Currently the Component type does not have any role annotations

This results in weird, and definitely unsound, things like these to pass the typechecker (note that these are coerce and not unsafeCoerce):

doBadThings :: forall q i o m. Monad m => H.Component q i o Maybe -> H.Component q i o Aff
doBadThings component = coerce component

doEvilThings :: forall q i o m. Monad m => H.Component q i o Effect -> H.Component q i o Aff
doEvilThings component = coerce component

doUglyThings :: forall q i o m. Monad m => H.Component q i o (ReaderT Int m) -> H.Component q i o (ReaderT String m)
doUglyThings component = coerce component

From what I understood, I think that that all of the parameters should have a representational role, however I am not 100% sure and someone who has a bit more experience and insight into Halogen should give that a second thought.

type role Component representational representational representational representational

Some Relevant examples on Try Purescript

IMO, This is especially important as coercing components is advertised in the Halogen Real World example:

https://github.com/thomashoneyman/purescript-halogen-realworld/blob/ab13d62f95f4eb3ca589c0f043fe415af8408ff9/src/AppM.purs#L86-L87