parameter of anonymous function cannot be given ?

[armanbilge]

Compiler version

3.1.1-RC1

Minimized code

Given:

class Foo:
  def bar = ()

This compiles:

Option(new Foo).map { implicit foo: Foo =>
  summon[Foo].bar
}

So does this:

for {
  given Foo <- Option(new Foo)
} yield summon[Foo].bar

But, none of these do. Am I writing it wrong, or is it just not possible?

Option(new Foo).map { given Foo =>
  // abstract givens cannot be annonymous
  summon[Foo].bar
}

Option(new Foo).map { (given Foo) =>
  // illegal start of simple expression
  summon[Foo].bar
}

Option(new Foo).map { (given foo: Foo) =>
  // illegal start of simple expression
  summon[Foo].bar
}

Option(new Foo).map { given foo: Foo =>
  // ; expected but => found
  summon[Foo].bar
}

[som-snytt]

Option(C()).map { ((x: C) ?=> summon[C])(using _) }

[som-snytt]

Option(C()).map { case given C => summon[C] }

As mentioned under "pattern-bound givens", same as for given.

https://docs.scala-lang.org/scala3/reference/contextual/givens.html

[armanbilge]

Aha! That's a reasonable syntax, thanks :)

I'd still love to see something similar to Scala 2, if possible, so we can skip the case keyword.