Repro of a bug in Flix v0.1

BugRepro.scala

package ca.uwaterloo.flix

import ca.uwaterloo.flix.api.{Flix, InvokableUnsafe, WrappedType}
import ca.uwaterloo.flix.language.ast.Type
import ca.uwaterloo.flix.runtime.{Model, Value}

object BugRepro {
  
  // To run this repro:
  //   Drop this file in main/src/ca/uwaterloo/flix/BugRepro.scala
  //   In IntelliJ, set up a configuration with the main class set to ca.uwaterloo.flix.BugRepro
  //
  // The bug only shows up when using <- (the "loop" operator) and interop.
  // The stack offsets for environment are computed incorrectly, so the wrong variables are evaluated.

  def main(argv: Array[String]): Unit = {
    val flix = new Flix().addStr(
      """
        |def g(i: Int): Set[Int] = Set((i + 1) :: Nil)
        |
        |rel A(a: Int)
        |rel B(b: Int)
        |
        |A(1).
        |B(x) :- A(y), x <- f(y).         // CRASH
        |//B(x) :- A(y), x <- f(2).         // CRASH
        |//B(x) :- A(y), x <- g(y).         // OK
        |//B(x) :- A(y), x <- g(2).         // CRASH
        |//B(x) :- x <- g(2).               // OK
      """.stripMargin)

    flix.addHookUnsafe(
      "f",
      flix.mkFunctionType(Array(flix.mkInt32Type), new WrappedType(Type.mkFSet(Type.Int32))),
      new InvokableUnsafe {
        def apply(args: Array[AnyRef]): AnyRef = {
          val i = args(0).asInstanceOf[Integer]
          val res = new java.lang.Integer(i+1)
          Value.mkTag("Set", Value.mkList(List(res)))
        }})

    val model = flix.solve().get
    printRelation(model, "B")
  }

  def printRelation(model: Model, name: String): Unit = {
    val rel = model.getRelation(name)
    rel.foreach(t => println(s"""$name(${t.mkString(",")})."""))
  }

}

BugRepro2.scala

package ca.uwaterloo.flix

import ca.uwaterloo.flix.api.{Flix, InvokableUnsafe}
import ca.uwaterloo.flix.language.ast.Type
import ca.uwaterloo.flix.runtime.Value.{Unit, mkTag}
import ca.uwaterloo.flix.runtime.{Model, Value}
import ca.uwaterloo.flix.util.{Evaluation, Options}

object BugRepro {

  // To run this repro:
  //   Drop this file in main/src/ca/uwaterloo/flix/BugRepro.scala
  //   In IntelliJ, set up a configuration with the main class set to ca.uwaterloo.flix.BugRepro
  //
  // This is a modified version for commit 4842ed938d6c36a1053222ac2add8e3fbf592dc1
  // 'unsafe native method' seems to work, but there's still an underlying bug with x <- f(2)
  // There's also a problem with using compiled sets (enums.Set), but interpreted sets are fine (Value.Tag)

  def main(argv: Array[String]): Unit = {
    val flix = new Flix()//.setOptions(Options.Default.copy(evaluation = Evaluation.Interpreted))

    flix.addStr(
      """
        |def g(i: Int): Set[Int] = Set((i + 1) :: Nil)
        |def f(i: Int): Set[Int] = unsafe native method ca.uwaterloo.flix.BugRepro.f(i)
        |
        |rel A(a: Int)
        |rel B(b: Int)
        |
        |A(1).
        |//B(x) :- A(y), x <- f(y).         // OK
        |//B(x) :- A(y), x <- f(2).         // CRASH compiled, OK interpreted
        |//B(x) :- A(y), x <- g(y).         // CRASH compiled, OK interpreted
        |//B(x) :- A(y), x <- g(2).         // CRASH compiled, OK interpreted
        |//B(x) :- x <- g(2).               // CRASH compiled, OK interpreted
      """.stripMargin)

//    flix.addHookUnsafe(
//      "f",
//      flix.mkFunctionType(Array(flix.mkInt32Type), new WrappedType(Type.mkFSet(Type.Int32))),
//      new InvokableUnsafe {
//        def apply(args: Array[AnyRef]): AnyRef = {
//          val i = args(0).asInstanceOf[Integer]
//          val res = new java.lang.Integer(i+1)
//          Value.mkTag("Set", Value.mkList(List(res)))
//        }})

    val model = flix.solve().get
    printRelation(model, "B")
  }

  def printRelation(model: Model, name: String): Unit = {
    val rel = model.getRelation(name)
    rel.foreach(t => println(s"""$name(${t.mkString(",")})."""))
  }

  def mkList(as: List[AnyRef]): Value.Tag = as.foldRight(mkTag("Nil", Unit)) {
    case (a, l) => mkTag("Cons", Array(a, l))
  }

  def f(i: Int): AnyRef = {
    val res = new java.lang.Integer(i+1)
    Value.mkTag("Set", mkList(List(res)))
  }

}