Merge pull request scala#5761 from lrytz/sd329

Don't use `equals` for comparing java.lang.Double/Float

src/compiler/scala/tools/nsc/backend/jvm/BCodeBodyBuilder.scala

@@ -1264,14 +1264,22 @@ abstract class BCodeBodyBuilder extends BCodeSkelBuilder {
     def genEqEqPrimitive(l: Tree, r: Tree, success: asm.Label, failure: asm.Label, targetIfNoJump: asm.Label, pos: Position) {
 
       /* True if the equality comparison is between values that require the use of the rich equality
-       * comparator (scala.runtime.Comparator.equals). This is the case when either side of the
+       * comparator (scala.runtime.BoxesRunTime.equals). This is the case when either side of the
        * comparison might have a run-time type subtype of java.lang.Number or java.lang.Character.
-       * When it is statically known that both sides are equal and subtypes of Number of Character,
-       * not using the rich equality is possible (their own equals method will do ok.)
+       *
+       * When it is statically known that both sides are equal and subtypes of Number or Character,
+       * not using the rich equality is possible (their own equals method will do ok), except for
+       * java.lang.Float and java.lang.Double: their `equals` have different behavior around `NaN`
+       * and `-0.0`, see Javadoc (scala-dev#329).
        */
       val mustUseAnyComparator: Boolean = {
-        val areSameFinals = l.tpe.isFinalType && r.tpe.isFinalType && (l.tpe =:= r.tpe)
-        !areSameFinals && platform.isMaybeBoxed(l.tpe.typeSymbol) && platform.isMaybeBoxed(r.tpe.typeSymbol)
+        platform.isMaybeBoxed(l.tpe.typeSymbol) && platform.isMaybeBoxed(r.tpe.typeSymbol) && {
+          val areSameFinals = l.tpe.isFinalType && r.tpe.isFinalType && (l.tpe =:= r.tpe) && {
+            val sym = l.tpe.typeSymbol
+            sym != BoxedFloatClass && sym != BoxedDoubleClass
+          }
+          !areSameFinals
+        }
       }
 
       if (mustUseAnyComparator) {

test/files/run/number-parsing.scala

@@ -3,8 +3,8 @@ object Test {
     val MinusZero = Float.box(-0.0f)
     val PlusZero  = Float.box(0.0f)
 
-    assert(PlusZero match { case MinusZero => false ; case _ => true })
-    assert(MinusZero match { case PlusZero => false ; case _ => true })
+    assert(PlusZero match { case MinusZero => true ; case _ => false })
+    assert(MinusZero match { case PlusZero => true ; case _ => false })
     assert((MinusZero: scala.Float) == (PlusZero: scala.Float))
     assert(!(MinusZero equals PlusZero))
 

test/files/run/sd329.scala

@@ -0,0 +1,76 @@
+object Test extends App {
+  def d1: Double = 0.0
+  def d2: Double = -0.0
+  def d3: Double = Double.NaN
+  def d4: Double = Double.NaN
+  assert(d1 == d2)
+  assert(d3 != d4)
+
+  def d1B: java.lang.Double = d1
+  def d2B: java.lang.Double = d2
+  def d3B: java.lang.Double = d3
+  def d4B: java.lang.Double = d4
+  assert(d1B == d2B)
+  assert(d1  == d1B)
+  assert(d1B == d1)
+  assert(d3B != d4B)
+  assert(d3  != d4B)
+  assert(d3B != d4)
+
+  assert(!d1B.equals(d2B)) // ! see javadoc
+  assert( d3B.equals(d4B)) // ! see javadoc
+
+  def d1A: Any = d1
+  def d2A: Any = d2
+  def d3A: Any = d3
+  def d4A: Any = d4
+  assert(d1A == d2A)
+  assert(d1  == d1A)
+  assert(d1A == d1)
+  assert(d1B == d1A)
+  assert(d1A == d1B)
+
+  assert(d3A != d4A)
+  assert(d3  != d4A)
+  assert(d3A != d4)
+  assert(d3B != d4A)
+  assert(d3A != d4B)
+
+
+  def f1: Float = 0.0f
+  def f2: Float = -0.0f
+  def f3: Float = Float.NaN
+  def f4: Float = Float.NaN
+  assert(f1 == f2)
+  assert(f3 != f4)
+
+  def f1B: java.lang.Float = f1
+  def f2B: java.lang.Float = f2
+  def f3B: java.lang.Float = f3
+  def f4B: java.lang.Float = f4
+  assert(f1B == f2B)
+  assert(f1  == f1B)
+  assert(f1B == f1)
+  assert(f3B != f4B)
+  assert(f3  != f4B)
+  assert(f3B != f4)
+
+  assert(!f1B.equals(f2B)) // ! see javadoc
+  assert( f3B.equals(f4B)) // ! see javadoc
+
+  def f1A: Any = f1
+  def f2A: Any = f2
+  def f3A: Any = f3
+  def f4A: Any = f4
+  assert(f1A == f2A)
+  assert(f1  == f1A)
+  assert(f1A == f1)
+  assert(f1B == f1A)
+  assert(f1A == f1B)
+
+  assert(f3A != f4A)
+  assert(f3  != f4A)
+  assert(f3A != f4)
+  assert(f3B != f4A)
+  assert(f3A != f4B)
+}