This inspection became deprecated.
It is not recommended to use procedure-like syntax for methods with Unit return type. It is inconsistent, may lead to errors and will be deprecated in future versions of Scala.

* Reference: The talk "Scala with Style" by Martin Odersky at ScalaDays 2013

Old description:
Methods with a result type of Unit are only executed for their side effects.

A better way to express such methods is to leave off the equals sign, and enclose the body of the method in curly braces.

In this form, the method looks like a procedure, a method that is executed only for its side effects:

// excessive clutter, looks like a function
def close() = { println("closed") } // may accidentally change its result type
// after changes in body
def close() = { file.delete() } // result type is Boolean
// concise form, side-effect is clearly stated
// result type is always Unit
def close() { file.delete() }

* Refer to Programming in Scala, 4.1 Classes, fields, and methods