Properly track 'abstract override' modifier. Ref #726.

compile/interface/src/main/scala/xsbt/API.scala

@@ -278,8 +278,10 @@ final class API(val global: CallbackGlobal) extends Compat
 	private def getModifiers(s: Symbol): xsbti.api.Modifiers =
 	{
 		import Flags._
-		new xsbti.api.Modifiers(s.hasFlag(ABSTRACT) || s.hasFlag(DEFERRED), s.hasFlag(OVERRIDE),
-			s.isFinal, s.hasFlag(SEALED), isImplicit(s), s.hasFlag(LAZY), hasMacro(s))
+		val absOver = s.hasFlag(ABSOVERRIDE)
+		val abs = s.hasFlag(ABSTRACT) || s.hasFlag(DEFERRED) || absOver
+		val over = s.hasFlag(OVERRIDE) || absOver
+		new xsbti.api.Modifiers(abs, over, s.isFinal, s.hasFlag(SEALED), isImplicit(s), s.hasFlag(LAZY), hasMacro(s))
 	}
 
 	private def isImplicit(s: Symbol) = s.hasFlag(Flags.IMPLICIT)

sbt/src/sbt-test/source-dependencies/abstract-override/A.scala

@@ -0,0 +1,3 @@
+trait A {
+	def x: Int
+}

sbt/src/sbt-test/source-dependencies/abstract-override/B.scala

@@ -0,0 +1,3 @@
+trait B extends A {
+	override def x = 2
+}

sbt/src/sbt-test/source-dependencies/abstract-override/C.scala

@@ -0,0 +1,3 @@
+trait C extends A {
+	def x = 5
+}

sbt/src/sbt-test/source-dependencies/abstract-override/D.scala

@@ -0,0 +1 @@
+trait D extends C with B

sbt/src/sbt-test/source-dependencies/abstract-override/changes/C2.scala

@@ -0,0 +1,3 @@
+trait C extends A {
+	abstract override def x = super.x + 5
+}

sbt/src/sbt-test/source-dependencies/abstract-override/test

@@ -0,0 +1,3 @@
+> compile
+$ copy-file changes/C2.scala C.scala
+-> compile