Closed
Description
Compiler version
3.3.1-RC1-bin-20230221-847eccc-NIGHTLY
(Works in 3.2.2, 3.3.0-RC3, so this is a regression.)
Code to reproduce
I apologize that this code is not as minimal as it could be.
class Funs {
sealed trait ->[A, B]
}
/**
* Binary tree with leafs holding values of types `F[X]`, `F[Y]`, ...
* The complete structure of the tree is expressed by the type `A`, using the tags for branches and leafs.
*
* @tparam <*> tag for branches
* @tparam T tag for leafs.
* @tparam F value type of leafs. Each leaf holds a value of type `F[T]`, for some type `T`.
* @tparam A captures the complete structure of the tree
*/
enum Tree[<*>[_, _], T[_], F[_], A] {
case Branch[<*>[_, _], T[_], F[_], A, B](
l: Tree[<*>, T, F, A],
r: Tree[<*>, T, F, B],
) extends Tree[<*>, T, F, A <*> B]
case Leaf[<*>[_, _], T[_], F[_], A](
value: F[A],
) extends Tree[<*>, T, F, T[A]]
def <*>[B](that: Tree[<*>, T, F, B]): Tree[<*>, T, F, A <*> B] =
Branch(this, that)
def partition[G[_], H[_]](
f: [x] => F[x] => Either[G[x], H[x]],
)(using
funs: Funs,
): Partitioned[G, H, funs.->] =
this match {
case Leaf(a) =>
f(a) match
case Left(a) => Partitioned.Left(Leaf(a))
case Right(a) => Partitioned.Right(Leaf(a))
case Branch(l, r) =>
import Partitioned.{Both, Left, Right}
import l.Partitioned.{Both => LBoth, Left => LLeft, Right => LRight}
import r.Partitioned.{Both => RBoth, Left => RLeft, Right => RRight}
(l.partition(f), r.partition(f)) match
case (LLeft(lg), RLeft(rg)) => Left(lg <*> rg)
case (LLeft(lg), RRight(rh)) => Both(lg, rh)
case (LLeft(lg), RBoth(rg, rh)) => Both(lg <*> rg, rh)
case (LRight(lh), RLeft(rg)) => Both(rg, lh)
case (LRight(lh), RRight(rh)) => Right(lh <*> rh)
case (LRight(lh), RBoth(rg, rh)) => Both(rg, lh <*> rh)
case (LBoth(lg, lh), RLeft(rg)) => Both(lg <*> rg, lh)
case (LBoth(lg, lh), RRight(rh)) => Both(lg, lh <*> rh)
case (LBoth(lg, lh), RBoth(rg, rh)) => Both(lg <*> rg, lh <*> rh)
}
// note that `->` is never even used, to keep this reproduction case small
enum Partitioned[G[_], H[_], ->[_, _]] {
case Left(value: Tree[<*>, T, G, A])
case Right(value: Tree[<*>, T, H, A])
case Both[G[_], H[_], X, Y, ->[_, _]](
l: Tree[<*>, T, G, X],
r: Tree[<*>, T, H, Y],
) extends Partitioned[G, H, ->]
}
}Output
Click to expand
% sbt compile
[info] welcome to sbt 1.8.2 (AdoptOpenJDK Java 16)
[info] loading global plugins from /Users/thomas/.sbt/1.0/plugins
[info] loading project definition from /Users/thomas/tmp/dotty-playground/pattern-matching-regression/project
[info] loading settings for project pattern-matching-regression from build.sbt ...
[info] set current project to pattern-matching-regression (in build file:/Users/thomas/tmp/dotty-playground/pattern-matching-regression/)
[info] Executing in batch mode. For better performance use sbt's shell
[info] compiling 1 Scala source to /Users/thomas/tmp/dotty-playground/pattern-matching-regression/target/scala-3.3.1-RC1-bin-20230221-847eccc-NIGHTLY/classes ...
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:43:61
[error] 43 | case (LLeft(lg), RLeft(rg)) => Left(lg <*> rg)
[error] | ^^
[error] | Found: (rg : Tree[<*>, T, G$2, B$1])
[error] | Required: Tree[<*>, T, G$1, B]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | B is a type variable
[error] | G$1 is a type in method partition with bounds <: [_] =>> Any
[error] | G$2 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:44:54
[error] 44 | case (LLeft(lg), RRight(rh)) => Both(lg, rh)
[error] | ^^
[error] | Found: (lg : Tree[<*>, T, G$3, A$2])
[error] | Required: Tree[<*>, T, G, X]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | G is a type in method partition with bounds <: [_] =>> Any
[error] | G$3 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] | X is a type variable
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:44:58
[error] 44 | case (LLeft(lg), RRight(rh)) => Both(lg, rh)
[error] | ^^
[error] | Found: (rh : Tree[<*>, T, H$4, B$1])
[error] | Required: Tree[<*>, T, H, Y]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | H is a type in method partition with bounds <: [_] =>> Any
[error] | H$4 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] | Y is a type variable
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:45:61
[error] 45 | case (LLeft(lg), RBoth(rg, rh)) => Both(lg <*> rg, rh)
[error] | ^^
[error] | Found: (rg : Tree[<*>, T, G$6, X$1])
[error] | Required: Tree[<*>, T, G$5, B]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | B is a type variable
[error] | G$5 is a type in method partition with bounds <: [_] =>> Any
[error] | G$6 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:45:65
[error] 45 | case (LLeft(lg), RBoth(rg, rh)) => Both(lg <*> rg, rh)
[error] | ^^
[error] | Found: (rh : Tree[<*>, T, H$6, Y$1])
[error] | Required: Tree[<*>, T, H, Y]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | H is a type in method partition with bounds <: [_] =>> Any
[error] | H$6 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] | Y is a type variable
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:46:54
[error] 46 | case (LRight(lh), RLeft(rg)) => Both(rg, lh)
[error] | ^^
[error] | Found: (rg : Tree[<*>, T, G$8, B$1])
[error] | Required: Tree[<*>, T, G, X]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | G is a type in method partition with bounds <: [_] =>> Any
[error] | G$8 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] | X is a type variable
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:46:58
[error] 46 | case (LRight(lh), RLeft(rg)) => Both(rg, lh)
[error] | ^^
[error] | Found: (lh : Tree[<*>, T, H$7, A$2])
[error] | Required: Tree[<*>, T, H, Y]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | H is a type in method partition with bounds <: [_] =>> Any
[error] | H$7 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] | Y is a type variable
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:47:62
[error] 47 | case (LRight(lh), RRight(rh)) => Right(lh <*> rh)
[error] | ^^
[error] | Found: (rh : Tree[<*>, T, H$10, B$1])
[error] | Required: Tree[<*>, T, H$9, B]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | B is a type variable
[error] | H$10 is a type in method partition with bounds <: [_] =>> Any
[error] | H$9 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:48:54
[error] 48 | case (LRight(lh), RBoth(rg, rh)) => Both(rg, lh <*> rh)
[error] | ^^
[error] | Found: (rg : Tree[<*>, T, G$12, X$2])
[error] | Required: Tree[<*>, T, G, X]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | G is a type in method partition with bounds <: [_] =>> Any
[error] | G$12 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] | X is a type variable
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:48:65
[error] 48 | case (LRight(lh), RBoth(rg, rh)) => Both(rg, lh <*> rh)
[error] | ^^
[error] | Found: (rh : Tree[<*>, T, H$12, Y$2])
[error] | Required: Tree[<*>, T, H$11, B]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | B is a type variable
[error] | H$11 is a type in method partition with bounds <: [_] =>> Any
[error] | H$12 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:49:61
[error] 49 | case (LBoth(lg, lh), RLeft(rg)) => Both(lg <*> rg, lh)
[error] | ^^
[error] | Found: (rg : Tree[<*>, T, G$14, B$1])
[error] | Required: Tree[<*>, T, G$13, B]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | B is a type variable
[error] | G$13 is a type in method partition with bounds <: [_] =>> Any
[error] | G$14 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:49:65
[error] 49 | case (LBoth(lg, lh), RLeft(rg)) => Both(lg <*> rg, lh)
[error] | ^^
[error] | Found: (lh : Tree[<*>, T, H$13, Y$3])
[error] | Required: Tree[<*>, T, H, Y]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | H is a type in method partition with bounds <: [_] =>> Any
[error] | H$13 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] | Y is a type variable
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:50:54
[error] 50 | case (LBoth(lg, lh), RRight(rh)) => Both(lg, lh <*> rh)
[error] | ^^
[error] | Found: (lg : Tree[<*>, T, G$15, X$4])
[error] | Required: Tree[<*>, T, G, X]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | G is a type in method partition with bounds <: [_] =>> Any
[error] | G$15 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] | X is a type variable
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:50:65
[error] 50 | case (LBoth(lg, lh), RRight(rh)) => Both(lg, lh <*> rh)
[error] | ^^
[error] | Found: (rh : Tree[<*>, T, H$16, B$1])
[error] | Required: Tree[<*>, T, H$15, B]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | B is a type variable
[error] | H$15 is a type in method partition with bounds <: [_] =>> Any
[error] | H$16 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:51:61
[error] 51 | case (LBoth(lg, lh), RBoth(rg, rh)) => Both(lg <*> rg, lh <*> rh)
[error] | ^^
[error] | Found: (rg : Tree[<*>, T, G$18, X$6])
[error] | Required: Tree[<*>, T, G$17, B]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | B is a type variable
[error] | G$17 is a type in method partition with bounds <: [_] =>> Any
[error] | G$18 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] -- [E007] Type Mismatch Error: /Users/thomas/tmp/dotty-playground/pattern-matching-regression/test.scala:51:72
[error] 51 | case (LBoth(lg, lh), RBoth(rg, rh)) => Both(lg <*> rg, lh <*> rh)
[error] | ^^
[error] | Found: (rh : Tree[<*>, T, H$18, Y$6])
[error] | Required: Tree[<*>, T, H$17, B]
[error] |
[error] | where: <*> is a type in class Tree with bounds <: [_, _] =>> Any
[error] | B is a type variable
[error] | H$17 is a type in method partition with bounds <: [_] =>> Any
[error] | H$18 is a type in method partition with bounds <: [_] =>> Any
[error] | T is a type in class Tree with bounds <: [_] =>> Any
[error] |
[error] | longer explanation available when compiling with `-explain`
[error] 16 errors found
[error] (Compile / compileIncremental) Compilation failed
[error] Total time: 10 s, completed Feb 22, 2023, 7:23:17 PMExpectation
The code should compile, as was the case with Scala 3.2.2.