Simplify erasure + mixin

Remove some old, obsolete & untested hacks from ExplicitOuter.
Added a test for one of them to show this is now fine.

There are a lot of `makeNotPrivate` invocations sprinkled around
the codebase. Lets see if we can centralize the ones dealing
with trait methods that need implementations in the phase that emits them.

For example Fields (accessors for fields/modules) or SuperAccessors.

1 files changed, 35 insertions, 70 deletions

diff --git a/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala b/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala
index 411ff6b9be..f3d5ceb0f0 100644
--- a/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala
+++ b/src/compiler/scala/tools/nsc/transform/ExplicitOuter.scala
@@ -158,13 +158,6 @@ abstract class ExplicitOuter extends InfoTransform
     case MethodType(params, resTp) =>
       val resTpTransformed = transformInfo(sym, resTp)
 
-      // juggle flags (and mangle names) after transforming info
-      if (sym.owner.isTrait) {
-        // TODO: I don't believe any private accessors remain after the fields phase
-        if ((sym hasFlag (ACCESSOR | SUPERACCESSOR)) || sym.isModule) sym.makeNotPrivate(sym.owner) // 5
-        if (sym.isProtected) sym setFlag notPROTECTED // 6
-      }
-
       val paramsWithOuter =
         if (sym.isClassConstructor && isInner(sym.owner)) // 1
           sym.newValueParameter(nme.OUTER_ARG, sym.pos).setInfo(sym.owner.outerClass.thisType) :: params
@@ -202,14 +195,6 @@ abstract class ExplicitOuter extends InfoTransform
       if (restp eq restp1) tp else PolyType(tparams, restp1)
 
     case _ =>
-      // Local fields of traits need to be unconditionally unprivatized.
-      // Reason: Those fields might need to be unprivatized if referenced by an inner class.
-      // On the other hand, mixing in the trait into a separately compiled
-      // class needs to have a common naming scheme, independently of whether
-      // the field was accessed from an inner class or not. See #2946
-      if (sym.owner.isTrait && sym.isLocalToThis &&
-              (sym.getterIn(sym.owner) == NoSymbol))
-        sym.makeNotPrivate(sym.owner)
       tp
   }
 
@@ -300,61 +285,41 @@ abstract class ExplicitOuter extends InfoTransform
     }
   }
 
-  /** <p>
-   *    The phase performs the following transformations on terms:
-   *  </p>
-   *  <ol>
-   *    <li> <!-- 1 -->
-   *      <p>
-   *        An class which is not an interface and is not static gets an outer
-   *        accessor (@see outerDefs).
-   *      </p>
-   *      <p>
-   *        1a. A class which is not a trait gets an outer field.
-   *      </p>
-   *    </li>
-   *    <li> <!-- 4 -->
-   *      A constructor of a non-trait inner class gets an outer parameter.
-   *    </li>
-   *    <li> <!-- 5 -->
-   *      A reference C.this where C refers to an
-   *      outer class is replaced by a selection
-   *      this.$outer$$C1 ... .$outer$$Cn (@see outerPath)
-   *    </li>
-   *    <li>
-   *    </li>
-   *    <li> <!-- 7 -->
-   *      A call to a constructor Q.<init>(args) or Q.$init$(args) where Q != this and
-   *      the constructor belongs to a non-static class is augmented by an outer argument.
-   *      E.g. Q.<init>(OUTER, args) where OUTER
-   *      is the qualifier corresponding to the singleton type Q.
-   *    </li>
-   *    <li>
-   *      A call to a constructor this.<init>(args) in a
-   *      secondary constructor is augmented to this.<init>(OUTER, args)
-   *      where OUTER is the last parameter of the secondary constructor.
-   *    </li>
-   *    <li> <!-- 9 -->
-   *      Remove private modifier from class members M
-   *      that are accessed from an inner class.
-   *    </li>
-   *    <li> <!-- 10 -->
-   *      Remove protected modifier from class members M
-   *      that are accessed without a super qualifier accessed from an inner
-   *      class or trait.
-   *    </li>
-   *    <li> <!-- 11 -->
-   *      Remove private and protected modifiers
-   *      from type symbols
-   *    </li>
-   *    <li> <!-- 12 -->
-   *      Remove private modifiers from members of traits
-   *    </li>
-   *  </ol>
-   *  <p>
-   *    Note: The whole transform is run in phase explicitOuter.next.
-   *  </p>
-   */
+  /** The phase performs the following transformations (more or less...):
+    *
+    * (1) An class which is not an interface and is not static gets an outer accessor (@see outerDefs).
+    * (1a) A class which is not a trait gets an outer field.
+    *
+    * (4) A constructor of a non-trait inner class gets an outer parameter.
+    *
+    * (5) A reference C.this where C refers to an outer class is replaced by a selection
+    *     `this.$outer$$C1 ... .$outer$$Cn` (@see outerPath)
+    *
+    * (7) A call to a constructor Q.(args) or Q.$init$(args) where Q != this and
+    *     the constructor belongs to a non-static class is augmented by an outer argument.
+    *     E.g. Q.(OUTER, args) where OUTER
+    *     is the qualifier corresponding to the singleton type Q.
+    *
+    * (8) A call to a constructor this.(args) in a
+    *     secondary constructor is augmented to this.(OUTER, args)
+    *     where OUTER is the last parameter of the secondary constructor.
+    *
+    * (9) Remove private modifier from class members M that are accessed from an inner class.
+    *
+    * (10) Remove protected modifier from class members M that are accessed
+    *      without a super qualifier accessed from an inner class or trait.
+    *
+    * (11) Remove private and protected modifiers from type symbols
+    *
+    * Note: The whole transform is run in phase explicitOuter.next.
+    *
+    * TODO: Make this doc reflect what's actually going on.
+    *       Some of the deviations are motivated by separate compilation
+    *       (name mangling based on usage is inherently unstable).
+    *       Now that traits are compiled 1:1 to interfaces, they can have private members,
+    *       so there's also less need to make trait members non-private
+    *       (they still may need to be implemented in subclasses, though we could make those protected...).
+    */
   class ExplicitOuterTransformer(unit: CompilationUnit) extends OuterPathTransformer(unit) {
     transformer =>