Handling Multiple Failure Types in Effect TypeScript

Argument of type '(x: number) => Effect<never, TestError1, never> | Effect<never, TestError2, never> | Effect<Option<never>, never, never>' is not assignable to parameter of type '(a: number) => Effect<Option<never>, TestError1, never>'.
Type 'Effect<never, TestError1, never> | Effect<never, TestError2, never> | Effect<Option<never>, never, never>' is not assignable to type 'Effect<Option<never>, TestError1, never>'.
Type 'Effect<never, TestError2, never>' is not assignable to type 'Effect<Option<never>, TestError1, never>'.
Type 'TestError2' is not assignable to type 'TestError1'.
Types of property '_tag' are incompatible.
Type '"TestError2"' is not assignable to type '"TestError1"'.

import { Cause, Data, Effect, pipe, Random } from "effect";

export class TestError1 extends Data.TaggedError("TestError1")<{}> {}
export class TestError2 extends Data.TaggedError("TestError2")<{}> {}

const testEffect = pipe(
  Random.next,
  Effect.flatMap((x) => {
    if (x < 0.3) {
        return Effect.failCause(Cause.fail(new TestError1()))
    } else if (x < 0.6) {
        return Effect.failCause(Cause.fail(new TestError2()))
    } else {
        return Effect.succeedNone;
    }
  }),
);

const res = await Effect.runPromise(testEffect)

import { Cause, Data, Effect, pipe, Random } from "effect";

export class TestError1 extends Data.TaggedError("TestError1")<{}> {}
export class TestError2 extends Data.TaggedError("TestError2")<{}> {}

const testEffect = pipe(
  Random.next,
  Effect.flatMap((x) => {
    if (x < 0.3) {
        return Effect.failCause(Cause.fail(new TestError1()))
    } else if (x < 0.6) {
        return Effect.failCause(Cause.fail(new TestError2()))
    } else {
        return Effect.succeedNone;
    }
  }),
);

const res = await Effect.runPromise(testEffect)