Questionable advice in bug report instructions

[kmcallister]

Noticed in #17824.

Your bug report instructions mention that "It's also helpful to copy/paste the output of re-running the erroneous rustc command with the -v flag", but since the -v flag causes rustc to print its version and exit, i am skeptical of this claim.

This is either a really odd way to ask for the version, or a bit of advice that's no longer relevant. What should we say instead? RUST_LOG=rustc rustc is a bit too verbose — I killed it after it wrote 8.1 GB of logs compiling fn main() { let x = 3u; }.

[pnkfelix]

I think the intent was indeed to get the version output. I think the phrasing is only odd in that it does not make that intent clear. (It is possible I am wrong about the intent here.)

But there is an additional problem: Sometime between 0.10 and 0.11, we revised the -v / --version output to ensure it would be only one line when you do not supply an argument to --version. This means we lose potentially relevant information, namely the host system type (e.g. x86_64-apple-darwin or i686-apple-darwin).

We could fix both of these problems by revising the instructions to say something like:

It's also helpful to provide the exact version and host by copying the output of re-running the erroneous rustc command with the --version=verbose flag, which will produce something like this:

rustc 0.12.0 (ba4081a5a 2014-10-07 13:44:41 -0700)
binary: rustc
commit-hash: ba4081a5a8573875fed17545846f6f6902c8ba8d
commit-date: 2014-10-07 13:44:41 -0700
host: i686-apple-darwin
release: 0.12.0

[steveklabnik]

Closing since #18217 was merged.