Working with Scala Show Type Info Action

IntelliJ IDEA offers an easy way to work with type inference feature such as Scala Show Type Info action.

• Entering code
• Invoking Show Type Info Action
• Adding Type Annotation
• Removing Type Annotation
• Seeing Type Annotation on Expression

Entering code

•  Let's enter a random code and see what can be done:

  

Invoking Show Type Info Action

• If you select Show type info on mouse hover after, ms check box in Settings | Languages and Frameworks | Scala, then in the Editor, you can simply navigate with the mouse to a value to see its type information.
• To invoke Show Type Info action in Editor, navigate to the value and press Alt + =
  (Ctrl + Shift + P for OS X):

  

• You can also see the type information on a value definition. Simply put the caret on a value definition and press Alt + =
  (Ctrl + Shift + P for OS X):

  

Adding Type Annotation

• To add a type annotation, highlight the value and press Alt + Enter:

  

  As a result, the type annotation is added:

  

• You can also use Adjust types action to shorten types with full qualified names.

  

  In this case the necessary imports are added.

  

Removing Type Annotation

•  You can also remove the type annotation the same way you have added it, by pressing Alt+ Enter:

  

Seeing Type Annotation on Expression

• To see the type information on an expression, simply navigate to the expression, highlight it and press Alt + =
  (Ctrl + Shift + P for OS X):