 --> [ local path prefix ]/state_machine/redef/guard.fpp:3:9
  |
3 |   guard g
  |         ^ redefinition of symbol g
  |
 ::: [ local path prefix ]/state_machine/redef/guard.fpp:2:3
  |
2 |   guard g
  |   ------- previous definition is here

 --> [ local path prefix ]/state_machine/redef/guard.fpp:1:15
  |
1 | state machine M {
  |               ^ state machine must have initial transition

