Error on a block used by syntax sugar

[mcamp]

Take the program:
(machine m
(state bar)
(state foo)
(on [1] bar -> foo)
)
(spawn m bar)

The block inside the transition "on" should return a boolean, but here it returns a number. The error window in LRP notify about this error, but in a non-understandable way, because of the syntax sugar behind this statement.

[jfabry]

The problem is generic for all errors that occur in a statement that is generated by sugar.