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package p {
class ViewEnv[AIn] {
type A = AIn
class SubView { def has(x: A): Boolean = ??? }
def get: SubView = new SubView
}
trait HasA { type A }
trait Indexable[R] extends HasA
class ArrayTC[AIn] extends Indexable[Array[AIn]] { type A = AIn }
}
package object p {
implicit def arrayTypeClass[A] : ArrayTC[A] = new ArrayTC[A]
object intArrayTC extends ArrayTC[Int]
type EnvAlias[W <: HasA] = ViewEnv[W#A]
type SubAlias[W <: HasA] = ViewEnv[W#A]#SubView
def f0[R](xs: R)(implicit tc: Indexable[R]): ViewEnv[tc.A]#SubView = new ViewEnv[tc.A]() get
def f1[R](xs: R)(implicit tc: Indexable[R]): EnvAlias[tc.type]#SubView = new ViewEnv[tc.A]() get
def f2[R](xs: R)(implicit tc: Indexable[R]): SubAlias[tc.type] = new ViewEnv[tc.A]() get
def g0 = f0(Array(1)) has 2 // ok
def g1 = f1(Array(1)) has 2 // ok
def g2 = f2(Array(1)) has 2 // "found: Int(2), required: tc.A"
def g3 = f2(Array(1))(new ArrayTC[Int]) has 2 // "found: Int(2), required: tc.A"
def g4 = f2(Array(1))(intArrayTC) has 2 // ok
}
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