public static boolean isIdentityLambda(PsiLambdaExpression lambda) {
    PsiParameterList parameters = lambda.getParameterList();
    if (parameters.getParametersCount() != 1) return false;
    PsiExpression expression = PsiUtil.skipParenthesizedExprDown(extractSingleExpressionFromBody(lambda.getBody()));
    return expression instanceof PsiReferenceExpression &&
           ((PsiReferenceExpression)expression).isReferenceTo(parameters.getParameters()[0]);
  }
public static boolean isIdentityLambda(PsiLambdaExpression lambda)