 --> [ local path prefix ]/state_machine/redef/action.fpp:3:10
  |
3 |   action a
  |          ^ redefinition of symbol a
  |
 ::: [ local path prefix ]/state_machine/redef/action.fpp:2:3
  |
2 |   action a
  |   -------- previous definition is here

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

