title: Which property of Scala's type-system make it Turing-complete?
body: <p>Scala uses a type-system based on System F ω, which is normally said to be strongly normalizing. Strongly normalizing implies non-Turing completeness.</p>
  
  <p>Nevertheless, Scala's type-system is Turing-complete.</p>
  
  <p>Which changes/additions/modifications make Scala's type-system Turing-complete compared to the formal algorithms and systems?</p>