Type Alias Method<T, K>

Method: T[K] extends (...args: infer A) => infer R
? (this: T, ...args: A) => R
: never

Conditional helper used by defineMethod: given T[K] is a function, produces a corresponding function type with this: T bound to the prototype owner. Non-function members resolve to never so prototype patches can't target accessors or fields by mistake.