#[rustc_pass_by_value] prevents lldb from showing the information correctly

[dev-ardi]

#![feature(rustc_attrs)]

#[rustc_pass_by_value]
#[derive(Debug, Clone)]
struct Val;

#[derive(Debug, Clone)]
enum E {
    Foo,
    Bar(Val),
}

fn main() {
    let x = E::Foo;
    let y = E::Bar(Val);
    dbg!(x, y);
}

As you can see x and y have the representation of {...}.

This makes it very hard to use a debugger in rustc.

[compiler-errors]

This seems like a rust-analyzer bug with macros.

[dev-ardi]

What does rust-analyzer have to do here? I thought that the debug representation was all lldb. In fact r-a server is stopped in that screenshot :P

[compiler-errors]

Well then it's some other aspect of IDE integration, and it doesn't have anything to do with rustc. All that rustc_pass_by_value does is mark it for lint purposes: 4c3e330.

Also, what do you mean the r-a server is stopped in that screenshot? Isn't the "2 implementations" hint over struct Val a rust-analyzer feature?

[compiler-errors]

Also, if you're trying to use rustc_pass_by_value in your own project? That is definitely not supported.

[compiler-errors]

Also, I'm pretty certain this has nothing to do with rustc_pass_by_value.

I deleted the annotations on your test example, attached CodeLLDB for the debugger in vscode, and I'm still getting the same output you shared:

From a cursory search on the internet, I don't believe Rust has very good lldb support for debug-printing its data. I'm gonna close this issue.

[dev-ardi]

This is embarrasing :D