UnnecessaryLet false positive when let is used for destructuring

[jcornaz]

Expected Behavior

I don't expect UnnecessaryLet to be reported for the following code:

val y = x.let { (a, b) -> a + b }

That is because, in this case, let is necessary for destructuring. If I really, want to get rid of let I have to destructure in a val (a, b) = x assigment. And to not let a and b leak in the scope, I'd have to replace val y = x.let { (a, b) -> a + b} by val y = run { val (a, b) = x ; a + b }. Not really an improvement in my opinion.

Observed Behavior

An UnnecessaryLet is reported for the code above.

Steps to Reproduce

1. Enable UnnecessaryLet rule
2. Write:

fun foo(x: Pair<Int, Int>): Int = x.let { (a, b) -> a + b }

3. Run detekt

Your Environment

• Version of detekt used: 1.11.0-RC2

[arturbosch]

Cool use case for let I wasn't aware off 👍