New const traits syntax
This PR only affects the AST and doesn't actually change anything semantically.
All occurrences of `~const` outside of libcore have been replaced by `[const]`. Within libcore we have to wait for rustfmt to be bumped in the bootstrap compiler. This will happen "automatically" (when rustfmt is run) during the bootstrap bump, as rustfmt converts `~const` into `[const]`. After this we can remove the `~const` support from the parser
Caveat discovered during impl: there is no legacy bare trait object recovery for `[const] Trait` as that snippet in type position goes down the slice /array parsing code and will error
r? ``@fee1-dead``
cc ``@nikomatsakis`` ``@traviscross`` ``@compiler-errors``
This centralizes the placeholder type error reporting in one location, but it also exposes the granularity at which we convert things from hir to ty more. E.g. previously infer types in where bounds were errored together with the function signature, but now they are independent.
Add note to `find_const_ty_from_env`
Add a note to `find_const_ty_from_env` to explain why it has an `unwrap` which "often" causes ICEs.
Also, uplift it into the new trait solver. This avoids needing to go through the interner to call this method which is otherwise an inherent method in the compiler. I can remove this part if desired.
r? `@boxyuwu`
make `tidy-alphabetical` use a natural sort
The idea here is that these lines should be correctly sorted, even though a naive string comparison would say they are not:
```
foo2
foo10
```
This is the ["natural sort order"](https://en.wikipedia.org/wiki/Natural_sort_order).
There is more discussion in [#t-compiler/help > tidy natural sort](https://rust-lang.zulipchat.com/#narrow/channel/182449-t-compiler.2Fhelp/topic/tidy.20natural.20sort/with/519111079)
Unfortunately, no standard sorting tools are smart enough to to this automatically (casting some doubt on whether we should make this change). Here are some sort outputs:
```
> cat foo.txt | sort
foo
foo1
foo10
foo2
mp
mp1e2
np",
np1e2",
> cat foo.txt | sort -n
foo
foo1
foo10
foo2
mp
mp1e2
np",
np1e2",
> cat foo.txt | sort -V
foo
foo1
foo2
foo10
mp
mp1e2
np1e2",
np",
```
Disappointingly, "numeric" sort does not actually have the behavior we want. It only sorts by numeric value if the line starts with a number. The "version" sort looks promising, but does something very unintuitive if you look at the final 4 values. None of the other options seem to have the desired behavior in all cases:
```
-b, --ignore-leading-blanks ignore leading blanks
-d, --dictionary-order consider only blanks and alphanumeric characters
-f, --ignore-case fold lower case to upper case characters
-g, --general-numeric-sort compare according to general numerical value
-i, --ignore-nonprinting consider only printable characters
-M, --month-sort compare (unknown) < 'JAN' < ... < 'DEC'
-h, --human-numeric-sort compare human readable numbers (e.g., 2K 1G)
-n, --numeric-sort compare according to string numerical value
-R, --random-sort shuffle, but group identical keys. See shuf(1)
--random-source=FILE get random bytes from FILE
-r, --reverse reverse the result of comparisons
--sort=WORD sort according to WORD:
general-numeric -g, human-numeric -h, month -M,
numeric -n, random -R, version -V
-V, --version-sort natural sort of (version) numbers within text
```
r? ```@Noratrieb``` (it sounded like you know this code?)
Withdraw the claim `extern "C-cmse-nonsecure-*"` always matches `extern "C"`
We currently claim that `extern "C-cmse-nonsecure-*"` ABIs will always match `extern "C"`, but that seems... **optimistic** when one considers that `extern "C"` is ambiguous enough to be redefined in ways we may not want the Cortex M Security Extensions ABIs to mirror. If some configuration, feature, or other platform quirk that applied to Arm CPUs with CMSE would modify the `extern "C"` ABI, it does not seem like we should guarantee that also applies to the `extern "cmse-nonsecure-*"` ABIs. Anything involving target modifiers that might affect register availability or usage could make us liars if, for instance, clang decides those apply to normal C functions but not ones with the CMSE attributes, but we still want to have interop with the C compiler.
We simply do not control enough of the factors involved to both force these ABIs to match and still provide useful interop, so we shouldn't implicitly promise they do. We should leave this judgement call to the decisions of platform experts who can afford to keep up with the latest news from Cambridge, instead of enshrining today's hopeful guess forever in Rust's permitted ABIs.
It's a bit weird anyways.
- The attributes are `__attribute__((cmse_nonsecure_call))` and `__attribute__((cmse_nonsecure_entry))`, so the obvious choice is `extern "cmse-nonsecure-call"` and `extern "cmse-nonsecure-entry"`.
- We do not prefix any other ABI that reflects (or even *is*) a C ABI with "C-", with the exception of the Rust-defined `extern "C-unwind`", e.g. we do not have `extern "C-aapcs"` or `extern "C-sysv64"`.
Tracking issues:
- rust-lang/rust#75835
- rust-lang/rust#81391
Taint body on invalid call ABI
Fixes https://github.com/rust-lang/rust/issues/142969
I'm not certain if there are any other paths that should be tainted, but they would operate similarly. Perhaps pointer coercion.
Introduces `extern "rust-invalid"` for testing purposes.
r? ```@workingjubilee``` or ```@oli-obk``` (or anyone)
Add `#[loop_match]` for improved DFA codegen
tracking issue: https://github.com/rust-lang/rust/issues/132306
project goal: https://github.com/rust-lang/rust-project-goals/issues/258
This PR adds the `#[loop_match]` attribute, which aims to improve code generation for state machines. For some (very exciting) benchmarks, see https://github.com/rust-lang/rust-project-goals/issues/258#issuecomment-2732965199
Currently, a very restricted syntax pattern is accepted. We'd like to get feedback and merge this now before we go too far in a direction that others have concerns with.
## current state
We accept code that looks like this
```rust
#[loop_match]
loop {
state = 'blk: {
match state {
State::A => {
#[const_continue]
break 'blk State::B
}
State::B => { /* ... */ }
/* ... */
}
}
}
```
- a loop should have the same semantics with and without `#[loop_match]`: normal `continue` and `break` continue to work
- `#[const_continue]` is only allowed in loops annotated with `#[loop_match]`
- the loop body needs to have this particular shape (a single assignment to the match scrutinee, with the body a labelled block containing just a match)
## future work
- perform const evaluation on the `break` value
- support more state/scrutinee types
## maybe future work
- allow `continue 'label value` syntax, which `#[const_continue]` could then use.
- allow the match to be on an arbitrary expression (e.g. `State::Initial`)
- attempt to also optimize `break`/`continue` expressions that are not marked with `#[const_continue]`
r? ``@traviscross``
rustc_std_internal_symbol is meant to call functions from crates where
there is no direct dependency on said crate. As they either have to be
added to symbols.o or rustc has to introduce an implicit dependency on
them to avoid linker errors. The latter is done for some things like the
panic runtime, but adding these symbols to symbols.o allows removing
those implicit dependencies.
Merge unboxed trait object error suggestion into regular dyn incompat error
Another hir-walker removed from the well-formed queries. This error was always a duplicate of another, but it was able to provide more information because it could invoke `is_dyn_compatible` without worrying about cycle errors. That's also the reason we can't put the error directly into hir_ty_lowering when lowering a `dyn Trait` within an associated item signature. So instead I packed it into the error handling of wf obligation checking.
Reduce uses of `hir_crate`.
I tried rebasing my old incremental-HIR branch. This is a by-product, which is required if we want to get rid of `hir_crate` entirely.
The second commit is a drive-by cleanup. It can be pulled into its own PR.
r? ````@oli-obk````
use `#[align]` attribute for `fn_align`
Tracking issue: https://github.com/rust-lang/rust/issues/82232https://github.com/rust-lang/rfcs/pull/3806 decides to add the `#[align]` attribute for alignment of various items. Right now it's used for functions with `fn_align`, in the future it will get more uses (statics, struct fields, etc.)
(the RFC finishes FCP today)
r? `@ghost`
Don't build `ParamEnv` and do trait solving in `ItemCtxt`s when lowering IATs
Fixesrust-lang/rust#108491Fixesrust-lang/rust#125879
This was due to updating inhabited predicate stuff which I had to do to make constructing ADTs with IATs in fields not ICE
Fixesrust-lang/rust#136678 (but no test added, I don't rly care about weird IAT edge cases under GCE)
Fixesrust-lang/rust#138131
Avoids doing "fully correct" candidate selection for IATs during hir ty lowering when in item signatures as it almost always leads to a query cycle from trying to build a `ParamEnv`. I replaced it with a use `DeepRejectCtxt` which should be able to handle this kind of conservative "could these types unify" while in a context where we don't want to do type equality.
This is a relatively simple scheme and should be forwards compatible with doing something more complex/powerful.
I'm not really sure how this interacts with rust-lang/rust#126651, though I'm also not really sure its super important to support projecting IATs from IAT self types given we don't even support `T::Assoc::Other` for trait-associated types so didn't give much thought to how this might fit in with that.
r? `@compiler-errors`
cc `@fmease`
Rollup of 6 pull requests
Successful merges:
- rust-lang/rust#135656 (Add `-Z hint-mostly-unused` to tell rustc that most of a crate will go unused)
- rust-lang/rust#138237 (Get rid of `EscapeDebugInner`.)
- rust-lang/rust#141614 (lint direct use of rustc_type_ir )
- rust-lang/rust#142123 (Implement initial support for timing sections (`--json=timings`))
- rust-lang/rust#142377 (Try unremapping compiler sources)
- rust-lang/rust#142674 (remove duplicate crash test)
r? `@ghost`
`@rustbot` modify labels: rollup
This commit adds a lint to prevent the use of rustc_type_ir in random
compiler crates, except for type system internals traits, which are
explicitly allowed. Moreover, this fixes diagnostic_items() to include
the CRATE_OWNER_ID, otherwise rustc_diagnostic_item attribute is ignored
on the crate root.
Sized Hierarchy: Part I
This patch implements the non-const parts of rust-lang/rfcs#3729. It introduces two new traits to the standard library, `MetaSized` and `PointeeSized`. See the RFC for the rationale behind these traits and to discuss whether this change makes sense in the abstract.
These traits are unstable (as is their constness), so users cannot refer to them without opting-in to `feature(sized_hierarchy)`. These traits are not behind `cfg`s as this would make implementation unfeasible, there would simply be too many `cfg`s required to add the necessary bounds everywhere. So, like `Sized`, these traits are automatically implemented by the compiler.
RFC 3729 describes changes which are necessary to preserve backwards compatibility given the introduction of these traits, which are implemented and as follows:
- `?Sized` is rewritten as `MetaSized`
- `MetaSized` is added as a default supertrait for all traits w/out an explicit sizedness supertrait already.
There are no edition migrations implemented in this, as these are primarily required for the constness parts of the RFC and prior to stabilisation of this (and so will come in follow-up PRs alongside the const parts). All diagnostic output should remain the same (showing `?Sized` even if the compiler sees `MetaSized`) unless the `sized_hierarchy` feature is enabled.
Due to the use of unstable extern types in the standard library and rustc, some bounds in both projects have had to be relaxed already - this is unfortunate but unavoidable so that these extern types can continue to be used where they were before. Performing these relaxations in the standard library and rustc are desirable longer-term anyway, but some bounds are not as relaxed as they ideally would be due to the inability to relax `Deref::Target` (this will be investigated separately).
It is hoped that this is implemented such that it could be merged and these traits could exist "under the hood" without that being observable to the user (other than in any performance impact this has on the compiler, etc). Some details might leak through due to the standard library relaxations, but this has not been observed in test output.
**Notes:**
- Any commits starting with "upstream:" can be ignored, as these correspond to other upstream PRs that this is based on which have yet to be merged.
- This best reviewed commit-by-commit. I've attempted to make the implementation easy to follow and keep similar changes and test output updates together.
- Each commit has a short description describing its purpose.
- This patch is large but it's primarily in the test suite.
- I've worked on the performance of this patch and a few optimisations are implemented so that the performance impact is neutral-to-minor.
- `PointeeSized` is a different name from the RFC just to make it more obvious that it is different from `std::ptr::Pointee` but all the names are yet to be bikeshed anyway.
- `@nikomatsakis` has confirmed [that this can proceed as an experiment from the t-lang side](https://rust-lang.zulipchat.com/#narrow/channel/435869-project-goals/topic/SVE.20and.20SME.20on.20AArch64.20.28goals.23270.29/near/506196491)
- FCP in https://github.com/rust-lang/rust/pull/137944#issuecomment-2912207485Fixesrust-lang/rust#79409.
r? `@ghost` (I'll discuss this with relevant teams to find a reviewer)
Opting-out of `Sized` with `?Sized` is now equivalent to adding a
`MetaSized` bound, and adding a `MetaSized` or `PointeeSized` bound
is equivalent to removing the default `Sized` bound - this commit
implements this change in `rustc_hir_analysis::hir_ty_lowering`.
`MetaSized` is also added as a supertrait of all traits, as this is
necessary to preserve backwards compatibility.
Unfortunately, non-global where clauses being preferred over item bounds
(where `PointeeSized` bounds would be proven) - which can result in
errors when a `PointeeSized` supertrait/bound/predicate is added to some
items. Rather than `PointeeSized` being a bound on everything, it can
be the absence of a bound on everything, as `?Sized` was.
As core uses an extern type (`ptr::VTable`), the default `?Sized` to
`MetaSized` migration isn't sufficient, and some code that previously
accepted `VTable` needs relaxed to continue to accept extern types.
Similarly, the compiler uses many extern types in `rustc_codegen_llvm`
and in the `rustc_middle::ty::List` implementation (`OpaqueListContents`)
some bounds must be relaxed to continue to accept these types.
Unfortunately, due to the current inability to relax `Deref::Target`,
some of the bounds in the standard library are forced to be stricter than
they ideally would be.
