From b174efbcbcf241903d2dc970f950f594b8c8c5e7 Mon Sep 17 00:00:00 2001
From: Paul Phillips <paulp@improving.org>
Date: Sat, 11 May 2013 13:02:54 -0700
Subject: Eliminated RETmode.

It becomes context mode "ReturnExpr".
---
 src/compiler/scala/tools/nsc/typechecker/Contexts.scala          | 9 +++++++++
 src/compiler/scala/tools/nsc/typechecker/Typers.scala            | 6 +++---
 .../plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala   | 4 ++--
 src/reflect/scala/reflect/internal/Mode.scala                    | 5 -----
 4 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
index dc75fa3746..48df7cb261 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Contexts.scala
@@ -243,6 +243,7 @@ trait Contexts { self: Analyzer =>
     def retyping                              = this(ReTyping)
     def inSecondTry                           = this(SecondTry)
     def inSecondTry_=(value: Boolean)         = this(SecondTry) = value
+    def inReturnExpr                          = this(ReturnExpr)
 
     /** These messages are printed when issuing an error */
     var diagnostic: List[String] = Nil
@@ -361,6 +362,11 @@ trait Contexts { self: Analyzer =>
     def withSuperInit[T](op: => T): T                        = withMode(enabled = SuperInit)(op)
     def withSecondTry[T](op: => T): T                        = withMode(enabled = SecondTry)(op)
 
+    def withReturnExpr[T](op: => T): T = {
+      enclMethod.returnsSeen = true
+      withMode(enabled = ReturnExpr)(op)
+    }
+
     /** @return true if the `expr` evaluates to true within a silent Context that incurs no errors */
     @inline final def inSilentMode(expr: => Boolean): Boolean = {
       withMode() { // withMode with no arguments to restore the mode mutated by `setBufferErrors`.
@@ -1355,6 +1361,9 @@ object ContextMode {
    */
   final val SecondTry: ContextMode                = 1 << 14
 
+  /** Are we in return position? Formerly RETmode. */
+  final val ReturnExpr: ContextMode               = 1 << 15
+
   final val DefaultMode: ContextMode      = MacrosEnabled
 
   private val contextModeNameMap = Map(
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 2066ab980d..3bcc670c89 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -4292,9 +4292,9 @@ trait Typers extends Adaptations with Tags {
           val DefDef(_, name, _, _, restpt, _) = enclMethod.tree
           if (restpt.tpe eq null) {
             ReturnWithoutTypeError(tree, enclMethod.owner)
-          } else {
-            context.enclMethod.returnsSeen = true
-            val expr1: Tree = typed(expr, EXPRmode | BYVALmode | RETmode, restpt.tpe)
+          }
+          else {
+            val expr1 = context withReturnExpr typed(expr, EXPRmode | BYVALmode, restpt.tpe)
             // Warn about returning a value if no value can be returned.
             if (restpt.tpe.typeSymbol == UnitClass) {
               // The typing in expr1 says expr is Unit (it has already been coerced if
diff --git a/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala b/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala
index 519b90f0c6..e6153596f7 100644
--- a/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala
+++ b/src/continuations/plugin/scala/tools/selectivecps/CPSAnnotationChecker.scala
@@ -169,7 +169,7 @@ abstract class CPSAnnotationChecker extends CPSUtils {
               true
             //}
           } else false
-        } else if (!hasPlusMarker(tree.tpe) && annots1.isEmpty && !annots2.isEmpty && mode.inRetMode) {
+        } else if (!hasPlusMarker(tree.tpe) && annots1.isEmpty && !annots2.isEmpty && typer.context.inReturnExpr) {
           vprintln("checking enclosing method's result type without annotations")
           tree.tpe <:< pt.withoutAnnotations
         } else if (!hasMinusMarker(tree.tpe) && !annots1.isEmpty && mode.inByValMode) {
@@ -219,7 +219,7 @@ abstract class CPSAnnotationChecker extends CPSUtils {
         val res = tree modifyType addMinusMarker
         vprintln("adapted annotations (by val) of " + tree + " to " + res.tpe)
         res
-      } else if (mode.inRetMode && !hasPlusMarker(tree.tpe) && isMissingExpectedAnnots) {
+      } else if (typer.context.inReturnExpr && !hasPlusMarker(tree.tpe) && isMissingExpectedAnnots) {
         // add a marker annotation that will make tree.tpe behave as pt, subtyping wise
         // tree will look like having any possible annotation
 
diff --git a/src/reflect/scala/reflect/internal/Mode.scala b/src/reflect/scala/reflect/internal/Mode.scala
index 89d6be0248..a15a3dcc84 100644
--- a/src/reflect/scala/reflect/internal/Mode.scala
+++ b/src/reflect/scala/reflect/internal/Mode.scala
@@ -71,10 +71,6 @@ object Mode {
    */
   final val TYPEPATmode: Mode   = 0x10000
 
-  /** RETmode is set when we are typing a return expression.
-   */
-  final val RETmode: Mode       = 0x20000
-
   final private val StickyModes: Mode = EXPRmode | PATTERNmode | TYPEmode
 
   /** Translates a mask of mode flags into something readable.
@@ -129,7 +125,6 @@ final class Mode private (val bits: Int) extends AnyVal {
   def inPatternMode = inAll(PATTERNmode)
   def inPolyMode    = inAll(POLYmode)
   def inQualMode    = inAll(QUALmode)
-  def inRetMode     = inAll(RETmode)
   def inSccMode     = inAll(SCCmode)
   def inTappMode    = inAll(TAPPmode)
   def inTypeMode    = inAll(TYPEmode)
-- 
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