private static PsiParameter getDocTagParam(PsiElement tag) {
    if (tag instanceof PsiDocTag && "param".equals(((PsiDocTag)tag).getName())) {
      PsiDocTagValue value = ((PsiDocTag)tag).getValueElement();
      if (value instanceof PsiDocParamRef) {
        final PsiReference psiReference = value.getReference();
        PsiElement target = psiReference != null ? psiReference.resolve() : null;
        if (target instanceof PsiParameter) {
          return (PsiParameter)target;
        }
      }
    }
    return null;
  }
private static PsiParameter getDocTagParam(PsiElement tag)