Add ClassInfo.emulatedConcreteMethods

Author: szeiger

core/src/main/scala/com/typesafe/tools/mima/core/ClassInfo.scala

@@ -160,6 +160,13 @@ abstract class ClassInfo(val owner: PackageInfo) extends HasDeclarationName with
     else Nil
   }
 
+  /** The subset of concrete methods of this trait that are abstract at the JVM level.
+    * This corresponds to the pre-Scala-2.12 trait encoding where all `concreteMethods`
+    * are `emulatedConcreteMethods`. In 2.12 most concrete trait methods are translated
+    * to concrete interface methods. */
+  lazy val emulatedConcreteMethods: List[MemberInfo] =
+    concreteMethods.filter(_.isDeferred)
+
   /** The deferred methods of this trait */
   lazy val deferredMethods: List[MemberInfo] = {
     val concreteSet = concreteMethods.toSet

reporter/src/main/scala/com/typesafe/tools/mima/lib/analyze/Analyzer.scala

@@ -130,7 +130,7 @@ private[analyze] class TraitAnalyzer extends Analyzer {
   override def analyzeNewClassMethods(oldclazz: ClassInfo, newclazz: ClassInfo): List[Problem] = {
     val res = collection.mutable.ListBuffer.empty[Problem]
 
-    for (newmeth <- newclazz.concreteMethods if newmeth.isDeferred && !oldclazz.hasStaticImpl(newmeth)) {
+    for (newmeth <- newclazz.emulatedConcreteMethods if !oldclazz.hasStaticImpl(newmeth)) {
       if (!oldclazz.lookupMethods(newmeth.bytecodeName).exists(_.sig == newmeth.sig)) {
         // this means that the method is brand new and therefore the implementation
         // has to be injected