rustc panics on non-utf8 filenames

[sp3d]

When invoking "rustc file-ÿ.rs", with the file stored on a Latin-1 encoded filesystem, rustc immediately panics:

thread '<main>' panicked at 'called `Result::unwrap()` on an `Err` value: "file-\u{fffd}"', ../src/libcore/result.rs:746
stack backtrace:
   1:     0x7f48876bf170 - sys::backtrace::tracing::imp::write::hbb9e76a649a66a56ZRu
   2:     0x7f48876cc95b - panicking::default_hook::_$u7b$$u7b$closure$u7d$$u7d$::closure.45161
   3:     0x7f48876cc5a3 - panicking::default_hook::h52b379d7e28163dbOoA
   4:     0x7f4887690faf - sys_common::unwind::begin_unwind_inner::hbc816cb06424e5a1dHt
   5:     0x7f48876929a8 - sys_common::unwind::begin_unwind_fmt::h2ffe904d33bcabedjGt
   6:     0x7f48876bca71 - rust_begin_unwind
   7:     0x7f48877162ef - panicking::panic_fmt::h02e62dce441c8af9USL
   8:     0x7f4887692069 - result::unwrap_failed::h573141488342841329
   9:     0x7f48876946e9 - env::Args.Iterator::next::hbd5e03814c81dfb5Jhe
  10:     0x7f4887bd3ac8 - main::ha3761125df75122eQ0d
  11:     0x7f48876cc044 - sys_common::unwind::try::try_fn::h17561491976180921527
  12:     0x7f48876bc9fb - __rust_try
  13:     0x7f48876cbadb - rt::lang_start::h123d5d5aa2b127831gA
  14:     0x7f488727c70f - __libc_start_main
  15:     0x556a19e88788 - <unknown>

[ivanceras]

I could not reproduce the error. What version of rust are you using?

$rustc -V
rustc 1.7.0 (a5d1e7a59 2016-02-29)

$cat file-ÿ.rs 

use std::io::prelude::*;
use std::fs::File;

fn main(){
    println!("hello world!");
    let mut f = File::open("file-ÿ.rs").unwrap();
    let mut s = String::new();
    f.read_to_string(&mut s);
    println!("{}",s);
}

[alexcrichton]

I think this is a dupe of #15890, but thanks for the report!