Add missing cases in tail return transform

Disabled warnings that no longer apply because of tail returns.
Add several test cases.

2 files changed, 11 insertions, 8 deletions

diff --git a/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala b/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala
index 46c644bcd6..90c961f195 100644
--- a/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala
+++ b/src/continuations/plugin/scala/tools/selectivecps/CPSUtils.scala
@@ -96,13 +96,8 @@ trait CPSUtils {
 
   // anf transform
 
-  def getExternalAnswerTypeAnn(tp: Type) = {
-    cpsParamTypes(tp) orElse {
-      if (hasPlusMarker(tp))
-        global.warning("trying to instantiate type " + tp + " to unknown cps type")
-      None
-    }
-  }
+  def getExternalAnswerTypeAnn(tp: Type) =
+    cpsParamTypes(tp) orElse None
 
   def getAnswerTypeAnn(tp: Type): Option[(Type, Type)] =
     cpsParamTypes(tp) filterNot (_ => hasPlusMarker(tp))
diff --git a/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala b/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala
index 1783264e5c..99838dfc25 100644
--- a/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala
+++ b/src/continuations/plugin/scala/tools/selectivecps/SelectiveANFTransform.scala
@@ -43,6 +43,12 @@ abstract class SelectiveANFTransform extends PluginComponent with Transform with
         case If(cond, r1 @ Return(thenExpr), r2 @ Return(elseExpr)) =>
           treeCopy.If(tree, cond, transform(thenExpr), transform(elseExpr))
 
+        case If(cond, r1 @ Return(thenExpr), elseExpr) =>
+          treeCopy.If(tree, cond, transform(thenExpr), transform(elseExpr))
+
+        case If(cond, thenExpr, r2 @ Return(elseExpr)) =>
+          treeCopy.If(tree, cond, transform(thenExpr), transform(elseExpr))
+
         case If(cond, thenExpr, elseExpr) =>
           treeCopy.If(tree, cond, transform(thenExpr), transform(elseExpr))
 
@@ -440,7 +446,9 @@ abstract class SelectiveANFTransform extends PluginComponent with Transform with
         // all is well
 
         if (hasPlusMarker(expr.tpe)) {
-          unit.warning(tree.pos, "expression " + expr + " of type " + expr.tpe + " is not expected to have a cps type")
+          // the following warning no longer applies, since expr may have originated from a tail return expr
+          // note that it would be illegal to remove the plus marker (thus disabling required transformations)
+          //unit.warning(tree.pos, "expression " + expr + " of type " + expr.tpe + " is not expected to have a cps type")
           expr modifyType removeAllCPSAnnotations
         }