When one uses itOnly to focus on the test, spec outputs result only for focused one, but still executes all the other tests, is this by design?

Seems this happens in case when pure test is used.

For example:

it "check some" do
  let res = 2 + 2
  res `shouldEqual` 4

This behaviour is prevented with for example putting pure unit in the test start:

it "check some" do
  pure unit
  let res = 2 + 2
  res `shouldEqual` 4