Make ImplicitInfo hashCode consistent with equals.

2 files changed, 43 insertions, 1 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
index bee2ae8e99..a7eab21942 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Implicits.scala
@@ -255,7 +255,10 @@ trait Implicits {
           this.sym == that.sym
       case _ => false
     }
-    override def hashCode = name.## + pre.## + sym.##
+    override def hashCode = {
+      import scala.util.hashing.MurmurHash3._
+      finalizeHash(mix(mix(productSeed, name.##), sym.##), 2)
+    }
     override def toString = (
       if (tpeCache eq null) name + ": ?"
       else name + ": " + tpe
diff --git a/test/junit/scala/tools/nsc/typechecker/Implicits.scala b/test/junit/scala/tools/nsc/typechecker/Implicits.scala
new file mode 100644
index 0000000000..75f4e70827
--- /dev/null
+++ b/test/junit/scala/tools/nsc/typechecker/Implicits.scala
@@ -0,0 +1,39 @@
+package scala.tools.nsc
+package typechecker
+
+import org.junit.Assert._
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+import scala.tools.testing.BytecodeTesting
+
+@RunWith(classOf[JUnit4])
+class ImplicitsTests extends BytecodeTesting {
+  import compiler.global._, definitions._, analyzer._
+
+  @Test
+  def implicitInfoHashCode(): Unit = {
+    val run = new global.Run
+
+    enteringPhase(run.typerPhase) {
+      val T0 = IntClass.tpeHK
+      val T1 = refinedType(List(T0), NoSymbol)
+
+      assert(T0 =:= T1)
+      assert(T0 != T1)
+      assert(T0.hashCode != T1.hashCode)
+
+      val I0 = new ImplicitInfo(TermName("dummy"), T0, NoSymbol)
+      val I1 = new ImplicitInfo(TermName("dummy"), T1, NoSymbol)
+
+      assert(I0 == I1)
+      assert(I0.hashCode == I1.hashCode)
+
+      val pHash = (TermName("dummy"), NoSymbol).hashCode
+
+      assert(I0.hashCode == pHash)
+      assert(I1.hashCode == pHash)
+    }
+  }
+}