:= and :=! too losely bound

[3noch]

I'm not sure it's even possible to fix this but you'll notice that when defining a record with function types, you must use parenthesis like this:

type MyRec = R ( "runThing" := (a -> IO b) )

Without parens, the parser thinks you are defining ("runThing" := a) -> IO b as an unlabeled record.

[PkmX]

I don't think this is fixable, since (->) is hard-wired as infixr 0 in GHC. As you mentioned, adding parentheses around would be the easiest workaround of this issue.