inline if and interfaces (polymorphism)

Question

public class Foo : IFooBarable {...}
public class Bar : IFooBarable {...}

So why then will this not compile...

int a = 1;
IFooBarable ting = a == 1 ? new Foo() : new Bar();

but this will...

IFooBarable ting = a == 1 ? new Foo() : new Foo();
IFooBarable ting = a == 1 ? new Bar() : new Bar();

Answer 1

The compiler first tries to evaluate the right-hand expression:

? new Foo() : new Bar();

There's no implicit conversion between those two hence the error message. You can do this:

IFooBarable ting = a == 1 ? (IFooBarable)(new Foo()) : (IFooBarable)(new Bar());