abi: unsized field in union - assert to delay bug
Fixes#113279.
> Unions cannot have unsized fields, and as such, layout computation for
unions asserts that each union field is sized (as this would normally
have halted compilation earlier).
>
> However, if a generator ends up with an unsized local - a circumstance
in which an error will always have been emitted earlier, for example, if
attempting to dereference a `&str` - then the generator transform will
produce a union with an unsized field.
>
> Since https://github.com/rust-lang/rust/pull/110107, later passes will be run, such as constant propagation,
and can attempt layout computation on the generator, which will result
in layout computation of `str` in the context of it being a field of a
union - and so the aforementioned assertion would cause an ICE.
>
> It didn't seem appropriate to try and detect this case in the MIR body
and skip this specific pass; tainting the MIR body or delaying a bug
from the generator transform (or elsewhere) wouldn't prevent this either
(as neither would prevent the later pass from running); and tainting when
the deref of `&str` is reported, if that's possible, would unnecessarily
prevent potential other errors from being reported later in compilation,
and is very tailored to this specific case of getting a unsized type in
a generator.
>
> Given that this circumstance can only happen when an error should have
already been reported, the correct fix appears to be just changing the
assert to a delayed bug. This will still assert if there is some
circumstance where this occurs and no error has been reported, but it
won't crash the compiler in this instance.
While debugging this, I noticed a translation ICE in a delayed bug, so I fixed that too:
> During borrowck, the `MultiSpan` from a buffered diagnostic is cloned and
used to emit a delayed bug indicating a diagnostic was buffered - when
the buffered diagnostic is translated, then the cloned `MultiSpan` may
contain labels which can only render with the diagnostic's arguments, but
the delayed bug being emitted won't have those arguments. Adds a function
which clones `MultiSpan` without also cloning the contained labels, and
use this function when creating the buffered diagnostic delayed bug.
Suggest `{Option,Result}::as_ref()` instead of `cloned()` in some cases
Fixes#114050
When we have an expr available that produces the type expectation, we can suggest appending `.as_ref()` to the span, instead of cloning the expr producing the mismatch
Add regression test for invalid "unused const" in method
The warning can be reproduced with 1.63 but not with 1.64.
$ rustc +1.63 tests/ui/lint/unused/const-local-var.rs
warning: constant `F` is never used
--> tests/ui/lint/unused/const-local-var.rs:14:9
|
14 | const F: i32 = 2;
| ^^^^^^^^^^^^^^^^^
|
= note: `#[warn(dead_code)]` on by default
$ rustc +1.64 tests/ui/lint/unused/const-local-var.rs
Add a regression test to prevent the problem from re-appearing.
Closes#69016
coverage: Obtain the `__llvm_covfun` section name outside a per-function loop
This section name is always constant for a given target, but obtaining it from LLVM requires a few intermediate allocations. There's no need to do so repeatedly from inside a per-function loop.
Unions cannot have unsized fields, and as such, layout computation for
unions asserts that each union field is sized (as this would normally
have halted compilation earlier).
However, if a generator ends up with an unsized local - a circumstance
in which an error will always have been emitted earlier, for example, if
attempting to dereference a `&str` - then the generator transform will
produce a union with an unsized field.
Since #110107, later passes will be run, such as constant propagation,
and can attempt layout computation on the generator, which will result
in layout computation of `str` in the context of it being a field of a
union - and so the aforementioned assertion would cause an ICE.
It didn't seem appropriate to try and detect this case in the MIR body
and skip this specific pass; tainting the MIR body or delaying a bug
from the generator transform (or elsewhere) wouldn't prevent this either
(as neither would prevent the later pass from running); and tainting when
the deref of `&str` is reported, if that's possible, would unnecessarily
prevent potential other errors from being reported later in compilation,
and is very tailored to this specific case of getting a unsized type in
a generator.
Given that this circumstance can only happen when an error should have
already been reported, the correct fix appears to be just changing the
assert to a delayed bug. This will still assert if there is some
circumstance where this occurs and no error has been reported, but it
won't crash the compiler in this instance.
Signed-off-by: David Wood <david@davidtw.co>
interpret: Unify projections for MPlaceTy, PlaceTy, OpTy
For ~forever, we didn't really have proper shared code for handling projections into those three types. This is mostly because `PlaceTy` projections require `&mut self`: they might have to `force_allocate` to be able to represent a project part-way into a local.
This PR finally fixes that, by enhancing `Place::Local` with an `offset` so that such an optimized place can point into a part of a place without having requiring an in-memory representation. If we later write to that place, we will still do `force_allocate` -- for now we don't have an optimized path in `write_immediate` that would avoid allocation for partial overwrites of immediately stored locals. But in `write_immediate` we have `&mut self` so at least this no longer pollutes all our type signatures.
(Ironically, I seem to distantly remember that many years ago, `Place::Local` *did* have an `offset`, and I removed it to simplify things. I guess I didn't realize why it was so useful... I am also not sure if this was actually used to achieve place projection on `&self` back then.)
The `offset` had type `Option<Size>`, where `None` represent "no projection was applied". This is needed because locals *can* be unsized (when they are arguments) but `Place::Local` cannot store metadata: if the offset is `None`, this refers to the entire local, so we can use the metadata of the local itself (which must be indirect); if a projection gets applied, since the local is indirect, it will turn into a `Place::Ptr`. (Note that even for indirect locals we can have `Place::Local`: when the local appears in MIR, we always start with `Place::Local`, and only check `frame.locals` later. We could eagerly normalize to `Place::Ptr` but I don't think that would actually simplify things much.)
Having done all that, we can finally properly abstract projections: we have a new `Projectable` trait that has the basic methods required for projecting, and then all projection methods are implemented for anything that implements that trait. We can even implement it for `ImmTy`! (Not that we need that, but it seems neat.) The visitor can be greatly simplified; it doesn't need its own trait any more but it can use the `Projectable` trait. We also don't need the separate `Mut` visitor any more; that was required only to reflect that projections on `PlaceTy` needed `&mut self`.
It is possible that there are some more `&mut self` that can now become `&self`... I guess we'll notice that over time.
r? `@oli-obk`
Reimplement C-str literals
This reverts #113334, cc `@fmease.`
While converting lexer tokens to ast Tokens in `rustc_parse`, we check the edition of the span of the token. If the edition < 2021, we split the token into two, one being the identifier and other being the str literal.
The warning can be reproduced with 1.63 but not with 1.64.
$ rustc +1.63 tests/ui/lint/unused/const-local-var.rs
warning: constant `F` is never used
--> tests/ui/lint/unused/const-local-var.rs:14:9
|
14 | const F: i32 = 2;
| ^^^^^^^^^^^^^^^^^
|
= note: `#[warn(dead_code)]` on by default
$ rustc +1.64 tests/ui/lint/unused/const-local-var.rs
Add a regression test to prevent the problem from re-appearing.
If a raw string was used in the `env!` invocation, then it should also
be shown in the diagnostic messages as a raw string.
Signed-off-by: David Wood <david@davidtw.co>
fix(resolve): skip panic when resolution is dummy
Fixes#113953
Skip the panic when the binding refers to a dummy node during the finalization.
r? `@petrochenkov`
Add `x86_64-unikraft-linux-musl` target
This introduces `x86_64-unikraft-linux-musl` as the first Rust target for the [Unikraft] Unikernel Development Kit.
[Unikraft]: https://unikraft.org/
Unikraft imitates Linux and uses musl as libc.
It is extremely configurable, and does not even provide a `poll` implementation or a network stack, unless enabled by the end user who compiles the application.
Our approach for integrating the build process with `rustc` is to hide the build process as well as the actual final linking step behind a linker-shim (`kraftld`, see https://github.com/unikraft/kraftkit/issues/612).
## Tier 3 target policy
> - A tier 3 target must have a designated developer or developers (the "target
> maintainers") on record to be CCed when issues arise regarding the target.
> (The mechanism to track and CC such developers may evolve over time.)
I will be the target maintainer.
> - Targets must use naming consistent with any existing targets; for instance, a
> target for the same CPU or OS as an existing Rust target should use the same
> name for that CPU or OS. Targets should normally use the same names and
> naming conventions as used elsewhere in the broader ecosystem beyond Rust
> (such as in other toolchains), unless they have a very good reason to
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> - Target names should not introduce undue confusion or ambiguity unless
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> - If possible, use only letters, numbers, dashes and underscores for the name.
> Periods (`.`) are known to cause issues in Cargo.
The target name `x86_64-unikraft-linux-musl` was derived from `x86_64-unknown-linux-musl`, setting Unikraft as vendor.
Unikraft exactly imitates Linux + musl.
> - Tier 3 targets may have unusual requirements to build or use, but must not
> create legal issues or impose onerous legal terms for the Rust project or for
> Rust developers or users.
> - The target must not introduce license incompatibilities.
> - Anything added to the Rust repository must be under the standard Rust
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> Rust project has no interest in maintaining such combinations within the
> scope of Rust itself, even at tier 3.
> - "onerous" here is an intentionally subjective term. At a minimum, "onerous"
> legal/licensing terms include but are *not* limited to: non-disclosure
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No dependencies were added to Rust.
Requirements for linking are [Unikraft] and [KraftKit] (both BSD-3-Clause), but none of these are added to Rust.
[KraftKit]: https://github.com/unikraft/kraftkit
> - Neither this policy nor any decisions made regarding targets shall create any
> binding agreement or estoppel by any party. If any member of an approving
> Rust team serves as one of the maintainers of a target, or has any legal or
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> decisions regarding the target's tier status, though they may otherwise
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> - This requirement does not prevent part or all of this policy from being
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> subjective matters or goes beyond the letter of these requirements.
Understood.
I am not a member of a Rust team.
> - Tier 3 targets should attempt to implement as much of the standard libraries
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Understood.
`std` is supported.
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Building is described in the platform support doc.
It will be updated once proper `kraftld` support has landed.
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Understood.
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I don't think this PR breaks anything.
r? compiler-team
fix intra-doc links on nested `use` and `extern crate` items
This PR fixes two rustdoc ICEs that happen if there are any intra-doc links on nested `use` or `extern crate` items, for example:
```rust
/// Re-export [`fmt`] and [`io`].
pub use std::{fmt, io}; // "nested" use = use with braces
/// Re-export [`std`].
pub extern crate std;
```
Nested use items were incorrectly considered private and therefore didn't have their intra-doc links resolved. I fixed this by always resolving intra-doc links for nested `use` items that are declared `pub`.
<details>
During AST->HIR lowering, nested `use` items are desugared like this:
```rust
pub use std::{}; // "list stem"
pub use std::fmt;
pub use std::io;
```
Each of these HIR nodes has it's own effective visibility and the list stem is always considered private.
To check the effective visibility of an AST node, the AST node is mapped to a HIR node with `Resolver::local_def_id`, which returns the (private) list stem for nested use items.
</details>
For `extern crate`, there was a hack in rustdoc that stored the `DefId` of the crate itself in the cleaned item, instead of the `DefId` of the `extern crate` item. This made rustdoc look at the resolved links of the extern crate's crate root instead of the `extern crate` item. I've removed this hack and instead translate the `DefId` in the appropriate places.
As as side effect of fixing `extern crate`, i've turned
```rust
#[doc(masked)]
extern crate self as _;
```
into a no-op instead of hiding all trait impls. Proper verification for `doc(masked)` is included as a bonus.
fixes https://github.com/rust-lang/rust/issues/113896
delete [allow(unused_unsafe)] from issue #74838
While looking into issue #111288 I noticed the following `#[allow(...)]` with a `FIXME` asking for it to be removed. Deleting the `#[allow(...)]` does not seem to break anything, it seems like the lint has been updated for unsafe blocks in macros?
Add #[inline] to core debug assertion helpers
These functions are called a lot and not inlined by default in a dev compiler. Adding `#[inline]` should improve things in a dev workflow and be irrelevant in the distributed library.
lint/ctypes: only try normalize
Fixes#113900.
Now that this lint runs on any external-ABI fn-ptr, normalization won't always succeed, so use `try_normalize_erasing_regions` instead.
Optimize format usage
Per #112156, using `&` in `format!` may cause a small perf delay, so I tried to clean up one module at a time format usage. This PR includes a few removals of the ref in format (they do compile locally without the ref), as well as a few format inlining for consistency.
Optimize format usage
Per #112156, using `&` in `format!` may cause a small perf delay, so I tried to clean up one module at a time format usage. This PR includes a few removals of the ref in format (they do compile locally without the ref), as well as a few format inlining for consistency.
arm-none fixups
- Remove "-unknown" from `llvm_target` for arm\*v7r-none-eabi\* targets.
- Remove redundant `c_enum_min_bits` option from the thumbv4t-none-eabi target.
- Fix comments about GCC/Clang's enum width for arm-none targets.
Previously part of #110482, which is a larger change to add a new target.
These nits were found along the way.
rustdoc: handle cross-crate RPITITs correctly
Filter out the internal associated types synthesized during the desugaring of RPITITs, they really shouldn't show up in the docs.
This also fixes#113929 since we're no longer invoking `is_impossible_associated_item` (renamed from `is_impossible_method`) which cannot handle them (leading to an ICE). I don't think it makes sense to try to make `is_impossible_associated_item` handle this exotic kind of associated type (CC original author `@compiler-errors).`
@ T-rustdoc reviewers, currently I'm throwing out ITIT assoc tys before cleaning assoc tys at each usage-site. I'm thinking about making `clean_middle_assoc_item` return an `Option<_>` instead and doing the check inside of it to prevent any call sites from forgetting the check for ITITs. Since I wasn't sure if you would like that approach, I didn't go through with it. Let me know what you think.
<details><summary>Explanation on why <code>is_impossible_associated_item(itit_assoc_ty)</code> leads to an ICE</summary>
Given the following code:
```rs
pub trait Trait { fn def<T>() -> impl Default {} }
impl Trait for () {}
```
The generated associated type looks something like (simplified):
```rs
type {opaque#0}<T>: Default = impl Default; // the name is actually `kw::Empty` but this is the `def_path_str` repr
```
The query `is_impossible_associated_item` goes through all predicates of the associated item – in this case `<T as Sized>` – to check if they contain any generic parameters from the (generic) associated type itself. For predicates that don't contain any *own* generics, it does further processing, part of which is instantiating the predicate with the generic arguments of the impl block (which is only correct if they truly don't contain any own generics since they wouldn't get instantiated this way leading to an ICE).
It checks if `parent_def_id(T) == assoc_ty_def_id` to get to know if `T` is owned by the assoc ty. Unfortunately this doesn't work for ITIT assoc tys. In this case, the parent of `T` is `Trait::def` (!) which is the associated function (I'm pretty sure this is very intentional) which is of course not equal to the assoc ty `Trait::{opaque#0}`.
</details>
`@rustbot` label A-cross-crate-reexports
