Expression body syntax is recommended by the style guide.

Convert to expression body quick-fix can be used to amend the code automatically.

Example:

  fun sign(x: Int): Int {
      return when { // <== can be simplified
          x < 0 -> -1
          x > 0 -> 1
          else -> 0
      }
  }

After the quick-fix is applied:

  fun sign(x: Int): Int = when {
      x < 0 -> -1
      x > 0 -> 1
      else -> 0
  }