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[CI only] Attempt a fix to a potential problem in RecursionOverflow #5862

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[CI only] Attempt a fix to a potential problem in RecursionOverflow #5862

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45476f2
Revert "Disable test"
abgruszecki Feb 6, 2019
c0a4ed0
Attempt a fix to a potential problem in RecursionOverflow
abgruszecki Feb 6, 2019
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16 changes: 11 additions & 5 deletions compiler/src/dotty/tools/dotc/core/TypeErrors.scala
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Original file line number Diff line number Diff line change
Expand Up @@ -40,16 +40,22 @@ class MissingType(pre: Type, name: Name) extends TypeError {
}
}

class RecursionOverflow(val op: String, details: => String, previous: Throwable, val weight: Int) extends TypeError {
class RecursionOverflow(val op: String, details: => String, val previous: Throwable, val weight: Int) extends TypeError {

def explanation: String = s"$op $details"

private def recursions: List[RecursionOverflow] = {
val nested = previous match {
case previous: RecursionOverflow => previous.recursions
case _ => Nil
import scala.collection.mutable.ListBuffer
val result = ListBuffer.empty[RecursionOverflow]
@annotation.tailrec def loop(throwable: Throwable): List[RecursionOverflow] = throwable match {
case ro: RecursionOverflow =>
if (result.contains(ro)) println("caught the issue")
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It’d be very surprising if the RecursionOverflow chain was cyclic. However, the length of the chain is proportional to the stack depth, so it’s best traversed in constant stack size. To see why, you need to see how RecursionOverflow is created by handleRecursive and how that’s used in certain recursive methods in Typer (I can explain in person if desired).

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Yeah, I wasn't sure if the RecursionOverflow chain can actually be cyclic. If it's really proportional to stack depth, then it makes sense to construct recursions in a loop. How about I simply open a separate PR with that change and we merge it on its own?

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Go ahead!

result += ro
loop(ro.previous)
case _ => result.toList

}
this :: nested
loop(this)
}

def opsString(rs: List[RecursionOverflow])(implicit ctx: Context): String = {
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0 tests/pending/neg/i4371b.scala → tests/neg/i4371b.scala
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