let%component myComponent - (~component, (), hooks) => { ... }

will expand to (approximately)

let myComponent ={
  let component =  Expert.component("myComponent");
  (~component, ()) => 
    component(hooks => { ... })
);

hence the locally defined component will be shadowed by the prop/labelled argument, resulting in a type error. The PPX should instead use an invalid identifier name, like brisk-component, so it cannot be shadowed.

Also do the same for %hook, which while it uses a more cryptic name also has a microscopic chance of being shadowed.