fix^3: bug744

git-svn-id: http://lampsvn.epfl.ch/svn-repos/scala/scala/trunk@8715 5e8d7ff9-d8ef-0310-90f0-a4852d11357a

src/compiler/scala/tools/nsc/transform/AddInterfaces.scala

@@ -251,15 +251,12 @@ abstract class AddInterfaces extends InfoTransform {
     def mixinConstructorCall(mixinClass: Symbol): Tree = atPos(tree.pos) {
       Apply(Select(This(clazz), mixinClass.primaryConstructor), List())
     }
-    def toImplClass(mc: Symbol) = 
-      if (mc.isImplClass) mc else implClass(mc)
-    def hasMixinConstructor(mc: Symbol) = {
-      mc.info;
-      (mc.isImplClass || mc.needsImplClass) && mc.toInterface != ScalaObjectClass
-    }
+    def toImplClass(sym: Symbol) = 
+      if (sym.needsImplClass) implClass(sym) else sym
     val mixinConstructorCalls: List[Tree] = {
-      for (val mc <- clazz.mixinClasses.reverse; hasMixinConstructor(mc))
-      yield mixinConstructorCall(toImplClass(mc))
+      for (val mc <- clazz.mixinClasses.reverse.map(toImplClass).removeDuplicates;
+           mc.isImplClass && mc.toInterface != ScalaObjectClass)
+      yield mixinConstructorCall(mc)
     }
     tree match { //todo: remove checking code
       case Block(supercall :: stats, expr) =>

test/files/run/bug744.check

@@ -0,0 +1,3 @@
+BEGIN
+Hello from linked
+END

test/files/run/bug744.scala

@@ -0,0 +1,20 @@
+trait Linked {
+  type File <: FileImpl;
+  trait FileImpl {
+    Console.println("Hello from linked");
+  }
+}
+object Test {
+  class Test extends Linked { 
+    trait FileImpl extends super.FileImpl {
+//      val x: int = 1
+    }
+    class File extends FileImpl;
+  }
+  def main(args : Array[String]) : Unit = {
+    Console.println("BEGIN");
+    val test = new Test;
+    val file = new test.File;
+    Console.println("END");
+  }
+}