scala nested case classes generate strange type error -

i'm trying use case class has 1 attribute reference case class. there conditions construct object strange type errors.

so works fine.

case class foo(a:int) case class bar(b:foo, c:foo) val t = bar(foo(1),foo(2)) //t: bar = bar(foo(1),foo(2)) 

when nest object, there doesn't seem problem

object w {     case class foo(a:int)     case class bar(b:foo, c:foo) } 

i can create object

val t = w.bar(w.foo(1),w.foo(2)) 

however, when try construct object defined foo, gives me crazy type error.

val f = w.foo(1) w.bar(f,f)  // error: type mismatch; //  found   : w.foo //  required: w.foo //               w.bar(f,f) 

any ideas? scala 2.10.5

this can happen if try on console, while redefine of classes.
if type in console:

scala> :paste // entering paste mode (ctrl-d finish)  case class foo(a:int) case class bar(b:foo, c:foo) val t = bar(foo(1),foo(2))  object w {     case class foo(a:int)     case class bar(b:foo, c:foo) }  // exiting paste mode, interpreting.  defined class foo defined class bar t: bar = bar(foo(1),foo(2)) defined module w  scala> val t = w.bar(w.foo(1),w.foo(2)) t: w.bar = bar(foo(1),foo(2))  scala> val f = w.foo(1) f: w.foo = foo(1)  scala> w.bar(f,f) res1: w.bar = bar(foo(1),foo(1)) 

it work. however, if redefine w object fail:

scala> object w {      |     case class foo(a:int)      |     case class bar(b:foo, c:foo)      | } defined module w  scala> w.bar(f,f) <console>:14: error: type mismatch;  found   : w.foo(in object w)(in object w)(in object w)(in object w)  required: w.foo(in object w)(in object w)(in object w)(in object w)               w.bar(f,f) 

this happen since @ w.bar(f,f) in second w, use w define on second type, f define in first time. since different object (same name , properties, type different), not fit.
if redefine depend class (f) works:

scala> object w {      |     case class foo(a:int)      |     case class bar(b:foo, c:foo)      | } defined module w  scala> val f = w.foo(1) f: w.foo = foo(1)  scala> w.bar(f,f) res3: w.bar = bar(foo(1),foo(1))