Include file name in IO errors (especially FileNotFound).

[orenbenkiki]

Here is an error message I just got (using the latest head version):

task '... failed at 'Unhandled condition: io_error: rt::io::IoError{kind: OtherIoError, desc: "no such file or directory", detail: None}', .../rust/src/libstd/condition.rs:131

It would be much easier to debug if the io error included the name of the offending file.

[itdaniher]

I agree with the sentiment - working on tracking down the codepath that emits that error. Pain in the neck to debug!

[cadencemarseille]

Probably depends on #10863

[pnkfelix]

it would be great to fix this.

I skimmed over the code in std::io::mod briefly, and while the IoErrorKind enum seems easy enough to modify, the hard part is probably to extract the necessary info e.g. in rustuv::uv_error_to_io_error

cc @alexcrichton

[aturon]

cc me
cc @wycats

[alexcrichton]

Closed by #14823