Overriding a method with an object

Why is it possible to override an empty-parentheses method with an object?

trait A {
  def meth = {}
  def meth_p() = {}
}

class B extends A {
  object meth_p
} // compiles

Overriding the method without parentheses does not compile:

class B1 extends A {
  object meth
} // does not compile

Neither do any of the following combinations work (without override modifier):

class BX extends A {
  // of course, each declaration should get its own class
  def meth = {}
  def meth_p() = {}
  def meth() = {}
  def meth_p = {}
  val meth = {}
  val meth_p = {}
  // ...
}

Is this documented and useful behaviour? I’ve just run into a very subtle bug because of this accidental override.