Imported From: https://issues.scala-lang.org/browse/SI-8227?orig=1
Reporter: @retronym
Affected Versions: 2.11.0

@paulp said:
Fun with when things happen. I guess when you supply type args the monomorphic alternative is cut out of overloading consideration.

scala> new C[T1 forSome { type T1 }, T2 forSome { type T2 }](null)
warning: there were 2 feature warning(s); re-run with -feature for details
res0: C[T1 forSome { type T1 },T2 forSome { type T2 }] = C@3839e07a

scala> new C(null: C[T1 forSome { type T1 }, T2 forSome { type T2 }])
<console>:8: error: type mismatch;
 found   : C[T1 forSome { type T1 },T2 forSome { type T2 }]
 required: Int
              new C(null: C[T1 forSome { type T1 }, T2 forSome { type T2 }])
                        ^

@retronym said (edited on Feb 5, 2014 7:59:25 PM UTC):
There is only one constructor which in each class; both are polymorphic (because the class has tparams)

Providing type args explicitly sidesteps the inference failure.

It's of course a bit embarrassing that Javac happily lets you omit the typeargs. But maybe it falls into raw-type mode. I wonder: does javac have -Xprint:typer that I can play with?