Behaviour of MultilineLambdaItParameter inconsistent with name

[emilydespas-faire]

Expected Behavior

A lambda that uses the implicit it parameter with a single statement spread over multiple lines should be reported by the MultilineLambdaItParameter rule

Observed Behavior

Nothing is reported

Steps to Reproduce

fun detektTest(strings: List<String>): List<String> {
  return strings
    .flatMap {
      it
        .reader()
        .readLines()
    }
}

Context

Based on the name of the rule, its reasonable to expect that any lambda with code spanning multiple lines should be flagged. I raised this in the kotlinlang discord here: https://kotlinlang.slack.com/archives/C88E12QH4/p1712167796864189

As mentioned there, this caused confusion in one of our PRs where code that we expected to fail the rule was passed and then had to be caught by a code reviewer. This behaviour was introduced in this PR and there was a comment thread in that PR asking similar questions about the behaviour not matching the rule name that doesn't have a conclusion.

Would appreciate some clarity around whether this rule intends to ban any multi-line lambda using an it parameter, or only multi statement lambdas

Your Environment

• Version of detekt used: 1.23.4
• Version of Gradle used (if applicable): 8.7
• Gradle scan link (add --scan option when running the gradle task):
• Operating System and version: MacOS 14.4.1
• Link to your project (if it's a public repository):

[cortinico]

cc @t-kameyama