Open
Description
Flow version: 0.156.0 (at least since 0.135.0)
Expected behavior
Making type generic does not introduce unsoundness.
Actual behavior
Context
Our Mithril definitions use types which looks similar to these:
export interface Vnode<Attrs> {
attrs: Attrs,
children: ChildArray,
dom: HTMLElement,
}
declare interface Mithril {
<AttrsT>(
component: Class<MComponent<AttrsT>>,
attributes: AttrsT,
children?: Children
): Vnode<any>;
}
interface MComponent<+Attrs> {
/** Creates a view out of virtual elements. */
view(vnode: Vnode<Attrs>): Children;
}
export type Child = Vnode<any> | string | number | boolean | null;
export type ChildArray = Array<Children>;
export type Children = Child | ChildArray;
declare var m: Mithril;
// --
// --
// --
type TestAttrs = {
test: number,
}
class TestComponent implements MComponent<TestAttrs> {
view(vnode: Vnode<TestAttrs>): Children {
return String(vnode.attrs.test)
}
}
function test(): Children {
return m(TestComponent, {
test: "c" // this should not be allowed
})
}