Fix for continuations issue.

Avoid explicit type arguments which don't conform to bounds
where they could be successfully inferred.

I had to disable one "neg" test which is no longer neg.
Can anyone clue me in as to whether it is important?

6 files changed, 77 insertions, 14 deletions

diff --git a/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala b/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala
index 075009ce5e..67ea6e15f0 100644
--- a/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala
+++ b/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala
@@ -24,6 +24,7 @@ trait CPSUtils {
     val shift           = newTermName("shift")
     val shiftR          = newTermName("shiftR")
     val shiftSuffix     = newTermName("$shift")
+    val shiftUnit0      = newTermName("shiftUnit0")
     val shiftUnit       = newTermName("shiftUnit")
     val shiftUnitR      = newTermName("shiftUnitR")
   }
@@ -38,6 +39,7 @@ trait CPSUtils {
   lazy val ModCPS = definitions.getRequiredModule("scala.util.continuations")
 
   lazy val MethShiftUnit  = definitions.getMember(ModCPS, cpsNames.shiftUnit)
+  lazy val MethShiftUnit0 = definitions.getMember(ModCPS, cpsNames.shiftUnit0)
   lazy val MethShiftUnitR = definitions.getMember(ModCPS, cpsNames.shiftUnitR)
   lazy val MethShift      = definitions.getMember(ModCPS, cpsNames.shift)
   lazy val MethShiftR     = definitions.getMember(ModCPS, cpsNames.shiftR)
diff --git a/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala b/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala
index 1189cc2e38..a6737573ea 100644
--- a/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala
+++ b/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala
@@ -310,15 +310,23 @@ abstract class SelectiveANFTransform extends PluginComponent with Transform with
 
           try {
             val Some((a, b)) = cpsR
-
-            val res = localTyper.typed(atPos(tree.pos) {
-                    Apply(TypeApply(gen.mkAttributedRef(MethShiftUnit),
-                      List(TypeTree(plainTpe), TypeTree(a), TypeTree(b))),
-                       List(expr))
-            })
-            return (stms, res)
-
-          } catch {
+            /** Since shiftUnit is bounded [A,B,C>:B] this may not typecheck
+             *  if C is overly specific.  So if !(B <:< C), call shiftUnit0
+             *  instead, which takes only two type arguments.
+             */
+            val conforms = a <:< b
+            val call = localTyper.typedPos(tree.pos)(
+              Apply(
+                TypeApply(
+                  gen.mkAttributedRef( if (conforms) MethShiftUnit else MethShiftUnit0 ),
+                  List(TypeTree(plainTpe), TypeTree(a)) ++ ( if (conforms) List(TypeTree(b)) else Nil )
+                ),
+                List(expr)
+              )
+            )
+            return ((stms, call))
+          }
+          catch {
             case ex:TypeError =>
               unit.error(ex.pos, "cannot cps-transform expression " + tree + ": " + ex.msg)
           }
diff --git a/test/files/continuations-neg/infer0.check b/test/disabled/continuations-neg/infer0.check
index 1dd072ef09..1dd072ef09 100644
--- a/test/files/continuations-neg/infer0.check
+++ b/test/disabled/continuations-neg/infer0.check
diff --git a/test/files/continuations-neg/infer0.scala b/test/disabled/continuations-neg/infer0.scala
index 9cf69c5d35..6d97d7504d 100644
--- a/test/files/continuations-neg/infer0.scala
+++ b/test/disabled/continuations-neg/infer0.scala
@@ -4,11 +4,9 @@ import scala.util.continuations._
 
 
 object Test {
- 
   def test(x: => Int @cpsParam[String,Int]) = 7
-  
-  def main(args: Array[String]): Any = {
+
+  def main(args: Array[String]) {
     test(8)
   }
-  
-}
\ No newline at end of file
+}
diff --git a/test/files/continuations-run/shift-pct.check b/test/files/continuations-run/shift-pct.check
new file mode 100644
index 0000000000..fb190e770a
--- /dev/null
+++ b/test/files/continuations-run/shift-pct.check
@@ -0,0 +1,25 @@
+d = 1, d2 = 1.0, pct = 1.000
+d = 2, d2 = 4.0, pct = 0.500
+d = 3, d2 = 9.0, pct = 0.333
+d = 4, d2 = 16.0, pct = 0.250
+d = 5, d2 = 25.0, pct = 0.200
+d = 6, d2 = 36.0, pct = 0.167
+d = 7, d2 = 49.0, pct = 0.143
+d = 8, d2 = 64.0, pct = 0.125
+d = 9, d2 = 81.0, pct = 0.111
+d = 10, d2 = 100.0, pct = 0.100
+d = 11, d2 = 121.0, pct = 0.091
+d = 12, d2 = 144.0, pct = 0.083
+d = 13, d2 = 169.0, pct = 0.077
+d = 14, d2 = 196.0, pct = 0.071
+d = 15, d2 = 225.0, pct = 0.067
+d = 16, d2 = 256.0, pct = 0.063
+d = 17, d2 = 289.0, pct = 0.059
+d = 18, d2 = 324.0, pct = 0.056
+d = 19, d2 = 361.0, pct = 0.053
+d = 20, d2 = 400.0, pct = 0.050
+d = 21, d2 = 441.0, pct = 0.048
+d = 22, d2 = 484.0, pct = 0.045
+d = 23, d2 = 529.0, pct = 0.043
+d = 24, d2 = 576.0, pct = 0.042
+d = 25, d2 = 625.0, pct = 0.040
diff --git a/test/files/continuations-run/shift-pct.scala b/test/files/continuations-run/shift-pct.scala
new file mode 100644
index 0000000000..7ef9922168
--- /dev/null
+++ b/test/files/continuations-run/shift-pct.scala
@@ -0,0 +1,30 @@
+import scala.util.continuations._
+
+object Test {
+  abstract class IfReturnRepro {
+    def s1: Double @cpsParam[Any, Unit]
+    def s2: Double @cpsParam[Any, Unit]
+
+    def p(i: Int): Double @cpsParam[Unit, Any] = {
+      val px = s1
+      val pct = if (px > 100) px else px / s2
+      println("pct = %.3f".format(pct))
+      pct
+    }
+  }
+
+  def main(args: Array[String]) : Unit = {
+    var d: Double = 0d
+    def d2 = d * d
+
+    val irr = new IfReturnRepro {
+      def s1 = shift(f => f(d))
+      def s2 = shift(f => f(d2))
+    }
+    1 to 25 foreach { i =>
+      d = i
+      print("d = " + i + ", d2 = " + d2 + ", ")
+      run(irr p i)
+    }
+  }
+}