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import scala.language.higherKinds
object TestExplicit {
trait TC[A]
def fTt[A,E[X] <: List[X]](a: A)(implicit tt: TC[E[A]]) = a
implicit def tc[T]: TC[T] = ???
// Typechecking results in SOE in TypeVar.isGround
fTt(1)(tc)
// fun = TestExplicit.this.fTt[Int, E](1)
// args = TestExplicit.this.tc[E[Int]]
// argTpes.head.instantiateTypeParams = TC[?E#1[Int]]
// formals.head.instantiateTypeParams = TC[?E#2[Int]]
// (where ?E#1 and ?E#2 as distinct AppliedTypeVars that resulted
// from separate applications of type args to the same HKTypeVar, ?E)
//
// As we check if the argument conforms to the formal, we would have
// AppliedTypeVars sharing the same TypeConstraints on the LHS and RHS,
// which leads to a cyclic constraint.
}
object TestImplicit {
trait TC[A]
def fTt[A,E[X] <: List[X]](a: A)(implicit tt: TC[E[A]]) = a
implicit def tc[T]: TC[T] = ???
// Oddly enough, this one works.
fTt(1)
}
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