rustc_resolve: don't treat uniform_paths canaries as ambiguities unless they resolve to distinct Def's.
In particular, this allows this pattern that @cramertj mentioned in https://github.com/rust-lang/rust/issues/53130#issuecomment-420848814:
```rust
use log::{debug, log};
fn main() {
use log::{debug, log};
debug!(...);
}
```
The canaries for the inner `use log::...;`, *in the macro namespace*, see the `log` macro imported at the module scope, and the (same) `log` macro, imported in the block scope inside `main`.
Previously, these two possible (macro namspace) `log` resolutions would be considered ambiguous (from a forwards-compat standpoint, where we might make imports aware of block scopes).
With this PR, such a case is allowed *if and only if* all the possible resolutions refer to the same definition (more specifically, because the *same* `log` macro is being imported twice).
This condition subsumes previous (weaker) checks like #54005 and the second commit of #54011.
Only the last commit is the main change, the other two are cleanups.
r? @petrochenkov cc @Centril @joshtriplett
[NLL] Suggest let binding
Closes#49821
Also adds an alternative to `explain_why_borrow_contains_point` that allows changing error messages based on the reason that will be given. This will also be useful for #51026, #51169 and maybe further changes to does not live long enough messages.
Rollup of 8 pull requests
Successful merges:
- #53218 (Add a implementation of `From` for converting `&'a Option<T>` into `Option<&'a T>`)
- #54024 (Fix compiling some rustc crates to wasm)
- #54095 (Rename all mentions of `nil` to `unit`)
- #54173 (Suggest valid crate type if invalid crate type is found)
- #54194 (Remove println!() statement from HashMap unit test)
- #54203 (Fix the stable release of os_str_str_ref_eq)
- #54207 (re-mark the never docs as unstable)
- #54210 (Update Cargo)
Failed merges:
r? @ghost
re-mark the never docs as unstable
Fixes https://github.com/rust-lang/rust/issues/54198
This stability attribute was removed in https://github.com/rust-lang/rust/pull/47630, but not replaced with a `#[stable]` attribute, and when https://github.com/rust-lang/rust/pull/50121 reverted that stabilization, it didn't set the docs back to unstable. I'm concerned as to why it was allowed to not have the stability attribute at all, but at least this can put it back.
I'm nominating this for beta backport because it's a really small change, and right now our docs are in an awkward position where the `!` type is technically unstable to use, but the docs don't say so the same way any other library feature would. (And this is also the case *on stable* now, but i'm not suggesting a stable backport for a docs fix.)
Fix the stable release of os_str_str_ref_eq
This was added and stabilized in commit 02503029b8, but while that
claimed to be for 1.28.0, it didn't actually make it until 1.29.0.
Fixes#54195.
Suggest valid crate type if invalid crate type is found
This adds a suggestion to the `invalid_crate_types` lint.
The suggestion is based on the Levenshtein distance to existing crate
types. If no suggestion is found it will show the lint without any
suggestions.
Closes#53958
Fix compiling some rustc crates to wasm
I was dabbling recently seeing what it would take to compile `rustfmt` to the
`wasm32-unknown-unknown` target and it turns out not much effort is needed!
Currently `rustfmt` depends on a few rustc crates published to crates.io, so
this commit touches up those crates to compile for wasm themselves. Notably:
* The `rustc_data_structures` crate's `flock` implementation is stubbed out to
unconditionally return errors on unsupported platforms.
* The `rustc_errors` crate is extended to not do any locking for all non-windows
platforms.
In both of these cases if we port the compiler to new platforms the
functionality isn't critical but will be discovered over time as it comes up, so
this hopefully doesn't make it too too hard to compile to new platforms!
Add a implementation of `From` for converting `&'a Option<T>` into `Option<&'a T>`
I'm not sure if any annotations regarding the stabilization are needed or in general what's the correct process of adding such an impl.
cc @sgrif (We have talked about this)
Rollup of 11 pull requests
Successful merges:
- #53371 (Do not emit E0277 on incorrect tuple destructured binding)
- #53829 (Add rustc SHA to released DWARF debuginfo)
- #53950 (Allow for opting out of ThinLTO and clean up LTO related cli flag handling.)
- #53976 (Replace unwrap calls in example by expect)
- #54070 (Add Error::description soft-deprecation to RELEASES)
- #54076 (miri loop detector hashing)
- #54119 (Add some unit tests for find_best_match_for_name)
- #54147 (Add a test that tries to modify static memory at compile-time)
- #54150 (Updated 1.29 release notes with --document-private-items flag)
- #54163 (Update stage 0 to latest beta)
- #54170 (COMPILER_TESTS.md has been moved)
This adds a suggestion to the `invalid_crate_types` lint.
The suggestion is based on the Levenshtein distance to existing crate
types. If no suggestion is found it will show the lint without any
suggestions.
Allow for opting out of ThinLTO and clean up LTO related cli flag handling.
It turns out that there currently is no way to explicitly disable ThinLTO (except for the nightly-only `-Zthinlto` flag). This PR extends `-C lto` to take `yes` and `no` in addition to `thin` and `fat`. It should be backwards compatible.
It also cleans up how LTO mode selection is handled.
Note that merging the PR in the current state would make the new values for `-C lto` available on the stable channel. I think that would be fine but maybe some team should vote on it.
Add rustc SHA to released DWARF debuginfo
This commit updates the debuginfo that is encoded in all of our released
artifacts by default. Currently it has paths like `/checkout/src/...` but these
are a little inconsistent and have changed over time. This commit instead
attempts to actually define the file paths in our debuginfo to be consistent
between releases.
All debuginfo paths are now intended to be `/rustc/$sha` where `$sha` is the git
sha of the released compiler. Sub-paths are all paths into the git repo at that
`$sha`.
Add some unit tests for find_best_match_for_name
There were only some UI tests that covered this function.
Since there's more diagnostic work going on, I think it makes
sense to have this unit tested.
miri loop detector hashing
* fix enum hashing to also consider discriminant
* do not hash extra machine state
* standalone miri is not interested in loop detection, so let it opt-out
In the future I think we want to move the hashing logic out of the miri engine, this is CTFE-only.
r? @oli-obk
Add target thumbv7a-pc-windows-msvc
This is an early draft of support for Windows/ARM. To test it,
1. Install Visual Studio 2017 and Windows SDK version 17134.
1. Obtain alexcrichton/xz2-rs#35, rust-lang-nursery/compiler-builtins#256, and the fix for [LLVM Bug 38620](https://bugs.llvm.org/show_bug.cgi?id=38620).
2. Open a command prompt and run
```
set CC_thumbv7a-pc-windows-msvc=C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\VC\Tools\MSVC\14.11.25503\bin\HostX64\arm\CL.exe
set CFLAGS_thumbv7a-pc-windows-msvc=/D_ARM_WINAPI_PARTITION_DESKTOP_SDK_AVAILABLE=1 /nologo
c:\python27\python.exe x.py build --host x86_64-pc-windows-msvc --build x86_64-pc-windows-msvc --target thumbv7a-pc-windows-msvc
```
It will build the stage 2 compiler, but fail building stage 2 test. To build an executable targeting windows/arm,
1. Copy `build\x86_64-pc-windows-msvc\stage0\bin\cargo.exe` to `build\x86_64-pc-windows-msvc\stage2\bin`
2. Open a command prompt and run
```
"C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\VC\Auxiliary\Build\vcvars64.bat"
set PATH=build\x86_64-pc-windows-msvc\stage2\bin;%PATH%
cargo new hello
cd hello
cargo build --target thumbv7a-pc-windows-msvc –release
```
Copy target\thumbv7a-pc-windows-msvc\release\hello.exe to your platform and run.
There are a number of open issues that I'm hoping to get help with:
- Error when compiling the `test` crate: `error: cannot link together two panic runtimes: panic_abort and panic_unwind`
- Warnings when building the compiler_builtins crate: `warning: cl : Command line warning D9002 : ignoring unknown option '-fvisibility=hidden'`. It looks like the build system is passing GCC-style flags to MSVC.
- How to specify the LIBPATH entries for ARM. Right now they are hardcoded as absolute paths in the target spec.
This pull request depends on
- alexcrichton/xz2-rs#35 - update vcxproj to Visual Studio 2017
- rust-lang-nursery/compiler-builtins#256 - fix compile errors when building for windows/arm
- [Bug 38620 - ARM: Incorrect COFF relocation type for thumb bl instruction](https://bugs.llvm.org/show_bug.cgi?id=38620)
This PR updates #52659
This requires the following changes.
- It moves parts of bitslice.rs into bitvec.rs: `bitwise()`,
`BitwiseOperator`, `bits_to_string()`.
- It changes `IdxSet` to just be a wrapper around `BitArray`.
- It changes `BitArray` and `BitVec` to use `usize` words instead of
`u128` words. (`BitSlice` and `IdxSet` already use `usize`.) Local
profiling showed `usize` was better.
- It moves some operations from `IdxSet` into `BitArray`:
`new_filled()`, `clear()`, `set_up_to()`, `trim_to()` (renamed
`clear_above()`), `words()` and `words_mut()`, `encode()` and
`decode(). The `IdxSet` operations now just call the `BitArray`
operations.
- It replaces `BitArray`'s iterator implementation with `IdxSet`'s,
because the latter is more concise. It also removes the buggy
`size_hint` function from `BitArray`'s iterator, which counted the
number of *words* rather than the number of *bits*. `IdxSet`'s
iterator is now just a thin wrapper around `BitArray`'s iterator.
- It moves some unit tests from `indexed_set.rs` to `bitvec.rs`.
