returnself.copy_common(t,NoneType())

defvisit_uninhabited_type(self,t:UninhabitedType)->ProperType:

dup=UninhabitedType(t.is_noreturn)

dup=UninhabitedType()

dup.ambiguous=t.ambiguous

returnself.copy_common(t,dup)

eliftype_var.variancein (INVARIANT,CONTRAVARIANT):

ifisinstance(ta_proper,UninhabitedType)andnotta_proper.is_noreturn:

ifisinstance(ta_proper,UninhabitedType)andta_proper.ambiguous:

elifisinstance(sa_proper,UninhabitedType)andnotsa_proper.is_noreturn:

elifisinstance(sa_proper,UninhabitedType)andsa_proper.ambiguous:

elifnotis_equivalent(ta,sa):

self.seen_instances.pop()

if (

type_stringin ["Module","overloaded function","Never","<deleted>"]

type_stringin ["Module","overloaded function","<deleted>"]

ortype_string.startswith("Module ")

orre.match(no_quote_regex,type_string)isnotNone

ortype_string.endswith("?")

elifisinstance(typ,DeletedType):

elifisinstance(typ,UninhabitedType):

iftyp.is_noreturn:

else:

elifisinstance(typ,TypeType):

type_name="type"ifoptions.use_lowercase_names()else"Type"

returnAnyType(TypeOfAny.from_error)

returnself.anal_type(t.args[0])

eliffullnameinNEVER_NAMES:

returnUninhabitedType(is_noreturn=True)

returnUninhabitedType()

eliffullnameinLITERAL_TYPE_NAMES:

returnself.analyze_literal_type(t)

eliffullnameinANNOTATED_TYPE_NAMES:

__slots__= ("ambiguous","is_noreturn")

__slots__= ("ambiguous",)

is_noreturn:bool# Does this come from a NoReturn? Purely for error messages.

ambiguous:bool# Is this a result of inference for a variable without constraints?

def__init__(self,is_noreturn:bool=False,line:int=-1,column:int=-1)->None:

def__init__(self,line:int=-1,column:int=-1)->None:

super().__init__(line,column)

self.is_noreturn=is_noreturn

self.ambiguous=False

defcan_be_true_default(self)->bool:

returnisinstance(other,UninhabitedType)

defserialize(self)->JsonDict:

return {".class":"UninhabitedType","is_noreturn":self.is_noreturn}

return {".class":"UninhabitedType"}

defdeserialize(cls,data:JsonDict)->UninhabitedType:

assertdata[".class"]=="UninhabitedType"

returnUninhabitedType(is_noreturn=data["is_noreturn"])

returnUninhabitedType()

classNoneType(ProperType):

a_or_b: Union[A[int], B]

_ = replace(a_or_b, x=42, y=True, init_var=42)

_ = replace(a_or_b, x=42, y=True) # E: Missing named argument "init_var" for "replace" of "Union[A[int], B]"

_ = replace(a_or_b, x=42, y=True, z='42', init_var=42) # E: Argument "z" to "replace" of "Union[A[int], B]" has incompatible type "str"; expected Never

_ = replace(a_or_b, x=42, y=True, w={}, init_var=42) # E: Argument "w" to "replace" of "Union[A[int], B]" has incompatible type "Dict[Never, Never]"; expected Never

_ = replace(a_or_b, x=42, y=True, z='42', init_var=42) # E: Argument "z" to "replace" of "Union[A[int], B]" has incompatible type "str"; expected"Never"

_ = replace(a_or_b, x=42, y=True, w={}, init_var=42) # E: Argument "w" to "replace" of "Union[A[int], B]" has incompatible type "Dict[Never, Never]"; expected"Never"

_ = replace(a_or_b, y=42, init_var=42) # E: Argument "y" to "replace" of "Union[A[int], B]" has incompatible type "int"; expected "bool"

[builtins fixtures/tuple.pyi]

# flags: --warn-no-return

from mypy_extensions import NoReturn

x = 0 # type: NoReturn # E: Incompatible types in assignment (expression has type "int", variable has type "NoReturn")

x = 0 # type: NoReturn # E: Incompatible types in assignment (expression has type "int", variable has type "Never")

[builtins fixtures/dict.pyi]

[case testNoReturnAsync]

def f() -> NoReturn:

no_return()

x: NoReturn = 0 # E: Incompatible types in assignment (expression has type "int", variable has type "NoReturn")

x: NoReturn = 0 # E: Incompatible types in assignment (expression has type "int", variable has type "Never")

[builtins fixtures/dict.pyi]

[case testShowErrorContextFunction]

c: None

fa(lit)

fb(lit) # E: Argument 1 to "fb" has incompatible type "Literal[1]"; expected "NoReturn"

fb(lit) # E: Argument 1 to "fb" has incompatible type "Literal[1]"; expected "Never"

fc(lit) # E: Argument 1 to "fc" has incompatible type "Literal[1]"; expected "None"

f_lit(a)

f_lit(b)

f_lit(c) # E: Argument 1 to "f_lit" has incompatible type "None"; expected "Literal[1]"

[builtins fixtures/tuple.pyi]

[out]

[case testLiteralCheckSubtypingNoStrictOptional]

# flags: --no-strict-optional

c: None

fa(lit)

fb(lit) # E: Argument 1 to "fb" has incompatible type "Literal[1]"; expected "NoReturn"

fb(lit) # E: Argument 1 to "fb" has incompatible type "Literal[1]"; expected "Never"

fc(lit) # E: Argument 1 to "fc" has incompatible type "Literal[1]"; expected "None"

f_lit(a)

f_lit(b)

f_lit(c)

[builtins fixtures/tuple.pyi]

[out]

[case testLiteralCallingOverloadedFunction]

from typing import overload, Generic, TypeVar, Any

a_or_b: A[int] | B

a2 = attrs.evolve(a_or_b, x=42, y=True)

a2 = attrs.evolve(a_or_b, x=42, y=True, z='42') # E: Argument "z" to "evolve" of "Union[A[int], B]" has incompatible type "str"; expected Never

a2 = attrs.evolve(a_or_b, x=42, y=True, w={}) # E: Argument "w" to "evolve" of "Union[A[int], B]" has incompatible type "Dict[Never, Never]"; expected Never

a2 = attrs.evolve(a_or_b, x=42, y=True, z='42') # E: Argument "z" to "evolve" of "Union[A[int], B]" has incompatible type "str"; expected"Never"

a2 = attrs.evolve(a_or_b, x=42, y=True, w={}) # E: Argument "w" to "evolve" of "Union[A[int], B]" has incompatible type "Dict[Never, Never]"; expected"Never"

[builtins fixtures/plugin_attrs.pyi]

case 2:

return 1

case o:

assert_never(o) # E: Argument 1 to "assert_never" has incompatible type "int"; expected "NoReturn"

assert_never(o) # E: Argument 1 to "assert_never" has incompatible type "int"; expected "Never"

[case testMatchExhaustiveNoError]

from typing import NoReturn, Union, Literal