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trait T
class V1(val l: Long) extends AnyVal { self: T =>
def foo: V1 = self
def bar: T = self
}
class V2(val l: Long) extends AnyVal { self =>
def foo: V2 = self
}
class V3(val l: Long) extends AnyVal { self: Long =>
def foo: V3 = self
def bar: Long = self
}
// non-value classes
class C1(val l: Long) { self: T =>
def foo: C1 = self
def bar: T = self
}
class C2(val l: Long) { self =>
def foo: C2 = self
}
class C3(val l: Long) { self: Long =>
def foo: C3 = self
def bar: Long = self
}
object Test extends App {
// Rejected: superclass V1 is not a subclass of the superclass Object of the mixin trait T
// new V1(1l) with T
assert(new V2(1l).foo.l == 1l)
// Rejected: V3 does not conform to its self-type V3 with Long
// new V3(1l)
val c2 = new C1(2l) with T
assert(c2.foo.l + c2.bar.asInstanceOf[C1].l == 4l)
assert(new C2(3l).foo.l == 3l)
// Rejected: C3 does not conform to its self-type C3 with Long
// new C3(4l)
// Rejected: class Long needs to be a trait to be mixed in
// new C3(4l) with Long
}
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