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class Foo {
type A = Int
type B >: Int <: Int
def get: A = 42
}
trait T {
lazy val x: Int
val y: Int
}
class Bar extends Foo with T {
override type A = Any // error
type B >: String <: Any // error
override def get: A = "bar"
val x = 2 // error
lazy val y = 3 // error
}
object Test {
def main(args: Array[String]): Unit = {
val foo: Foo = new Bar
val i: Int = foo.get
}
}
package p1 {
abstract class T1 {
protected def bug(p: Int = 1): Int // without 'protected' compiles fine
}
}
package p2 { // all being in the same package compiles fine
import p1._
abstract class T2 extends T1 {
class A {
bug()
}
}
abstract class T3 extends T2 {
class A { // error: classes cannot be overridden
bug()
}
}
}
class A[T] {
def f(x: T)(y: T = x) = y
}
class B extends A[Int] {
def f(x: Int)(y: Int) = y // error: needs `override' modifier
f(2)()
}
class X {
def f: A[Int] = ???
}
class Y extends X {
def f: A[Int] = ??? // error: needs `override' modifier
}
class A1
class B1
class X1 {
def f(): A1 = ???
}
class Y1 extends X1 {
override def f(): B1 = ??? // error: has incompatible type
}
class X2 {
type T = A1
}
class Y2 extends X2 {
type T = B1 // error: needs `override' modifier
}
class X3 {
override type T = A1 // error: overrides nothing
}
package p3 {
// Dotty change of rules: Toverrider#f does not
// override TCommon#f, hence the accidental override rule
// applies.
trait TCommon {
def f: String
}
class C1 extends TCommon {
def f = "in C1"
}
trait TOverrider { this: TCommon =>
override def f = "in TOverrider" // The overridden self-type member...
}
class C2 extends C1 with TOverrider // ... fails to override, here. // error: accidental override
}
package p4 {
abstract class C[T] { def head: T }
case class D[T](head: Int) extends C[T] // error: has incompatible type
}
package p5 {
class A {
def m: String = "foo"
}
class B extends A {
override val m: Int = 42 // error: has incompatible type
}
class C extends A {
override def m: Int = 42 // error: has incompatible type
}
}
|
