Question: closing resources (like std::io::Write)

libs
6

Just an idea:

trait TryDrop {
    type Error;
    fn try_drop(&mut self) -> Result<(), Self::Error>;
}

and a T that implements TryDrop can only be dropped in a scope that returns Result<T, U> where U: From<<T as TryDrop>::Error>

so code like this:

impl TryDrop for File {
    /* -snip- */
}

fn main() -> Result<(), Box<dyn Error>> {
    let file = File::open("foo")?;
    // do something with file
    Ok(())
}

is converted to code like this

/* -snip- */

fn main() -> Result<(), Box<dyn Error>> {
    let file = File::open("foo")?;
    // do something with file
    
   file.try_drop()?;
    
    Ok(())
}

similarly how Drop works (sort of)