Comment by codebje

When you need to use an effect, you need it in the type. If you directly call a function using some other effect, it propagates into your function. So far, so colourful.

But you can have generic effects. Your arguments and return type can specify "any effect", indicating your function can use a type with any effect safely, or can be used in any effect context safely.

Passing an async value to a function doesn't mean that function must now also be an async function. It can be a "for all effects, do the thing" function. The code duplication problem is gone.