Fix #879

Don't insert a constructor call when typechecking Java classes.

Author: odersky

src/dotty/tools/dotc/parsing/JavaParsers.scala

@@ -145,9 +145,9 @@ object JavaParsers {
     // ------------- general parsing ---------------------------
 
     /** skip parent or brace enclosed sequence of things */
-    def skipAhead(): Unit = {
+    def skipAhead(openBraces: Int = 0): Unit = {
       var nparens = 0
-      var nbraces = 0
+      var nbraces = openBraces
       do {
         in.token match {
           case LPAREN =>

src/dotty/tools/dotc/typer/Typer.scala

@@ -1027,7 +1027,7 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
    */
   def ensureConstrCall(cls: ClassSymbol, parents: List[Tree])(implicit ctx: Context): List[Tree] = {
     val firstParent :: otherParents = parents
-    if (firstParent.isType && !(cls is Trait))
+    if (firstParent.isType && !(cls is Trait) && !cls.is(JavaDefined))
       typed(untpd.New(untpd.TypedSplice(firstParent), Nil)) :: otherParents
     else parents
   }

tests/pos/i879.java

@@ -0,0 +1,11 @@
+class Foo {
+  Foo(int i) {
+  }
+}
+
+
+class Bar extends Foo {
+  Bar() {
+    super(10);
+  }
+}