mypy-play

import typing as t
from dataclasses import dataclass


if t.TYPE_CHECKING:
    base = t.Tuple[str, bool]
else:
    base = object

@dataclass

mypy-play

from typing import TYPE_CHECKING, TypeVar, Generic
from typing_extensions import reveal_type

T1 = TypeVar("T1")
T2 = TypeVar("T2")

if TYPE_CHECKING:
    # This is how Group looks like to the type checker
    class Group(tuple[T1, T2], Generic[T1, T2]):
        def __new__(cls, key: T1, group: T2) -> "Group[T1, T2]": ...

mypy-play

from dataclasses import dataclass

@dataclass
class Test:
    text: str

    @staticmethod
    def gen_text() -> Text:
        return Test("some text")

mypy-play

from typing import Iterator


def fib(n: int) -> Iterator[int]:
    a, b = 0, 1
    while a < n:
        yield a
        a, b = b, a + b

mypy-play

from typing import Generic, TypeVar
T = TypeVar("T", contravariant=True)
class N(Generic[T]): ...
class C(N[N["C"]]): ...
x: N[C] = C()

mypy-play

from typing import *
from pathlib import Path

T = TypeVar("T")

def reverse_directory_search(filename: str, search_base: Path) -> Optional[Path]:
    """Search backwards for a file starting on a given directory.

    E.g.: from /a/b/c a file d.txt will be checked in the following order:
        - /a/b/c/d.txt

mypy-play

from typing import Any, Generic, TypeVar

_T = TypeVar("_T")
_U = TypeVar("_U", covariant=True)

class Node(Generic[_T, _U]):
  children: "dict[str, Node[_U, object]]"

  def __init__(self, children: "dict[str, Node[_U, object]]"):
    self.children = children

mypy-play

from typing import Callable
def dec(f) -> Callable[[int], None]: raise NotImplementedError

if int():
    def f(x: str): pass
else:
    @dec
    def f() -> None: pass

mypy-play

from typing import Literal
from typing_extensions import assert_never


def doit_if(result: Literal[1, -1]) -> None:
    if result == 1:
        pass
    elif result == -1:
        reveal_type(result)
    else:

mypy-play

from typing import (
    Generic,
    TypeVar,
    Callable,
    Concatenate,
    ParamSpec,
    reveal_type,
)
from dataclasses import dataclass