attempted fix for the TypeSkolem problem under ...

attempted fix for the TypeSkolem problem under specialize.

3 files changed, 19 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 3e54b68daf..16bff5d399 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -255,6 +255,8 @@ class Global(var settings: Settings, var reporter: Reporter) extends SymbolTable
     override def flatClasses: Boolean = isFlat
     private val isDevirtualized = prev.name == "devirtualize" || prev.devirtualized
     override def devirtualized: Boolean = isDevirtualized  // (part of DEVIRTUALIZE)
+    private val isSpecialized = prev.name == "specialize" || prev.specialized
+    override def specialized: Boolean = isSpecialized
 
     /** Is current phase cancelled on this unit? */
     def cancelled(unit: CompilationUnit) =
diff --git a/src/compiler/scala/tools/nsc/Phase.scala b/src/compiler/scala/tools/nsc/Phase.scala
index cd5a399c12..98f0f840ff 100644
--- a/src/compiler/scala/tools/nsc/Phase.scala
+++ b/src/compiler/scala/tools/nsc/Phase.scala
@@ -34,6 +34,7 @@ abstract class Phase(val prev: Phase) {
   // Will running with -Ycheck:name work?
   def checkable: Boolean = true
   def devirtualized: Boolean = false
+  def specialized: Boolean = false
   def erasedTypes: Boolean = false
   def flatClasses: Boolean = false
   def keepsTypeParams = true
diff --git a/src/compiler/scala/tools/nsc/symtab/Types.scala b/src/compiler/scala/tools/nsc/symtab/Types.scala
index 2cd690fbbf..7af61a009f 100644
--- a/src/compiler/scala/tools/nsc/symtab/Types.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Types.scala
@@ -3801,6 +3801,19 @@ A type's typeSymbol should never be inspected directly.
   private def isUnifiable(pre1: Type, pre2: Type) =
     (beginsWithTypeVarOrIsRefined(pre1) || beginsWithTypeVarOrIsRefined(pre2)) && (pre1 =:= pre2)
 
+  /** Returns true iff we are past phase specialize,
+   *  sym1 and sym2 are two existential skolems with equal names and bounds,
+   *  and pre1 and pre2 are equal prefixes
+   */
+  private def isSameSpecializedSkolem(sym1: Symbol, sym2: Symbol, pre1: Type, pre2: Type) = {
+    sym1.isExistentialSkolem && sym2.isExistentialSkolem &&
+    util.trace("is same specialized skolem "+sym1+" "+sym2+" at "+phase+phase.specialized+" ?") {
+    sym1.name == sym2.name &&
+    phase.specialized &&
+    sym1.info =:= sym2.info
+    pre1 =:= pre2
+  }}
+
   private def equalSymsAndPrefixes(sym1: Symbol, pre1: Type, sym2: Symbol, pre2: Type): Boolean =
     if (sym1 == sym2) sym1.hasFlag(PACKAGE) || phase.erasedTypes || pre1 =:= pre2
     else (sym1.name == sym2.name) && isUnifiable(pre1, pre2)
@@ -4264,8 +4277,9 @@ A type's typeSymbol should never be inspected directly.
             val pre1 = tr1.pre
             val pre2 = tr2.pre
             (((if (sym1 == sym2) phase.erasedTypes || pre1 <:< pre2
-              else (sym1.name == sym2.name && isUnifiable(pre1, pre2))) &&
-             isSubArgs(tr1.args, tr2.args, sym1.typeParams))
+               else (sym1.name == sym2.name &&
+                     (isUnifiable(pre1, pre2) || isSameSpecializedSkolem(sym1, sym2, pre1, pre2)))) &&
+                    isSubArgs(tr1.args, tr2.args, sym1.typeParams))
              ||
              sym2.isClass && {
                val base = tr1 baseType sym2