Like we have `add`/`sub` which are the `usize` version of `offset`, this adds the `usize` equivalent of `offset_from`. Like how `.add(d)` replaced a whole bunch of `.offset(d as isize)`, you can see from the changes here that it's fairly common that code actually knows the order between the pointers and *wants* a `usize`, not an `isize`.
As a bonus, this can do `sub nuw`+`udiv exact`, rather than `sub`+`sdiv exact`, which can be optimized slightly better because it doesn't have to worry about negatives. That's why the slice iterators weren't using `offset_from`, though I haven't updated that code in this PR because slices are so perf-critical that I'll do it as its own change.
This is an intrinsic, like `offset_from`, so that it can eventually be allowed in CTFE. It also allows checking the extra safety condition -- see the test confirming that CTFE catches it if you pass the pointers in the wrong order.
Like we have `add`/`sub` which are the `usize` version of `offset`, this adds the `usize` equivalent of `offset_from`. Like how `.add(d)` replaced a whole bunch of `.offset(d as isize)`, you can see from the changes here that it's fairly common that code actually knows the order between the pointers and *wants* a `usize`, not an `isize`.
As a bonus, this can do `sub nuw`+`udiv exact`, rather than `sub`+`sdiv exact`, which can be optimized slightly better because it doesn't have to worry about negatives. That's why the slice iterators weren't using `offset_from`, though I haven't updated that code in this PR because slices are so perf-critical that I'll do it as its own change.
This is an intrinsic, like `offset_from`, so that it can eventually be allowed in CTFE. It also allows checking the extra safety condition -- see the test confirming that CTFE catches it if you pass the pointers in the wrong order.
Implement a lint to warn about unused macro rules
This implements a new lint to warn about unused macro rules (arms/matchers), similar to the `unused_macros` lint added by #41907 that warns about entire macros.
```rust
macro_rules! unused_empty {
(hello) => { println!("Hello, world!") };
() => { println!("empty") }; //~ ERROR: 1st rule of macro `unused_empty` is never used
}
fn main() {
unused_empty!(hello);
}
```
Builds upon #96149 and #96156.
Fixes#73576
Gracefully fail to resolve associated items instead of `delay_span_bug`.
`codegen_fulfill_obligation` is used during instance resolution for trait items.
In case of insufficient normalization issues during MIR inlining, it caused ICEs.
It's better to gracefully refuse to resolve the associated item, and let the caller decide what to do with this.
Split from https://github.com/rust-lang/rust/pull/91743Closes#69121Closes#73021Closes#88599Closes#93008Closes#93248Closes#94680Closes#96170
r? `@oli-obk`
tighten sanity checks around Scalar and ScalarPair
While investigating https://github.com/rust-lang/rust/issues/96185 I noticed codegen has tighter sanity checks here than Miri does, so I added some more assertions. Strangely, some of them fail, so I also needed to add a HACK... that is probably worth looking into.
This does not fix that issue, but it changes the ICE messages, making it quite clear that we have a scalar whose size is not the same as that of the surrounding layout.
r? `@oli-obk`
PR #94586 added support for using
`rustc_nonnull_optimization_guaranteed` on values where the "null" value
is the all-ones bitpattern.
Now that #94586 has made it to the stage0 compiler, add
`rustc_nonnull_optimization_guaranteed` to `OwnedFd`, `BorrowedFd`,
`OwnedSocket`, and `BorrowedSocket`, since these types all exclude
all-ones bitpatterns.
This allows `Option<OwnedFd>`, `Option<BorrowedFd>`, `Option<OwnedSocket>`,
and `Option<BorrowedSocket>` to be used in FFI declarations, as described
in the [I/O safety RFC].
[I/O safety RFC]: https://github.com/rust-lang/rfcs/blob/master/text/3128-io-safety.md#ownedfd-and-borrowedfdfd-1
logging: add env var to control verbose scope entry/exit logging
~~This got removed in https://github.com/rust-lang/rust/pull/75143, and I find this makes long traces a lot harder to read, so I propose we add this back.~~
Example trace:
```
│ │ ├─0ms INFO rustc_const_eval::interpret::step return
│ │ ├─0ms INFO rustc_const_eval::interpret::eval_context popping stack frame (returning from function)
│ │┌┘rustc_const_eval::interpret::eval_context::frame std::ptr::mut_ptr::<impl *mut u8>::guaranteed_eq
│ ├┘rustc_const_eval::interpret::eval_context::frame std::ptr::mut_ptr::<impl *mut u8>::is_null
│ ├─1ms INFO rustc_const_eval::interpret::step // executing bb2
│ ├─1ms INFO rustc_const_eval::interpret::step StorageDead(_4)
│ ├─1ms INFO rustc_const_eval::interpret::step StorageDead(_2)
│ ├─1ms INFO rustc_const_eval::interpret::step return
│ ├─1ms INFO rustc_const_eval::interpret::eval_context popping stack frame (returning from function)
│┌┘rustc_const_eval::interpret::eval_context::frame std::ptr::mut_ptr::<impl *mut u8>::is_null
├┘rustc_const_eval::interpret::eval_context::frame std::sys_common::thread_local_dtor::register_dtor_fallback::run_dtors
├─178ms INFO rustc_const_eval::interpret::step // executing bb2
├─178ms INFO rustc_const_eval::interpret::step StorageDead(_5)
```
r? `@oli-obk`
Fix inaccurate function name in `rustc_const_eval` docs
Looks to me like this fixes#85513. I had trouble making a intra-docs link to `eval_place_to_op` work, though...
ast: Introduce some traits to get AST node properties generically
And use them to avoid constructing some artificial `Nonterminal` tokens during expansion
r? `@nnethercote` `@Aaron1011`
Update books
## nomicon
9 commits in c7d8467ca9158da58ef295ae65dbf00a308752d9..10d40c59a581c66d8ecd29ad18d410bf97ed524d
2022-04-06 14:26:54 +0900 to 2022-05-07 10:45:07 +0900
- Introducing init/uninit before its use (rust-lang/nomicon#355)
- Change will to would to discuss what don't occur (rust-lang/nomicon#361)
- State that pop for length 1 is an example (rust-lang/nomicon#360)
- Correct a sentence that didn't seem to be proper (rust-lang/nomicon#358)
- Indicate that C reference are C reference (rust-lang/nomicon#357)
- Introduce and avoid dropck (rust-lang/nomicon#353)
- Rephrase improperly reduced borrows introduction (rust-lang/nomicon#352)
- Two lifetime clarification (rust-lang/nomicon#350)
- "UB" vs "Undefined Behavior" (rust-lang/nomicon#349)
## reference
9 commits in b5f6c2362baf932db9440fbfcb509b309237ee85..8e36971959ff238b5aa2575fbc7a2e09e1313e82
2022-04-10 19:19:51 -0700 to 2022-05-09 17:20:59 -0700
- Stop saying that const functions cannot use 'extern' (rust-lang/reference#1207)
- Moved the option variant imports (rust-lang/reference#1208)
- #[must_use] on traits also affects trait objects (rust-lang/reference#1203)
- Don't use PathPattern in RangePattern bounds (rust-lang/reference#1204)
- Inline assembly: Add kreg0 register class (rust-lang/reference#1205)
- Fix crate_type attribute examples (rust-lang/reference#1201)
- Say that that the default function return type is the unit type (rust-lang/reference#1199)
- Clarify guarantees provided by repr(packed) (rust-lang/reference#1163)
- Document the Termination trait for main() and test functions (rust-lang/reference#1194)
## book
43 commits in de0dbffc5812fd885700874e8d258dd334733ac4..d9415b7cbfcb4b24062683f429bd0ff535396362
2022-04-18 19:29:45 -0400 to 2022-05-09 09:10:44 -0400
- Update ch09-02-recoverable-errors-with-result.md
- Added missing be 2
- Added missing be
- Move hardcoded string into status_line to be consistent
- Fix trailing space
- Propagate tech review edits back to src
- Change "semantics" to "mechanics"; when referring to compiler behavior, rather than syntax.
- Propagate some edits to ch4 snapshot
- Suggestions from tech review
- Propagate edits to src
- Propagate edits back to nostarch version
- Clarify sentences about lock types. Fixesrust-lang/book#2937.
- Edits to edits to chapter 16
- Edits from nostarch for chapter 16
- Propagate nostarch edits back to src
- Add words to dictionary
- Propagating edits back to the nostarch snapshot
- Small wording change. Fixesrust-lang/book#3112.
- Clarify the kind of manual cleanup meant here
- Edits to edits to chapter 15
- Edits from nostarch
- Add missing word
- Improve sentence structure
- fix unidiomatic new functions in chapter 15
- Propagate nostarch ch14 to src
- Update a link and the -p publishing instructions
- Actually, I don't think we need to show the command output here
- Edits to edits to chapter 14
- Update manual regeneration instructions
- Reflect the addition of the -p flag in Cargo 1.56 in chapter 14
- Change polarity and names of variables in env var section
- Propagate nostarch edits back to ch 12
- Change environment variable and field name to perhaps be less confusing
- Responses to nostarch edits
- Merge remote-tracking branch 'origin/ch13'
- Fixrust-lang/book#3002 use noplayground with common.rs
- Propagate ch3 edits to src
- Updating chapter 3 to use new println style
- Specify loop label format. Fixesrust-lang/book#3105.
- Clarify function definition must be in an accessible scope. Fixesrust-lang/book#3003
- Addressing tech review comments, propagating other changes
- Comments from tech review
- Chapter 3, section 2 - Add explicit type annotation to example of scalar type char.
## rust-by-example
6 commits in 44a80e8d8bfc5881c9bd69a2cb3a570776ee4181..e9f93cfcf410bc092c9107b8a41a82f144c761f2
2022-04-19 07:46:28 -0300 to 2022-05-08 18:24:06 -0300
- Add empty slice example (rust-lang/rust-by-example#1538)
- Enhancement/print (rust-lang/rust-by-example#1536)
- Update cast.md (rust-lang/rust-by-example#1521)
- Update iter_any.md (rust-lang/rust-by-example#1522)
- Update tuples.md (rust-lang/rust-by-example#1524)
- fix indent in fs.md (rust-lang/rust-by-example#1535)
## rustc-dev-guide
8 commits in 043e60f4f191651e9f8bf52fa32df14defbb23d9..0c02acdb6f48f03907a02ea8e537c3272b4fde9f
2022-04-20 18:57:49 +0900 to 2022-05-10 09:45:31 -0300
- Update overview.md (rust-lang/rustc-dev-guide#1351)
- Update date references on parallel-rustc (rust-lang/rustc-dev-guide#1348)
- mention `WithOptConstParam` (rust-lang/rustc-dev-guide#1346)
- Fix format (rust-lang/rustc-dev-guide#1349)
- correct type of SubstsRef (rust-lang/rustc-dev-guide#1347)
- Document ErrorGuaranteed (rust-lang/rustc-dev-guide#1316)
- Edit "What the compiler does to your code" (rust-lang/rustc-dev-guide#1306)
- Update some date refs
Clarify that when `BorrowedHandle`, `OwnedHandle`, or `HandleOrNull`
hold the value `-1`, it always means the current process handle, and not
`INVALID_HANDLE_VALUE`.
Use lifetimes on type-alias-impl-trait used in function signatures to infer output type lifetimes
fixes https://github.com/rust-lang/rust/issues/96564
TLDR:
```rust
fn execute(ty: Ty<'_>) -> &str { todo!() }
```
(`Ty` being a type alias impl trait) used to produce the following error before this PR
```
error[E0581]: return type references an anonymous lifetime, which is not constrained by the fn input types
--> src/lib.rs:4:27
|
4 | fn execute(ty: Ty<'_>) -> &str { todo!() }
| ^^^^
|
= note: lifetimes appearing in an associated type are not considered constrained
```
Remove hacks in `make_token_stream`.
`make_tokenstream` has three commented hacks, and a comment at the top
referring to #67062. These hacks have no observable effect, at least as judged
by running the test suite. The hacks were added in #82608, with an explanation
[here](https://github.com/rust-lang/rust/pull/82608#issuecomment-812877329). It
appears that one of the following is true: (a) they never did anything useful,
(b) they do something useful but we have no test coverage for them, or (c)
something has changed in the meantime that means they are no longer necessary.
This commit removes the hacks and the comments, in the hope that (b) is not
true.
r? `@Aaron1011`
