Generic extending class AND implements interface i

问题:

Say I want a type variable, T, that extends a certain class and implements an interface. Something like:

class Foo <T : Bar implements Baz> { ... }

What is the syntax for this in Kotlin?

回答1:

Only one upper bound can be specified inside the angle brackets.

Kotlin offers different syntax for generic constraints when there is more than one constraint:

class Foo<T>(val t: T) where T : Bar, T : Baz { ... }

and for functions:

fun <T> f(): Foo where T : Bar, T : Baz { ... }

It is documented here.