Support HIR wf checking for function signatures
During function type-checking, we normalize any associated types in
the function signature (argument types + return type), and then
create WF obligations for each of the normalized types. The HIR wf code
does not currently support this case, so any errors that we get have
imprecise spans.
This commit extends `ObligationCauseCode::WellFormed` to support
recording a function parameter, allowing us to get the corresponding
HIR type if an error occurs. Function typechecking is modified to
pass this information during signature normalization and WF checking.
The resulting code is fairly verbose, due to the fact that we can
no longer normalize the entire signature with a single function call.
As part of the refactoring, we now perform HIR-based WF checking
for several other 'typed items' (statics, consts, and inherent impls).
As a result, WF and projection errors in a function signature now
have a precise span, which points directly at the responsible type.
If a function signature is constructed via a macro, this will allow
the error message to point at the code 'most responsible' for the error
(e.g. a user-supplied macro argument).
Fix implicit Sized relaxation when attempting to relax other, unsupported trait
Fixes#87199.
Do note that this bug fix causes code like the `ref_arg::<[i32]>(&[5]);` line in the test case in combination with an affected function to no longer compile.
When pretty printing, name placeholders as bound regions
Split from #85499
When we see a placeholder that we are going to print, treat it as a bound var (and add it to a `for<...>`
Improve caching during trait evaluation
Previously, we would 'forget' that we had `'static` regions in some
place during trait evaluation. This lead to us producing
`EvaluatedToOkModuloRegions` when we could have produced
`EvaluatedToOk`, causing us to perform unnecessary work.
This PR preserves `'static` regions when we canonicalize a predicate for
`evaluate_obligation`, and when we 'freshen' a predicate during trait
evaluation. Thie ensures that evaluating a predicate containing
`'static` regions can produce `EvaluatedToOk` (assuming that we
don't end up introducing any region dependencies during evaluation).
Building off of this improved caching, we use
`predicate_must_hold_considering_regions` during fulfillment of
projection predicates to see if we can skip performing additional work.
We already do this for trait predicates, but doing this for projection
predicates lead to mixed performance results without the above caching
improvements.
Previously, we would 'forget' that we had `'static` regions in some
place during trait evaluation. This lead to us producing
`EvaluatedToOkModuloRegions` when we could have produced
`EvaluatedToOk`, causing us to perform unnecessary work.
This PR preserves `'static` regions when we canonicalize a predicate for
`evaluate_obligation`, and when we 'freshen' a predicate during trait
evaluation. Thie ensures that evaluating a predicate containing
`'static` regions can produce `EvaluatedToOk` (assuming that we
don't end up introducing any region dependencies during evaluation).
Building off of this improved caching, we use
`predicate_must_hold_considering_regions` during fulfillment of
projection predicates to see if we can skip performing additional work.
We already do this for trait predicates, but doing this for projection
predicates lead to mixed performance results without the above caching
improvements.
Rename force-warns to force-warn
The renames the `--force-warns` option to `--force-warn`. This mirrors other lint options like `--warn` and `--deny` which are in the singular.
r? `@nikomatsakis`
cc `@ehuss` - this option is being used by Cargo. How do we make sure the transition to using the new name is as smooth as possible?
docs: GlobalAlloc: completely replace example with one that works
Since this is an example, this could really do with some review from someone familiar with unsafe stuff!
I made the example no longer `no_run` since it works for me.
Fixes#81847
Get back the more precise suggestion spans of old regionck
I noticed that when you turn on nll, the structured suggestion replaces a snippet instead of appending a snippet. It seems clearer to the user to only highlight the newly added characters instead of the entire `impl Trait` (and old regionck already does it this way).
r? ``@estebank``
Add comments explaining the unix command-line argument support.
Following up on #87236, add comments to the unix command-line argument
support explaining that the code doesn't mutate the system-provided
argc/argv, and that this is why the code doesn't need a lock or special
memory ordering.
r? ```@RalfJung```
avoid temporary vectors/reuse iterators
Avoid collecting an interator just to re-iterate immediately.
Rather reuse the previous iterator. (clippy::needless_collect)
add `Stdin::lines`, `Stdin::split` forwarder methods
Add forwarder methods `Stdin::lines` and `Stdin::split`, which consume
and lock a `Stdin` handle, and forward on to the corresponding `BufRead`
methods. This should make it easier for beginners to use those iterator
constructors without explicitly dealing with locks or lifetimes.
Replaces #86412.
~~Based on #86846 to get the tracking issue number for the `stdio_locked` feature.~~ Rebased after merge, so it's only one commit now.
r? `@joshtriplett`
`@rustbot` label +A-io +C-enhancement +D-newcomer-roadblock +T-libs-api
Update all submodules that rustbuild doesn't depend on lazily
This only updates the submodules the first time they're needed, instead
of unconditionally the first time you run x.py.
Ideally, this would move *all* submodules to rustbuild and not exclude some tools and
backtrace. Unfortunately, cargo requires all `Cargo.toml` files in the
whole workspace to be present to build any crate.
On my machine, this takes the time for an initial submodule clone (for
`x.py --help`) from 55.70 to 15.87 seconds.
Helps with https://github.com/rust-lang/rust/issues/76653. Builds on https://github.com/rust-lang/rust/pull/86015 and should not be merged before (only the last commit is relevant).
This only updates the submodules the first time they're needed, instead
of unconditionally the first time you run x.py.
Ideally, this would move *all* submodules and not exclude some tools and
backtrace. Unfortunately, cargo requires all `Cargo.toml` files in the
whole workspace to be present to build any crate.
On my machine, this takes the time for an initial submodule clone (for
`x.py --help`) from 55.70 to 15.87 seconds.
This uses exactly the same logic as the LLVM update used, modulo some
minor cleanups:
- Use a local variable for `src.join(relative_path)`
- Remove unnecessary arrays for `book!` macro and make the macro simpler to use
- Add more comments
implement TrustedLen for Flatten/FlatMap if the U: IntoIterator == [T; N]
This only works if arrays are passed directly instead of array iterators
because we need to be sure that they have not been advanced before
Flatten does its size calculation.
resolves#87094
Update books
## reference
6 commits in ab60513a3a5a0591e237fddff5d027a982648392..82d75cf423e4a7824fb36e73ccb18519d6900610
2021-07-05 08:27:31 -0700 to 2021-07-15 06:49:08 -0700
- fix wording/punctuation in "Lifetime bounds" (rust-lang/reference#1062)
- mention implicit `Sized` bound in more places (rust-lang/reference#1053)
- (rust-lang/reference#1060)
- Remove inner attributes from non-block expressions. (rust-lang/reference#1051)
- Add note about the sign of the remainder (rust-lang/reference#1073)
- Clarify closure capture modes slightly (rust-lang/reference#1064)
## book
21 commits in a90f07f1e9a7fc75dc9105a6c6f16d5c13edceb0..eac55314210519238652f12b30fec9daea61f7fe
2021-07-05 14:43:12 -0400 to 2021-07-19 11:08:01 -0400
- (rust-lang/book#2791)
- Add Deref trait to overload the deref operator in appendix table
- Revise linker installation instructions. Fixesrust-lang/book#2151.
- Clarify number literal type suffixes. Fixesrust-lang/book#1979.
- Add a note that lifetimes are coming up but aren't required
- Zip creates an iterator, not a vector. Fixesrust-lang/book#2762.
- Add Thai translation to the appendix. Connects to rust-lang/book#2636
- Derive Copy and Clone for Point to match stdlib docs example; fixesrust-lang/book#2657
- Make the definition of Option match the stdlib's, fixesrust-lang/book#2634
- Explain double quote backslash; closesrust-lang/book#2597
- Don't use the term 'anonymous struct' to fixrust-lang/book#2584
- Reword a sentence to fixrust-lang/book#2525
- Add Hindi translation. Connects to rust-lang/book#2496
- Remove unsafe Ferris designations from code. Fixesrust-lang/book#2555
- Add Traditional Chinese translation. Connects to rust-lang/book#2470
- Remove some more references to the authors field
- Make Appendix E be a link
- fix line wrapping
- remove description about the authors field
- remove the authors field
- remove the authors field
## rust-by-example
6 commits in 028f93a61500fe8f746ee7cc6b204ea6c9f42935..1db6bb483cc87ad3b424d9aba764fe622960a1be
2021-07-06 06:28:53 -0300 to 2021-07-15 06:17:42 -0300
- Updated the file destructure_tuple.md (rust-lang/rust-by-example#1452)
- Fix nomenclature around methods (rust-lang/rust-by-example#1450)
- std_misc/path.md: update `Show` to `Display` (rust-lang/rust-by-example#1449)
- Fix up github action (rust-lang/rust-by-example#1451)
- Remove github pages
- Support GitHub Actions (rust-lang/rust-by-example#1330)
## rustc-dev-guide
2 commits in 60e282559104035985331645907c3d9f842312c5..93422c21baca585dc88357ec886a48f6ddc7d665
2021-07-05 11:21:03 -0400 to 2021-07-13 12:45:58 -0400
- Update for merge of CrateDisambiguator into StableCrateId
- Minor capitalization fix (rust-lang/rustc-dev-guide#1170)
## edition-guide
8 commits in 5d57b3832f8d308a9f478ce0a69799548f27ad4d..af696ce8ea526445590ae0ca66a8128d2a95a69a
2021-07-05 10:33:32 +0200 to 2021-07-20 11:38:03 -0400
- Add migration section for panic-macro-consistency (rust-lang/edition-guide#258)
- Update transitioning chapter. (rust-lang/edition-guide#255)
- Add details on migrating the Cargo feature resolver. (rust-lang/edition-guide#259)
- Improve panic macro consistency summary (rust-lang/edition-guide#256)
- Add migration details to or-patterns guide (rust-lang/edition-guide#252)
- Add migration section to into-iterator (rust-lang/edition-guide#253)
- Add Rust 2021 prelude migration details (rust-lang/edition-guide#251)
- Provide more information about disjoint capture in closures and migration instructions (rust-lang/edition-guide#246)
## embedded-book
1 commits in 506840eb73b0749336e1d5274e16d6393892ee82..09986cd352404eb4659db44613b27cac9aa652fc
2021-06-24 00:01:32 +0000 to 2021-07-18 19:26:46 +0000
- Stop referring to the alloc crate as unstable (rust-embedded/book#297)
Merge libterm into libtest
I think it's quite clear at this point that rust won't stablize the current libterm APIs to the outside world. And its only user is libtest. The compiler doesn't use this api at all. So I'm merging the crate into libtest as a module.
This also allows me to remove 15% of the libterm code, since these APIs are dead-code now.
During function type-checking, we normalize any associated types in
the function signature (argument types + return type), and then
create WF obligations for each of the normalized types. The HIR wf code
does not currently support this case, so any errors that we get have
imprecise spans.
This commit extends `ObligationCauseCode::WellFormed` to support
recording a function parameter, allowing us to get the corresponding
HIR type if an error occurs. Function typechecking is modified to
pass this information during signature normalization and WF checking.
The resulting code is fairly verbose, due to the fact that we can
no longer normalize the entire signature with a single function call.
As part of the refactoring, we now perform HIR-based WF checking
for several other 'typed items' (statics, consts, and inherent impls).
As a result, WF and projection errors in a function signature now
have a precise span, which points directly at the responsible type.
If a function signature is constructed via a macro, this will allow
the error message to point at the code 'most responsible' for the error
(e.g. a user-supplied macro argument).
Since this is an example, this could really do with some review from
someone familiar with unsafe stuff !
I made the example no longer `no_run` since it works for me.
Fixes#81847
Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>
Co-authored-by: Amanieu d'Antras <amanieu@gmail.com>
Better diagnostics with mismatched types due to implicit static lifetime
Fixes#78113
I think this is my first diagnostics PR...definitely happy to hear thoughts on the direction/implementation here.
I was originally just trying to solve the error above, where the lifetime on a GAT was causing a cryptic "mismatched types" error. But as I was writing this, I realized that this (unintentionally) also applied to a different case: `wf-in-foreign-fn-decls-issue-80468.rs`. I'm not sure if this diagnostic should get a new error code, or even reuse an existing one. And, there might be some ways to make this even more generalized. Also, the error is a bit more lengthy and verbose than probably needed. So thoughts there are welcome too.
This PR essentially ended up adding a new nice region error pass that triggers if a type doesn't match the self type of an impl which is selected because of a predicate because of an implicit static bound on that self type.
r? `@estebank`
