`Schema.omit` collapses union types

[ethanniser]

What version of Effect is running?

No response

What steps can reproduce the bug?

https://effect.website/play#1f5da688e517

What is the expected behavior?

The union type is maintained (see C)

What do you see instead?

The union is collapsed (see B)

Additional information

No response

[gcanti]

This is working as intended. The behavior is consistent with how Omit works in TypeScript:

type AA =
  | {
      readonly foo: "foo1"
      readonly bar: "bar1"
    }
  | {
      readonly foo: "foo2"
      readonly bar: "bar2"
    }

/*
type BB = {
  readonly bar: "bar1" | "bar2";
}
*/
type BB = Omit<AA, "foo">