## Motivation

While black keeps parentheses nearly everywhere, with the notable exception of in the body of for loops:
```python
for (a, b) in x:
    pass
```
becomes
```python
for a, b in x:
    pass
```

This currently blocks #5163, which this PR should unblock.

## Solution

This changes the `ExprTuple` formatting option to include one additional option that removes the parentheses when not using magic trailing comma and not breaking. It is supposed to be used through
```
#[derive(Debug)]
struct ExprTupleWithoutParentheses<'a>(&'a Expr);

impl Format<PyFormatContext<'_>> for ExprTupleWithoutParentheses<'_> {
    fn fmt(&self, f: &mut Formatter<PyFormatContext<'_>>) -> FormatResult<()> {
        match self.0 {
            Expr::Tuple(expr_tuple) => expr_tuple
                .format()
                .with_options(TupleParentheses::StripInsideForLoop)
                .fmt(f),
            other => other.format().with_options(Parenthesize::IfBreaks).fmt(f),
        }
    }
}
```

## Testing

The for loop formatting isn't merged due to missing this (and i didn't want to create more git weirdness across two people), but I've confirmed that when applying this to while loops instead of for loops, then
```rust
        write!(
            f,
            [
                text("while"),
                space(),
                ExprTupleWithoutParentheses(test.as_ref()),
                text(":"),
                trailing_comments(trailing_condition_comments),
                block_indent(&body.format())
            ]
        )?;
```
makes
```python
while (a, b):
    pass

while (
    ajssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssa,
    b,
):
    pass

while (a,b,):
    pass
```
formatted as
```python
while a, b:
    pass

while (
    ajssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssa,
    b,
):
    pass

while (
    a,
    b,
):
    pass
```

## Motivation

While black keeps parentheses nearly everywhere, with the notable exception of in the body of for loops:
```python
for (a, b) in x:
    pass
```
becomes
```python
for a, b in x:
    pass
```

This currently blocks #5163, which this PR should unblock.

## Solution

This changes the `ExprTuple` formatting option to include one additional option that removes the parentheses when not using magic trailing comma and not breaking. It is supposed to be used through
```
#[derive(Debug)]
struct ExprTupleWithoutParentheses<'a>(&'a Expr);

impl Format<PyFormatContext<'_>> for ExprTupleWithoutParentheses<'_> {
    fn fmt(&self, f: &mut Formatter<PyFormatContext<'_>>) -> FormatResult<()> {
        match self.0 {
            Expr::Tuple(expr_tuple) => expr_tuple
                .format()
                .with_options(TupleParentheses::StripInsideForLoop)
                .fmt(f),
            other => other.format().with_options(Parenthesize::IfBreaks).fmt(f),
        }
    }
}
```

## Testing

The for loop formatting isn't merged due to missing this (and i didn't want to create more git weirdness across two people), but I've confirmed that when applying this to while loops instead of for loops, then
```rust
        write!(
            f,
            [
                text("while"),
                space(),
                ExprTupleWithoutParentheses(test.as_ref()),
                text(":"),
                trailing_comments(trailing_condition_comments),
                block_indent(&body.format())
            ]
        )?;
```
makes
```python
while (a, b):
    pass

while (
    ajssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssa,
    b,
):
    pass

while (a,b,):
    pass
```
formatted as
```python
while a, b:
    pass

while (
    ajssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssa,
    b,
):
    pass

while (
    a,
    b,
):
    pass
```

## Motivation

While black keeps parentheses nearly everywhere, the notable exception
is in the body of for loops:
```python
for (a, b) in x:
    pass
```
becomes
```python
for a, b in x:
    pass
```

This currently blocks #5163, which this PR should unblock.

## Solution

This changes the `ExprTuple` formatting option to include one additional
option that removes the parentheses when not using magic trailing comma
and not breaking. It is supposed to be used through
```rust
#[derive(Debug)]
struct ExprTupleWithoutParentheses<'a>(&'a Expr);

impl Format<PyFormatContext<'_>> for ExprTupleWithoutParentheses<'_> {
    fn fmt(&self, f: &mut Formatter<PyFormatContext<'_>>) -> FormatResult<()> {
        match self.0 {
            Expr::Tuple(expr_tuple) => expr_tuple
                .format()
                .with_options(TupleParentheses::StripInsideForLoop)
                .fmt(f),
            other => other.format().with_options(Parenthesize::IfBreaks).fmt(f),
        }
    }
}
```


## Testing

The for loop formatting isn't merged due to missing this (and i didn't
want to create more git weirdness across two people), but I've confirmed
that when applying this to while loops instead of for loops, then
```rust
        write!(
            f,
            [
                text("while"),
                space(),
                ExprTupleWithoutParentheses(test.as_ref()),
                text(":"),
                trailing_comments(trailing_condition_comments),
                block_indent(&body.format())
            ]
        )?;
```
makes
```python
while (a, b):
    pass

while (
    ajssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssa,
    b,
):
    pass

while (a,b,):
    pass
```
formatted as
```python
while a, b:
    pass

while (
    ajssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssa,
    b,
):
    pass

while (
    a,
    b,
):
    pass
```