Application of a method with a dependent type (wrong argument used by typechecker)

[scabug]

The following code includes a method with a dependent type. It should normally typecheck (when using the option -Xexperimental of the Scala compiler).

object Bug {
  class C { type T }
  def foo(x: Int)(y: C)(z: y.T) {}
  foo(3)(new C { type T = String })("hello")
}

However the compiler (version 2.7.2.final) signals the following
error.

bug.scala:4: error: type mismatch;
 found   : java.lang.String("hello")
 required: Int(3)#T
  foo(3)(new C { type T = String })("hello")
                                    ^

In the application of the method foo, when determining the expected type of the third argument (which, according to the method signature, refers to the second argument), the typechecher wrongly uses the first argument, of type Int.

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-1569?orig=1
Reporter: cremet

[scabug]

@lrytz said:
this is an old one which was floating around in the scala_devteam bucket.

[scabug]

@adriaanm said:
(In r23010) closes #1569, #3731: refactored dependent method types to get rid of debruijn indices and use singleton types instead.

this is the core of the dependent types refactoring, no implicit or inference changes

(one baffling discovery: resultType should drop annotations that don't subclass TypeConstraint, even in the trivial case... wow -- thanks to Tiark for helping me figure it out on a terrace in Barcelona
TODO: probably need a more principled approach to the propagation of plugin type-annotations)

review by odersky