# Narrowing for `in` conditionals

## `in` for tuples

```py
def _(x: int):
    if x in (1, 2, 3):
        reveal_type(x)  # revealed: int
    else:
        reveal_type(x)  # revealed: int
```

```py
def _(x: str):
    if x in ("a", "b", "c"):
        reveal_type(x)  # revealed: str
    else:
        reveal_type(x)  # revealed: str
```

```py
from typing import Literal

def _(x: Literal[1, 2, "a", "b", False, b"abc"]):
    if x in (1,):
        reveal_type(x)  # revealed: Literal[1]
    elif x in (2, "a"):
        reveal_type(x)  # revealed: Literal[2, "a"]
    elif x in (b"abc",):
        reveal_type(x)  # revealed: Literal[b"abc"]
    elif x not in (3,):
        reveal_type(x)  # revealed: Literal["b", False]
    else:
        reveal_type(x)  # revealed: Never
```

```py
def _(x: Literal["a", "b", "c", 1]):
    if x in ("a", "b", "c", 2):
        reveal_type(x)  # revealed: Literal["a", "b", "c"]
    else:
        reveal_type(x)  # revealed: Literal[1]
```

## `in` for `str` and literal strings

```py
def _(x: str):
    if x in "abc":
        reveal_type(x)  # revealed: str
    else:
        reveal_type(x)  # revealed: str
```

```py
from typing import Literal

def _(x: Literal["a", "b", "c", "d"]):
    if x in "abc":
        reveal_type(x)  # revealed: Literal["a", "b", "c"]
    else:
        reveal_type(x)  # revealed: Literal["d"]
```

```py
def _(x: Literal["a", "b", "c", "e"]):
    if x in "abcd":
        reveal_type(x)  # revealed: Literal["a", "b", "c"]
    else:
        reveal_type(x)  # revealed: Literal["e"]
```

```py
def _(x: Literal[1, "a", "b", "c", "d"]):
    # error: [unsupported-operator]
    if x in "abc":
        reveal_type(x)  # revealed: Literal["a", "b", "c"]
    else:
        reveal_type(x)  # revealed: Literal[1, "d"]
```

## Assignment expressions

```py
from typing import Literal

def f() -> Literal[1, 2, 3]:
    return 1

if (x := f()) in (1,):
    reveal_type(x)  # revealed: Literal[1]
else:
    reveal_type(x)  # revealed: Literal[2, 3]
```