Return type of method not checked when overriding methods from self type in trait #9736
Description
When overriding a method from the self type of a trait the return type is not checked so this compiles:
trait A {
def a: Int
}
trait B { self: A =>
override def a: String = "Well this should not compile"
} The compile error happens when B is used:
scala> class C extends A with B
<console>:9: error: overriding method a in trait A of type => Int;
method a in trait B of type => String has incompatible type
class C extends A with B
^The compile error should already happen when defining B as the method overrides nothing.