Show root of stackoverflow in IsFullyDefinedAccumulator #12649
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smarter
reviewed
May 30, 2021
| case tp => | ||
| foldOver(x, tp) | ||
| catch case ex: Throwable => | ||
| handleRecursive("traverse ", s"${tp.show}" , ex) |
There was a problem hiding this comment.
Might be useful to print the constraints here too, since the loop might be due to cyclic constraints as we traverse type variables.
There was a problem hiding this comment.
Here you go. With that we get:
-- Error: i12640.scala:15:42 ---------------------------------------------------
15 | case Some(s1,a) => Cons(a, () => unfold(s1,f))
| ^
|Recursion limit exceeded.
|Maybe there is an illegal cyclic reference?
|If that's not the case, you could also try to increase the stacksize using the -Xss JVM option.
|A recurring operation is (inner to outer):
|
| traverse (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
|) => R in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse ([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R) in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
|] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse ((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
|) => R in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse ([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R) in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
|] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse ((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
|) => R in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse ([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R) in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| ...
|
| traverse x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
|] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse ((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
|) => R in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
|) => R in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse ([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R) in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse Nothing in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse Nothing[Option[((S, S => F[Option[(S, T)]]), Nothing)]] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
| traverse ((S, S => F[Option[(S, T)]])) =>
| Nothing[Option[((S, S => F[Option[(S, T)]]), Nothing)]] in Constraint(
| uninstantiated variables:
| constrained types: [A, B](fa: F[A])(f: A => F[B]): F[B],
| [F[_$3], T](head: T, tailFun: () => F[x.CpsStream[F, T]]): x.Cons[F, T]
|,
| [S, F[_$5], T]
| (s0: S)
| (f: S => F[Option[(S, T)]])
| (implicit evidence$1: x.CpsMonad[F]): F[x.CpsStream[F, T]]
| bounds:
| A := Option[(S, T)]
| B := x.CpsStream[F, T]
| F :=
| [R] =>> (((S, S => F[Option[(S, T)]])) =>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R),
| Option[((S, S => F[Option[(S, T)]]), Nothing)]
| ]
| ) => R
| T
| >: (a : T) |
| x.CpsStream[
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R)
| ,
| T]
| , Nothing]
| S := (S, S => F[Option[(S, T)]])
| F :=
| [T] =>>
| x.CpsStream[([R] =>> (((S, S => F[Option[(S, T)]])) => Nothing) => R), T]
| T
| ordering:
|)
@rssh My gut feeling is that you are trying to push higher-kinded types too far here. I mean nobody stops you, but if you want code to be widely used then crazy types and constraints like this are a show-stopper. Even if the compiler survives this, how will anybody be able to debug type errors when they arise?
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Interestingly, that original (unminimized) bug source is an attempt to create adapter for a well-known library [fs2 if anybody care], so the genie was already released from the bottle a long time ago.
smarter
requested changes
May 30, 2021
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Actually it looks like this is already fixed on master, if I run the testcase there I only get type errors and no stackoverflow, in this PR we get a stackoverflow because it's based on a week-old version of master but meanwhile e58ece8 already added stackoverflow handling.
|
I added a regression test. I still have some doubts what goes on here since with the added |
|
That's because handleRecursive throws a RecursionOverflow so it's not caught by the |
|
Doh! Completely forgot about that one. |
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This gives a better diagnosis for #12640.