Merge pull request #3519 from adriaanm/rebase-3483

SI-8244 Fix raw type regression under separate compilation

2 files changed, 11 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
index 664645e53e..2f9cc01c0b 100644
--- a/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
+++ b/src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala
@@ -665,8 +665,11 @@ abstract class ClassfileParser {
               // so have to check unsafeTypeParams.isEmpty before worrying about raw type case below,
               // or we'll create a boatload of needless existentials.
               else if (classSym.isMonomorphicType || classSym.unsafeTypeParams.isEmpty) tp
-              // raw type - existentially quantify all type parameters
-              else debuglogResult(s"raw type from $classSym")(unsafeClassExistentialType(classSym))
+              else debuglogResult(s"raw type from $classSym"){
+                // raw type - existentially quantify all type parameters
+                val eparams = typeParamsToExistentials(classSym, classSym.unsafeTypeParams)
+                newExistentialType(eparams, typeRef(pre, classSym, eparams.map(_.tpeHK)))
+              }
             case tp =>
               assert(sig.charAt(index) != '<', s"sig=$sig, index=$index, tp=$tp")
               tp
diff --git a/src/reflect/scala/reflect/internal/Definitions.scala b/src/reflect/scala/reflect/internal/Definitions.scala
index 78e639fdff..645d6aa4ff 100644
--- a/src/reflect/scala/reflect/internal/Definitions.scala
+++ b/src/reflect/scala/reflect/internal/Definitions.scala
@@ -898,12 +898,15 @@ trait Definitions extends api.StandardDefinitions {
      *
      *    C[E1, ..., En] forSome { E1 >: LB1 <: UB1 ... en >: LBn <: UBn }.
      */
+    // TODO Review the way this is used. I see two potential problems:
+    //  1. `existentialAbstraction` here doesn't create fresh existential type symbols, it just
+    //     uses the class type parameter symbols directly as the list of quantified symbols.
+    //     See SI-8244 for the trouble that this can cause.
+    //     Compare with callers of `typeParamsToExistentials` (used in Java raw type handling)
+    //  2. Why don't we require a prefix? Could its omission lead to wrong results in CheckabilityChecker?
     def classExistentialType(clazz: Symbol): Type =
       existentialAbstraction(clazz.typeParams, clazz.tpe_*)
 
-    def unsafeClassExistentialType(clazz: Symbol): Type =
-      existentialAbstraction(clazz.unsafeTypeParams, clazz.tpe_*)
-
     // members of class scala.Any
 
     // TODO these aren't final! They are now overriden in AnyRef/Object. Prior to the fix