fix ItemKind::DefaultImpl doc comment
Upgrade comment to doc comment.
...Is this actually used? If so, why does the `Impl` variant right below have a `Defaultness`?
Add links to headers in README and CONTRIBUTING
this also adds dependencies to CONTRIBUTING
I'm just getting started building the rust compiler and noticed this information/ability was missing.
It was also missing the gdb dependency for running tests. I pulled the information out of `appveyor.yml` and recommended later than 7.1 because that is what [apt ships](https://packages.ubuntu.com/search?suite=trusty&keywords=gdb). Feel free to tell me something different!
Don't unwrap work item results as the panic trace is useless
Fixes#43402 now there's no multithreaded panic printouts
Also update a comment
--------
Likely regressed in #43506, where the code was changed to panic in worker threads on error.
Unwrapping gives zero extra information since the stack trace is so short, so we may as well just surface that there was an error and exit the thread properly. Because there are then no multithreaded printouts, I think it should mean the output of the test for #26199 is deterministic and not interleaved (thanks to @philipc https://github.com/rust-lang/rust/issues/43402#issuecomment-333835271 for a hint).
Sadly the output is now:
```
thread '<unnamed>' panicked at 'aborting due to worker thread panic', src/librustc_trans/back/write.rs:1643:20
note: Run with `RUST_BACKTRACE=1` for a backtrace.
error: could not write output to : No such file or directory
error: aborting due to previous error
```
but it's an improvement over the multi-panic situation before.
r? @alexcrichton
Extend `dump_mir` and functions it calls in order to allow callers to
add custom information. We do this by adding an enum `PassWhere` and
an extra argument of type `FnMut(PassWhere, &mut Write) ->
io::Result<()>`. This callback is responsible for printing the extra
information when MIR is dumped at various stages.
For the "nll" pass, use the new mechanism to dump the `Region`
information after the header, but before the control flow graph for
every function.
In the interest of keeping the output somewhat concise, implement
a custom Debug impl for `Region`
Open Questions:
* What should we call what has been called `PassWhere` so far?
* Use size_t where size_t is used, while it's not critical on our
specifically supported architectures, this is more accurate.
* Update HND_SPECIAL_COUNT to the correct value, and give it the size
that enum is likely to be.
incr.comp.: Switch to red/green change tracking, remove legacy system.
This PR finally switches incremental compilation to [red/green tracking](https://github.com/rust-lang/rust/issues/42293) and completely removes the legacy dependency graph implementation -- which includes a few quite costly passes that are simply not needed with the new system anymore.
There's still some documentation to be done and there's certainly still lots of optimizing and tuning ahead -- but the foundation for red/green is in place with this PR. This has been in the making for a long time `:)`
r? @nikomatsakis
cc @alexcrichton, @rust-lang/compiler
Remove mem::transmute used in Box<str> conversions
Given that https://github.com/rust-lang/rust/pull/44877 is failing, I decided to make a separate PR. This is done with the same motivation: to avoid `mem::transmute`-ing non `#[repr(C)]` types.
Also ignore `attr-on-trait` test on stage-1 to keep `./x.py test --stage 1` successful.
Fixes#30355.
Fixes#33241.
Fixes#36400.
Fixes#37887.
Fixes#44578.
This commit tests *just* the subset of the tests that were previously
ICE'ing and where now AST- and MIR-borrowck both match in terms of the
errors they report.
In other words: there remain *other* tests that previously ICE'd, and
now no longer ICE, but their remains a divergence between the errors
reported by AST-borrowck and by MIR-borrowck.
Implicitly threaded `Location` through MoveData construction via a
`Gatherer` struct (so that we could look up the span corresponding to
the location when we need to signal an error).
