Shrinking goes into semi-infinite recursion

[noresttherein]

Here is a commit, for which IteratorExtensionSpec never ends after entering Prop.findFirstFailure: sugar.

This happens fairly often for me; here is another one

Stacktrace:

  java.lang.Thread.State: RUNNABLE
	at scala.collection.Iterator.sameElements(Iterator.scala:843)
	at scala.collection.Iterator.sameElements$(Iterator.scala:840)
	at scala.collection.AbstractIterator.sameElements(Iterator.scala:1300)
	at net.noresttherein.sugar.collections.IteratorExtensionSpec$.prop$2(IteratorExtensionSpec.scala:38)
	at net.noresttherein.sugar.collections.IteratorExtensionSpec$.$anonfun$mappingProperty$10(IteratorExtensionSpec.scala:45)
	at net.noresttherein.sugar.collections.IteratorExtensionSpec$$$Lambda$117/0x0000000801124e38.apply(Unknown Source)
	at scala.Function1.$anonfun$andThen$1(Function1.scala:87)
	at scala.Function1$$Lambda$80/0x000000080110d388.apply(Unknown Source)
	at org.scalacheck.Prop$.$anonfun$forAllShrink$2(Prop.scala:769)
	at org.scalacheck.Prop$$$Lambda$95/0x0000000801114d98.apply(Unknown Source)
	at org.scalacheck.Prop$.secure(Prop.scala:479)
	at org.scalacheck.Prop$.result$1(Prop.scala:769)
	at org.scalacheck.Prop$.$anonfun$forAllShrink$4(Prop.scala:778)
	at org.scalacheck.Prop$$$Lambda$234/0x000000080114ca58.apply(Unknown Source)
	at scala.collection.immutable.Stream.map(Stream.scala:173)
	at org.scalacheck.Prop$.getFirstFailure$1(Prop.scala:778)
	at org.scalacheck.Prop$.shrinker$1(Prop.scala:792)
	at org.scalacheck.Prop$.$anonfun$forAllShrink$1(Prop.scala:813)
	at org.scalacheck.Prop$$$Lambda$81/0x000000080110d740.apply(Unknown Source)
	at org.scalacheck.Prop$.$anonfun$apply$1(Prop.scala:309)
	at org.scalacheck.Prop$$$Lambda$17/0x000000080102a7a0.apply(Unknown Source)
	at org.scalacheck.PropFromFun.apply(Prop.scala:22)
	at org.scalacheck.Prop.$anonfun$map$1(Prop.scala:52)
	at org.scalacheck.Prop$$Lambda$106/0x000000080111ceb8.apply(Unknown Source)
	at org.scalacheck.Prop$.$anonfun$apply$1(Prop.scala:309)
	at org.scalacheck.Prop$$$Lambda$17/0x000000080102a7a0.apply(Unknown Source)
	at org.scalacheck.PropFromFun.apply(Prop.scala:22)
	at org.scalacheck.Prop.$anonfun$flatMap$1(Prop.scala:58)
	at org.scalacheck.Prop$$Lambda$85/0x000000080110e6e8.apply(Unknown Source)
	at org.scalacheck.Prop$.$anonfun$apply$1(Prop.scala:309)
	at org.scalacheck.Prop$$$Lambda$17/0x000000080102a7a0.apply(Unknown Source)
	at org.scalacheck.PropFromFun.apply(Prop.scala:22)
	at org.scalacheck.Prop.$anonfun$flatMap$1(Prop.scala:56)
	at org.scalacheck.Prop$$Lambda$85/0x000000080110e6e8.apply(Unknown Source)
	at org.scalacheck.Prop$.$anonfun$apply$1(Prop.scala:309)
	at org.scalacheck.Prop$$$Lambda$17/0x000000080102a7a0.apply(Unknown Source)
	at org.scalacheck.PropFromFun.apply(Prop.scala:22)
	at org.scalacheck.Prop$.$anonfun$delay$1(Prop.scala:484)
	at org.scalacheck.Prop$$$Lambda$16/0x000000080102a3e8.apply(Unknown Source)
	at org.scalacheck.Prop$.$anonfun$apply$1(Prop.scala:309)
	at org.scalacheck.Prop$$$Lambda$17/0x000000080102a7a0.apply(Unknown Source)
	at org.scalacheck.PropFromFun.apply(Prop.scala:22)
	at org.scalacheck.Prop.$anonfun$viewSeed$1(Prop.scala:41)
	at org.scalacheck.Prop$$Lambda$18/0x000000080102ab58.apply(Unknown Source)
	at org.scalacheck.Prop$.$anonfun$apply$1(Prop.scala:309)
	at org.scalacheck.Prop$$$Lambda$17/0x000000080102a7a0.apply(Unknown Source)
	at org.scalacheck.PropFromFun.apply(Prop.scala:22)
	at org.scalacheck.Test$.workerFun$1(Test.scala:474)
	at org.scalacheck.Test$.$anonfun$check$4(Test.scala:506)
	at org.scalacheck.Test$.$anonfun$check$4$adapted(Test.scala:506)
	at org.scalacheck.Test$$$Lambda$29/0x00000008010c27b0.apply(Unknown Source)
	at org.scalacheck.Platform$.runWorkers(Platform.scala:40)
	at org.scalacheck.Test$.check(Test.scala:506)
	at org.scalacheck.Test$.$anonfun$checkProperties$2(Test.scala:547)
	at org.scalacheck.Test$$$Lambda$28/0x00000008010c6d08.apply(Unknown Source)
	at scala.collection.StrictOptimizedIterableOps.map(StrictOptimizedIterableOps.scala:100)
	at scala.collection.StrictOptimizedIterableOps.map$(StrictOptimizedIterableOps.scala:87)
	at scala.collection.mutable.ListBuffer.map(ListBuffer.scala:39)
	at org.scalacheck.Test$.checkProperties(Test.scala:538)
	at org.scalacheck.Properties.main(Properties.scala:77)
	at net.noresttherein.sugar.collections.IteratorExtensionSpec.main(IteratorExtensionSpec.scala)