instantiate mix traits is compiling while single trait is not

Question

I have two traits

trait Person
trait Food

why this is compiling :

val pf = new Person with Food //OK

and this is not

val p = new Person //result  error: trait Person is abstract; cannot be instantiated

Answer 1

Traits are abstract (not instantiable) by definition. Even if they're fully implemented they may not be instantiated. As senia states in a comment, you can get an anonymous class from a fully implemented trait like this:

trait T1
val t1 = new T1 {}