closure_parameter_position not triggering with lack of parameter in closure

[gannon-eero]

New Issue Checklist

• Updated SwiftLint to the latest version
• I searched for existing GitHub issues

What I expected from this rule was that regardless of whether there was a parameter or not (although I understand it does go against the name of the rule in a sense), it would still trigger. Instead, I would expect the rule to really apply to the in syntax altogether. For instance, this currently triggers:

closureFunc {
    ↓[weak self] param in
    ...
}

However, this does not

closureFunc {
    [weak self] in
    ...
}

This appears kind of odd, when you have multiple closures for a function with some with parameters and some without, such as below. The middle onFailure closure will trigger, but the onSuccess and onReset do not.

thing.doStuff(onSuccess: {
    [weak self] in
    doSuccess()
}, onFailure: {
    ↓[weak self] rules in
    doFailure()
}, onReset: {
    [weak self] in
    doReset()
})

Will update this if I figure out a good custom rule or change that achieves this result.

[gannon-eero]

Likewise, in the situation where the closure is a member variable of a struct/class, the rule also doesn't trigger. Such as:

struct Foo {
    var completionHandler: ((Int) -> Void)? = nil
}

var f = Foo()
f.completionHandler = {
    thing in // Should trigger here
    doStuff()
}