private static boolean hasOnlyClosureParam(GrReferenceExpression ref) {
    if (ref.resolve() != null) return false;

    GroovyResolveResult[] results = ref.multiResolve(true);
    for (GroovyResolveResult result : results) {
      final PsiElement element = result.getElement();
      if (element instanceof PsiMethod) {
        final PsiParameter[] parameters = ((PsiMethod)element).getParameterList().getParameters();
        if (parameters.length == 1 && parameters[0].getType().equalsToText(GroovyCommonClassNames.GROOVY_LANG_CLOSURE)) {
          return true;
        }
      }
    }
    return false;
  }
private static boolean hasOnlyClosureParam(GrReferenceExpression ref)