- Accessing fields of a union require unsafe block
- As part of 2229 we don't allow precision where we need an unsafe block
to capture.
Fixes: #87378
r? @nikomatsakis
In the event a pattern starts with a leading pipe
the pattern span will contain, and begin with, the pipe.
This updates the process to see if a match arm contains
a leading pipe by leveraging this recent(ish) change to
the patterns in the AST, and avoids an indexing bug that
occurs when a pattern starts with a non-ascii char in the
old implementation.
* Updating outdated links
Updating the links to the docs and source code for `ast.rs`. Seems like it was moved to a new crate at some point.
* Updating more outdated links
This time, the links to the `fmt-rfcs` repository, which is now owned by
`rust-dev-tools` (although GitHub was redirecting anyway).
* Update Contributing.md
Co-authored-by: Caleb Cartwright <calebcartwright@users.noreply.github.com>
Co-authored-by: Caleb Cartwright <calebcartwright@users.noreply.github.com>
On stable, running with `--help|-h` shows information about `file-lines`
which is a nightly-only option. This commit removes all mention of
`file-lines` from the help message on stable.
There is room for improvement here; perhaps a new struct called, e.g.,
`StableOptions` could be added to complement the existing
`GetOptsOptions` struct. `StableOptions` could have a field for each
field in `GetOptsOptions`, with each field's value being a `bool` that
specifies whether or not the option exists on stable. Or is this adding
too much complexity?
This was added to Configurations.md in #4618, but the option wasn't
actually made available. This should let people who are using Rust 2021
on nightly rustc run `cargo fmt` again.
rename const checking visitor module to check_consts::check
This avoids naming ambiguities with "const validation" which is in `interpret/validity.rs` and checks *values*.
r? `@oli-obk`
`structhead` is used for `render_struct` so that the logic for rendering
structs can be shared between struct variants and struct items. However,
`render_union` is not used anywhere except for rendering union items, so
its `structhead` parameter is unnecessary.
Add support for custom allocator in `VecDeque`
This follows the [roadmap](https://github.com/rust-lang/wg-allocators/issues/7) of the allocator WG to add custom allocators to collections.
`@rustbot` modify labels: +A-allocators +T-libs
MIR opt: separate constant predecessors of a switch
For each block S ending with a switch, this pass copies S for each of S's predecessors that seem to assign the value being switched over as a const. This is done using a somewhat simple heuristic to determine what seems to be a const transitively.
More precisely, this is what the pass does:
- find a block that ends in a switch
- track if there is an unique place set before the current basic block that determines the result of the switch (this is the part that resolves switching over discriminants)
- if there is, iterate over the parents that have a reasonable terminator and find if the found determining place is likely to be (transitively) set from a const within that parent block
- if so, add the corresponding edge to a vector of edges to duplicate
- once this is done, iterate over the found edges: copy the target block and replace the reference to the target block in the origin block with the new block
This pass is not optimal and could probably duplicate in more cases, but the intention was mostly to address cases like in #85133 or #85365, to avoid creating new enums that get destroyed immediately afterwards (notably making the new try v2 `?` desugar zero-cost).
A benefit of this pass working the way it does is that it is easy to ensure its correctness: the worst that can happen is for it to needlessly copy a basic block, which is likely to be destroyed by cleanup passes afterwards. The complex parts where aliasing matters are only heuristics and the hard work is left to further passes like ConstProp.
# LLVM blocker
Unfortunately, I believe it would be unwise to enable this optimization by default for now. Indeed, currently switch lowering passes like SimplifyCFG in LLVM lose the information on the set of possible variant values, which means it tends to actually generate worse code with this optimization enabled. A fix would have to be done in LLVM itself. This is something I also want to look into. I have opened [a bug report at the LLVM bug tracker](https://bugs.llvm.org/show_bug.cgi?id=50455).
When this is done, I hope we can enable this pass by default. It should be fairly fast and I think it is beneficial in many cases. Notably, it should be a sound alternative to simplify-arm-identity. By the way, ConstProp only seems to pick up the optimization in functions that are not generic. This is however most likely an issue in ConstProp that I will look into afterwards.
This is my first contribution to rustc, and I would like to thank everyone on the Zulip mir-opt chat for the help and support, and especially `@scottmcm` for the guidance.
This commit closes#7389. As stated in the issue, `cargo clippy --help`
provides explanation for some flags and states that the rest are same
as in `cargo check --help`, even though some clippy specific flags
exist.
This commit extends the `cargo clippy --help` with two additional flags,
- `cargo clippy --fix`
- `cargo clippy --no-deps`
If there are more flags which are not present in `cargo check --help`
please bring these to my attention, I will include these aswell.
For now, I noticed only the two flags mentioned above.
Store all HIR owners in the same container
This replaces the previous storage in a BTreeMap for each of Item/ImplItem/TraitItem/ForeignItem.
This should allow for a more compact storage.
Based on https://github.com/rust-lang/rust/pull/83114
Store all HIR owners in the same container
This replaces the previous storage in a BTreeMap for each of Item/ImplItem/TraitItem/ForeignItem.
This should allow for a more compact storage.
Based on https://github.com/rust-lang/rust/pull/83114
