JavaParsers: fix call to annotation methods

Previously, for tests/run/i2760/Fork.java, the parser output was:

    abstract class Fork(val value: Int = ???,  val warmups: Int = ???)
    extends ...

Since Fork is JavaDefined, calls to `value` were translated into
field calls, but `value` is a method, not a field, so i2760 crashed at
runtime with NoSuchFieldError. We now generate instead:

    abstract class Fork private[this](x$1: _root_.scala.Unit)
    extends ... {
       def <init>(value: Int = ???, warmups: Int = ???)

       def value(): Int = 1
       def warmups(): Int = 1
    }

This way we get both named parameters for the constructor and real
method calls.

Author: smarter

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

@@ -123,6 +123,7 @@ object JavaParsers {
       // A dummy first constructor is needed for Java classes so that the real constructors see the
       // import of the companion object. The constructor has parameter of type Unit so no Java code
       // can call it.
+      // This also avoids clashes between the constructor parameter names and member names.
       if (needsDummyConstr) {
         stats1 = constr1 :: stats1
         constr1 = makeConstructor(List(scalaDot(tpnme.Unit)), tparams, Flags.JavaDefined | Flags.PrivateLocal)
@@ -133,7 +134,7 @@ object JavaParsers {
     def makeSyntheticParam(count: Int, tpt: Tree): ValDef =
       makeParam(nme.syntheticParamName(count), tpt)
     def makeParam(name: TermName, tpt: Tree, defaultValue: Tree = EmptyTree): ValDef =
-      ValDef(name, tpt, defaultValue).withMods(Modifiers(Flags.JavaDefined | Flags.ParamAccessor))
+      ValDef(name, tpt, defaultValue).withMods(Modifiers(Flags.JavaDefined | Flags.Param))
 
     def makeConstructor(formals: List[Tree], tparams: List[TypeDef], flags: FlagSet = Flags.JavaDefined) = {
       val vparams = formals.zipWithIndex.map { case (p, i) => makeSyntheticParam(i + 1, p) }
@@ -787,8 +788,7 @@ object JavaParsers {
       }
       val constr = DefDef(nme.CONSTRUCTOR,
         List(), List(constructorParams), TypeTree(), EmptyTree).withMods(Modifiers(Flags.JavaDefined))
-      val body1 = body.filterNot(_.isInstanceOf[DefDef])
-      val templ = makeTemplate(annotationParents, constr :: body1, List(), false)
+      val templ = makeTemplate(annotationParents, constr :: body, List(), true)
       val annot = atPos(start, nameOffset) {
         TypeDef(name, templ).withMods(mods | Flags.Abstract)
       }