Weird panic from Parity main when --help output piped through malformed 'grep' command

[tjayrush]

I entered this command on my command line because I wanted to try to figure out how to do tracing:

parity --help | grep -i

It's malformed because I forgot to include what I was searching for.

Grep complained, but then parity also cored dumped with an ugly message. I thought I should report it. It's not a killer bug or anything, but it fails less gracefully than I would think it should with this message:

thread 'main' panicked at 'failed printing to stdout: Broken pipe (os error 32)', ../src/libstd/io/stdio.rs:650
stack backtrace:
1: 0x105f186ca - std::sys::imp::backtrace::tracing::imp::write::h917062bce4ff48c3
2: 0x105f1fd8f - std::panicking::default_hook::{{closure}}::h0bacac31b5ed1870
3: 0x105f1e47f - std::panicking::default_hook::h5897799da33ece67
4: 0x105f1eab6 - std::panicking::rust_panic_with_hook::h109e116a3a861224
5: 0x105f1e954 - std::panicking::begin_panic::hbb38be1379e09df0
6: 0x105f1e872 - std::panicking::begin_panic_fmt::h26713cea9bce3ab0
7: 0x105f0d6f0 - std::io::stdio::_print::he48522be5b0a80d9
8: 0x105651cb7 - docopt::dopt::Error::exit::h6d74aa76313a7d2a
9: 0x10550f049 - parity::main_direct::h29f665ab518f467e
10: 0x10551136f - parity::main::he6796bb79ca73b7d

[svyatonik]

rust-lang/rust#24821

[5chdn]

Seems to be fixed upstream.

parity --help | grep -i 
Usage: grep [OPTION]... PATTERN [FILE]...
Try 'grep --help' for more information.