How to use a trait several times in a class?

问题

The following code:

trait T {
    function foo() {}
}

class C {
    use T { T::foo as bar; }
    use T { T::foo as baz; }
}

Produces the following error:

Trait method bar has not been applied, because there are collisions with other trait methods on C

Is it possible to use a trait twice in a class?

回答1:

To "import" a method defined in a trait multiple times with different names do this:

class C {
  use T {
    foo as bar;
    foo as baz;
  }
}

回答2:

Yes, you can use a trait twice:

trait T {
    function foo() {}
}

class C {
    use T { T::foo as bar; T::foo as baz; }
}

来源：https://stackoverflow.com/questions/13582061/how-to-use-a-trait-several-times-in-a-class