Merge pull request #2923 from retronym/ticket/7825

SI-7825 Consider DEFAULTMETHOD when refchecking concreteness

2 files changed, 5 insertions, 2 deletions

diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 09c4878b2f..83afb3a728 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -383,7 +383,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
             overrideError("cannot be used here - classes can only override abstract types");
           } else if (other.isEffectivelyFinal) { // (1.2)
             overrideError("cannot override final member");
-          } else if (!other.isDeferred && !other.hasFlag(DEFAULTMETHOD) && !member.isAnyOverride && !member.isSynthetic) { // (*)
+          } else if (!other.isDeferredOrDefault && !member.isAnyOverride && !member.isSynthetic) { // (*)
             // (*) Synthetic exclusion for (at least) default getters, fixes SI-5178. We cannot assign the OVERRIDE flag to
             // the default getter: one default getter might sometimes override, sometimes not. Example in comment on ticket.
               if (isNeitherInClass && !(other.owner isSubClass member.owner))
@@ -565,7 +565,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
         def checkNoAbstractMembers(): Unit = {
           // Avoid spurious duplicates: first gather any missing members.
           def memberList = clazz.info.nonPrivateMembersAdmitting(VBRIDGE)
-          val (missing, rest) = memberList partition (m => m.isDeferred && !ignoreDeferred(m))
+          val (missing, rest) = memberList partition (m => m.isDeferredNotDefault && !ignoreDeferred(m))
           // Group missing members by the name of the underlying symbol,
           // to consolidate getters and setters.
           val grouped = missing groupBy (sym => analyzer.underlyingSymbol(sym).name)
diff --git a/src/reflect/scala/reflect/internal/HasFlags.scala b/src/reflect/scala/reflect/internal/HasFlags.scala
index 4a3663b8ea..12fd3a31cd 100644
--- a/src/reflect/scala/reflect/internal/HasFlags.scala
+++ b/src/reflect/scala/reflect/internal/HasFlags.scala
@@ -115,6 +115,9 @@ trait HasFlags {
   def isSynthetic        = hasFlag(SYNTHETIC)
   def isTrait            = hasFlag(TRAIT) && !hasFlag(PARAM)
 
+  def isDeferredOrDefault  = hasFlag(DEFERRED | DEFAULTMETHOD)
+  def isDeferredNotDefault = isDeferred && !hasFlag(DEFAULTMETHOD)
+
   def flagBitsToString(bits: Long): String = {
     // Fast path for common case
     if (bits == 0L) "" else {