two more minor cleanups to Duration

- copy partest TestUtil.intercept change from PR 1279 branch
- add comment on non-obvious match cases

2 files changed, 13 insertions, 3 deletions

diff --git a/src/library/scala/concurrent/util/Duration.scala b/src/library/scala/concurrent/util/Duration.scala
index 6d44c93bc2..8fd47630cb 100644
--- a/src/library/scala/concurrent/util/Duration.scala
+++ b/src/library/scala/concurrent/util/Duration.scala
@@ -306,8 +306,8 @@ object Duration {
   val Inf: Infinite = new Infinite {
     override def toString = "Duration.Inf"
     def compare(other: Duration) = other match {
-      case x if x eq Undefined => -1
-      case x if x eq this      => 0
+      case x if x eq Undefined => -1 // Undefined != Undefined
+      case x if x eq this      => 0  // `case Inf` will include null checks in the byte code
       case _                   => 1
     }
     def unary_- : Duration = MinusInf
diff --git a/src/partest/scala/tools/partest/TestUtil.scala b/src/partest/scala/tools/partest/TestUtil.scala
index b86a8e2c7f..146e6fc69f 100644
--- a/src/partest/scala/tools/partest/TestUtil.scala
+++ b/src/partest/scala/tools/partest/TestUtil.scala
@@ -1,5 +1,7 @@
 package scala.tools.partest
 
+import reflect.{ classTag, ClassTag }
+
 trait TestUtil {
   /** Given function and block of code, evaluates code block,
    *  calls function with nanoseconds elapsed, and returns block result.
@@ -29,8 +31,16 @@ trait TestUtil {
 
     assert(mult <= acceptableMultiple, "Performance difference too great: multiple = " + mult)
   }
+
+  def intercept[T <: Exception : ClassTag](code: => Unit): Unit =
+    try {
+      code
+      assert(false, "did not throw " + classTag[T])
+    } catch {
+      case ex: Exception if classTag[T].runtimeClass isInstance ex =>
+    }
 }
 
 object TestUtil extends TestUtil {
 
-}
\ No newline at end of file
+}