Extracting a Schema for a Tagged Union Member in Effect Typescript

import { Schema as S } from "effect"

const Animal = S.Union(
  S.TaggedStruct("Cow", {
    moo: S.String,
  }),
  S.TaggedStruct("Dog", {
    roof: S.String,
  }),
)

const Dog = Animal.pipe(
  S.extend(S.TaggedStruct("Cow", {})),
)

file:///Users/harrysolovay/Desktop/internal/node_modules/.pnpm/[email protected]/node_modules/effect/dist/esm/Schema.js:1633
  throw new Error(errors_.getSchemaExtendErrorMessage(x, y, path));
        ^

Error: Unsupported schema or overlapping types
at path: ["_tag"]
details: cannot extend "Cow" with "Cow"