Incorrect captures for interface operations with block parameters

[marzipankaiser]

In the following example, the captures are annotated as indicated in the comments:

interface Bar {
  def bar(): Unit
}
interface Foo {
  def foo(){b: Bar}: Unit
}

// {b}
def baz() = {
  // {b}
  def x = new Foo { 
    def foo(){b} = { b.bar() }
  }
  // {}
  def b2 = new Bar { def bar() = () }
  x.foo{b2}
}

// {}
def foof(){b: Bar} = b.bar()

// {b}
def main() = {
  baz()
}

Here, the capture for x contains b, which is not even in scope outside of the definition of foo.
(This is also inconsistent with the captures of foof).

[marzipankaiser]

I think we need to add the captures for block parameters here (not just the capabilities from effects), so we remove them in the result:

effekt/effekt/shared/src/main/scala/effekt/Typer.scala

Lines 437 to 445 in e0e5c60

	// these capabilities are later introduced as parameters in capability passing
	val capabilities = (effs.canonical zip cparamsForEffects).map {
	case (tpe, capt) => Context.freshCapabilityFor(tpe, CaptureSet(capt))
	}
	val Result(bodyType, bodyEffs) = Context.bindingCapabilities(d, capabilities) {
	body checkAgainst tpe
	}
	Result(bodyType, bodyEffs -- effs)

[b-studios]

Yes, that sounds about right

[jiribenes]

I'll mark this as a good first issue, since it's pretty understandable and the solution should be straightforward.
However, if this actually blocks someone's flow, feel free to do it sooner/yourself without waiting for the Hackathon :)