Reports when a return keyword is used inside an anonymous function to jump out of it early. Nonlocal returns are implemented by throwing and catching scala.runtime.NonLocalReturnException-s. This is rarely what is intended by the programmer. It can be problematic because of the hidden performance cost of throwing and catching exceptions.

Furthermore, it is a leaky implementation: a catch-all exception handler can intercept a NonLocalReturnException.

def foo(numbers: Seq[Int]): Int =
  numbers.map { n =>
    if (n > 5)
      return 0 // highlighted
    n * 2
  }.sum