test-data/unit/check-errorcodes.test

-- Tests for error codes and ignoring errors using error codes
--
-- These implicitly use --show-error-codes.

[case testErrorCodeNoAttribute]
import m
m.x  # E: Module has no attribute "x"  [attr-defined]
'x'.foobar  # E: "str" has no attribute "foobar"  [attr-defined]
from m import xx  # E: Module "m" has no attribute "xx"  [attr-defined]
from m import think  # E: Module "m" has no attribute "think"; maybe "thing"?  [attr-defined]
for x in 1:  # E: "int" has no attribute "__iter__" (not iterable)  [attr-defined]
    pass
[file m.py]
thing = 0
[builtins fixtures/module.pyi]

[case testErrorCodeUndefinedName]
x # E: Name "x" is not defined  [name-defined]
def f() -> None:
    y # E: Name "y" is not defined  [name-defined]
[file m.py]
[builtins fixtures/module.pyi]

[case testErrorCodeUnclassifiedError]
class A:
    def __init__(self) -> int: \
        # E: The return type of "__init__" must be None  [misc]
        pass

[case testErrorCodeNoteHasNoCode]
reveal_type(1) # N: Revealed type is "Literal[1]?"

[case testErrorCodeSyntaxError]
1 ''
[out]
main:1: error: Invalid syntax  [syntax]
[out version==3.10.0]
main:1: error: Invalid syntax. Perhaps you forgot a comma?  [syntax]

[case testErrorCodeSyntaxError2]
def f(): # E: Type signature has too many arguments  [syntax]
    # type: (int) -> None
    1

x = 0  # type: x y  # E: Syntax error in type comment "x y"  [syntax]

[case testErrorCodeSyntaxError3]
# This is a bit inconsistent -- syntax error would be more logical?
x: 'a b'  # E: Invalid type comment or annotation  [valid-type]
for v in x:  # type: int, int  # E: Syntax error in type annotation  [syntax] \
    # N: Suggestion: Use Tuple[T1, ..., Tn] instead of (T1, ..., Tn)
    pass

[case testErrorCodeSyntaxErrorIgnoreNote]
# This is a bit inconsistent -- syntax error would be more logical?
x: 'a b'  # type: ignore[valid-type]
for v in x:  # type: int, int  # type: ignore[syntax]
    pass

[case testErrorCodeIgnore1]
'x'.foobar  # type: ignore[attr-defined]
'x'.foobar  # type: ignore[xyz]  # E: "str" has no attribute "foobar"  [attr-defined] \
    # N: Error code "attr-defined" not covered by "type: ignore" comment
'x'.foobar  # type: ignore

[case testErrorCodeIgnore2]
a = 'x'.foobar  # type: int  # type: ignore[attr-defined]
b = 'x'.foobar  # type: int  # type: ignore[xyz]  # E: "str" has no attribute "foobar"  [attr-defined] \
    # N: Error code "attr-defined" not covered by "type: ignore" comment
c = 'x'.foobar  # type: int  # type: ignore

[case testErrorCodeIgnoreMultiple1]
a = 'x'.foobar(b)  # type: ignore[name-defined, attr-defined]
a = 'x'.foobar(b)  # type: ignore[name-defined, xyz]  # E: "str" has no attribute "foobar"  [attr-defined] \
    # N: Error code "attr-defined" not covered by "type: ignore" comment
a = 'x'.foobar(b)  # type: ignore[xyz, w, attr-defined]  # E: Name "b" is not defined  [name-defined] \
    # N: Error code "name-defined" not covered by "type: ignore" comment

[case testErrorCodeIgnoreMultiple2]
a = 'x'.foobar(c) # type: int # type: ignore[name-defined, attr-defined]
b = 'x'.foobar(c) # type: int # type: ignore[name-defined, xyz]  # E: "str" has no attribute "foobar"  [attr-defined] \
    # N: Error code "attr-defined" not covered by "type: ignore" comment

[case testErrorCodeWarnUnusedIgnores1]
# flags: --warn-unused-ignores
x # type: ignore[name-defined, attr-defined] # E: Unused "type: ignore[attr-defined]" comment  [unused-ignore]

[case testErrorCodeWarnUnusedIgnores2]
# flags: --warn-unused-ignores
"x".foobar(y) # type: ignore[name-defined, attr-defined]

[case testErrorCodeWarnUnusedIgnores3]
# flags: --warn-unused-ignores
"x".foobar(y) # type: ignore[name-defined, attr-defined, xyz] # E: Unused "type: ignore[xyz]" comment  [unused-ignore]

[case testErrorCodeWarnUnusedIgnores4]
# flags: --warn-unused-ignores
"x".foobar(y) # type: ignore[name-defined, attr-defined, valid-type] # E: Unused "type: ignore[valid-type]" comment  [unused-ignore]

[case testErrorCodeWarnUnusedIgnores5]
# flags: --warn-unused-ignores
"x".foobar(y) # type: ignore[name-defined, attr-defined, valid-type, xyz] # E: Unused "type: ignore[valid-type, xyz]" comment  [unused-ignore]

[case testErrorCodeWarnUnusedIgnores6_NoDetailWhenSingleErrorCode]
# flags: --warn-unused-ignores
"x" # type: ignore[name-defined] # E: Unused "type: ignore" comment  [unused-ignore]

[case testErrorCodeWarnUnusedIgnores7_WarnWhenErrorCodeDisabled]
# flags: --warn-unused-ignores --disable-error-code name-defined
x              # type: ignore                              # E: Unused "type: ignore" comment  [unused-ignore]
x              # type: ignore[name-defined]                # E: Unused "type: ignore" comment  [unused-ignore]
"x".foobar(y)  # type: ignore[name-defined, attr-defined]  # E: Unused "type: ignore[name-defined]" comment  [unused-ignore]

[case testErrorCodeWarnUnusedIgnores8_IgnoreUnusedIgnore]
# flags: --warn-unused-ignores --disable-error-code name-defined
"x"  # type: ignore[unused-ignore]
"x"  # type: ignore[name-defined, unused-ignore]
"x"  # type: ignore[xyz, unused-ignore]
x    # type: ignore[name-defined, unused-ignore]

[case testErrorCodeMissingWhenRequired]
# flags: --enable-error-code ignore-without-code
"x" # type: ignore # E: "type: ignore" comment without error code  [ignore-without-code]
y # type: ignore # E: "type: ignore" comment without error code (consider "type: ignore[name-defined]" instead)  [ignore-without-code]
z # type: ignore[name-defined]
"a" # type: ignore[ignore-without-code]

[case testErrorCodeMissingDoesntTrampleUnusedIgnoresWarning]
# flags: --enable-error-code ignore-without-code --warn-unused-ignores
"x" # type: ignore # E: Unused "type: ignore" comment  [unused-ignore]
"y" # type: ignore[ignore-without-code] # E: Unused "type: ignore" comment  [unused-ignore]
z # type: ignore[ignore-without-code] # E: Unused "type: ignore" comment  [unused-ignore] \
                                      # E: Name "z" is not defined  [name-defined] \
                                      # N: Error code "name-defined" not covered by "type: ignore" comment

[case testErrorCodeMissingWholeFileIgnores]
# flags: --enable-error-code ignore-without-code
# type: ignore  # whole file ignore
x
y # type: ignore  # ignore the lack of error code since we ignore the whole file

[case testErrorCodeMissingMultiple]
# flags: --enable-error-code ignore-without-code
from __future__ import annotations
class A:
    attr: int
    def func(self, var: int) -> A | None: ...

a: A | None
# 'union-attr' should only be listed once (instead of twice) and list should be sorted
a.func("invalid string").attr  # type: ignore  # E: "type: ignore" comment without error code (consider "type: ignore[arg-type, union-attr]" instead)  [ignore-without-code]
[builtins fixtures/tuple.pyi]

[case testErrorCodeIgnoreWithExtraSpace]
x  # type: ignore   [name-defined]
x2 # type: ignore   [ name-defined ]
x3 # type: ignore   [ xyz , name-defined ]
x4 # type: ignore[xyz,name-defined]
y  # type: ignore   [xyz]  # E: Name "y" is not defined  [name-defined] \
    # N: Error code "name-defined" not covered by "type: ignore" comment
y  # type: ignore[  xyz  ]  # E: Name "y" is not defined  [name-defined] \
    # N: Error code "name-defined" not covered by "type: ignore" comment
y  # type: ignore[ xyz , foo  ]  # E: Name "y" is not defined  [name-defined] \
    # N: Error code "name-defined" not covered by "type: ignore" comment

a = z  # type: int  # type: ignore  [name-defined]
b = z2  # type: int  # type: ignore  [ name-defined ]
c = z2  # type: int  # type: ignore  [ name-defined , xyz ]
d = zz # type: int  # type: ignore  [xyz]  # E: Name "zz" is not defined  [name-defined] \
    # N: Error code "name-defined" not covered by "type: ignore" comment
e = zz # type: int  # type: ignore  [ xyz ]  # E: Name "zz" is not defined  [name-defined] \
    # N: Error code "name-defined" not covered by "type: ignore" comment
f = zz # type: int  # type: ignore  [ xyz,foo ]  # E: Name "zz" is not defined  [name-defined] \
    # N: Error code "name-defined" not covered by "type: ignore" comment

[case testErrorCodeIgnoreAfterArgComment]
def f(x  # type: xyz  # type: ignore[name-defined]  # Comment
      ):
    # type () -> None
    pass

def g(x  # type: xyz  # type: ignore  # Comment
      ):
    # type () -> None
    pass

def h(x  # type: xyz  # type: ignore[foo]  # E: Name "xyz" is not defined  [name-defined] \
      # N: Error code "name-defined" not covered by "type: ignore" comment
      ):
    # type () -> None
    pass

[case testErrorCodeIgnoreWithNote]
import nostub  # type: ignore[import]
from defusedxml import xyz  # type: ignore[import]

[case testErrorCodeBadIgnore]
import nostub # type: ignore xyz  # E: Invalid "type: ignore" comment  [syntax] \
                                  # E: Cannot find implementation or library stub for module named "nostub"  [import-not-found] \
                                  # N: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
import nostub # type: ignore[  # E: Invalid "type: ignore" comment  [syntax]
import nostub # type: ignore[foo  # E: Invalid "type: ignore" comment  [syntax]
import nostub # type: ignore[foo,  # E: Invalid "type: ignore" comment  [syntax]
import nostub # type: ignore[foo]]  # E: Invalid "type: ignore" comment  [syntax]
import nostub # type: ignore[foo][bar]  # E: Invalid "type: ignore" comment  [syntax]
import nostub # type: ignore[foo] [bar]  # E: Invalid "type: ignore" comment  [syntax]

x = 0  # type: ignore[  # E: Invalid "type: ignore" comment  [syntax]

def f(x,  # type: int  # type: ignore[  # E: Invalid "type: ignore" comment  [syntax]
      ):
    # type: (...) -> None
    pass

[case testErrorCodeBadIgnoreNoExtraComment]
# Omit the E: ... comments, as they affect parsing
import nostub # type: ignore xyz
import nostub # type: ignore[xyz
import nostub # type: ignore[xyz][xyz]
x = 0  # type: ignore[
def f(x,  # type: int  # type: ignore[
      ):
    # type: (...) -> None
    pass
[out]
main:2: error: Invalid "type: ignore" comment  [syntax]
main:2: error: Cannot find implementation or library stub for module named "nostub"  [import-not-found]
main:2: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
main:3: error: Invalid "type: ignore" comment  [syntax]
main:4: error: Invalid "type: ignore" comment  [syntax]
main:5: error: Invalid "type: ignore" comment  [syntax]
main:6: error: Invalid "type: ignore" comment  [syntax]

[case testErrorCodeArgKindAndCount]
def f(x: int) -> None: pass  # N: "f" defined here
f()  # E: Missing positional argument "x" in call to "f"  [call-arg]
f(1, 2)  # E: Too many arguments for "f"  [call-arg]
f(y=1)  # E: Unexpected keyword argument "y" for "f"  [call-arg]

def g(*, x: int) -> None: pass
g()  # E: Missing named argument "x" for "g"  [call-arg]

def h(x: int, y: int, z: int) -> None: pass
h(y=1, z=1)  # E: Missing positional argument "x" in call to "h"  [call-arg]
h(y=1)  # E: Missing positional arguments "x", "z" in call to "h"  [call-arg]

[case testErrorCodeArgType]
def f(x: int) -> None: pass
f('')  # E: Argument 1 to "f" has incompatible type "str"; expected "int"  [arg-type]

class A:
    def g(self, *, x: int) -> None: pass

A().g(x='')  # E: Argument "x" to "g" of "A" has incompatible type "str"; expected "int"  [arg-type]

[case testErrorCodeInvalidType]
def f(): pass

x: f  # E: Function "__main__.f" is not valid as a type  [valid-type] \
      # N: Perhaps you need "Callable[...]" or a callback protocol?

import sys
y: sys  # E: Module "sys" is not valid as a type  [valid-type] \
        # N: Perhaps you meant to use a protocol matching the module structure?
z: y  # E: Variable "__main__.y" is not valid as a type  [valid-type] \
      # N: See https://mypy.readthedocs.io/en/stable/common_issues.html#variables-vs-type-aliases
[builtins fixtures/tuple.pyi]

[case testErrorCodeNeedTypeAnnotation]
from typing import TypeVar

T = TypeVar('T')
def f() -> T: pass # E: A function returning TypeVar should receive at least one argument containing the same TypeVar  [type-var]
x = f()  # E: Need type annotation for "x"  [var-annotated]
y = []  # E: Need type annotation for "y" (hint: "y: list[<type>] = ...")  [var-annotated]
[builtins fixtures/list.pyi]

[case testErrorCodeBadOverride]
from typing import overload

class A:
    def f(self) -> int:
        return 0
class B(A):
    def f(self) -> str:  # E: Return type "str" of "f" incompatible with return type "int" in supertype "A"  [override]
        return ''
class C(A):
    def f(self, x: int) -> int:  # E: Signature of "f" incompatible with supertype "A"  [override] \
                                 # N:      Superclass: \
                                 # N:          def f(self) -> int \
                                 # N:      Subclass: \
                                 # N:          def f(self, x: int) -> int
        return 0
class D:
    def f(self, x: int) -> int:
        return 0
class E(D):
    def f(self, x: str) -> int:  # E: Argument 1 of "f" is incompatible with supertype "D"; supertype defines the argument type as "int"  [override] \
                                 # N: This violates the Liskov substitution principle \
                                 # N: See https://mypy.readthedocs.io/en/stable/common_issues.html#incompatible-overrides
        return 0

class O:
    @overload
    def f(self, x: int) -> None: pass
    @overload
    def f(self, x: str) -> None: pass
    def f(self, x):
        pass

class OO(O):
    @overload  # E: Signature of "f" incompatible with supertype "O"  [override] \
               # N: Overload variants must be defined in the same order as they are in "O"
    def f(self, x: str) -> None: pass
    @overload
    def f(self, x: int) -> None: pass
    def f(self, x):
        pass

[case testErrorCodeReturnValue]
def f() -> int:
    return ''  # E: Incompatible return value type (got "str", expected "int")  [return-value]

[case testErrorCodeMissingReturnValueInReturnStatement]
def f() -> int:
    return  # E: Return value expected  [return-value]

[case testErrorCodeAssignment]
x: str = 0  # E: Incompatible types in assignment (expression has type "int", variable has type "str")  [assignment]

def f(x: str = 0) -> None:  # E: Incompatible default for argument "x" (default has type "int", argument has type "str")  [assignment]
    pass

class A:
    x = 0

class B(A):
    x = ''  # E: Incompatible types in assignment (expression has type "str", base class "A" defined the type as "int")  [assignment]

a: A
a.x = ''  # E: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]

[case testErrorCodeMissingTypeArg]
# flags: --disallow-any-generics
from typing import List, TypeVar
x: List  # E: Missing type parameters for generic type "List"  [type-arg]
y: list  # E: Missing type parameters for generic type "list"  [type-arg]
T = TypeVar('T')
L = List[List[T]]
z: L  # E: Missing type parameters for generic type "L"  [type-arg]
[builtins fixtures/list.pyi]

[case testErrorCodeUnionAttribute]
from typing import Union
class A:
    x: int
class B:
    y: str
a: Union[A, B]
a.x  # E: Item "B" of "Union[A, B]" has no attribute "x"  [union-attr]

[case testErrorCodeFunctionHasNoAnnotation]
# flags: --disallow-untyped-defs

def f(x):  # E: Function is missing a type annotation  [no-untyped-def]
    pass

def g(x: int):  # E: Function is missing a return type annotation  [no-untyped-def]
    pass

def h(x) -> None:  # E: Function is missing a type annotation for one or more arguments  [no-untyped-def]
    pass

def gen():  # E: Function is missing a return type annotation  [no-untyped-def]
    yield 1

def gen2(x: int):  # E: Function is missing a return type annotation  [no-untyped-def]
    yield 1

async def asyncf():  # E: Function is missing a return type annotation  [no-untyped-def]
    return 0

async def asyncf2(x: int):  # E: Function is missing a return type annotation  [no-untyped-def]
    return 0
[typing fixtures/typing-async.pyi]
[builtins fixtures/tuple.pyi]

[case testErrorCodeCallUntypedFunction]
# flags: --disallow-untyped-calls

def f() -> None:
    g()  # E: Call to untyped function "g" in typed context  [no-untyped-call]

def g():
    pass

[case testErrorCodeUntypedDecorator]
# flags: --disallow-untyped-decorators --warn-unused-ignores
def d(f): return f

@d  # E: Untyped decorator makes function "x" untyped  [untyped-decorator]
def x() -> int: return 1
@d  # type: ignore
def y() -> int: return 2
@d  # type: ignore[untyped-decorator]
def best() -> int: return 3
@d  # type: ignore[misc]  # E: Unused "type: ignore" comment  [unused-ignore] \
                          # E: Untyped decorator makes function "z" untyped  [untyped-decorator] \
                          # N: Error code "untyped-decorator" not covered by "type: ignore" comment
def z() -> int: return 4

[case testErrorCodeIndexing]
from typing import Dict
x: Dict[int, int]
x['']  # E: Invalid index type "str" for "dict[int, int]"; expected type "int"  [index]
1['']  # E: Value of type "int" is not indexable  [index]
1[''] = 1  # E: Unsupported target for indexed assignment ("int")  [index]
[builtins fixtures/dict.pyi]

[case testErrorCodeInvalidTypeArg]
from typing import TypeVar, Generic

T = TypeVar('T', int, str)
TT = TypeVar('TT', int, None)
S = TypeVar('S', bound=str)

def f(x: T) -> T:
    return x

f(object())  # E: Value of type variable "T" of "f" cannot be "object"  [type-var]

def g(x: S) -> S:
    return x

g(1)  # E: Value of type variable "S" of "g" cannot be "int"  [type-var]

class C(Generic[T]): pass
class D(Generic[S]): pass
class E(Generic[S, T]): pass

x: C[object]  # E: Value of type variable "T" of "C" cannot be "object"  [type-var]
y: D[int]  # E: Type argument "int" of "D" must be a subtype of "str"  [type-var]
z: D[int, int]  # E: "D" expects 1 type argument, but 2 given  [type-arg]

def h(a: TT, s: S) -> None:
    b: C[TT]  # E: Invalid type argument value for "C"  [type-var]
    c: C[S]  # E: Type variable "S" not valid as type argument value for "C"  [type-var]

[case testErrorCodeOperators]
class A: pass
A() + 1  # E: Unsupported left operand type for + ("A")  [operator]
1 in A()  # E: Unsupported right operand type for in ("A")  [operator]
A() < 1  # E: Unsupported left operand type for < ("A")  [operator]
-A()  # E: Unsupported operand type for unary - ("A")  [operator]
+A()  # E: Unsupported operand type for unary + ("A")  [operator]
~A()  # E: Unsupported operand type for ~ ("A")  [operator]

class B:
    def __add__(self, other: int) -> 'B':
        return self
    def __radd__(self, other: int) -> 'B':
        return self
    def __contains__(self, other: int) -> int:
        return 0

B() + ''  # E: Unsupported operand types for + ("B" and "str")  [operator]
'' + B()  # E: Unsupported operand types for + ("str" and "B")  [operator]
'' in B()  # E: Unsupported operand types for in ("str" and "B")  [operator]

1()  # E: "int" not callable  [operator]
[builtins fixtures/tuple.pyi]

[case testErrorCodeListOrDictItem]
from typing import List, Dict
x: List[int] = ['']  # E: List item 0 has incompatible type "str"; expected "int"  [list-item]
y: Dict[int, int] = {1: ''}  # E: Dict entry 0 has incompatible type "int": "str"; expected "int": "int"  [dict-item]
[builtins fixtures/dict.pyi]

[case testErrorCodeTypedDict]
from typing import TypedDict
class D(TypedDict):
    x: int
class E(TypedDict):
    x: int
    y: int

a: D = {'x': ''}  # E: Incompatible types (expression has type "str", TypedDict item "x" has type "int")  [typeddict-item]
b: D = {'y': ''}  # E: Missing key "x" for TypedDict "D"  [typeddict-item] \
                  # E: Extra key "y" for TypedDict "D"  [typeddict-unknown-key]
c = D(x=0) if int() else E(x=0, y=0)
c = {}  # E: Missing key "x" for TypedDict "D"  [typeddict-item]
d: D = {'x': '', 'y': 1}  # E: Extra key "y" for TypedDict "D"  [typeddict-unknown-key] \
                          # E: Incompatible types (expression has type "str", TypedDict item "x" has type "int")  [typeddict-item]


a['y'] = 1  # E: TypedDict "D" has no key "y"  [typeddict-unknown-key]
a['x'] = 'x'  # E: Value of "x" has incompatible type "str"; expected "int"  [typeddict-item]
a['y']  # E: TypedDict "D" has no key "y"  [typeddict-item]
[builtins fixtures/dict.pyi]
[typing fixtures/typing-typeddict.pyi]

[case testErrorCodeTypedDictNoteIgnore]
from typing import TypedDict
class A(TypedDict):
    one_commonpart: int
    two_commonparts: int

a: A = {'one_commonpart': 1, 'two_commonparts': 2}
a['other_commonpart'] = 3  # type: ignore[typeddict-unknown-key]
not_exist = a['not_exist'] # type: ignore[typeddict-item]
[builtins fixtures/dict.pyi]
[typing fixtures/typing-typeddict.pyi]

[case testErrorCodeTypedDictSubCodeIgnore]
from typing import TypedDict
class D(TypedDict):
    x: int
d: D = {'x': 1, 'y': 2}  # type: ignore[typeddict-item]
[builtins fixtures/dict.pyi]
[typing fixtures/typing-typeddict.pyi]

[case testErrorCodeCannotDetermineType]
y = x  # E: Cannot determine type of "x"  [has-type]  # E: Name "x" is used before definition  [used-before-def]
reveal_type(y)  # N: Revealed type is "Any"
x = None

[case testErrorCodeRedundantCast]
# flags: --warn-redundant-casts
from typing import cast

x = cast(int, int())  # E: Redundant cast to "int"  [redundant-cast]

[case testErrorCodeInvalidCommentSignature]
def f(x):  # E: Type signature has too few arguments  [syntax]
    # type: () -> None
    pass

def g(x):  # E: Type signature has too many arguments  [syntax]
    # type: (int, int) -> None
    pass

[case testErrorCodeNonOverlappingEquality]
# flags: --strict-equality
if int() == str():  # E: Non-overlapping equality check (left operand type: "int", right operand type: "str")  [comparison-overlap]
    pass
if int() != str():  # E: Non-overlapping equality check (left operand type: "int", right operand type: "str")  [comparison-overlap]
    pass
if int() is str():  # E: Non-overlapping identity check (left operand type: "int", right operand type: "str")  [comparison-overlap]
    pass
[builtins fixtures/primitives.pyi]

[case testErrorCodeMissingModule]
from defusedxml import xyz  # E: Library stubs not installed for "defusedxml"  [import-untyped] \
                            # N: Hint: "python3 -m pip install types-defusedxml" \
                            # N: (or run "mypy --install-types" to install all missing stub packages)
from nonexistent import foobar  # E: Cannot find implementation or library stub for module named "nonexistent"  [import-not-found]
import nonexistent2  # E: Cannot find implementation or library stub for module named "nonexistent2"  [import-not-found]
from nonexistent3 import *  # E: Cannot find implementation or library stub for module named "nonexistent3"  [import-not-found]
from pkg import bad  # E: Module "pkg" has no attribute "bad"  [attr-defined]
from pkg.bad2 import bad3  # E: Cannot find implementation or library stub for module named "pkg.bad2"  [import-not-found] \
                           # N: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports

[file pkg/__init__.py]

[case testErrorCodeAlreadyDefined]
x: int
x: str  # E: Name "x" already defined on line 1  [no-redef]

def f():
    pass
def f(): # E: Name "f" already defined on line 4  [no-redef]
    pass

[case testErrorCodeMissingReturn]
def f() -> int:  # E: Missing return statement  [return]
    x = 0

[case testErrorCodeReturnValueNotExpected]
def f() -> None:
    return 1  # E: No return value expected  [return-value]

[case testErrorCodeFunctionDoesNotReturnValue]
from typing import Callable

def f() -> None: pass

x = f()  # E: "f" does not return a value (it only ever returns None)  [func-returns-value]

class A:
    def g(self) -> None: pass

y = A().g()  # E: "g" of "A" does not return a value (it only ever returns None)  [func-returns-value]

c: Callable[[], None]
z = c()  # E: Function does not return a value (it only ever returns None)  [func-returns-value]

[case testErrorCodeInstantiateAbstract]
from abc import abstractmethod

class A:
    @abstractmethod
    def f(self): pass

class B(A):
    pass

B()  # E: Cannot instantiate abstract class "B" with abstract attribute "f"  [abstract]

[case testErrorCodeNewTypeNotSubclassable]
from typing import Union, NewType

X = NewType('X', Union[int, str])  # E: Argument 2 to NewType(...) must be subclassable (got "Union[int, str]")  [valid-newtype]

[case testErrorCodeOverloadVariant]
from typing import overload

@overload
def f(x: int) -> int: ...
@overload
def f(x: str) -> str: ...
def f(x):
    return x

f(object())  # E: No overload variant of "f" matches argument type "object"  [call-overload] \
  # N: Possible overload variants: \
  # N:     def f(x: int) -> int \
  # N:     def f(x: str) -> str

f()  # E: All overload variants of "f" require at least one argument  [call-overload] \
  # N: Possible overload variants: \
  # N:     def f(x: int) -> int \
  # N:     def f(x: str) -> str

f(1, 1)  # E: No overload variant of "f" matches argument types "int", "int"  [call-overload] \
  # N: Possible overload variants: \
  # N:     def f(x: int) -> int \
  # N:     def f(x: str) -> str

[case testErrorCodeOverloadVariantIgnore]
from typing import overload

@overload
def f(x: int) -> int: ...
@overload
def f(x: str) -> str: ...
def f(x):
    return x

f(object())  # type: ignore[call-overload]

[case testErrorCodeAnyFromUnfollowedImport]
# flags: --disallow-any-unimported
from m import C  # type: ignore
def f(x: C) -> None:  # E: Argument 1 to "f" becomes "Any" due to an unfollowed import  [no-any-unimported]
    pass

def g() -> C: ...  # E: Return type becomes "Any" due to an unfollowed import  [no-any-unimported]

[case testErrorCodeReturnAny]
# flags: --warn-return-any
def f(): pass

def g() -> int:
    return f()  # E: Returning Any from function declared to return "int"  [no-any-return]

[case testErrorCodeFormatCall]
'{:d}'.format('no')  # E: Incompatible types in string interpolation (expression has type "str", placeholder has type "int")  [str-format]
'{!x}'.format('Hm...')  # E: Invalid conversion type "x", must be one of "r", "s" or "a"  [str-format]
'}{'.format()  # E: Invalid conversion specifier in format string: unexpected }  [str-format]

'%d' % 'no'  # E: Incompatible types in string interpolation (expression has type "str", placeholder has type "Union[int, float, SupportsInt]")  [str-format]
'%d + %d' % (1, 2, 3)  # E: Not all arguments converted during string formatting  [str-format]

'{}'.format(b'abc')  # E: If x = b'abc' then f"{x}" or "{}".format(x) produces "b'abc'", not "abc". If this is desired behavior, use f"{x!r}" or "{!r}".format(x). Otherwise, decode the bytes  [str-bytes-safe]
'%s' % b'abc'  # E: If x = b'abc' then "%s" % x produces "b'abc'", not "abc". If this is desired behavior use "%r" % x. Otherwise, decode the bytes  [str-bytes-safe]
[builtins fixtures/primitives.pyi]
[typing fixtures/typing-medium.pyi]

[case testErrorCodeIgnoreNamedDefinedNote]
x: List[int]  # type: ignore[name-defined]

[case testErrorCodeProtocolProblemsIgnore]
from typing import Protocol

class P(Protocol):
    def f(self, x: str) -> None: ...

class A:
    def f(self, x: int) -> None: ...

def g(p: P) -> None: pass

p: A
g(p)  # type: ignore[arg-type]
[builtins fixtures/tuple.pyi]

[case testErrorCodeNoneReturnNoteIgnore]
# flags: --disallow-untyped-defs

def f():  # type: ignore[no-untyped-def]
    pass

[case testErrorCodeVarianceNoteIgnore]
from typing import List
def f(x: List[object]) -> None: pass
a = [1]
f(a)  # type: ignore[arg-type]
[builtins fixtures/list.pyi]

[case testErrorCodeAssignToMethod]
class A:
    def f(self) -> None: pass

def g(self: A) -> None: pass

A.f = g  # E: Cannot assign to a method  [method-assign]

[case testErrorCodeDefinedHereNoteIgnore]
import m
m.f(kw=1)  # type: ignore[call-arg]
[file m.py]
def f() -> None: pass

[case testErrorCodeUnionNoteIgnore]
from typing import Union

class Foo:
    def __add__(self, x: Foo) -> Foo: pass
    def __radd__(self, x: Foo) -> Foo: pass

class Bar:
    def __add__(self, x: Bar) -> Bar: pass
    def __radd__(self, x: Bar) -> Bar: pass

a: Union[Foo, Bar]

a + a  # type: ignore[operator]
a + Foo()  # type: ignore[operator]
Foo() + a  # type: ignore[operator]

[case testErrorCodeTypeIgnoreMisspelled1]
x = y  # type: ignored[foo]
xx = y  # type: ignored [foo]
[out]
main:1: error: Name "ignored" is not defined  [name-defined]
main:1: error: Name "y" is not defined  [name-defined]
main:2: error: Name "ignored" is not defined  [name-defined]
main:2: error: Name "y" is not defined  [name-defined]

[case testErrorCodeTypeIgnoreMisspelled2]
x = y  # type: int  # type: ignored[foo]
x = y  # type: int  # type: ignored [foo]
[out]
main:1: error: Syntax error in type comment "int"  [syntax]
main:2: error: Syntax error in type comment "int"  [syntax]

[case testErrorCode__exit__Return]
class InvalidReturn:
    def __exit__(self, x, y, z) -> bool:  # E: "bool" is invalid as return type for "__exit__" that always returns False  [exit-return] \
# N: Use "typing.Literal[False]" as the return type or change it to "None" \
# N: If return type of "__exit__" implies that it may return True, the context manager may swallow exceptions
        return False
[builtins fixtures/bool.pyi]

[case testErrorCodeOverloadedOperatorMethod]
from typing import Optional, overload

class A:
    @overload
    def __add__(self, x: int) -> A: ...
    @overload
    def __add__(self, x: str) -> str: ...
    def __add__(self, x): pass

class B:
    pass

x: Optional[B]
A() + x  # type: ignore[operator]

class C:
    @overload
    def __rsub__(self, x: int) -> A: ...
    @overload
    def __rsub__(self, x: str) -> str: ...
    def __rsub__(self, x): pass

x - C()  # type: ignore[operator]

[case testErrorCodeMultiLineBinaryOperatorOperand]
from typing import Optional

class C: pass

def f() -> Optional[C]:
    return None

f(  # type: ignore[operator]
) + C()

[case testErrorCodeSpecialArgTypeErrors]
from typing import TypedDict

class C(TypedDict):
    x: int

c: C
c.setdefault('x', '1')  # type: ignore[typeddict-item]

class A:
    pass

class B(A):
    def f(self) -> None:
        super(1, self).foo()  # type: ignore[arg-type]

def f(**x: int) -> None:
    pass

f(**1)  # type: ignore[arg-type]
[builtins fixtures/dict.pyi]
[typing fixtures/typing-typeddict.pyi]

[case testRedundantExpressions]
# flags: --enable-error-code redundant-expr
def foo() -> bool: ...

lst = [1, 2, 3, 4]

b = False or foo()                       # E: Left operand of "or" is always false  [redundant-expr]
c = True and foo()                       # E: Left operand of "and" is always true  [redundant-expr]
g = 3 if True else 4                     # E: If condition is always true  [redundant-expr]
h = 3 if False else 4                    # E: If condition is always false  [redundant-expr]
i = [x for x in lst if True]             # E: If condition in comprehension is always true  [redundant-expr]
j = [x for x in lst if False]            # E: If condition in comprehension is always false  [redundant-expr]
k = [x for x in lst if isinstance(x, int) or foo()]  # E: If condition in comprehension is always true  [redundant-expr]
[builtins fixtures/isinstancelist.pyi]

[case testRedundantExprTruthiness]
# flags: --enable-error-code redundant-expr
from typing import List

def maybe() -> bool: ...

class Foo:
    def __init__(self, x: List[int]) -> None:
        self.x = x or []

    def method(self) -> int:
        if not self.x or maybe():
            return 1
        return 2
[builtins fixtures/list.pyi]

[case testNamedTupleNameMismatch]
from typing import NamedTuple

Foo = NamedTuple("Bar", [])  # E: First argument to namedtuple() should be "Foo", not "Bar"  [name-match]
[builtins fixtures/tuple.pyi]

[case testTypedDictNameMismatch]
from typing import TypedDict

Foo = TypedDict("Bar", {})  # E: First argument "Bar" to TypedDict() does not match variable name "Foo"  [name-match]
[builtins fixtures/dict.pyi]
[typing fixtures/typing-typeddict.pyi]

[case testTruthyBool]
# flags: --enable-error-code truthy-bool --no-local-partial-types
from typing import List, Union, Any

class Foo:
    pass
class Bar:
    pass

foo = Foo()
if foo:  # E: "__main__.foo" has type "Foo" which does not implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
    pass

not foo  # E: "__main__.foo" has type "Foo" which does not implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]

zero = 0
if zero:
    pass

not zero

false = False
if false:
    pass

not false

null = None
if null:
    pass

not null

s = ''
if s:
    pass

not s

good_union: Union[str, int] = 5
if good_union:
    pass
if not good_union:
    pass

not good_union

bad_union: Union[Foo, Bar] = Foo()
if bad_union:  # E: "__main__.bad_union" has type "Union[Foo, Bar]" of which no members implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
    pass
if not bad_union:  # E: "__main__.bad_union" has type "Union[Foo, Bar]" of which no members implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
    pass

not bad_union  # E: "__main__.bad_union" has type "Union[Foo, Bar]" of which no members implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]

# 'object' is special and is treated as potentially falsy
obj: object = Foo()
if obj:
    pass
if not obj:
    pass

not obj

lst: List[int] = []
if lst:
    pass

not lst

a: Any
if a:
    pass

not a

any_or_object: Union[object, Any]
if any_or_object:
    pass

not any_or_object

if (my_foo := Foo()):  # E: "__main__.my_foo" has type "Foo" which does not implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
    pass

if my_a := (a or Foo()):  # E: "__main__.Foo" returns "Foo" which does not implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
    pass
[builtins fixtures/list.pyi]

[case testTruthyFunctions]
def f():
    pass
if f:  # E: Function "f" could always be true in boolean context  [truthy-function]
    pass
if not f:  # E: Function "f" could always be true in boolean context  [truthy-function]
    pass
conditional_result = 'foo' if f else 'bar'  # E: Function "f" could always be true in boolean context  [truthy-function]

not f  # E: Function "f" could always be true in boolean context  [truthy-function]

[case testTruthyIterable]
# flags: --enable-error-code truthy-iterable
from typing import Iterable
def func(var: Iterable[str]) -> None:
    if var:  # E: "var" has type "Iterable[str]" which can always be true in boolean context. Consider using "Collection[str]" instead.  [truthy-iterable]
        ...

    not var  # E: "var" has type "Iterable[str]" which can always be true in boolean context. Consider using "Collection[str]" instead.  [truthy-iterable]

[case testNoOverloadImplementation]
from typing import overload

@overload  # E: An overloaded function outside a stub file must have an implementation  [no-overload-impl]
def f(arg: int) -> int:
    ...

@overload
def f(arg: str) -> str:
    ...

[case testSliceInDictBuiltin]
# flags: --show-column-numbers
b: dict[int, x:y]
c: dict[x:y]

[builtins fixtures/dict.pyi]
[out]
main:2:14: error: Invalid type comment or annotation  [valid-type]
main:2:14: note: did you mean to use ',' instead of ':' ?
main:3:4: error: "dict" expects 2 type arguments, but 1 given  [type-arg]
main:3:9: error: Invalid type comment or annotation  [valid-type]
main:3:9: note: did you mean to use ',' instead of ':' ?

[case testSliceInDictTyping]
# flags: --show-column-numbers
from typing import Dict
b: Dict[int, x:y]
c: Dict[x:y]

[builtins fixtures/dict.pyi]
[out]
main:3:14: error: Invalid type comment or annotation  [valid-type]
main:3:14: note: did you mean to use ',' instead of ':' ?
main:4:4: error: "dict" expects 2 type arguments, but 1 given  [type-arg]
main:4:9: error: Invalid type comment or annotation  [valid-type]
main:4:9: note: did you mean to use ',' instead of ':' ?


[case testSliceInCustomTensorType]
# syntactically mimics torchtyping.TensorType
class TensorType: ...
t: TensorType["batch":..., float]  # type: ignore
reveal_type(t)  # N: Revealed type is "__main__.TensorType"
[builtins fixtures/tuple.pyi]

[case testNoteAboutChangedTypedDictErrorCode]
from typing import TypedDict
class D(TypedDict):
    x: int

def f(d: D, s: str) -> None:
    d[s]  # type: ignore[xyz] \
    # E: TypedDict key must be a string literal; expected one of ("x")  [literal-required] \
    # N: Error code "literal-required" not covered by "type: ignore" comment
    d[s] # E: TypedDict key must be a string literal; expected one of ("x")  [literal-required]
    d[s]  # type: ignore[misc]  \
    # E: TypedDict key must be a string literal; expected one of ("x")  [literal-required] \
    # N: Error code changed to literal-required; "type: ignore" comment may be out of date
    d[s]  # type: ignore[literal-required]
[builtins fixtures/dict.pyi]
[typing fixtures/typing-typeddict.pyi]

[case testRecommendErrorCode]
# type: ignore[whatever]  # E: type ignore with error code is not supported for modules; use `# mypy: disable-error-code="whatever"`  [syntax] \
                          # N: Error code "syntax" not covered by "type: ignore" comment
1 + "asdf"

[case testRecommendErrorCode2]
# type: ignore[whatever, other]  # E: type ignore with error code is not supported for modules; use `# mypy: disable-error-code="whatever, other"`  [syntax] \
                                 # N: Error code "syntax" not covered by "type: ignore" comment
1 + "asdf"

[case testShowErrorCodesInConfig]
# flags: --config-file tmp/mypy.ini
# Test 'show_error_codes = True' in config doesn't raise an exception
var: int = ""  # E: Incompatible types in assignment (expression has type "str", variable has type "int")  [assignment]

[file mypy.ini]
\[mypy]
show_error_codes = True

[case testErrorCodeUnsafeSuper_no_empty]
from abc import abstractmethod

class Base:
    @abstractmethod
    def meth(self) -> int:
        raise NotImplementedError()
class Sub(Base):
    def meth(self) -> int:
        return super().meth()  # E: Call to abstract method "meth" of "Base" with trivial body via super() is unsafe  [safe-super]
[builtins fixtures/exception.pyi]

[case testDedicatedErrorCodeForEmpty_no_empty]
from typing import Optional
def foo() -> int: ...  # E: Missing return statement  [empty-body]
def bar() -> None: ...
# This is inconsistent with how --warn-no-return behaves in general
# but we want to minimize fallout of finally handling empty bodies.
def baz() -> Optional[int]: ...  # OK

[case testDedicatedErrorCodeTypeAbstract]
import abc
from typing import TypeVar, Type

class C(abc.ABC):
    @abc.abstractmethod
    def foo(self) -> None: ...

T = TypeVar("T")
def test(tp: Type[T]) -> T: ...
test(C)  # E: Only concrete class can be given where "type[C]" is expected  [type-abstract]

class D(C):
    @abc.abstractmethod
    def bar(self) -> None: ...
cls: Type[C] = D  # E: Can only assign concrete classes to a variable of type "type[C]"  [type-abstract]

[case testUncheckedAnnotationCodeShown]
def f():
    x: int = "no"  # N: By default the bodies of untyped functions are not checked, consider using --check-untyped-defs  [annotation-unchecked]

[case testUncheckedAnnotationSuppressed]
# flags: --disable-error-code=annotation-unchecked
def f():
    x: int = "no"  # No warning here

[case testMethodAssignmentSuppressed]
# flags: --disable-error-code=method-assign
class A:
    def f(self) -> None: pass
    def g(self) -> None: pass

def h(self: A) -> None: pass

A.f = h
# This actually works at runtime, but there is no way to express this in current type system
A.f = A().g  # E: Incompatible types in assignment (expression has type "Callable[[], None]", variable has type "Callable[[A], None]")  [assignment]

[case testMethodAssignCoveredByAssignmentIgnore]
class A:
    def f(self) -> None: pass
def h(self: A) -> None: pass
A.f = h  # type: ignore[assignment]

[case testMethodAssignCoveredByAssignmentFlag]
# flags: --disable-error-code=assignment
class A:
    def f(self) -> None: pass
def h(self: A) -> None: pass
A.f = h  # OK

[case testMethodAssignCoveredByAssignmentUnused]
# flags: --warn-unused-ignores
class A:
    def f(self) -> None: pass
def h(self: A) -> None: pass
A.f = h  # type: ignore[assignment]  # E: Unused "type: ignore" comment, use narrower [method-assign] instead of [assignment] code  [unused-ignore]

[case testUnusedIgnoreEnableCode]
# flags: --enable-error-code=unused-ignore
x = 1  # type: ignore  # E: Unused "type: ignore" comment  [unused-ignore]

[case testErrorCodeUnsafeOverloadError]
from typing import overload, Union

@overload
def unsafe_func(x: int) -> int: ...  # E: Overloaded function signatures 1 and 2 overlap with incompatible return types  [overload-overlap]
@overload
def unsafe_func(x: object) -> str: ...
def unsafe_func(x: object) -> Union[int, str]:
    if isinstance(x, int):
        return 42
    else:
        return "some string"
[builtins fixtures/isinstancelist.pyi]


###
# unimported-reveal
###

[case testUnimportedRevealType]
# flags: --enable-error-code=unimported-reveal
x = 1
reveal_type(x)
[out]
main:3: error: Name "reveal_type" is not defined  [unimported-reveal]
main:3: note: Did you forget to import it from "typing_extensions"? (Suggestion: "from typing_extensions import reveal_type")
main:3: note: Revealed type is "builtins.int"
[builtins fixtures/isinstancelist.pyi]

[case testUnimportedRevealTypePy311]
# flags: --enable-error-code=unimported-reveal --python-version=3.11
x = 1
reveal_type(x)
[out]
main:3: error: Name "reveal_type" is not defined  [unimported-reveal]
main:3: note: Did you forget to import it from "typing"? (Suggestion: "from typing import reveal_type")
main:3: note: Revealed type is "builtins.int"
[builtins fixtures/isinstancelist.pyi]

[case testUnimportedRevealTypeInUncheckedFunc]
# flags: --enable-error-code=unimported-reveal
def unchecked():
    x = 1
    reveal_type(x)
[out]
main:4: error: Name "reveal_type" is not defined  [unimported-reveal]
main:4: note: Did you forget to import it from "typing_extensions"? (Suggestion: "from typing_extensions import reveal_type")
main:4: note: Revealed type is "Any"
main:4: note: 'reveal_type' always outputs 'Any' in unchecked functions
[builtins fixtures/isinstancelist.pyi]

[case testUnimportedRevealTypeImportedTypingExtensions]
# flags: --enable-error-code=unimported-reveal
from typing_extensions import reveal_type
x = 1
reveal_type(x)  # N: Revealed type is "builtins.int"
[builtins fixtures/isinstancelist.pyi]

[case testUnimportedRevealTypeImportedTyping311]
# flags: --enable-error-code=unimported-reveal --python-version=3.11
from typing import reveal_type
x = 1
reveal_type(x)  # N: Revealed type is "builtins.int"
[builtins fixtures/isinstancelist.pyi]
[typing fixtures/typing-full.pyi]

[case testUnimportedRevealLocals]
# flags: --enable-error-code=unimported-reveal
x = 1
reveal_locals()
[out]
main:3: note: Revealed local types are:
main:3: note:     x: builtins.int
main:3: error: Name "reveal_locals" is not defined  [unimported-reveal]
[builtins fixtures/isinstancelist.pyi]

[case testCovariantMutableOverride]
# flags: --enable-error-code=mutable-override
from typing import Any

class C:
    x: float
    y: float
    z: float
    w: Any
    @property
    def foo(self) -> float: ...
    @property
    def bar(self) -> float: ...
    @bar.setter
    def bar(self, val: float) -> None: ...
    baz: float
    bad1: float
    bad2: float
class D(C):
    x: int  # E: Covariant override of a mutable attribute (base class "C" defined the type as "float", expression has type "int")  [mutable-override]
    y: float
    z: Any
    w: float
    foo: int
    bar: int  # E: Covariant override of a mutable attribute (base class "C" defined the type as "float", expression has type "int")  [mutable-override]
    def one(self) -> None:
        self.baz = 5
    bad1 = 5  # E: Covariant override of a mutable attribute (base class "C" defined the type as "float", expression has type "int")  [mutable-override]
    def other(self) -> None:
        self.bad2: int = 5  # E: Covariant override of a mutable attribute (base class "C" defined the type as "float", expression has type "int")  [mutable-override]
[builtins fixtures/property.pyi]

[case testNarrowedTypeNotSubtype]
from typing_extensions import TypeIs

def f(x: str) -> TypeIs[int]:  # E: Narrowed type "int" is not a subtype of input type "str"  [narrowed-type-not-subtype]
    pass

[builtins fixtures/tuple.pyi]

[case testDynamicMetaclass]
class A(metaclass=type(tuple)): pass  # E: Dynamic metaclass not supported for "A"  [metaclass]
[builtins fixtures/tuple.pyi]

[case testMetaclassOfTypeAny]
# mypy: disallow-subclassing-any=True
from typing import Any
foo: Any = ...
class A(metaclass=foo): pass  # E: Class cannot use "foo" as a metaclass (has type "Any")  [metaclass]

[case testMetaclassOfWrongType]
class Foo:
    bar = 1
class A2(metaclass=Foo.bar): pass  # E: Invalid metaclass "Foo.bar"  [metaclass]

[case testMetaclassNotTypeSubclass]
class M: pass
class A(metaclass=M): pass  # E: Metaclasses not inheriting from "type" are not supported  [metaclass]

[case testMultipleMetaclasses]
import six
class M1(type): pass

@six.add_metaclass(M1)
class A1(metaclass=M1): pass  # E: Multiple metaclass definitions  [metaclass]

class A2(six.with_metaclass(M1), metaclass=M1): pass  # E: Multiple metaclass definitions  [metaclass]

@six.add_metaclass(M1)
class A3(six.with_metaclass(M1)): pass  # E: Multiple metaclass definitions  [metaclass]
[builtins fixtures/tuple.pyi]

[case testInvalidMetaclassStructure]
class X(type): pass
class Y(type): pass
class A(metaclass=X): pass
class B(A, metaclass=Y): pass  # E: Metaclass conflict: the metaclass of a derived class must be a (non-strict) subclass of the metaclasses of all its bases  [metaclass] \
                               # N: "__main__.Y" (metaclass of "__main__.B") conflicts with "__main__.X" (metaclass of "__main__.A")


[case testOverloadedFunctionSignature]
from typing import overload, Union

@overload
def process(response1: float,response2: float) -> float:
    ...
@overload
def process(response1: int,response2: int) -> int: # E: Overloaded function signature 2 will never be matched: signature 1's parameter type(s) are the same or broader  [overload-cannot-match]
    ...

def process(response1,response2)-> Union[float,int]:
   return response1 + response2