Declaring properties for class methods seem to cause invariant use errors #2770
Description
Here is an example code:
/* @flow */
class Task <x, a> {
fork: (succeed:(value:a) =>void, fail:?(error:x) => void) => void
}
class Succeed <x, a> extends Task <x, a> {
value: a
constructor(value:a) {
super()
this.value = value
}
fork(succeed:(value:a) =>void, fail:?(error:x) => void):void {
succeed(this.value)
}
}Which produces following error:
7: class Succeed <x, a> extends Task <x, a> {
^ Succeed. Covariant property `fork` incompatible with invariant use in
7: class Succeed <x, a> extends Task <x, a> {
^ Task
As far as I can tell there is no mismatch between property type and a method but never the less error seems to appear.