guess-representation := λ(: tt Type). (: (
   (if (has-representation tt) () (
      (let sz (sizeof-type tt))
      (match sz (
         ()
         ( 0_u64 () )
         ( 1_u64 (set tt (and( tt (t1( 'Reg8_s )) ))) )
         ( 2_u64 (set tt (and( tt (t1( 'Reg16_s )) ))) )
         ( 4_u64 (set tt (and( tt (t1( 'Reg32_s )) ))) )
         ( 8_u64 (set tt (and( tt (t1( 'Reg64_s )) ))) )
         ( _ (set tt (and( tt (t1( 'StackVariable_s )) ))) )
      ))
   ))
   tt
) Type);