Supporting generic type inference over the other higher-order functions #9366
Description
Currently, TypeScript infers generic types when referring its type immediately. Its behavior is undesirable for using higher-order functions. The type inference of generics should delay until it will be called.
function flip<a, b, c>(f: (a: a, b: b) => c): (b: b, a: a) => c {
return (b: b, a: a) => f(a, b);
}
function zip<T, U>(x: T, y: U): [T, U] {
return [x, y];
}
var expected: <T, U>(y: U, x: T) => [T, U] = flip(zip);
var actual: (y: {}, x: {}) => [{}, {}] = flip(zip);