Allow BCode to emit default interface methods

A DefDef owned by a trait may now have have a method body.
Such a method must be emitted without ACC_ABSTRACT, and
with the code attribute.

Tested by intercepting the compile pipeline and adding the
DEFAULTMETHOD flag and a method body before running
the backend.

4 files changed, 7 insertions, 5 deletions

diff --git a/src/compiler/scala/tools/nsc/backend/icode/Members.scala b/src/compiler/scala/tools/nsc/backend/icode/Members.scala
index 64146585e5..c0e0240210 100644
--- a/src/compiler/scala/tools/nsc/backend/icode/Members.scala
+++ b/src/compiler/scala/tools/nsc/backend/icode/Members.scala
@@ -9,6 +9,7 @@ package backend
 package icode
 
 import scala.collection.{ mutable, immutable }
+import scala.reflect.internal.Flags
 import scala.reflect.internal.util.{ SourceFile, NoSourceFile }
 
 trait ReferenceEquality {
@@ -217,7 +218,7 @@ trait Members {
 
     /** Is this method deferred ('abstract' in Java sense)?
      */
-    def isAbstractMethod = symbol.isDeferred || symbol.owner.isInterface || native
+    def isAbstractMethod = symbol.isDeferred || (symbol.owner.isInterface && !symbol.hasFlag(Flags.JAVA_DEFAULTMETHOD)) || native
 
     def isStatic: Boolean = symbol.isStaticMember
 
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala b/src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala
index a9b6a312e9..df4a715245 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BCodeSkelBuilder.scala
@@ -587,10 +587,10 @@ abstract class BCodeSkelBuilder extends BCodeHelpers {
       }
 
       val isNative         = methSymbol.hasAnnotation(definitions.NativeAttr)
-      val isAbstractMethod = (methSymbol.isDeferred || methSymbol.owner.isInterface)
+      val isAbstractMethod = (methSymbol.isDeferred || methSymbol.owner.isInterface) && !methSymbol.hasFlag(Flags.JAVA_DEFAULTMETHOD)
       val flags = GenBCode.mkFlags(
         javaFlags(methSymbol),
-        if (claszSymbol.isInterface) asm.Opcodes.ACC_ABSTRACT   else 0,
+        if (isAbstractMethod)        asm.Opcodes.ACC_ABSTRACT   else 0,
         if (methSymbol.isStrictFP)   asm.Opcodes.ACC_STRICT     else 0,
         if (isNative)                asm.Opcodes.ACC_NATIVE     else 0  // native methods of objects are generated in mirror classes
       )
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala b/src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala
index 45d9cc3ff3..88d07ce917 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala
@@ -571,7 +571,7 @@ class BTypesFromSymbols[G <: Global](val global: G) extends BTypes {
     import asm.Opcodes._
     GenBCode.mkFlags(
       if (privateFlag) ACC_PRIVATE else ACC_PUBLIC,
-      if (sym.isDeferred || sym.hasAbstractFlag) ACC_ABSTRACT else 0,
+      if ((sym.isDeferred && !sym.hasFlag(symtab.Flags.JAVA_DEFAULTMETHOD))|| sym.hasAbstractFlag) ACC_ABSTRACT else 0,
       if (sym.isInterface) ACC_INTERFACE else 0,
       if (finalFlag && !sym.hasAbstractFlag) ACC_FINAL else 0,
       if (sym.isStaticMember) ACC_STATIC else 0,
diff --git a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
index 7096f16d75..872feefc8e 100644
--- a/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
+++ b/src/compiler/scala/tools/nsc/backend/jvm/GenASM.scala
@@ -1391,10 +1391,11 @@ abstract class GenASM extends SubComponent with BytecodeWriters { self =>
       var resTpe: asm.Type = javaType(m.symbol.tpe.resultType)
       if (m.symbol.isClassConstructor)
         resTpe = asm.Type.VOID_TYPE
+      val isAbstractTraitMeth = isJInterface && !m.symbol.hasFlag(Flags.JAVA_DEFAULTMETHOD)
 
       val flags = mkFlags(
         javaFlags(m.symbol),
-        if (isJInterface)          asm.Opcodes.ACC_ABSTRACT   else 0,
+        if (isAbstractTraitMeth)   asm.Opcodes.ACC_ABSTRACT   else 0,
         if (m.symbol.isStrictFP)   asm.Opcodes.ACC_STRICT     else 0,
         if (method.native)         asm.Opcodes.ACC_NATIVE     else 0, // native methods of objects are generated in mirror classes
         if(isDeprecated(m.symbol)) asm.Opcodes.ACC_DEPRECATED else 0  // ASM pseudo access flag