Refused Bequest

Symptom

A subclass inherits methods or fields it doesn't actually use — overriding to no-ops, throwing 'unsupported', or just ignoring the inheritance.

Goal

Sharing happens through composition (a delegate object) rather than forced inheritance.

Smellier version

class Animal { fly() {} swim() {} }
class Dog extends Animal {
  fly() { throw new Error('no'); }
}

Fresher version

class Dog {
  // composes a Mover delegate that knows it's a swimmer
}

Savings

Each class has only what it needs; surprises in polymorphic use disappear.

Note

Liskov violations: callers can't trust subclass instances to honor the parent contract; polymorphism becomes a trap.