================================================================================
Simplified:
Rec {
`$g0'  ::  `GHC.Int# -> PrelBase.Int'
`$g0' =
    \ `$x0'  ::  `GHC.Int#'
      `$x0' ->
	case# `$x0' of {
	  0 -> `PrelBase.I#' {2};
	  `$x1' ->
	      case `$g0' `$x0' of { `PrelBase.I#' `$x2'  ->
	      case# *#! `$x2' `$x0' of { `$x3' -> `PrelBase.I#' {`$x3'};};};
	}
end Rec }
`fact'  ::  `PrelBase.Int -> PrelBase.Int'
`fact' =
    \ `$x0'  ::  `PrelBase.Int'
      `$x0' ->
	case `$x0' of { `PrelBase.I#' `$x1'  -> `$g0' `$x1';}