diff options
| -rw-r--r-- | src/reflect/scala/reflect/internal/tpe/TypeComparers.scala | 25 | ||||
| -rw-r--r-- | src/reflect/scala/reflect/runtime/JavaUniverseForce.scala | 1 | ||||
| -rw-r--r-- | test/files/pos/t8146a.scala (renamed from test/pending/pos/t8146a.scala) | 0 | ||||
| -rw-r--r-- | test/files/pos/t8146b.scala (renamed from test/pending/pos/t8146b.scala) | 0 |
4 files changed, 11 insertions, 15 deletions
diff --git a/src/reflect/scala/reflect/internal/tpe/TypeComparers.scala b/src/reflect/scala/reflect/internal/tpe/TypeComparers.scala index b60fecd66e..027da6ed50 100644 --- a/src/reflect/scala/reflect/internal/tpe/TypeComparers.scala +++ b/src/reflect/scala/reflect/internal/tpe/TypeComparers.scala @@ -17,20 +17,15 @@ trait TypeComparers { private val _pendingSubTypes = new mutable.HashSet[SubTypePair] def pendingSubTypes = _pendingSubTypes - class SubTypePair(val tp1: Type, val tp2: Type) { - override def hashCode = tp1.hashCode * 41 + tp2.hashCode - override def equals(other: Any) = (this eq other.asInstanceOf[AnyRef]) || (other match { - // suspend TypeVars in types compared by =:=, - // since we don't want to mutate them simply to check whether a subtype test is pending - // in addition to making subtyping "more correct" for type vars, - // it should avoid the stackoverflow that's been plaguing us (https://groups.google.com/d/topic/scala-internals/2gHzNjtB4xA/discussion) - // this method is only called when subtyping hits a recursion threshold (subsametypeRecursions >= LogPendingSubTypesThreshold) - case stp: SubTypePair => - val tvars = List(tp1, stp.tp1, tp2, stp.tp2) flatMap (t => if (t.isGround) Nil else typeVarsInType(t)) - suspendingTypeVars(tvars)(tp1 =:= stp.tp1 && tp2 =:= stp.tp2) - case _ => - false - }) + final case class SubTypePair(tp1: Type, tp2: Type) { + // SI-8146 we used to implement equality here in terms of pairwise =:=. + // But, this was inconsistent with hashCode, which was based on the + // Type#hashCode, based on the structure of types, not the meaning. + // Now, we use `Type#{equals,hashCode}` as the (consistent) basis for + // detecting cycles (aka keeping subtyping decidable.) + // + // I added a tests to show that we detect the cycle: neg/t8146-no-finitary* + override def toString = tp1+" <:<? "+tp2 } @@ -262,7 +257,7 @@ trait TypeComparers { if (subsametypeRecursions >= LogPendingSubTypesThreshold) { val p = new SubTypePair(tp1, tp2) if (pendingSubTypes(p)) - false + false // see neg/t8146-no-finitary* else try { pendingSubTypes += p diff --git a/src/reflect/scala/reflect/runtime/JavaUniverseForce.scala b/src/reflect/scala/reflect/runtime/JavaUniverseForce.scala index c87995275f..a2d3206156 100644 --- a/src/reflect/scala/reflect/runtime/JavaUniverseForce.scala +++ b/src/reflect/scala/reflect/runtime/JavaUniverseForce.scala @@ -198,6 +198,7 @@ trait JavaUniverseForce { self: runtime.JavaUniverse => this.ErroneousCollector this.adaptToNewRunMap // inaccessible: this.commonOwnerMapObj + this.SubTypePair this.SymbolKind this.NoSymbol this.CyclicReference diff --git a/test/pending/pos/t8146a.scala b/test/files/pos/t8146a.scala index e4eb8d3fd1..e4eb8d3fd1 100644 --- a/test/pending/pos/t8146a.scala +++ b/test/files/pos/t8146a.scala diff --git a/test/pending/pos/t8146b.scala b/test/files/pos/t8146b.scala index dd031f66c8..dd031f66c8 100644 --- a/test/pending/pos/t8146b.scala +++ b/test/files/pos/t8146b.scala |