How to print full help message manually?

[0x7FFFFFFFFFFFFFFF]

I have the following program and I want to print the full help message for some logic branches.

use clap::{App, Arg};

fn main() {
    let mut app = App::new("test15")
        .version("version [2021.3.3]")
        .about("test15")
        .arg(Arg::with_name("param1")
            .short("p")
            .long("param1")
            .value_name("param1")
            .help("param1")
            .takes_value(true)
            .required(false));
    let matches = app.get_matches();

    let mut input = matches.value_of("param1").unwrap_or("");

    if input == "" {
        println!("Please specify a correct value for param1. Below is the help message of the program.\r\n");
        app.print_help();
        return;
    }
}

When I run the program using cargo run, I got the following errors:

error[E0382]: borrow of moved value: `app`
    --> src\main.rs:20:9
     |
4    |     let mut app = App::new("test15")
     |         ------- move occurs because `app` has type `App<'_, '_>`, which does not implement the `Copy` trait
...
14   |     let matches = app.get_matches();
     |                       ------------- `app` moved due to this method call
...
20   |         app.print_help();
     |         ^^^ value borrowed here after move
I tried but failed to fix the issue. Could anyone help me to take a look?

I played around with the code but can't fix the issue. Could anyone help me to take a look? Thanks in advance.

[pksunkara]

I guess you are new to rust. The error messages explains it pretty clearly. You moved the value on line 14 and are trying to access it on line 20. You would need to clone on line 14 to make sure you don't move the value.

let matches = app.clone().get_matches();

[0x7FFFFFFFFFFFFFFF]

Yes I'm still learning Rust. Thanks for the answer!