You can quickly look up parameters of a method. Place the caret inside of method parentheses and press Ctrl+P
The editor will display a tip showing method parameters. The parameter currently selected by caret (if any) is displayed in bold. You can press Tab to jump to next parameter or Shift+Tab to jump to previous parameter.
If symbol at caret does not conform to an appropriate type, then a line in parameter info is marked gray. Lines that display the only possible combination of parameters are marked green.
This feature also supports named and default parameters. If you are using named parameters, then after pressing Ctrl+P you'll see them in a different order:
Also, you can try it for patterns (if they're using an unapply method), and for type parameters (in this case, for constructors):