Fix InnerClass/EnclosingMethod for trait impl and specialized classes

Trait implementation classes and specialized classes are always
considered top-level in terms of the InnerClass / EnclosingMethod
attributes. These attributes describe source-level properties, and
such classes are a compilation artifact.

Note that the same is true for delambdafy:method closure classes
(they are always top-level).

1 files changed, 19 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
index 09d78fdf41..fb9804be7f 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeAsmCommon.scala
@@ -22,6 +22,14 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
   }
 
   /**
+   * True for classes generated by the Scala compiler that are considered top-level in terms of
+   * the InnerClass / EnclosingMethod classfile attributes. See comment in BTypes.
+   */
+  def considerAsTopLevelImplementationArtifact(classSym: Symbol) = {
+    classSym.isImplClass || classSym.isSpecialized
+  }
+
+  /**
    * Cache the value of delambdafy == "inline" for each run. We need to query this value many
    * times, so caching makes sense.
    */
@@ -148,7 +156,10 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
       if (sym.isClass) sym
       else enclosingClass(nextEnclosing(sym))
     }
-    enclosingClass(nextEnclosing(classSym))
+    val r = enclosingClass(nextEnclosing(classSym))
+    // this should be an assertion, but we are more cautious for now as it was introduced before the 2.11.6 minor release
+    if (considerAsTopLevelImplementationArtifact(r)) devWarning(s"enclosing class of $classSym should not be an implementation artifact class: $r")
+    r
   }
 
   final case class EnclosingMethodEntry(owner: String, name: String, methodDescriptor: String)
@@ -162,7 +173,8 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
    * on the implementation of GenASM / GenBCode, so they need to be passed in.
    */
   def enclosingMethodAttribute(classSym: Symbol, classDesc: Symbol => String, methodDesc: Symbol => String): Option[EnclosingMethodEntry] = {
-    if (isAnonymousOrLocalClass(classSym)) {
+    // trait impl classes are always top-level, see comment in BTypes
+    if (isAnonymousOrLocalClass(classSym) && !considerAsTopLevelImplementationArtifact(classSym)) {
       val methodOpt = enclosingMethodForEnclosingMethodAttribute(classSym)
       debuglog(s"enclosing method for $classSym is $methodOpt (in ${methodOpt.map(_.enclClass)})")
       Some(EnclosingMethodEntry(
@@ -191,11 +203,13 @@ final class BCodeAsmCommon[G <: Global](val global: G) {
    * The member classes of a class symbol. Note that the result of this method depends on the
    * current phase, for example, after lambdalift, all local classes become member of the enclosing
    * class.
+   *
+   * Impl classes are always considered top-level, see comment in BTypes.
    */
-  def memberClassesOf(classSymbol: Symbol): List[Symbol] = classSymbol.info.decls.collect({
-    case sym if sym.isClass =>
+  def memberClassesForInnerClassTable(classSymbol: Symbol): List[Symbol] = classSymbol.info.decls.collect({
+    case sym if sym.isClass && !considerAsTopLevelImplementationArtifact(sym) =>
       sym
-    case sym if sym.isModule =>
+    case sym if sym.isModule && !considerAsTopLevelImplementationArtifact(sym) => // impl classes get the lateMODULE flag in mixin
       val r = exitingPickler(sym.moduleClass)
       assert(r != NoSymbol, sym.fullLocationString)
       r