Scastie compiler crash

[Bersier]

Compiler version

3.8.0-RC1

Minimized code

import scala.compiletime.constValue
import scala.compiletime.ops.int.+

def foo(): Unit =
  Bits.withAddedBit(Bits.Some(Bit.I, Bits.None), Bit.I)

sealed trait Bits
object Bits:
  type None = None.type
  case object None extends Bits
  final case class Some[+First <: Bit, Rest <: Bits](first: First, rest: Rest) extends Bits

  type WithAddedBit[B <: Bits, C <: Bit] <: Bits = B match
    case None => AsBits[C]
    case Some[f, r] => Bit.Sum2[f, C] match
      case (Bit.O, bit) => Some[bit, r]
      case (Bit.I, Bit.O) => Some[Bit.O, WithAddedBit[r, Bit.I]]

  inline def withAddedBit[B <: Bits, C <: Bit](b: B, c: C): WithAddedBit[B, C] = b match
    case _: None => asBits(c)
    case s: Some[?, ?] =>
      val (f, r) = s
      Bit.sum2(f, c) match
        case s2: (Bit.O, ?) =>
          val (Bit.O, bit) = s2
          Some(bit, r)
        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))

  type AsBits[B <: Bit] <: Bits = B match
      case Bit.O => None
      case Bit.I => Some[Bit.I, None]

  inline def asBits[B <: Bit](b: B): AsBits[B] = b match
    case _: Bit.O => None
    case _: Bit.I => Some(Bit.I, None)
end Bits

sealed trait Bit derives CanEqual
object Bit:
  type O = O.type
  case object O extends Bit

  type I = I.type
  case object I extends Bit

  type Sum2[B1 <: Bit, B2 <: Bit] <: (Bit, Bit) = AsInt[B1] + AsInt[B2] match
    case 0 => (O, O)
    case 1 => (O, I)
    case 2 => (I, O)

  inline def sum2[B1 <: Bit, B2 <: Bit](t1: B1, t2: B2): Sum2[B1, B2] =
    constValue[AsInt[B1] + AsInt[B2]] match
      case _: 0 => (O, O)
      case _: 1 => (O, I)
      case _: 2 => (I, O)

  type AsInt[B <: Bit] <: Int = B match
    case O => 0
    case I => 1
end Bit

Scastie Compiler Output

  unhandled exception while running inlining on /tmp/scastie1192066731423425022/src/main/scala/main.scala

  An unhandled exception was thrown in the compiler.
  Please file a crash report here:
  https://github.com/scala/scala3/issues/new/choose
  For non-enriched exceptions, compile with -Xno-enrich-error-messages.


     while compiling: /tmp/scastie1192066731423425022/src/main/scala/main.scala
        during phase: inlining
                mode: Mode(ImplicitsEnabled)
     library version: version 3.8.0-RC1
    compiler version: version 3.8.0-RC1
            settings: -classpath /tmp/scastie1192066731423425022/target/scala-3.8.0-RC1/classes:/scastie-cache/coursier/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3/3.8.0-RC1/scala3-library_3-3.8.0-RC1.jar:/home/sbtRunnerContainer/.ivy2/local/org.scastie/runtime-scala_3/1.0.0-SNAPSHOT/jars/runtime-scala_3.jar:/scastie-cache/coursier/https/repo1.maven.org/maven2/org/scala-lang/scala-library/3.8.0-RC1/scala-library-3.8.0-RC1.jar -d /tmp/scastie1192066731423425022/target/scala-3.8.0-RC1/classes -deprecation true -feature true

[som-snytt]

I wonder if the A.I. assistant would know how to increase stack for scala-cli.

➜  snips JDK_JAVA_OPTIONS=-Xss2m scala-cli compile --server=false -S 3.8.0-RC1 i24521.scala
Warning: Only java properties are supported in JAVA_OPTS and JDK_JAVA_OPTIONS environment variables. Other options are ignored: -Xss2m
NOTE: Picked up JDK_JAVA_OPTIONS: -Xss2m
-- Warning: /home/amarki/snips/i24521.scala:22:19 ------------------------------
22 |      val (f, r) = s
   |                   ^
   |pattern's type (Any, Any) does not match the right hand side expression's type Bits.Some[_, _²] & B
   |
   |If the narrowing is intentional, this can be communicated by adding `: @unchecked` after the expression,
   |which may result in a MatchError at runtime.
   |This patch can be rewritten automatically under -rewrite -source 3.2-migration.
   |
   |where:    B  is a type in method withAddedBit with bounds <: Bits
   |          _  is a type in method withAddedBit with bounds <: Bit
   |          _² is a type in method withAddedBit with bounds <: Bits
-- [E182] Type Error: /home/amarki/snips/i24521.scala:5:19 ---------------------
 5 |  Bits.withAddedBit(Bits.Some(Bit.I, Bits.None), Bit.I)
   |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   | Bit.AsInt[_] + (1 : Int) is not a constant type; cannot take constValue
   |
   | Note: a match type could not be fully reduced:
   |
   |   trying to reduce  Bit.AsInt[_]
   |   failed since selector _
   |   does not match  case Bit.O => (0 : Int)
   |   and cannot be shown to be disjoint from it either.
   |   Therefore, reduction cannot advance to the remaining case
   |
   |     case Bit.I => (1 : Int)
   |----------------------------------------------------------------------------
   |Inline stack trace
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:52
52 |    constValue[AsInt[B1] + AsInt[B2]] match
   |               ^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:52
23 |      Bit.sum2(f, c) match
   |      ^^^^^^^^^^^^^^
    ----------------------------------------------------------------------------
-- Error: /home/amarki/snips/i24521.scala:5:19 ---------------------------------
 5 |  Bits.withAddedBit(Bits.Some(Bit.I, Bits.None), Bit.I)
   |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |  Maximal number of successive inlines (32) exceeded,
   |  Maybe this is caused by a recursive inline method?
   |  You can use -Xmax-inlines to change the limit.
   |----------------------------------------------------------------------------
   |Inline stack trace
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
23 |      Bit.sum2(f, c) match
   |      ^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
    ----------------------------------------------------------------------------
1 warning found
2 errors found
Compilation failed

[som-snytt]

Or using -Xmax-inlines instead. That works on scastie.

I didn't look at whether the errors make sense, only to avoid the stack overflow.

➜  snips scala-cli compile --server=false -S 3.8.0-RC1 -Xmax-inlines:10 i24521.scala
-- Warning: /home/amarki/snips/i24521.scala:22:19 ------------------------------
22 |      val (f, r) = s
   |                   ^
   |pattern's type (Any, Any) does not match the right hand side expression's type Bits.Some[_, _²] & B
   |
   |If the narrowing is intentional, this can be communicated by adding `: @unchecked` after the expression,
   |which may result in a MatchError at runtime.
   |This patch can be rewritten automatically under -rewrite -source 3.2-migration.
   |
   |where:    B  is a type in method withAddedBit with bounds <: Bits
   |          _  is a type in method withAddedBit with bounds <: Bit
   |          _² is a type in method withAddedBit with bounds <: Bits
-- [E182] Type Error: /home/amarki/snips/i24521.scala:5:19 ---------------------
 5 |  Bits.withAddedBit(Bits.Some(Bit.I, Bits.None), Bit.I)
   |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   | Bit.AsInt[_] + (1 : Int) is not a constant type; cannot take constValue
   |
   | Note: a match type could not be fully reduced:
   |
   |   trying to reduce  Bit.AsInt[_]
   |   failed since selector _
   |   does not match  case Bit.O => (0 : Int)
   |   and cannot be shown to be disjoint from it either.
   |   Therefore, reduction cannot advance to the remaining case
   |
   |     case Bit.I => (1 : Int)
   |----------------------------------------------------------------------------
   |Inline stack trace
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:52
52 |    constValue[AsInt[B1] + AsInt[B2]] match
   |               ^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:52
23 |      Bit.sum2(f, c) match
   |      ^^^^^^^^^^^^^^
    ----------------------------------------------------------------------------
-- Error: /home/amarki/snips/i24521.scala:5:19 ---------------------------------
 5 |  Bits.withAddedBit(Bits.Some(Bit.I, Bits.None), Bit.I)
   |  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |  Maximal number of successive inlines (10) exceeded,
   |  Maybe this is caused by a recursive inline method?
   |  You can use -Xmax-inlines to change the limit.
   |----------------------------------------------------------------------------
   |Inline stack trace
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
23 |      Bit.sum2(f, c) match
   |      ^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
   |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
   |This location contains code that was inlined from i24521.scala:5
27 |        case _: (Bit.I, Bit.O) => Some(Bit.O, withAddedBit(r, Bit.I))
   |                                              ^^^^^^^^^^^^^^^^^^^^^^
    ----------------------------------------------------------------------------
1 warning found
2 errors found
Compilation failed