difference between "object A" and A.type

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The problem exists in both 2.7 and 2.8. When I try to compile this code:

object Test extends Application {
  def x: A.type = A
  def y: B[A.type] = new B(A)
}

object A

class B[N](n: N)

, I have no problem with defining x. For the definition of y however I get:

Test.scala:3: error: type mismatch;
 found   : B[object A]
 required: B[A.type]

If I look at the compiler's typer phase, the two definitions are as follows:

scalac -Xprint:typer Test.scala

    def x: object A = A;
    def y: B[A.type] = new B[object A](A)

We see in the first definition that "A.type" is simply translated into "object A" : the two expressions seem to mean the same thing. However in the second definition they obviously do not, as they are causing a type mismatch.

I can compile the definition of y if I force the type parameter to A.type:

  def y: B[A.type] = new B[A.type](A)

My question : do "object A" and A.type mean the same thing, or not ? If not, why does the definition of x work ? If they do, why does the definition of y fail ? Thanks

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Imported From: https://issues.scala-lang.org/browse/SI-3083?orig=1
Reporter: @rjolly

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@paulp said:
This is a duplicate of perennial favorite #1208. If you want more explanation than you can find in that ticket (and others) please ask on one of the mailing lists.