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 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 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 check_for_explicit_any(typ: Optional[Type],
options: Options,
is_typeshed_stub: bool,
msg: MessageBuilder,
context: Context) -> None:
if (options.disallow_any_explicit and
not is_typeshed_stub and
typ and
has_explicit_any(typ)):
msg.explicit_any(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 apply_generic_arguments(callable: CallableType, types: List[Type],
msg: MessageBuilder, context: Context) -> Type:
"""Apply generic type arguments to a callable type.
For example, applying [int] to 'def [T] (T) -> T' results in
'def [-1:int] (int) -> int'. Here '[-1:int]' is an implicit bound type
variable.
Note that each type can be None; in this case, it will not be applied.
"""
tvars = callable.variables
if len(tvars) != len(types):
msg.incompatible_type_application(len(tvars), len(types), context)
return AnyType()
# Check that inferred type variable values are compatible with allowed
# values. Also, promote subtype values to allowed values.
types = types[:]
for i, type in enumerate(types):
values = callable.variables[i].values
if values and type:
if isinstance(type, AnyType):
continue
for value in values:
if mypy.subtypes.is_subtype(type, value):
types[i] = value
break
else:
msg.incompatible_typevar_value(callable, i + 1, type, context)
# Create a map from type variable id to target type.
id_to_type = {} # type: Dict[int, Type]
for i, tv in enumerate(tvars):
if types[i]:
id_to_type[tv.id] = types[i]
# Apply arguments to argument types.
arg_types = [expand_type(at, id_to_type) for at in callable.arg_types]
bound_vars = [(tv.id, id_to_type[tv.id])
for tv in tvars
if tv.id in id_to_type]
# The callable may retain some type vars if only some were applied.
remaining_tvars = [tv for tv in tvars if tv.id not in id_to_type]
return CallableType(arg_types,
callable.arg_kinds,
callable.arg_names,
expand_type(callable.ret_type, id_to_type),
callable.fallback,
callable.name,
remaining_tvars,
callable.bound_vars + bound_vars,
callable.line, callable.repr)
def handle_partial_attribute_type(typ: PartialType, is_lvalue: bool, msg: MessageBuilder, context: Context) -> Type:
if typ.type is None:
# 'None' partial type. It has a well-defined type -- 'None'.
# In an lvalue context we want to preserver the knowledge of
# it being a partial type.
if not is_lvalue:
return NoneTyp()
return typ
else:
msg.fail(messages.NEED_ANNOTATION_FOR_VAR, context)
return AnyType()
def apply_generic_arguments(callable: CallableType, orig_types: Sequence[Optional[Type]],
msg: MessageBuilder, context: Context) -> CallableType:
"""Apply generic type arguments to a callable type.
For example, applying [int] to 'def [T] (T) -> T' results in
'def (int) -> int'.
Note that each type can be None; in this case, it will not be applied.
"""
tvars = callable.variables
assert len(tvars) == len(orig_types)
# Check that inferred type variable values are compatible with allowed
# values and bounds. Also, promote subtype values to allowed values.
types = list(orig_types)
for i, type in enumerate(types):
assert not isinstance(type, PartialType), "Internal error: must never apply partial type"
values = callable.variables[i].values
if values and type:
if isinstance(type, AnyType):
continue
if isinstance(type, TypeVarType) and type.values:
# Allow substituting T1 for T if every allowed value of T1
# is also a legal value of T.
if all(any(is_same_type(v, v1) for v in values)
for v1 in type.values):
continue
for value in values:
if mypy.subtypes.is_subtype(type, value):
types[i] = value
break
else:
msg.incompatible_typevar_value(callable, type, callable.variables[i].name, context)
upper_bound = callable.variables[i].upper_bound
if type and not mypy.subtypes.is_subtype(type, upper_bound):
msg.incompatible_typevar_value(callable, type, callable.variables[i].name, context)
# Create a map from type variable id to target type.
id_to_type = {} # type: Dict[TypeVarId, Type]
for i, tv in enumerate(tvars):
typ = types[i]
if typ:
id_to_type[tv.id] = typ
# Apply arguments to argument types.
arg_types = [expand_type(at, id_to_type) for at in callable.arg_types]
# The callable may retain some type vars if only some were applied.
remaining_tvars = [tv for tv in tvars if tv.id not in id_to_type]
return callable.copy_modified(
arg_types=arg_types,
ret_type=expand_type(callable.ret_type, id_to_type),
variables=remaining_tvars,
)
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 handle_partial_attribute_type(typ: PartialType, is_lvalue: bool, msg: MessageBuilder,
node: SymbolNode) -> Type:
if typ.type is None:
# 'None' partial type. It has a well-defined type -- 'None'.
# In an lvalue context we want to preserver the knowledge of
# it being a partial type.
if not is_lvalue:
return NoneTyp()
return typ
else:
msg.need_annotation_for_var(node, node)
return AnyType(TypeOfAny.from_error)
def analyze_member_var_access(name: str, itype: Instance, info: TypeInfo,
node: Context, is_lvalue: bool, is_super: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
original_type: Type,
chk: 'mypy.checker.TypeChecker' = None) -> Type:
"""Analyse attribute access that does not target a method.
This is logically part of analyze_member_access and the arguments are similar.
original_type is the type of E in the expression E.var
"""
# 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):
return analyze_var(name, v, itype, info, node, is_lvalue, msg,
original_type, not_ready_callback)
elif isinstance(v, FuncDef):
assert False, "Did not expect a function"
elif not v and name not in ['__getattr__', '__setattr__', '__getattribute__']:
if not is_lvalue:
for method_name in ('__getattribute__', '__getattr__'):
method = info.get_method(method_name)
# __getattribute__ is defined on builtins.object and returns Any, so without
# the guard this search will always find object.__getattribute__ and conclude
# that the attribute exists
if method and method.info.fullname() != 'builtins.object':
function = function_type(method, builtin_type('builtins.function'))
bound_method = bind_self(function, original_type)
typ = map_instance_to_supertype(itype, method.info)
getattr_type = expand_type_by_instance(bound_method, typ)
if isinstance(getattr_type, CallableType):
return getattr_type.ret_type
if itype.type.fallback_to_any:
return AnyType()
# Could not find the member.
if is_super:
msg.undefined_in_superclass(name, node)
return AnyType()
else:
if chk and chk.should_suppress_optional_error([itype]):
return AnyType()
return msg.has_no_attr(original_type, 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) -> 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_member_var_access(
name: str,
itype: Instance,
info: TypeInfo,
node: Context,
is_lvalue: bool,
is_super: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context], None],
msg: MessageBuilder,
report_type: Type = None,
chk: "mypy.checker.TypeChecker" = None,
) -> Type:
"""Analyse attribute access that does not target a method.
This is logically part of analyze_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):
return analyze_var(name, v, itype, info, node, is_lvalue, msg, not_ready_callback)
elif isinstance(v, FuncDef):
assert False, "Did not expect a function"
elif not v and name not in ["__getattr__", "__setattr__"]:
if not is_lvalue:
method = info.get_method("__getattr__")
if method:
typ = map_instance_to_supertype(itype, method.info)
getattr_type = expand_type_by_instance(
method_type_with_fallback(method, builtin_type("builtins.function")), typ
)
if isinstance(getattr_type, CallableType):
return getattr_type.ret_type
if itype.type.fallback_to_any:
return AnyType()
# Could not find the member.
if is_super:
msg.undefined_in_superclass(name, node)
return AnyType()
else:
if chk and chk.should_suppress_optional_error([itype]):
return AnyType()
return msg.has_no_attr(report_type or itype, name, node)
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 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_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)
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:
not_ready_callback(var.name(), node)
# Implicit 'Any' type.
return AnyType()
def analyse_class_attribute_access(itype: Instance, name: str,
context: Context, is_lvalue: bool,
msg: MessageBuilder) -> Type:
node = itype.type.get(name)
if node:
if is_lvalue and isinstance(node.node, FuncDef):
msg.fail(messages.CANNOT_ASSIGN_TO_METHOD, context)
if is_lvalue and isinstance(node.node, TypeInfo):
msg.fail(messages.CANNOT_ASSIGN_TO_TYPE, context)
t = node.type
if t:
return add_class_tvars(t, itype.type)
elif isinstance(node.node, TypeInfo):
# TODO add second argument
return type_object_type(cast(TypeInfo, node.node), None)
else:
return function_type(cast(FuncBase, node.node))
else:
return None
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 __init__(self, errors, modules):
"""Construct a type checker.
Use errors to report type check errors. Assume symtable has been
populated by the semantic analyzer.
"""
self.expr_checker
self.errors = errors
self.modules = modules
self.msg = MessageBuilder(errors)
self.type_map = {}
self.expr_checker = mypy.checkexpr.ExpressionChecker(self, self.msg)
self.stack = [None]
self.return_types = []
self.type_context = []
self.dynamic_funcs = []
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],
original_type: Type = None) -> 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
"""
original_type = original_type or itype
# 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) 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)
if var.is_property:
# A property cannot have an overloaded type => the cast
# is fine.
assert isinstance(signature, CallableType)
return 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 check_for_explicit_any(typ: Optional[Type], options: Options,
is_typeshed_stub: bool, msg: MessageBuilder,
context: Context) -> None:
if ('explicit' in options.disallow_any and not is_typeshed_stub and typ
and has_explicit_any(typ)):
msg.explicit_any(context)
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 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 check_final_member(name: str, info: TypeInfo, msg: MessageBuilder, ctx: Context) -> None:
"""Give an error if the name being assigned was declared as final."""
for base in info.mro:
sym = base.names.get(name)
if sym and is_final_node(sym.node):
msg.cant_assign_to_final(name, attr_assign=True, ctx=ctx)
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_var_access(name: str, itype: Instance, info: TypeInfo,
node: Context, is_lvalue: bool, is_super: bool,
builtin_type: Callable[[str], Instance],
not_ready_callback: Callable[[str, Context],
None],
msg: MessageBuilder, original_type: Type,
chk: 'mypy.checker.TypeChecker') -> Type:
"""Analyse attribute access that does not target a method.
This is logically part of analyze_member_access and the arguments are similar.
original_type is the type of E in the expression E.var
"""
# 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(vv, TypeInfo):
# If the associated variable is a TypeInfo synthesize a Var node for
# the purposes of type checking. This enables us to type check things
# like accessing class attributes on an inner class.
v = Var(name, type=type_object_type(vv, builtin_type))
v.info = info
if isinstance(v, Var):
return analyze_var(name,
v,
itype,
info,
node,
is_lvalue,
msg,
original_type,
not_ready_callback,
chk=chk)
elif isinstance(v, FuncDef):
assert False, "Did not expect a function"
elif not v and name not in [
'__getattr__', '__setattr__', '__getattribute__'
]:
if not is_lvalue:
for method_name in ('__getattribute__', '__getattr__'):
method = info.get_method(method_name)
# __getattribute__ is defined on builtins.object and returns Any, so without
# the guard this search will always find object.__getattribute__ and conclude
# that the attribute exists
if method and method.info.fullname() != 'builtins.object':
function = function_type(method,
builtin_type('builtins.function'))
bound_method = bind_self(function, original_type)
typ = map_instance_to_supertype(itype, method.info)
getattr_type = expand_type_by_instance(bound_method, typ)
if isinstance(getattr_type, CallableType):
return getattr_type.ret_type
else:
setattr_meth = info.get_method('__setattr__')
if setattr_meth and setattr_meth.info.fullname(
) != 'builtins.object':
setattr_func = function_type(setattr_meth,
builtin_type('builtins.function'))
bound_type = bind_self(setattr_func, original_type)
typ = map_instance_to_supertype(itype, setattr_meth.info)
setattr_type = expand_type_by_instance(bound_type, typ)
if isinstance(
setattr_type,
CallableType) and len(setattr_type.arg_types) > 0:
return setattr_type.arg_types[-1]
if itype.type.fallback_to_any:
return AnyType(TypeOfAny.special_form)
# Could not find the member.
if is_super:
msg.undefined_in_superclass(name, node)
return AnyType(TypeOfAny.from_error)
else:
if chk and chk.should_suppress_optional_error([itype]):
return AnyType(TypeOfAny.from_error)
return msg.has_no_attr(original_type, itype, 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 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,
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_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_descriptor_access(instance_type: Type,
descriptor_type: Type,
builtin_type: Callable[[str], Instance],
msg: MessageBuilder,
context: Context, *,
chk: 'mypy.checker.TypeChecker') -> Type:
"""Type check descriptor access.
Arguments:
instance_type: The type of the instance on which the descriptor
attribute is being accessed (the type of ``a`` in ``a.f`` when
``f`` is a descriptor).
descriptor_type: The type of the descriptor attribute being accessed
(the type of ``f`` in ``a.f`` when ``f`` is a descriptor).
context: The node defining the context of this inference.
Return:
The return type of the appropriate ``__get__`` overload for the descriptor.
"""
if isinstance(descriptor_type, UnionType):
# Map the access over union types
return UnionType.make_simplified_union([
analyze_descriptor_access(instance_type, typ, builtin_type,
msg, context, chk=chk)
for typ in descriptor_type.items
])
elif not isinstance(descriptor_type, Instance):
return descriptor_type
if not descriptor_type.type.has_readable_member('__get__'):
return descriptor_type
dunder_get = descriptor_type.type.get_method('__get__')
if dunder_get is None:
msg.fail(message_registry.DESCRIPTOR_GET_NOT_CALLABLE.format(descriptor_type), context)
return AnyType(TypeOfAny.from_error)
function = function_type(dunder_get, builtin_type('builtins.function'))
bound_method = bind_self(function, descriptor_type)
typ = map_instance_to_supertype(descriptor_type, dunder_get.info)
dunder_get_type = expand_type_by_instance(bound_method, typ)
if isinstance(instance_type, FunctionLike) and instance_type.is_type_obj():
owner_type = instance_type.items()[0].ret_type
instance_type = NoneTyp()
elif isinstance(instance_type, TypeType):
owner_type = instance_type.item
instance_type = NoneTyp()
else:
owner_type = instance_type
_, inferred_dunder_get_type = chk.expr_checker.check_call(
dunder_get_type,
[TempNode(instance_type), TempNode(TypeType.make_normalized(owner_type))],
[ARG_POS, ARG_POS], context)
if isinstance(inferred_dunder_get_type, AnyType):
# check_call failed, and will have reported an error
return inferred_dunder_get_type
if not isinstance(inferred_dunder_get_type, CallableType):
msg.fail(message_registry.DESCRIPTOR_GET_NOT_CALLABLE.format(descriptor_type), context)
return AnyType(TypeOfAny.from_error)
return inferred_dunder_get_type.ret_type
def check_final_member(name: str, info: TypeInfo, msg: MessageBuilder, ctx: Context) -> None:
"""Give an error if the name being assigned was declared as final."""
for base in info.mro:
sym = base.names.get(name)
if sym and is_final_node(sym.node):
msg.cant_assign_to_final(name, attr_assign=True, ctx=ctx)
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)
def apply_generic_arguments(callable: CallableType,
orig_types: Sequence[Optional[Type]],
msg: MessageBuilder,
context: Context) -> CallableType:
"""Apply generic type arguments to a callable type.
For example, applying [int] to 'def [T] (T) -> T' results in
'def (int) -> int'.
Note that each type can be None; in this case, it will not be applied.
"""
tvars = callable.variables
assert len(tvars) == len(orig_types)
# Check that inferred type variable values are compatible with allowed
# values and bounds. Also, promote subtype values to allowed values.
types = list(orig_types)
for i, type in enumerate(types):
assert not isinstance(
type, PartialType), "Internal error: must never apply partial type"
values = callable.variables[i].values
if values and type:
if isinstance(type, AnyType):
continue
if isinstance(type, TypeVarType) and type.values:
# Allow substituting T1 for T if every allowed value of T1
# is also a legal value of T.
if all(
any(is_same_type(v, v1) for v in values)
for v1 in type.values):
continue
for value in values:
if mypy.subtypes.is_subtype(type, value):
types[i] = value
break
else:
msg.incompatible_typevar_value(callable, type,
callable.variables[i].name,
context)
upper_bound = callable.variables[i].upper_bound
if type and not mypy.subtypes.is_subtype(type, upper_bound):
msg.incompatible_typevar_value(callable, type,
callable.variables[i].name, context)
# Create a map from type variable id to target type.
id_to_type = {} # type: Dict[TypeVarId, Type]
for i, tv in enumerate(tvars):
typ = types[i]
if typ:
id_to_type[tv.id] = typ
# Apply arguments to argument types.
arg_types = [expand_type(at, id_to_type) for at in callable.arg_types]
# The callable may retain some type vars if only some were applied.
remaining_tvars = [tv for tv in tvars if tv.id not in id_to_type]
return callable.copy_modified(
arg_types=arg_types,
ret_type=expand_type(callable.ret_type, id_to_type),
variables=remaining_tvars,
)
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, 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 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)
or (isinstance(node.node, FuncBase) and node.node.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 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 analyse_member_access(name: str,
typ: Type,
node: Context,
is_lvalue: bool,
is_super: bool,
basic_types: BasicTypes,
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.fail(messages.CANNOT_ASSIGN_TO_METHOD, node)
typ = map_instance_to_supertype(typ, method.info)
return expand_type_by_instance(method_type(method), 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, TupleType):
# Actually look up from the 'tuple' type.
return analyse_member_access(name, basic_types.tuple, node, is_lvalue,
is_super, basic_types, 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,
msg)
if result:
return result
# Look up from the 'type' type.
return analyse_member_access(name,
basic_types.type_type,
node,
is_lvalue,
is_super,
basic_types,
msg,
report_type=report_type)
elif isinstance(typ, FunctionLike):
# Look up from the 'function' type.
return analyse_member_access(name,
basic_types.function,
node,
is_lvalue,
is_super,
basic_types,
msg,
report_type=report_type)
return msg.has_no_attr(report_type, name, node)
def analyze_descriptor_access(instance_type: Type, descriptor_type: Type,
builtin_type: Callable[[str], Instance],
msg: MessageBuilder, context: Context, *,
chk: 'mypy.checker.TypeChecker') -> Type:
"""Type check descriptor access.
Arguments:
instance_type: The type of the instance on which the descriptor
attribute is being accessed (the type of ``a`` in ``a.f`` when
``f`` is a descriptor).
descriptor_type: The type of the descriptor attribute being accessed
(the type of ``f`` in ``a.f`` when ``f`` is a descriptor).
context: The node defining the context of this inference.
Return:
The return type of the appropriate ``__get__`` overload for the descriptor.
"""
instance_type = get_proper_type(instance_type)
descriptor_type = get_proper_type(descriptor_type)
if isinstance(descriptor_type, UnionType):
# Map the access over union types
return make_simplified_union([
analyze_descriptor_access(instance_type,
typ,
builtin_type,
msg,
context,
chk=chk) for typ in descriptor_type.items
])
elif not isinstance(descriptor_type, Instance):
return descriptor_type
if not descriptor_type.type.has_readable_member('__get__'):
return descriptor_type
dunder_get = descriptor_type.type.get_method('__get__')
if dunder_get is None:
msg.fail(
message_registry.DESCRIPTOR_GET_NOT_CALLABLE.format(
descriptor_type), context)
return AnyType(TypeOfAny.from_error)
function = function_type(dunder_get, builtin_type('builtins.function'))
bound_method = bind_self(function, descriptor_type)
typ = map_instance_to_supertype(descriptor_type, dunder_get.info)
dunder_get_type = expand_type_by_instance(bound_method, typ)
if isinstance(instance_type, FunctionLike) and instance_type.is_type_obj():
owner_type = instance_type.items()[0].ret_type
instance_type = NoneType()
elif isinstance(instance_type, TypeType):
owner_type = instance_type.item
instance_type = NoneType()
else:
owner_type = instance_type
_, inferred_dunder_get_type = chk.expr_checker.check_call(
dunder_get_type, [
TempNode(instance_type, context=context),
TempNode(TypeType.make_normalized(owner_type), context=context)
], [ARG_POS, ARG_POS], context)
inferred_dunder_get_type = get_proper_type(inferred_dunder_get_type)
if isinstance(inferred_dunder_get_type, AnyType):
# check_call failed, and will have reported an error
return inferred_dunder_get_type
if not isinstance(inferred_dunder_get_type, CallableType):
msg.fail(
message_registry.DESCRIPTOR_GET_NOT_CALLABLE.format(
descriptor_type), context)
return AnyType(TypeOfAny.from_error)
return inferred_dunder_get_type.ret_type
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 apply_generic_arguments(callable: CallableType, orig_types: Sequence[Optional[Type]],
msg: MessageBuilder, context: Context,
skip_unsatisfied: bool = False) -> CallableType:
"""Apply generic type arguments to a callable type.
For example, applying [int] to 'def [T] (T) -> T' results in
'def (int) -> int'.
Note that each type can be None; in this case, it will not be applied.
If `skip_unsatisfied` is True, then just skip the types that don't satisfy type variable
bound or constraints, instead of giving an error.
"""
tvars = callable.variables
assert len(tvars) == len(orig_types)
# Check that inferred type variable values are compatible with allowed
# values and bounds. Also, promote subtype values to allowed values.
types = list(orig_types)
for i, type in enumerate(types):
assert not isinstance(type, PartialType), "Internal error: must never apply partial type"
values = callable.variables[i].values
if type is None:
continue
if values:
if isinstance(type, AnyType):
continue
if isinstance(type, TypeVarType) and type.values:
# Allow substituting T1 for T if every allowed value of T1
# is also a legal value of T.
if all(any(is_same_type(v, v1) for v in values)
for v1 in type.values):
continue
matching = []
for value in values:
if mypy.subtypes.is_subtype(type, value):
matching.append(value)
if matching:
best = matching[0]
# If there are more than one matching value, we select the narrowest
for match in matching[1:]:
if mypy.subtypes.is_subtype(match, best):
best = match
types[i] = best
else:
if skip_unsatisfied:
types[i] = None
else:
msg.incompatible_typevar_value(callable, type, callable.variables[i].name,
context)
else:
upper_bound = callable.variables[i].upper_bound
if not mypy.subtypes.is_subtype(type, upper_bound):
if skip_unsatisfied:
types[i] = None
else:
msg.incompatible_typevar_value(callable, type, callable.variables[i].name,
context)
# Create a map from type variable id to target type.
id_to_type = {} # type: Dict[TypeVarId, Type]
for i, tv in enumerate(tvars):
typ = types[i]
if typ:
id_to_type[tv.id] = typ
# Apply arguments to argument types.
arg_types = [expand_type(at, id_to_type) for at in callable.arg_types]
# The callable may retain some type vars if only some were applied.
remaining_tvars = [tv for tv in tvars if tv.id not in id_to_type]
return callable.copy_modified(
arg_types=arg_types,
ret_type=expand_type(callable.ret_type, id_to_type),
variables=remaining_tvars,
)
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)
class TypeChecker(NodeVisitor):
"""Mypy type checker.
Type check mypy source files that have been semantically analysed.
"""
errors = None # Error message reporting
symtable = None # Symbol table for the whole program
msg = None # Utility for generating messages
type_map = None # Types of type checked nodes
expr_checker = None
stack = None # Stack of local variable definitions
# None separates nested functions
return_types = None # Stack of function return types
type_context = None # Type context for type inference
dynamic_funcs = None # Flags; true for dynamically typed functions
globals = None
class_tvars = None
locals = None
modules = None
def __init__(self, errors, modules):
"""Construct a type checker.
Use errors to report type check errors. Assume symtable has been
populated by the semantic analyzer.
"""
self.expr_checker
self.errors = errors
self.modules = modules
self.msg = MessageBuilder(errors)
self.type_map = {}
self.expr_checker = mypy.checkexpr.ExpressionChecker(self, self.msg)
self.stack = [None]
self.return_types = []
self.type_context = []
self.dynamic_funcs = []
def visit_file(self, file_node, path):
"""Type check a mypy file with the given path."""
self.errors.set_file(path)
self.globals = file_node.names
self.locals = None
self.class_tvars = None
for d in file_node.defs:
self.accept(d)
def accept(self, node, type_context=None):
"""Type check a node in the given type context."""
self.type_context.append(type_context)
typ = node.accept(self)
self.type_context.pop()
self.store_type(node, typ)
if self.is_dynamic_function():
return Any()
else:
return typ
#
# Definitions
#
def visit_var_def(self, defn):
"""Type check a variable definition.
It can be of any kind: local, member or global.
"""
# Type check initializer.
if defn.init:
# There is an initializer.
if defn.items[0].type:
# Explicit types.
if len(defn.items) == 1:
self.check_single_assignment(defn.items[0].type, None,
defn.init, defn.init)
else:
# Multiple assignment.
lvt = []
for v in defn.items:
lvt.append(v.type)
self.check_multi_assignment(
lvt, [None] * len(lvt),
defn.init, defn.init)
else:
init_type = self.accept(defn.init)
if defn.kind == LDEF and not defn.is_top_level:
# Infer local variable type if there is an initializer
# except if the# definition is at the top level (outside a
# function).
self.infer_local_variable_type(defn.items, init_type, defn)
else:
# No initializer
if (defn.kind == LDEF and not defn.items[0].type and
not defn.is_top_level and not self.is_dynamic_function()):
self.fail(messages.NEED_ANNOTATION_FOR_VAR, defn)
def infer_local_variable_type(self, x, y, z):
# TODO
raise RuntimeError('Not implemented')
def visit_overloaded_func_def(self, defn):
for fdef in defn.items:
self.check_func_item(fdef)
if defn.info:
self.check_method_override(defn)
def visit_func_def(self, defn):
"""Type check a function definition."""
self.check_func_item(defn)
if defn.info:
self.check_method_override(defn)
def check_func_item(self, defn, type_override=None):
# We may be checking a function definition or an anonymous function. In
# the first case, set up another reference with the precise type.
fdef = None
if isinstance(defn, FuncDef):
fdef = defn
self.dynamic_funcs.append(defn.type is None and not type_override)
if fdef:
self.errors.push_function(fdef.name())
typ = function_type(defn)
if type_override:
typ = type_override
if isinstance(typ, Callable):
self.check_func_def(defn, typ)
else:
raise RuntimeError('Not supported')
if fdef:
self.errors.pop_function()
self.dynamic_funcs.pop()
def check_func_def(self, defn, typ):
"""Check a function definition."""
# We may be checking a function definition or an anonymous function. In
# the first case, set up another reference with the precise type.
if isinstance(defn, FuncDef):
fdef = defn
else:
fdef = None
self.enter()
if fdef:
# The cast below will work since non-method create will cause
# semantic analysis to fail, and type checking won't be done.
if (fdef.info and fdef.name() == '__init__' and
not isinstance((typ).ret_type, Void) and
not self.dynamic_funcs[-1]):
self.fail(messages.INIT_MUST_NOT_HAVE_RETURN_TYPE, defn.type)
# Push return type.
self.return_types.append((typ).ret_type)
# Store argument types.
ctype = typ
nargs = len(defn.args)
for i in range(len(ctype.arg_types)):
arg_type = ctype.arg_types[i]
if ctype.arg_kinds[i] == nodes.ARG_STAR:
arg_type = self.named_generic_type('builtins.list', [arg_type])
elif ctype.arg_kinds[i] == nodes.ARG_STAR2:
arg_type = self.named_generic_type('builtins.dict',
[self.str_type(), arg_type])
defn.args[i].type = arg_type
# Type check initialization expressions.
for j in range(len(defn.init)):
if defn.init[j]:
self.accept(defn.init[j])
# Type check body.
self.accept(defn.body)
# Pop return type.
self.return_types.pop()
self.leave()
def check_method_override(self, defn):
"""Check that function definition is compatible with any overridden
definitions defined in superclasses or implemented interfaces.
"""
# Check against definitions in superclass.
self.check_method_or_accessor_override_for_base(defn, defn.info.base)
# Check against definitions in implemented interfaces.
for iface in defn.info.interfaces:
self.check_method_or_accessor_override_for_base(defn, iface)
def check_method_or_accessor_override_for_base(self, defn, base):
"""Check that function definition is compatible with any overridden
definition in the specified supertype.
"""
if base:
if defn.name() != '__init__':
# Check method override (create is special).
base_method = base.get_method(defn.name())
if base_method and base_method.info == base:
# There is an overridden method in the supertype.
# Construct the type of the overriding method.
typ = method_type(defn)
# Map the overridden method type to subtype context so that
# it can be checked for compatibility. Note that multiple
# types from multiple implemented interface instances may
# be present.
original_type = map_type_from_supertype(
method_type(base_method), defn.info, base)
# Check that the types are compatible.
# TODO overloaded signatures
self.check_override(typ,
original_type,
defn.name(),
base_method.info.name(),
defn)
# Also check interface implementations.
for iface in base.interfaces:
self.check_method_or_accessor_override_for_base(defn, iface)
# We have to check that the member is compatible with all
# supertypes due to the dynamic type. Otherwise we could first
# override with dynamic and then with an arbitary type.
self.check_method_or_accessor_override_for_base(defn, base.base)
def check_override(self, override, original, name, supertype, node):
"""Check a method override with given signatures.
Arguments:
override: The signature of the overriding method.
original: The signature of the original supertype method.
name: The name of the subtype. This and the next argument are
only used for generating error messages.
supertype: The name of the supertype.
"""
if (isinstance(override, Overloaded) or
isinstance(original, Overloaded) or
len((override).arg_types) !=
len((original).arg_types) or
(override).min_args !=
(original).min_args):
if not is_subtype(override, original):
self.msg.signature_incompatible_with_supertype(
name, supertype, node)
return
else:
# Give more detailed messages for the common case of both
# signatures having the same number of arguments and no
# intersection types.
coverride = override
coriginal = original
for i in range(len(coverride.arg_types)):
if not is_equivalent(coriginal.arg_types[i],
coverride.arg_types[i]):
self.msg.argument_incompatible_with_supertype(
i + 1, name, supertype, node)
if not is_subtype(coverride.ret_type, coriginal.ret_type):
self.msg.return_type_incompatible_with_supertype(
name, supertype, node)
def visit_type_def(self, defn):
"""Type check a type definition (class or interface)."""
typ = self.lookup(defn.name, GDEF).node
self.errors.set_type(defn.name, defn.is_interface)
self.check_unique_interface_implementations(typ)
self.check_interface_errors(typ)
self.check_no_constructor_if_interface(typ)
self.accept(defn.defs)
self.errors.set_type(None, False)
def check_no_constructor_if_interface(self, typ):
if not typ.is_interface:
return
ctor = typ.get_method('__init__')
if ctor is None:
return
self.msg.interface_has_constructor(ctor)
def check_unique_interface_implementations(self, typ):
"""Check that each interface is implemented only once."""
ifaces = typ.interfaces[:]
dup = find_duplicate(ifaces)
if dup:
self.msg.duplicate_interfaces(typ, dup)
return
base = typ.base
while base:
# Avoid duplicate error messages.
if find_duplicate(base.interfaces):
return
ifaces.extend(base.interfaces)
dup = find_duplicate(ifaces)
if dup:
self.msg.duplicate_interfaces(typ, dup)
return
base = base.base
def check_interface_errors(self, typ):
interfaces = typ.all_directly_implemented_interfaces()
for iface in interfaces:
for n in iface.methods.keys():
if not typ.has_method(n):
self.msg.interface_member_not_implemented(typ, iface, n)
#
# Statements
#
def visit_block(self, b):
for s in b.body:
self.accept(s)
def visit_assignment_stmt(self, s):
"""Type check an assignment statement.
Handle all kinds of assignment statements (simple, indexed, multiple).
"""
# TODO support chained assignment x = y = z
if len(s.lvalues) > 1:
self.msg.not_implemented('chained assignment', s)
self.check_assignments(self.expand_lvalues(s.lvalues[0]), s.rvalue)
def check_assignments(self, lvalues, rvalue):
# Collect lvalue types. Index lvalues require special consideration,
# since we cannot typecheck them until we know the rvalue type.
# For each lvalue, one of lvalue_types[i] or index_lvalues[i] is not
# None.
lvalue_types = [] # Each may be None
index_lvalues = [] # Each may be None
inferred = []
is_inferred = False
for lv in lvalues:
if self.is_definition(lv):
is_inferred = True
if isinstance(lv, NameExpr):
n = lv
inferred.append((n.node))
else:
m = lv
self.accept(m.expr)
inferred.append(m.def_var)
lvalue_types.append(None)
index_lvalues.append(None)
elif isinstance(lv, IndexExpr):
ilv = lv
lvalue_types.append(None)
index_lvalues.append(ilv)
inferred.append(None)
else:
lvalue_types.append(self.accept(lv))
index_lvalues.append(None)
inferred.append(None)
if len(lvalues) == 1:
# Single lvalue.
self.check_single_assignment(lvalue_types[0],
index_lvalues[0], rvalue, rvalue)
else:
self.check_multi_assignment(lvalue_types, index_lvalues,
rvalue, rvalue)
if is_inferred:
self.infer_variable_type(inferred, lvalues, self.accept(rvalue),
rvalue)
def is_definition(self, s):
return ((isinstance(s, NameExpr) or isinstance(s, MemberExpr)) and
s.is_def)
def expand_lvalues(self, n):
if isinstance(n, TupleExpr):
return self.expr_checker.unwrap_list((n).items)
elif isinstance(n, ListExpr):
return self.expr_checker.unwrap_list((n).items)
elif isinstance(n, ParenExpr):
return self.expand_lvalues((n).expr)
else:
return [n]
def infer_variable_type(self, names, lvalues, init_type, context):
"""Infer the type of initialized variables from initializer type."""
if isinstance(init_type, Void):
self.check_not_void(init_type, context)
elif not self.is_valid_inferred_type(init_type):
# We cannot use the type of the initialization expression for type
# inference (it's not specific enough).
self.fail(messages.NEED_ANNOTATION_FOR_VAR, context)
else:
# Infer type of the target.
# Make the type more general (strip away function names etc.).
init_type = strip_type(init_type)
if len(names) > 1:
if isinstance(init_type, TupleType):
tinit_type = init_type
# Initializer with a tuple type.
if len(tinit_type.items) == len(names):
for i in range(len(names)):
self.set_inferred_type(names[i], lvalues[i],
tinit_type.items[i])
else:
self.msg.incompatible_value_count_in_assignment(
len(names), len(tinit_type.items), context)
elif (isinstance(init_type, Instance) and
(init_type).type.full_name() ==
'builtins.list'):
# Initializer with an array type.
item_type = (init_type).args[0]
for i in range(len(names)):
self.set_inferred_type(names[i], lvalues[i], item_type)
elif isinstance(init_type, Any):
for i in range(len(names)):
self.set_inferred_type(names[i], lvalues[i], Any())
else:
self.fail(messages.INCOMPATIBLE_TYPES_IN_ASSIGNMENT,
context)
else:
for v in names:
self.set_inferred_type(v, lvalues[0], init_type)
def set_inferred_type(self, var, lvalue, type):
"""Store inferred variable type.
Store the type to both the variable node and the expression node that
refers to the variable (lvalue). If var is None, do nothing.
"""
if var:
var.type = type
self.store_type(lvalue, type)
def is_valid_inferred_type(self, typ):
"""Is an inferred type invalid?
Examples include the None type or a type with a None component.
"""
if is_same_type(typ, NoneTyp()):
return False
elif isinstance(typ, Instance):
for arg in (typ).args:
if not self.is_valid_inferred_type(arg):
return False
elif isinstance(typ, TupleType):
for item in (typ).items:
if not self.is_valid_inferred_type(item):
return False
return True
def check_multi_assignment(self, lvalue_types, index_lvalues, rvalue, context, msg=None):
if not msg:
msg = messages.INCOMPATIBLE_TYPES_IN_ASSIGNMENT
rvalue_type = self.accept(rvalue) # TODO maybe elsewhere; redundant
# Try to expand rvalue to lvalue(s).
if isinstance(rvalue_type, Any):
pass
elif isinstance(rvalue_type, TupleType):
# Rvalue with tuple type.
trvalue = rvalue_type
items = []
for i in range(len(lvalue_types)):
if lvalue_types[i]:
items.append(lvalue_types[i])
elif i < len(trvalue.items):
# TODO Figure out more precise type context, probably
# based on the type signature of the _set method.
items.append(trvalue.items[i])
trvalue = (self.accept(rvalue, TupleType(items)))
if len(trvalue.items) != len(lvalue_types):
self.msg.incompatible_value_count_in_assignment(
len(lvalue_types), len(trvalue.items), context)
else:
# The number of values is compatible. Check their types.
for j in range(len(lvalue_types)):
self.check_single_assignment(
lvalue_types[j], index_lvalues[j],
self.temp_node(trvalue.items[j]), context, msg)
elif (isinstance(rvalue_type, Instance) and
(rvalue_type).type.full_name() == 'builtins.list'):
# Rvalue with list type.
item_type = (rvalue_type).args[0]
for k in range(len(lvalue_types)):
self.check_single_assignment(lvalue_types[k],
index_lvalues[k],
self.temp_node(item_type),
context, msg)
else:
self.fail(msg, context)
def check_single_assignment(self, lvalue_type, index_lvalue, rvalue, context, msg=messages.INCOMPATIBLE_TYPES_IN_ASSIGNMENT):
"""Type check an assignment.
If lvalue_type is None, the index_lvalue argument must be the
index expr for indexed assignment (__setitem__).
Otherwise, lvalue_type is used as the type of the lvalue.
"""
if lvalue_type:
rvalue_type = self.accept(rvalue, lvalue_type)
self.check_subtype(rvalue_type, lvalue_type, context, msg)
elif index_lvalue:
self.check_indexed_assignment(index_lvalue, rvalue, context)
def check_indexed_assignment(self, lvalue, rvalue, context):
"""Type check indexed assignment base[index] = rvalue.
The lvalue argument is the base[index] expression.
"""
basetype = self.accept(lvalue.base)
method_type = self.expr_checker.analyse_external_member_access(
'__setitem__', basetype, context)
lvalue.method_type = method_type
self.expr_checker.check_call(method_type, [lvalue.index, rvalue],
[nodes.ARG_POS, nodes.ARG_POS],
context)
def visit_expression_stmt(self, s):
self.accept(s.expr)
def visit_return_stmt(self, s):
"""Type check a return statement."""
if self.is_within_function():
if s.expr:
# Return with a value.
typ = self.accept(s.expr, self.return_types[-1])
# Returning a value of type dynamic is always fine.
if not isinstance(typ, Any):
if isinstance(self.return_types[-1], Void):
self.fail(messages.NO_RETURN_VALUE_EXPECTED, s)
else:
self.check_subtype(
typ, self.return_types[-1], s,
messages.INCOMPATIBLE_RETURN_VALUE_TYPE)
else:
# Return without a value.
if (not isinstance(self.return_types[-1], Void) and
not self.is_dynamic_function()):
self.fail(messages.RETURN_VALUE_EXPECTED, s)
def visit_yield_stmt(self, s):
return_type = self.return_types[-1]
if isinstance(return_type, Instance):
inst = return_type
if inst.type.full_name() != 'builtins.Iterator':
self.fail(messages.INVALID_RETURN_TYPE_FOR_YIELD, s)
return None
expected_item_type = inst.args[0]
elif isinstance(return_type, Any):
expected_item_type = Any()
else:
self.fail(messages.INVALID_RETURN_TYPE_FOR_YIELD, s)
return None
actual_item_type = self.accept(s.expr, expected_item_type)
self.check_subtype(actual_item_type, expected_item_type, s)
def visit_if_stmt(self, s):
"""Type check an if statement."""
for e in s.expr:
t = self.accept(e)
self.check_not_void(t, e)
for b in s.body:
self.accept(b)
if s.else_body:
self.accept(s.else_body)
def visit_while_stmt(self, s):
"""Type check a while statement."""
t = self.accept(s.expr)
self.check_not_void(t, s)
self.accept(s.body)
if s.else_body:
self.accept(s.else_body)
def visit_operator_assignment_stmt(self, s):
"""Type check an operator assignment statement, e.g. x += 1."""
lvalue_type = self.accept(s.lvalue)
rvalue_type, method_type = self.expr_checker.check_op(
nodes.op_methods[s.op], lvalue_type, s.rvalue, s)
if isinstance(s.lvalue, IndexExpr):
lv = s.lvalue
self.check_single_assignment(None, lv, s.rvalue, s.rvalue)
else:
if not is_subtype(rvalue_type, lvalue_type):
self.msg.incompatible_operator_assignment(s.op, s)
def visit_assert_stmt(self, s):
self.accept(s.expr)
def visit_raise_stmt(self, s):
"""Type check a raise statement."""
typ = self.accept(s.expr)
self.check_subtype(typ, self.named_type('builtins.BaseException'), s,
messages.INVALID_EXCEPTION_TYPE)
def visit_try_stmt(self, s):
"""Type check a try statement."""
self.accept(s.body)
for i in range(len(s.handlers)):
if s.types[i]:
t = self.exception_type(s.types[i])
if s.vars[i]:
s.vars[i].type = t
self.accept(s.handlers[i])
if s.finally_body:
self.accept(s.finally_body)
if s.else_body:
self.accept(s.else_body)
def exception_type(self, n):
if isinstance(n, NameExpr):
name = n
if isinstance(name.node, TypeInfo):
return self.check_exception_type(name.node, n)
elif isinstance(n, MemberExpr):
m = n
if isinstance(m.node, TypeInfo):
return self.check_exception_type(m.node, n)
elif isinstance(self.expr_checker.unwrap(n), TupleExpr):
self.fail('Multiple exception types not supported yet', n)
return Any()
self.fail('Unsupported exception', n)
return Any()
def check_exception_type(self, info, context):
t = Instance(info, [])
if is_subtype(t, self.named_type('builtins.BaseException')):
return t
else:
self.fail(messages.INVALID_EXCEPTION_TYPE, context)
return Any()
def visit_for_stmt(self, s):
"""Type check a for statement."""
item_type = self.analyse_iterable_item_type(s.expr)
self.analyse_index_variables(s.index, s.is_annotated(), item_type, s)
self.accept(s.body)
def analyse_iterable_item_type(self, expr):
"""Analyse iterable expression and return iterator item type."""
iterable = self.accept(expr)
self.check_not_void(iterable, expr)
self.check_subtype(iterable,
self.named_generic_type('builtins.Iterable',
[Any()]),
expr, messages.ITERABLE_EXPECTED)
echk = self.expr_checker
method = echk.analyse_external_member_access('__iter__', iterable,
expr)
iterator = echk.check_call(method, [], [], expr)[0]
method = echk.analyse_external_member_access('__next__', iterator,
expr)
return echk.check_call(method, [], [], expr)[0]
def analyse_index_variables(self, index, is_annotated, item_type, context):
"""Type check or infer for loop or list comprehension index vars."""
if not is_annotated:
# Create a temporary copy of variables with Node item type.
# TODO this is ugly
node_index = []
for i in index:
node_index.append(i)
self.check_assignments(node_index,
self.temp_node(item_type, context))
elif len(index) == 1:
v = index[0].node
if v.type:
self.check_single_assignment(v.type, None,
self.temp_node(item_type), context,
messages.INCOMPATIBLE_TYPES_IN_FOR)
else:
t = []
for ii in index:
v = ii.node
if v.type:
t.append(v.type)
else:
t.append(Any())
self.check_multi_assignment(t, [None] * len(index),
self.temp_node(item_type), context,
messages.INCOMPATIBLE_TYPES_IN_FOR)
def visit_del_stmt(self, s):
if isinstance(s.expr, IndexExpr):
e = s.expr # Cast
m = MemberExpr(e.base, '__delitem__')
m.line = s.line
c = CallExpr(m, [e.index], [nodes.ARG_POS], [None])
c.line = s.line
return c.accept(self)
else:
return None # this case is handled in semantical analysis
#
# Expressions
#
def visit_name_expr(self, e):
return self.expr_checker.visit_name_expr(e)
def visit_paren_expr(self, e):
return self.expr_checker.visit_paren_expr(e)
def visit_call_expr(self, e):
return self.expr_checker.visit_call_expr(e)
def visit_member_expr(self, e):
return self.expr_checker.visit_member_expr(e)
def visit_int_expr(self, e):
return self.expr_checker.visit_int_expr(e)
def visit_str_expr(self, e):
return self.expr_checker.visit_str_expr(e)
def visit_bytes_expr(self, e):
return self.expr_checker.visit_bytes_expr(e)
def visit_float_expr(self, e):
return self.expr_checker.visit_float_expr(e)
def visit_op_expr(self, e):
return self.expr_checker.visit_op_expr(e)
def visit_unary_expr(self, e):
return self.expr_checker.visit_unary_expr(e)
def visit_index_expr(self, e):
return self.expr_checker.visit_index_expr(e)
def visit_cast_expr(self, e):
return self.expr_checker.visit_cast_expr(e)
def visit_super_expr(self, e):
return self.expr_checker.visit_super_expr(e)
def visit_type_application(self, e):
return self.expr_checker.visit_type_application(e)
def visit_list_expr(self, e):
return self.expr_checker.visit_list_expr(e)
def visit_tuple_expr(self, e):
return self.expr_checker.visit_tuple_expr(e)
def visit_dict_expr(self, e):
return self.expr_checker.visit_dict_expr(e)
def visit_slice_expr(self, e):
return self.expr_checker.visit_slice_expr(e)
def visit_func_expr(self, e):
return self.expr_checker.visit_func_expr(e)
def visit_list_comprehension(self, e):
return self.expr_checker.visit_list_comprehension(e)
def visit_generator_expr(self, e):
return self.expr_checker.visit_generator_expr(e)
def visit_temp_node(self, e):
return e.type
#
# Currently unsupported features
#
def visit_set_expr(self, e):
return self.msg.not_implemented('set literal', e)
def visit_conditional_expr(self, e):
return self.msg.not_implemented('conditional expression', e)
def visit_decorator(self, e):
return self.msg.not_implemented('decorator', e)
def visit_with_stmt(self, s):
self.msg.not_implemented('with statement', s)
#
# Helpers
#
def check_subtype(self, subtype, supertype, context, msg=messages.INCOMPATIBLE_TYPES):
"""Generate an error if the subtype is not compatible with
supertype."""
if not is_subtype(subtype, supertype):
if isinstance(subtype, Void):
self.msg.does_not_return_value(subtype, context)
else:
self.fail(msg, context)
def named_type(self, name):
"""Return an instance type with type given by the name and no
type arguments. For example, named_type('builtins.object')
produces the object type.
"""
# Assume that the name refers to a type.
sym = self.lookup_qualified(name)
return Instance(sym.node, [])
def named_type_if_exists(self, name):
"""Return named instance type, or UnboundType if the type was
not defined.
This is used to simplify test cases by avoiding the need to
define basic types not needed in specific test cases (tuple
etc.).
"""
try:
# Assume that the name refers to a type.
sym = self.lookup_qualified(name)
return Instance(sym.node, [])
except KeyError:
return UnboundType(name)
def named_generic_type(self, name, args):
"""Return an instance with the given name and type
arguments. Assume that the number of arguments is correct.
"""
# Assume that the name refers to a compatible generic type.
sym = self.lookup_qualified(name)
return Instance(sym.node, args)
def type_type(self):
"""Return instance type 'type'."""
return self.named_type('builtins.type')
def object_type(self):
"""Return instance type 'object'."""
return self.named_type('builtins.object')
def bool_type(self):
"""Return instance type 'bool'."""
return self.named_type('builtins.bool')
def str_type(self):
"""Return instance type 'str'."""
return self.named_type('builtins.str')
def tuple_type(self):
"""Return instance type 'tuple'."""
# We need the tuple for analysing member access. We want to be able to
# do this even if tuple type is not available (useful in test cases),
# so we return an unbound type if there is no tuple type.
return self.named_type_if_exists('builtins.tuple')
def check_type_equivalency(self, t1, t2, node, msg=messages.INCOMPATIBLE_TYPES):
"""Generate an error if the types are not equivalent. The
dynamic type is equivalent with all types.
"""
if not is_equivalent(t1, t2):
self.fail(msg, node)
def store_type(self, node, typ):
"""Store the type of a node in the type map."""
self.type_map[node] = typ
def is_dynamic_function(self):
return len(self.dynamic_funcs) > 0 and self.dynamic_funcs[-1]
def lookup(self, name, kind):
"""Look up a definition from the symbol table with the given name.
TODO remove kind argument
"""
if self.locals is not None and name in self.locals:
return self.locals[name]
elif self.class_tvars is not None and name in self.class_tvars:
return self.class_tvars[name]
elif name in self.globals:
return self.globals[name]
else:
b = self.globals.get('__builtins__', None)
if b:
table = (b.node).names
if name in table:
return table[name]
raise KeyError('Failed lookup: {}'.format(name))
def lookup_qualified(self, name):
if '.' not in name:
return self.lookup(name, GDEF) # FIX kind
else:
parts = name.split('.')
n = self.modules[parts[0]]
for i in range(1, len(parts) - 1):
n = ((n.names.get(parts[i], None).node))
return n.names[parts[-1]]
def enter(self):
self.locals = SymbolTable()
def leave(self):
self.locals = None
def basic_types(self):
"""Return a BasicTypes instance that contains primitive types that are
needed for certain type operations (joins, for example).
"""
# TODO function type
return BasicTypes(self.object_type(), self.type_type(),
self.named_type_if_exists('builtins.tuple'),
self.named_type_if_exists('builtins.function'))
def is_within_function(self):
"""Are we currently type checking within a function (i.e. not
at class body or at the top level)?
"""
return self.return_types != []
def check_not_void(self, typ, context):
"""Generate an error if the type is Void."""
if isinstance(typ, Void):
self.msg.does_not_return_value(typ, context)
def temp_node(self, t, context=None):
"""Create a temporary node with the given, fixed type."""
temp = TempNode(t)
if context:
temp.set_line(context.get_line())
return temp
def fail(self, msg, context):
"""Produce an error message."""
self.msg.fail(msg, context)