From the readme: > The go-sumtype command recognizes this pattern, but it needs a small amount of help to recognize which interfaces should be treated as sum t

From the readme: > The go-sumtype command recognizes this pattern, but it needs a small amount of help to recognize which interfaces should be treated as sum types Why is this? Have you tried detecting sum types automatically? Maybe some heuristics like: package-level declaration of the interface, has an unexported method, has more than one type that implements it, maybe also the interface itself is exported.