node f(x:int) returns (y:int)
var z :int;
let
  z = 3;
  y = 0 fby z;
tel

node ff(x:int; c:bool) returns (y:int)
var z :int;
let
  z = 3;
  y = (0 fby z) when c;
tel

node fff(x:int; c:bool) returns ()
var z :int; y:int;
let
  z = 3;
  y = (0 fby z) when c;
tel

node main() returns (x,y:int)
var c:bool;
let
  x = f(0);
  c = false fby false fby true fby c;
  y = merge c (ff(0,c)) 0;
  () = fff(0,c);
tel