fix logic error in #44269's `prune_cache_value_obligations`
We want to retain obligations that *contain* inference variables, not
obligations that *don't contain* them, in order to fix#43132. Because
of surrounding changes to inference, the ICE doesn't occur in its
original case, but I believe it could still be made to occur on master.
Maybe I should try to write a new test case? Certainly not right now
(I'm mainly trying to get us a beta that we can ship) but maybe before
we land this PR on nightly?
This seems to cause a 10% performance regression in my imprecise
attempt to benchmark item-body checking for #43613, but it's better to
be slow and right than fast and wrong. If we want to recover that, I
think we can change the constrained-type-parameter code to actually
give a list of projections that are important for resolving inference
variables and filter everything else out.
We want to retain obligations that *contain* inference variables, not
obligations that *don't contain* them, in order to fix#43132. Because
of surrounding changes to inference, the ICE doesn't occur in its
original case, but I believe it could still be made to occur on master.
Maybe I should try to write a new test case? Certainly not right now
(I'm mainly trying to get us a beta that we can ship) but maybe before
we land this PR on nightly?
This seems to cause a 10% performance regression in my imprecise
attempt to benchmark item-body checking for #43613, but it's better to
be slow and right than fast and wrong. If we want to recover that, I
think we can change the constrained-type-parameter code to actually
give a list of projections that are important for resolving inference
variables and filter everything else out.
Implement `and_modify` on `Entry`
## Motivation
`Entry`s are useful for allowing access to existing values in a map while also allowing default values to be inserted for absent keys. The existing API is similar to that of `Option`, where `or` and `or_with` can be used if the option variant is `None`.
The `Entry` API is, however, missing an equivalent of `Option`'s `and_then` method. If it were present it would be possible to modify an existing entry before calling `or_insert` without resorting to matching on the entry variant.
Tracking issue: https://github.com/rust-lang/rust/issues/44733.
replace libc::res_init with res_init_if_glibc_before_2_26
The previous workaround for gibc's res_init bug is not thread-safe on
other implementations of libc, and it can cause crashes. Use a runtime
check to make sure we only call res_init when we need to, which is also
when it's safe. See https://github.com/rust-lang/rust/issues/43592.
~This PR is returning an InvalidData IO error if the glibc version string fails to parse. We could also have treated that case as "not glibc", and gotten rid of the idea that these functions could return an error. (Though I'm not a huge fan of ignoring error returns from `res_init` in any case.) Do other folks agree with these design choices?~
I'm pretty new to hacking on libstd. Is there an easy way to build a toy rust program against my changes to test this, other than doing an entire `sudo make install` on my system? What's the usual workflow?
Improve resolution of associated types in declarative macros 2.0
Make various identifier comparisons for associated types (and sometimes other associated items) hygienic.
Now declarative macros 2.0 can use `Self::AssocTy`, `TyParam::AssocTy`, `Trait<AssocTy = u8>` where `AssocTy` is an associated type of a trait `Trait` visible from the macro. Also, `Trait` can now be implemented inside the macro and specialization should work properly (fixes https://github.com/rust-lang/rust/pull/40847#issuecomment-310867299).
r? @jseyfried or @eddyb
incr compilation struct_defs.rs
I am prematurely openeing this as I need mentoring help from @michaelwoerister (also pinged @nikomatsakis)
First, is this the right approach for these changes?
Second, I'm a bit confused by the results so far.
- Changing `TupleStructFieldType(i32)` -> `...(u32)` changes only Hir and HirBody, not TypeOfItem
- Chaning `TupleStructAddField(i32)` -> `...(i32, u32)` *does* change TypeOfItem
This seems wrong. I feel like it should change TypeOfItem in both cases. Is this a bug in incr compilation or is it expected?
Faster compile times for release builds with llvm fix
Run global optimizations after the inliner to avoid spending time on optimizing dead code.
fixes#44655
The previous workaround for gibc's res_init bug is not thread-safe on
other implementations of libc, and it can cause crashes. Use a runtime
check to make sure we only call res_init when we need to, which is also
when it's safe. See https://github.com/rust-lang/rust/issues/43592.
`EndRegion` do not always correspond to borrow-data entries
Remove assertion that the argument to every `EndRegion` correspond to some dataflow-tracked borrow-data entry.
Fix#44828
(The comment thread on the aforementioned issue discusses why its best to just remove this assertion.)
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
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.
Overlapping borrows can point to different lvalues.
Overlapping borrows can point to different lvalues.
There's always a basis for the overlap, so instead of removing the assert entirely, I instead pass in the prefix that we found and check that it actually is a prefix of both lvalues.
Fix#44829
make `backtrace = false` compile for windows targets.
when building for windows with `backtrace = false`, `libstd` fails to compile because some modules that use items from `sys_common::backtrace::*` are still included, even though those modules aren't used or referenced by anything.
`sys_common::backtrace` doesn't exist when the backtrace feature is turned off.
--
i've also added `#[cfg(feature = "backtrace")]` to various items that exist exclusively to support `mod backtrace` since the compilation would fail since they would be unused in a configuration with backtraces turned off.
Made `fs::copy` return the length of the main stream
On Windows with the NTFS filesystem, `fs::copy` would return the sum of the
lengths of all streams, which can be different from the length reported by
`metadata` and thus confusing for users unaware of this NTFS peculiarity.
This makes `fs::copy` return the same length `metadata` reports which is the
value it used to return before PR #26751. Note that alternate streams are still
copied; their length is just not included in the returned value.
This change relies on the assumption that the stream with index 1 is always the
main stream in the `CopyFileEx` callback. I could not find any official
document confirming this but empirical testing has shown this to be true,
regardless of whether the alternate stream is created before or after the main
stream.
Resolves#44532
