Scala implicit conversions is a powerful tool for Scala coding. It lets you decrease redundancy in your code and lets you make the code easier to read.

Implicit Conversion Highlighting

If Scala type-aware highlighting type_aware_highlighting_icon is enabled then IntelliJ IDEA highlights methods that are added via implicit conversions with a grey underline:

grey_underline

Invoking Implicit Conversion Methods

  • Select an expression and press ⇧ ^ Q (^ Q for OS X) to invoke the list of applicable implicit conversions. The list shows the regular scope displayed on the top and the expanded scope that is displayed on the bottom of the list.

    Note that IntelliJ IDEA highlights an implicit conversion that was used for the selected expression. If IntelliJ IDEA cannot find the implicit conversion or if it finds more than one match then the list of Introduce Variable opens.

    choose_implicit_conv

  • You can make the implicit conversion method explicit. Press ⌥⏎ or ⌥⏎⌥⏎ or ⌥⏎⌘1 or ⌘1⌥ Enter, ⌥⏎ or ⌥⏎⌥ Enter, ⌥⏎ or ⌥⏎ and select Make explicit or Make explicit (Import method):

    choose_implicit_with_make_exp

  • If you select Make explicit then IntelliJ IDEA returns a method call with the class name. It might be helpful if you need to make sure that the compiler imports the particular implicit conversion method that you originally wanted:

    make_explicit

  • If you select Make explicit (Import method) then the method is imported statically and IntelliJ IDEA returns just its call without the class name. Also, the next time you open the list of useful implicit conversions you will see this method in the regular scope:

    make_explicit_import_met

Invoking Implicit Parameters

  • Place a cursor to the method where implicit conversion was used and press ⌃⇧P or ⌃⇧P⌃⇧P or ⌃⇧P^ ⇧ P, ⌃⇧P or ⌃⇧P to invoke implicit parameters. It might be helpful for code analyzing when you want to find out what implicit parameters were passed to the particular call. IntelliJ IDEA also lets you view the recursive implicit parameters.

    Note that IntelliJ IDEA highlights the method call where implicit parameters were used.

    implicit_param

  • If IntelliJ IDEA cannot find method calls where implicit parameters were passed, it displays a pop-up message:

    no_implicit_param