Weird error when working with StreamConverters

[nartamonov]

Hi all! Following semantically correct code throws weird runtime error:

import scala.compat.java8.StreamConverters._
import java.util.stream.Collectors

val sampleItems = Iterator.fill(120)("a").toVector
val subset = sampleItems.slice(0, 40)
val subsetAsStream = subset.seqStream

// Throws
// java.lang.NullPointerException:
// at scala.compat.java8.converterImpl.StepsAnyVector.next(StepsVector.scala:66)
// at scala.compat.java8.collectionImpl.AnyStepper.forEachRemaining(Stepper.scala:230)
// at scala.compat.java8.collectionImpl.AnyStepper.forEachRemaining$(Stepper.scala:230)
// at scala.compat.java8.converterImpl.StepsLikeIndexed.forEachRemaining(StepsLikeIndexed.scala:28)
// at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
// at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
// at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
// at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
// at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
val subsetAsJList = subsetAsStream.collect(Collectors.toList())

[SethTisue]

still reproducible. more compactly, it's Vector.fill(120)("a").slice(0, 40).seqStream.collect(Collectors.toList())

[SethTisue]

looks like a subtle bug in StepsVector

[SethTisue]

Rex says scold him if he doesn't get to it this week.

[SethTisue]

ping @Ichoran

[SethTisue]

Rex, you are SCOLDED 🔥

[Ichoran]

@SethTisue - Thanks! Unfortunately I'm at a conference all week and will forget it ever happened before I get back home. You will probably have to scold me again next week!

[SethTisue]

I'm good at scolding. And I like it, a little.

[SethTisue]

@Ichoran scold scold scold

[Ichoran]

Okay, okay! I'll get to it this weekend. (Where the "'ll" should be interpreted as "intend to, with fairly high (~85%) probability of success".)

[Ichoran]

Didn't quite get finished. I'll wrap it up tonight if I get any more time.

[Ichoran]

I won't get time to finish until Wednesday night.

[Ichoran]

Argh, place I intended to work closed an hour early. I think I'm very close.

[Ichoran]

@SethTisue - #117 (I forgot the magic words that would link it automatically to the issue.)