How do I activate type annotations hints in Kotlin like depicted?

Adding to @Simulant answer.

In Latest Version of IntelliJ (2019.3.1) , You will NOT find this in Settings -> Editor -> General -> Appearance -> "Show parameter name hints"

Its available in Settings -> Editor -> Inlay Hints -> Kotlin -> "Show parameter hints"

enter image description here


Adding to @Simulant and @zero answers

In the latest version of IntelliJ (2020.3) you need to go to Settings -> Editor -> Inlay Hints where you can specify "Show hints for" (for specific language) and then in Settings -> Editor -> Inlay Hints -> Kotlin -> Parameter hints -> Types you can specify what type of hints you want.

enter image description here


For IntelliJ (2022.1) onwards got to Settings -> Editor -> Inlay Hints -> Types -> Kotlin -> Types -> Parameter hints -> Local variable types or check all.

I think you are allowed to say, that this feature configuration is a little bit hidden in the menues and was moved a lot between different releases.

Configure parameter name hints

Thanks to @vitfo, adding this to the top here. For IntelliJ (2020.3) onwards got to: Settings -> Editor -> Inlay Hints -> Kotlin -> Parameter hints -> Types

In IntelliJ 2019.3.1 onwards it is located at: Settings -> Editor -> Inlay Hints -> Kotlin -> "Show parameter hints" (thanks to @zero).

Original Answer for IntelliJ 2018
Go to Settings -> Editor -> General -> Appearance -> "Show parameter name hints" -> Configure... -> Language: Kotlin -> Options -> "Show local variable type hints"