Has there ever been discussion about an annotation to disallow trailing lambdas for a given function...

# language-evolution

[eygraber]

Has there ever been discussion about an annotation to disallow trailing lambdas for a given function?

For example

fun handleClicks(
  onClick: () -> Unit,
  onLongClick: () -> Unit
)

loses context when called like

handleClicks(
  onClick = {...}
) {
  ...
}

[wasyl]

Related, I'd definitely use an annotation that strongly suggests that a function should be called only using named parameters

[PHondogo]

Ugly solution:

fun handleClicks(
  onClick: () -> Unit,
  onLongClick: () -> Unit,
  noLambda: Nothing? = null
)

[mbonnin]

For named parameters: https://youtrack.jetbrains.com/issue/KT-14934

[ephemient]

possibly https://youtrack.jetbrains.com/issue/KT-47182 is more related

[Ruckus]

Also, instead of noLambda: Nothing? = null, I would recommend vararg noLambda: Nothing, It reduces the potential confusion of something like:

handleClicks(
    { ... },
    { ... },
    someFunctionThatReturnsNull(),
)

Though it's probably not a big deal.