Test.scala:4: error: class C1 inherits conflicting members:
  method f in trait A of type ()Int  and
  method f in trait T of type => Int
(Note: this can be resolved by declaring an override in class C1.)
class C1 extends A with T // error
      ^
Test.scala:5: error: class C2 inherits conflicting members:
  method f in trait T of type => Int  and
  method f in trait A of type ()Int
(Note: this can be resolved by declaring an override in class C2.)
class C2 extends T with A // error
      ^
Test.scala:14: error: overriding method f in trait A of type ()Int;
 method f needs `override' modifier
  def f() = 9999 // need override modifier
      ^
three errors found