Rust compiler-explorer produce error with -g or no output with -O

When I use the below valid code written in Rust, I see assembly generated - it’s all good. I use the default GUI options of compiler-explorer and no compiler options. However, if I use the compiler option:

• -g, the result is <Compilation failed>.
• -O, the result is 7 empty lines.

In both cases, I expect to see assembly code.

fn main() {
    let mut sum: u32 = 0;
    let (from, to) = (0, 500);

    for i in from..to {
        sum += i;
    }

    println!("{}", sum) // 124750
}

https://godbolt.org/g/QgcCMQ

[ludwigpacifici]

I agree. To save place on screen, these hard coded options required for compiler-explorer could be toggled between a “…” and the hidden options.

An ASCII drawing of the compiler and its options. Default view will hide the required options. Example with rust:

|------------------------------------------|
| rustc 1.15.1 | ... | compiler options... |
|------------------------------------------|
|                 <asm code>               |
|------------------------------------------|

If I clic on “…”, the compiler bar would become for example a read only text showing hidden options:

|------------------------------------------------------------------------------------|
| rustc 1.15.1 | -g --emit=asm --crate-type rlib -o <filename> | compiler options... |
|------------------------------------------------------------------------------------|
|                                     <asm code>                                     |
|------------------------------------------------------------------------------------|

Tell me if my ASCII drawings are not clear enough.

[mattgodbolt]

It’s not quite what you wanted but if you click on the compilation results indicator (between the compiler selection dropdown and the flags) you see all the options we pass. I hope this is good enough: If you feel strongly that this doesn’t quite cover your idea then please reply and we’ll consider alternatives. Thanks!