without-tag := λ(: tt Type). (: (
   (match tt (
      ()
      ( (TAnd( lt rt )) (
         (let lt1 (without-tag lt))
         (let rt1 (without-tag rt))
         (match (Tuple( lt1 rt1 )) (
            ()
            ( (Tuple( TAny rt2 )) (set tt rt2) )
            ( (Tuple( lt2 TAny )) (set tt lt2) )
            ( (Tuple( lt2 rt2 )) (
               (set tt (TAnd( (close lt2) (close rt2) )))
            ))
         ))
      ))
      ( (TGround( 'Constructor_s _ )) (set tt TAny) )
      ( (TGround( 'Tag_s _ )) (set tt TAny) )
      ( (TGround( 'Fields_s _ )) (set tt TAny) )
      ( (TGround( 'FieldsSized_s _ )) (set tt TAny) )
      ( _ () )
   ))
   tt
) Type);

without-tag := λ(: tt List<Type>). (: (
   (match tt (
      ()
      ( (LCons( p1 rst )) (
         (set tt (cons( (without-tag p1) (without-tag rst) )))
      ))
      ( LEOF () )
   ))
   tt
) List<Type>);