Fixes #3728. No review.

3 files changed, 19 insertions, 11 deletions

diff --git a/src/compiler/scala/tools/nsc/symtab/Definitions.scala b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
index 667bdd5386..198c225e8b 100644
--- a/src/compiler/scala/tools/nsc/symtab/Definitions.scala
+++ b/src/compiler/scala/tools/nsc/symtab/Definitions.scala
@@ -448,6 +448,7 @@ trait Definitions extends reflect.generic.StandardDefinitions {
     lazy val DeprecatedAttr: Symbol = getClass("scala.deprecated")
     lazy val DeprecatedNameAttr: Symbol = getClass("scala.deprecatedName")
     lazy val MigrationAnnotationClass: Symbol = getClass("scala.annotation.migration")
+    lazy val TraitSetterAnnotationClass: Symbol = getClass("scala.runtime.TraitSetter")
     lazy val BeanPropertyAttr: Symbol = getClass(sn.BeanProperty)
     lazy val BooleanBeanPropertyAttr: Symbol = getClass(sn.BooleanBeanProperty)
 
diff --git a/src/compiler/scala/tools/nsc/transform/Erasure.scala b/src/compiler/scala/tools/nsc/transform/Erasure.scala
index 8c2f79374c..28ff336f60 100644
--- a/src/compiler/scala/tools/nsc/transform/Erasure.scala
+++ b/src/compiler/scala/tools/nsc/transform/Erasure.scala
@@ -259,7 +259,8 @@ abstract class Erasure extends AddInterfaces with typechecker.Analyzer with ast.
           def classSigSuffix: String =
             "."+sym.name
           if (sym == ArrayClass)
-            ARRAY_TAG.toString+(args map jsig).mkString
+            if (unboundedGenericArrayLevel(tp) == 1) jsig(ObjectClass.tpe)
+            else ARRAY_TAG.toString+(args map jsig).mkString
           else if (sym.isTypeParameterOrSkolem &&
                   // only refer to type params that will actually make it into the sig, this excludes:
                   !sym.owner.isTypeParameterOrSkolem && // higher-order type parameters (!sym.owner.isTypeParameterOrSkolem), and parameters of methods
@@ -1088,4 +1089,4 @@ abstract class Erasure extends AddInterfaces with typechecker.Analyzer with ast.
       }
     }
   }
-}
\ No newline at end of file
+}
diff --git a/src/compiler/scala/tools/nsc/transform/Mixin.scala b/src/compiler/scala/tools/nsc/transform/Mixin.scala
index d1b3142c8a..a9922a50f2 100644
--- a/src/compiler/scala/tools/nsc/transform/Mixin.scala
+++ b/src/compiler/scala/tools/nsc/transform/Mixin.scala
@@ -475,16 +475,22 @@ abstract class Mixin extends InfoTransform with ast.TreeDSL {
           if (!currentOwner.isTrait) addMixedinMembers(currentOwner,unit)
           else if (currentOwner hasFlag lateINTERFACE) addLateInterfaceMembers(currentOwner)
           tree
-        case DefDef(mods, name, tparams, List(vparams), tpt, rhs) if currentOwner.isImplClass =>
-          if (isImplementedStatically(sym)) {
-            sym setFlag notOVERRIDE
-            self = sym.newValue(sym.pos, nme.SELF)
-              .setFlag(PARAM)
-              .setInfo(toInterface(currentOwner.typeOfThis));
-            val selfdef = ValDef(self) setType NoType
-            treeCopy.DefDef(tree, mods, name, tparams, List(selfdef :: vparams), tpt, rhs)
+        case DefDef(mods, name, tparams, List(vparams), tpt, rhs) =>
+          if (currentOwner.isImplClass) {
+            if (isImplementedStatically(sym)) {
+              sym setFlag notOVERRIDE
+              self = sym.newValue(sym.pos, nme.SELF)
+                .setFlag(PARAM)
+                .setInfo(toInterface(currentOwner.typeOfThis));
+              val selfdef = ValDef(self) setType NoType
+              treeCopy.DefDef(tree, mods, name, tparams, List(selfdef :: vparams), tpt, rhs)
+            } else {
+              EmptyTree
+            }
           } else {
-            EmptyTree
+            if (currentOwner.isTrait && sym.isSetter)
+              sym.addAnnotation(AnnotationInfo(TraitSetterAnnotationClass.tpe, List(), List()))
+            tree
           }
         case Apply(tapp @ TypeApply(fn, List(arg)), List()) =>
           if (arg.tpe.typeSymbol.isImplClass) {