Rust Experts Question: Symbol is getting allocated on the stack

qustion_stack_borrow_checker.rs

struct Context<'a> {
    bytes_pool: Vec<Vec<u8>>,
    symbols: Vec<Symbol<'a>>,
}

#[allow(dead_code)]
struct Symbol<'a> {
    name: &'a str,
    is_defined: bool
}

fn parse_symbols<'a>(bytes: &'a [u8], symbols: &'a mut Vec<Symbol<'a>>) {
    for i in 1..10 {
        let name = std::str::from_utf8(&bytes[i*10..i*10+1]).unwrap();
        let is_defined = &bytes[i*10]+1 == 1;
        let sym = Symbol{name, is_defined};
        symbols.push(sym);
    }
}

fn main() {

    let file_path_str = std::env::args().next().unwrap();
    let file_path = std::path::PathBuf::from(file_path_str.clone());
    let mut ctx = Box::new(Context{ symbols: Vec::new(), bytes_pool: Vec::new()});
    let bytes = std::fs::read(file_path);
    if let Ok(bytes) = bytes {
        ctx.bytes_pool.push(bytes);
        parse_symbols(ctx.bytes_pool.last().unwrap(), &mut ctx.symbols);
    }
    //for sym in &ctx.symbols {
    //
    //}
}