Description:
------------
When we use a Trait in a class we define behavior for that class like interfaces.
But we can't use them as an input type. Checkout "Test Script" to find out more.

I think you got idea.
Best regards, motammem

Test script:
---------------
trait Foo {
  sayHello(){
    echo "Hello";
  }
}

class Bar {
  use Foo;
}

function test(Foo $foo){
  $foo->sayHello();
}

//////////////////////////////

$bar = new Bar();

test($bar);

Expected result:
----------------
Hello

Actual result:
--------------
"Catchable fatal error: Argument 1 passed to go() must be an instance of Foo, instance of Bar given..."