protected PsiElement @Nullable [] getVariables(Expression[] params, final ExpressionContext context) {
    if (params.length != 1) return null;
    final Result result = params[0].calculateResult(context);
    if (result == null) return null;

    Project project = context.getProject();
    final int offset = context.getStartOffset();

    final ArrayList<PsiElement> array = new ArrayList<>();
    PsiType type = MacroUtil.resultToPsiType(result, context);
    PsiFile file = PsiDocumentManager.getInstance(project).getPsiFile(context.getEditor().getDocument());
    PsiElement place = file.findElementAt(offset);

    PsiVariable[] variables = MacroUtil.getVariablesVisibleAt(place, "");
    PsiManager manager = PsiManager.getInstance(project);
    for (PsiVariable var : variables) {
      if (var instanceof PsiField && var.hasModifierProperty(PsiModifier.STATIC)) {
        PsiClass varClass = ((PsiField)var).getContainingClass();
        PsiClass placeClass = PsiTreeUtil.getParentOfType(place, PsiClass.class);
        if (!manager.areElementsEquivalent(varClass, placeClass)) continue;
      }
      else if (var instanceof PsiLocalVariable) {
        final TextRange range = var.getNameIdentifier().getTextRange();
        if (range != null && range.contains(offset)) {
          continue;
        }
      }

      PsiType type1 = VariableTypeCalculator.getVarTypeAt(var, place);
      if (type == null || type.isAssignableFrom(type1)) {
        array.add(var);
      }
    }

    PsiExpression[] expressions = MacroUtil.getStandardExpressionsOfType(place, type);
    ContainerUtil.addAll(array, expressions);
    return PsiUtilCore.toPsiElementArray(array);
  }
protected PsiElement @Nullable [] getVariables(Expression[] params, final ExpressionContext context)