From Discord: The Possibility of `schema.pipe(S.optional)` about effect HOT 2 OPEN

It seems that ts encounters difficulty inferring the correct type when optional is used tacitly:

const x = S.string.pipe(S.optional); // error

const y = pipe(S.string, S.optional); // error

This might be due to the presence of different overloads in the optional signature. In both cases above, the inferred schema is Schema<unknown, unknown>.

I'm unsure about how to resolve this issue. However, isn't tacit usage never recommended?

from effect.

It seems that ts encounters difficulty inferring the correct type when optional is used tacitly:

const x = S.string.pipe(S.optional); // error

const y = pipe(S.string, S.optional); // error

This might be due to the presence of different overloads in the optional signature. In both cases above, the inferred schema is Schema<unknown, unknown>.

I'm unsure about how to resolve this issue. However, isn't tacit usage never recommended?

While tacit usage is never recommended pipe is kind of an exceptional case, otherwise we could also say that pipe([0, 1], ReadonlyArray.map((n) => n + 1) is discouraged.

Re overloads, this is indeed the issue, namely overload selection, I think we need to decide if the reason we have overloads is absolute necessity or if we can encode what we do with overloads with a conditional return type (that would solve tacit usage).

It's up to @gcanti if you decide that overloads are needed then feel free to close the issue as "intended behaviour"

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