(typ, FunctionLike) and
cast(FunctionLike, typ).is_type_obj()):
# Class attribute.
# TODO super?
sig = cast(FunctionLike, typ)
itype = cast(Instance, sig.items()[0].ret_type)
result = analyse_class_attribute_access(itype, name, node, is_lvalue, builtin_type, msg)
if result:
return result
# Look up from the 'type' type.
return analyse_member_access(name, sig.fallback, node, is_lvalue, is_super,
builtin_type, msg, report_type=report_type)
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyse_member_access(name, typ.fallback, node, is_lvalue, is_super,
builtin_type, msg, report_type=report_type)
return msg.has_no_attr(report_type, name, node)
def analyze_var(name: str, var: Var, itype: Instance, info: TypeInfo, node: Context,
is_lvalue: bool, msg: MessageBuilder, original_type: Type,
not_ready_callback: Callable[[str, Context], None], *,
chk: 'mypy.checker.TypeChecker') -> Type:
"""Analyze access to an attribute via a Var node.
This is conceptually part of analyze_member_access and the arguments are similar.
itype is the class object in which var is dedined
original_type is the type of E in the expression E.var
"""
# Found a member variable.
itype = map_instance_to_supertype(itype, var.info)
typ = var.type
if typ:
if isinstance(typ, PartialType):
return handle_partial_attribute_type(typ, is_lvalue, msg, var)
t = expand_type_by_instance(typ, itype)
if is_lvalue and var.is_property and not var.is_settable_property:
# TODO allow setting attributes in subclass (although it is probably an error)
msg.read_only_property(name, info, node)
if is_lvalue and var.is_classvar:
msg.cant_assign_to_classvar(name, node)
result = t
if var.is_initialized_in_class and isinstance(t, FunctionLike) and not t.is_type_obj():
if is_lvalue:
if var.is_property:
if not var.is_settable_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound methods:
# the former to the instance, the latter to the class.
functype = t
# Use meet to narrow original_type to the dispatched type.
# For example, assume
# * A.f: Callable[[A1], None] where A1 <: A (maybe A1 == A)
# * B.f: Callable[[B1], None] where B1 <: B (maybe B1 == B)
# * x: Union[A1, B1]
# In `x.f`, when checking `x` against A1 we assume x is compatible with A
# and similarly for B1 when checking agains B
dispatched_type = meet.meet_types(original_type, itype)
check_self_arg(functype, dispatched_type, var.is_classmethod, node, name, msg)
signature = bind_self(functype, original_type, var.is_classmethod)
if var.is_property:
# A property cannot have an overloaded type => the cast is fine.
assert isinstance(signature, CallableType)
result = signature.ret_type
else:
result = signature
else:
if not var.is_ready:
not_ready_callback(var.name(), node)
# Implicit 'Any' type.
result = AnyType(TypeOfAny.special_form)
fullname = '{}.{}'.format(var.info.fullname(), name)
hook = chk.plugin.get_attribute_hook(fullname)
if hook:
result = hook(AttributeContext(original_type, result, node, chk))
return result
def analyze_var(name: str, var: Var, itype: Instance, info: TypeInfo,
node: Context, is_lvalue: bool, msg: MessageBuilder,
original_type: Type,
not_ready_callback: Callable[[str, Context], None], *,
chk: 'mypy.checker.TypeChecker') -> Type:
"""Analyze access to an attribute via a Var node.
This is conceptually part of analyze_member_access and the arguments are similar.
itype is the class object in which var is dedined
original_type is the type of E in the expression E.var
"""
# Found a member variable.
itype = map_instance_to_supertype(itype, var.info)
typ = var.type
if typ:
if isinstance(typ, PartialType):
return handle_partial_attribute_type(typ, is_lvalue, msg, var)
t = expand_type_by_instance(typ, itype)
if is_lvalue and var.is_property and not var.is_settable_property:
# TODO allow setting attributes in subclass (although it is probably an error)
msg.read_only_property(name, info, node)
if is_lvalue and var.is_classvar:
msg.cant_assign_to_classvar(name, node)
result = t
if var.is_initialized_in_class and isinstance(
t, FunctionLike) and not t.is_type_obj():
if is_lvalue:
if var.is_property:
if not var.is_settable_property:
msg.read_only_property(name, info, node)
else:
msg.cant_assign_to_method(node)
if not var.is_staticmethod:
# Class-level function objects and classmethods become bound methods:
# the former to the instance, the latter to the class.
functype = t
# Use meet to narrow original_type to the dispatched type.
# For example, assume
# * A.f: Callable[[A1], None] where A1 <: A (maybe A1 == A)
# * B.f: Callable[[B1], None] where B1 <: B (maybe B1 == B)
# * x: Union[A1, B1]
# In `x.f`, when checking `x` against A1 we assume x is compatible with A
# and similarly for B1 when checking agains B
dispatched_type = meet.meet_types(original_type, itype)
check_self_arg(functype, dispatched_type, var.is_classmethod,
node, name, msg)
signature = bind_self(functype, original_type,
var.is_classmethod)
if var.is_property:
# A property cannot have an overloaded type => the cast is fine.
assert isinstance(signature, CallableType)
result = signature.ret_type
else:
result = signature
else:
if not var.is_ready:
not_ready_callback(var.name(), node)
# Implicit 'Any' type.
result = AnyType(TypeOfAny.special_form)
fullname = '{}.{}'.format(var.info.fullname(), name)
hook = chk.plugin.get_attribute_hook(fullname)
if hook:
result = hook(AttributeContext(original_type, result, node, chk))
return result
def analyze_class_attribute_access(itype: Instance,
name: str,
context: Context,
is_lvalue: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
original_type: Type,
chk: 'mypy.checker.TypeChecker') -> Optional[Type]:
"""original_type is the type of E in the expression E.var"""
node = itype.type.get(name)
if not node:
if itype.type.fallback_to_any:
return AnyType(TypeOfAny.special_form)
return None
is_decorated = isinstance(node.node, Decorator)
is_method = is_decorated or isinstance(node.node, FuncBase)
if is_lvalue:
if is_method:
msg.cant_assign_to_method(context)
if isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
# If a final attribute was declared on `self` in `__init__`, then it
# can't be accessed on the class object.
if node.implicit and isinstance(node.node, Var) and node.node.is_final:
msg.fail('Cannot access final instance '
'attribute "{}" on class object'.format(node.node.name()), context)
# An assignment to final attribute on class object is also always an error,
# independently of types.
if is_lvalue and not chk.get_final_context():
check_final_member(name, itype.type, msg, context)
if itype.type.is_enum and not (is_lvalue or is_decorated or is_method):
return itype
t = node.type
if t:
if isinstance(t, PartialType):
symnode = node.node
assert isinstance(symnode, Var)
return chk.handle_partial_var_type(t, is_lvalue, symnode, context)
if not is_method and (isinstance(t, TypeVarType) or get_type_vars(t)):
msg.fail(messages.GENERIC_INSTANCE_VAR_CLASS_ACCESS, context)
is_classmethod = ((is_decorated and cast(Decorator, node.node).func.is_class)
or (isinstance(node.node, FuncBase) and node.node.is_class))
result = add_class_tvars(t, itype, is_classmethod, builtin_type, original_type)
if not is_lvalue:
result = analyze_descriptor_access(original_type, result, builtin_type,
msg, context, chk=chk)
return result
elif isinstance(node.node, Var):
not_ready_callback(name, context)
return AnyType(TypeOfAny.special_form)
if isinstance(node.node, TypeVarExpr):
msg.fail('Type variable "{}.{}" cannot be used as an expression'.format(
itype.type.name(), name), context)
return AnyType(TypeOfAny.from_error)
if isinstance(node.node, TypeInfo):
return type_object_type(node.node, builtin_type)
if isinstance(node.node, MypyFile):
# Reference to a module object.
return builtin_type('types.ModuleType')
if isinstance(node.node, TypeAlias) and isinstance(node.node.target, Instance):
return instance_alias_type(node.node, builtin_type)
if is_decorated:
assert isinstance(node.node, Decorator)
if node.node.type:
return node.node.type
else:
not_ready_callback(name, context)
return AnyType(TypeOfAny.from_error)
else:
return function_type(cast(FuncBase, node.node), builtin_type('builtins.function'))
def analyze_member_access(name: str, typ: Type, node: Context, is_lvalue: bool,
is_super: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder, override_info: TypeInfo = None,
report_type: Type = None) -> Type:
"""Analyse attribute access.
This is a general operation that supports various different variations:
1. lvalue or non-lvalue access (i.e. setter or getter access)
2. supertype access (when using super(); is_super == True and
override_info should refer to the supertype)
"""
report_type = report_type or typ
if isinstance(typ, Instance):
if name == '__init__' and not is_super:
# Accessing __init__ in statically typed code would compromise
# type safety unless used via super().
msg.fail(messages.CANNOT_ACCESS_INIT, node)
return AnyType()
# The base object has an instance type.
info = typ.type
if override_info:
info = override_info
# Look up the member. First look up the method dictionary.
method = info.get_method(name)
if method:
if method.is_property:
assert isinstance(method, OverloadedFuncDef)
method = cast(OverloadedFuncDef, method)
return analyze_var(name, method.items[0].var, typ, info, node, is_lvalue, msg,
not_ready_callback)
if is_lvalue:
msg.cant_assign_to_method(node)
typ = map_instance_to_supertype(typ, method.info)
if name == '__new__':
# __new__ is special and behaves like a static method -- don't strip
# the first argument.
signature = function_type(method, builtin_type('builtins.function'))
else:
signature = method_type_with_fallback(method, builtin_type('builtins.function'))
return expand_type_by_instance(signature, typ)
else:
# Not a method.
return analyze_member_var_access(name, typ, info, node,
is_lvalue, is_super, builtin_type,
not_ready_callback, msg,
report_type=report_type)
elif isinstance(typ, AnyType):
# The base object has dynamic type.
return AnyType()
elif isinstance(typ, UnionType):
# The base object has dynamic type.
msg.disable_type_names += 1
results = [analyze_member_access(name, subtype, node, is_lvalue,
is_super, builtin_type, not_ready_callback, msg)
for subtype in typ.items]
msg.disable_type_names -= 1
return UnionType.make_simplified_union(results)
elif isinstance(typ, TupleType):
# Actually look up from the fallback instance type.
return analyze_member_access(name, typ.fallback, node, is_lvalue,
is_super, builtin_type, not_ready_callback, msg)
elif isinstance(typ, FunctionLike) and typ.is_type_obj():
# Class attribute.
# TODO super?
ret_type = typ.items()[0].ret_type
if isinstance(ret_type, TupleType):
ret_type = ret_type.fallback
if isinstance(ret_type, Instance):
result = analyze_class_attribute_access(ret_type, name, node, is_lvalue,
builtin_type, not_ready_callback, msg)
if result:
return result
# Look up from the 'type' type.
return analyze_member_access(name, typ.fallback, node, is_lvalue, is_super,
builtin_type, not_ready_callback, msg,
report_type=report_type)
else:
assert False, 'Unexpected type {}'.format(repr(ret_type))
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyze_member_access(name, typ.fallback, node, is_lvalue, is_super,
builtin_type, not_ready_callback, msg,
report_type=report_type)
elif isinstance(typ, TypeVarType):
return analyze_member_access(name, typ.upper_bound, node, is_lvalue, is_super,
builtin_type, not_ready_callback, msg,
report_type=report_type)
elif isinstance(typ, DeletedType):
msg.deleted_as_rvalue(typ, node)
return AnyType()
return msg.has_no_attr(report_type, name, node)
