rustc should return error code for unsupported command line option (-Wall)

[astoeckel]

I tried this code:

rustc -Wall main.rs && ./main

I expected to see this happen: rustc prints an error message saying that -Wall is not supported and exits with a non-zero exit status.

Instead, this happened: rustc prints an error message and immediately returns with a zero exit status, causing an old version of "./main" to be executed. I would expect all error messages that cancel compilation to cause a non-zero exit code.

Additional details:
This problem is caused by handle_options in src/librust_driver/lib.rs not really distinguishing between cases such as -help (in which the return None makes sense); and downright invalid options such as -Wall, which should explicitly print an error message and abort with an error code.

An alternative solution would be to inform about the missing -Wall parameter as a warning, and to continue compilation normally (the way the deprecated "no-stack-check" is handled).

[SummerGram]

Hi,
I would like to work on this issue.

[tmiasko]

Since #92504 rustc -Wall now results in non-zero exit status.