Encourage removing `{ .. }` from a pattern if enum variant is field-less

[urben1680]

What it does

Match patterns using Enum::Variant { .. } should be linted on if the enum variant is field-less.

Example:

match Some(42) {
    Some(v) => v,
    None { .. } /* <- lint this */ => 1
}

Advantage

• Removes noise from when the vairant used to have fields (before refactoring for example)

Drawbacks

• This pattern may still useful in macros so this should still be possible to be ignored with an [allow(...)]

Example

None { .. } => 1
     ^^^^^^

Could be written as:

None => 1

[lolbinarycat]

This pattern may still useful in macros so this should still be possible to be ignored with an [allow(...)]

1. all lints can be ignored in that way, if they couldn't be, they wouldn't be lints, they would be errors
2. macro generated code is usually not linted