ILHA004: Generator resumed while an instruction was in flight

Ilha tried to drive a generator component again before the instruction it yielded finished.

A generator component yields one instruction at a time, such as an Effect or a Stream. Ilha resumes the generator when that instruction finishes. If anything drives the same component again while an instruction is pending, Ilha throws ILHA004.

Why it happens

• Two mount() calls target the same running component fiber.
• Custom renderer code calls the runtime’s generator driver twice for one fiber.

You rarely see this from ordinary components. It signals that two drivers share one fiber.

Bad

import * as Effect from "effect/Effect";
import { mount } from "ilha";

function* Status() {
  yield Effect.never;
}

// A renderer that re-enters the same fiber while `Effect.never` is pending.

Fixed

Mount each generator component once per host, and let Ilha resume it:

import * as import EffectEffect from "effect/Effect";
import { const mount: (el: Element, fn: Component, opts?: MountOptions) => (() => void)mount } from "ilha";

function* function Status(): Generator<string | number | bigint | boolean | (() => View | undefined | Promise<View | undefined>) | GeneratorFn | VNode | UnsafeHtml | AtomView | Stream<View, unknown, unknown> | Iterable<View> | Effect.Effect<void, never, never> | null | undefined, void, unknown>Status() {
  yield <JSX.IntrinsicElements.p: HTMLAttributes<HTMLParagraphElement>p>loading</JSX.IntrinsicElements.p: HTMLAttributes<HTMLParagraphElement>p>;
  yield import EffectEffect.const sleep: (duration: Input) => Effect.Effect<void>
Returns an effect that suspends the current fiber for the specified duration
without blocking a JavaScript thread.

**Example** (Pausing without blocking)

```ts import.meta.vitest
import { Effect } from "effect"
const output: Array<unknown> = []

const program = Effect.gen(function*() {
  yield* Effect.sync(() => { output.push("Start") })
  yield* Effect.sleep(0)
  yield* Effect.sync(() => { output.push("End") })
})

await Effect.runPromise(program)
output // => ["Start", "End"]
```
@categorydelays & timeouts@since2.0.0sleep(100);
  yield <JSX.IntrinsicElements.p: HTMLAttributes<HTMLParagraphElement>p>ready</JSX.IntrinsicElements.p: HTMLAttributes<HTMLParagraphElement>p>;
}

function mount(el: Element, fn: Component, opts?: MountOptions): (() => void)mount(var document: Document
**`window.document`** returns a reference to the document contained in the window.

[MDN Reference](https://developer.mozilla.org/docs/Web/API/Window/document)document.Document.body: HTMLElement
The **`Document.body`** property represents the <body> or <frameset> node of the current document, or null if no such element exists.

[MDN Reference](https://developer.mozilla.org/docs/Web/API/Document/body)body, function Status(): Generator<string | number | bigint | boolean | (() => View | undefined | Promise<View | undefined>) | GeneratorFn | VNode | UnsafeHtml | AtomView | Stream<View, unknown, unknown> | Iterable<View> | Effect.Effect<void, never, never> | null | undefined, void, unknown>Status);