private BitSet getAmbiguousParameters(List<StructMethod> matches) {
    StructClass cl = DecompilerContext.getStructContext().getClass(classname);
    if (cl == null || matches.size() == 1) {
      return EMPTY_BIT_SET;
    }

    BitSet missed = new BitSet(lstParameters.size());

    // check if a call is unambiguous
    StructMethod mt = cl.getMethod(InterpreterUtil.makeUniqueKey(name, stringDescriptor));
    if (mt != null) {
      MethodDescriptor md = MethodDescriptor.parseDescriptor(mt.getDescriptor());
      if (md.params.length == lstParameters.size()) {
        boolean exact = true;
        for (int i = 0; i < md.params.length; i++) {
          if (!md.params[i].equals(lstParameters.get(i).getExprType())) {
            missed.set(i);
            exact = false;
          }
        }
        if (exact) return EMPTY_BIT_SET;
      }
    }

    List<StructMethod> mtds = new ArrayList<>();
    for (StructMethod mtt : matches) {
      boolean failed = false;
      MethodDescriptor md = MethodDescriptor.parseDescriptor(mtt.getDescriptor());
      for (int i = 0; i < lstParameters.size(); i++) {
        VarType ptype = lstParameters.get(i).getExprType();
        if (!missed.get(i)) {
          if (!md.params[i].equals(ptype)) {
            failed = true;
            break;
          }
        }
        else {
          if (md.params[i].type == CodeConstants.TYPE_OBJECT) {
            if (ptype.type != CodeConstants.TYPE_NULL) {
              if (!Util.instanceOf(DecompilerContext.getStructContext(), ptype.value, md.params[i].value)) {
                failed = true;
                break;
              }
            }
          }
        }
      }
      if (!failed) {
        mtds.add(mtt);
      }
    }

    // mark parameters
    BitSet ambiguous = new BitSet(descriptor.params.length);
    for (int i = 0; i < descriptor.params.length; i++) {
      VarType paramType = descriptor.params[i];
      for (StructMethod mtt : mtds) {

        if (mtt.getSignature() != null && mtt.getSignature().params.get(i).isGeneric()) {
          break;
        }

        MethodDescriptor md = MethodDescriptor.parseDescriptor(mtt.getDescriptor());
        if (!paramType.equals(md.params[i])) {
          ambiguous.set(i);
          break;
        }
      }
    }
    return ambiguous;
  }