react/compiler/crates/react_hermes_parser/tests/fixtures/reactive-scopes.js

function f(a, b) {
  let x = []; // <- x starts being mutable here.
  if (a.length === 1) {
    if (b) {
      x.push(b); // <- x stops being mutable here.
    }
  }

  return <div>{x}</div>;
}