lint: add bad opt access internal lint
Prompted by [Zulip discussion](https://rust-lang.zulipchat.com/#narrow/stream/131828-t-compiler/topic/sess.2Ecrate_types.28.29.20vs.20sess.2Eopts.2Ecrate_types/near/290682847).
Some command-line options accessible through `sess.opts` are best accessed through wrapper functions on `Session`, `TyCtxt` or otherwise, rather than through field access on the option struct in the `Session`.
Adds a new lint which triggers on those options that should be accessed through a wrapper function so that this is prohibited. Options are annotated with a new attribute `rustc_lint_opt_deny_field_access` which can specify the error message (i.e. "use this other function instead") to be emitted.
A simpler alternative would be to simply rename the options in the option type so that it is clear they should not be used, however this doesn't prevent uses, just discourages them. Another alternative would be to make the option fields private, and adding accessor functions on the option types, however the wrapper functions sometimes rely on additional state from `Session` or `TyCtxt` which wouldn't be available in an function on the option type, so the accessor would simply make the field available and its use would be discouraged too.
**Leave a comment if there's an option I should add this to.**
Deeply deny fn and raw ptrs in const generics
I think this is right -- just because we wrap a fn ptr in a wrapper type does not mean we should allow it in a const parameter.
We now reject both of these in the same way:
```
#![feature(adt_const_params)]
#[derive(Eq, PartialEq)]
struct Wrapper();
fn foo<const W: Wrapper>() {}
fn foo2<const F: fn()>() {}
```
This does regress one test (`src/test/ui/consts/refs_check_const_eq-issue-88384.stderr`), but I'm not sure it should've passed in the first place.
cc: ``@b-naber`` who introduced that test^
fixes#99641
Some command-line options accessible through `sess.opts` are best
accessed through wrapper functions on `Session`, `TyCtxt` or otherwise,
rather than through field access on the option struct in the `Session`.
Adds a new lint which triggers on those options that should be accessed
through a wrapper function so that this is prohibited. Options are
annotated with a new attribute `rustc_lint_opt_deny_field_access` which
can specify the error message (i.e. "use this other function instead")
to be emitted.
A simpler alternative would be to simply rename the options in the
option type so that it is clear they should not be used, however this
doesn't prevent uses, just discourages them. Another alternative would
be to make the option fields private, and adding accessor functions on
the option types, however the wrapper functions sometimes rely on
additional state from `Session` or `TyCtxt` which wouldn't be available
in an function on the option type, so the accessor would simply make the
field available and its use would be discouraged too.
Signed-off-by: David Wood <david.wood@huawei.com>
Check that RPITs constrained by a recursive call in a closure are compatible
Fixes#99073
Adapts a similar visitor pattern to `find_opaque_ty_constraints` (that we use to check TAITs), but with some changes:
0. Only walk the "OnlyBody" children, instead of all items in the RPIT's defining scope
1. Only walk through the body's children if we found a constraining usage
2. Don't actually do any inference, just do a comparison and error if they're mismatched
----
r? `@oli-obk` -- you know all this impl-trait stuff best... is this the right approach? I can explain the underlying issue better if you'd like, in case that might reveal a better solution. Not sure if it's possible to gather up the closure's defining usages of the RPIT while borrowck'ing the outer function, that might be a better place to put this check...
passes: port more of `check_attr` module
Continues from #99213.
Port more diagnostics in `rustc_passes::check_attr` to using the diagnostic derive and translation machinery.
r? `@compiler-errors`
Add a clickable link to the layout section
The layout section (activated by `--show-type-layout`) is currently not linkable to (outside of chrome's link to text feature). This PR makes it linkable via `#layout`.
Prefer visibility map parents that are not `doc(hidden)` first
Far simpler approach to #98876.
This only fixes the case where the parent is `doc(hidden)`, not where the child is `doc(hidden)` since I don't know how to get the attrs on the import statement given a `ModChild`... I'll try to follow up with that, but this is a good first step.
codegen: use new {re,de,}allocator annotations in llvm
This obviates the patch that teaches LLVM internals about
_rust_{re,de}alloc functions by putting annotations directly in the IR
for the optimizer.
The sole test change is required to anchor FileCheck to the body of the
`box_uninitialized` method, so it doesn't see the `allocalign` on
`__rust_alloc` and get mad about the string `alloca` showing up. Since I
was there anyway, I added some checks on the attributes to prove the
right attributes got set.
r? `@nikic`
rustdoc: Add support for `#[rustc_must_implement_one_of]`
This PR adds support for `#[rustc_must_implement_one_of]` attribute added in #92164. There is a desire to eventually use this attribute of `Read`, so making it show up in docs is a good thing.
I "stole" the styling from cfg notes, not sure what would be a proper styling. Currently it looks like this:
<details><summary>Code to reproduce</summary>
<p>
```rust
#![feature(rustc_attrs)]
#[rustc_must_implement_one_of(a, b)]
pub trait Trait {
fn req();
fn a(){ Self::b() }
fn b(){ Self::a() }
}
```
</p>
</details>
This obviates the patch that teaches LLVM internals about
_rust_{re,de}alloc functions by putting annotations directly in the IR
for the optimizer.
The sole test change is required to anchor FileCheck to the body of the
`box_uninitialized` method, so it doesn't see the `allocalign` on
`__rust_alloc` and get mad about the string `alloca` showing up. Since I
was there anyway, I added some checks on the attributes to prove the
right attributes got set.
While we're here, we also emit allocator attributes on
__rust_alloc_zeroed. This should allow LLVM to perform more
optimizations for zeroed blocks, and probably fixes#90032. [This
comment](https://github.com/rust-lang/rust/issues/24194#issuecomment-308791157)
mentions "weird UB-like behaviour with bitvec iterators in
rustc_data_structures" so we may need to back this change out if things
go wrong.
The new test cases require LLVM 15, so we copy them into LLVM
14-supporting versions, which we can delete when we drop LLVM 14.
Use full type name instead of just saying `impl Trait` in "captures lifetime" error
I think this is very useful, especially when there's >1 `impl Trait`, and it just means passing around a bit more info that we already have access to.
Remove erroneous E0133 code from an error message.
This error message is about `derive` and `packed`, but E0133 is for
"Unsafe code was used outside of an unsafe function or block".
r? ``@estebank``
interpret, ptr_offset_from: refactor and test too-far-apart check
We didn't have any tests for the "too far apart" message, and indeed that check mostly relied on the in-bounds check and was otherwise probably not entirely correct... so I rewrote that check, and it is before the in-bounds check so we can test it separately.
Restore `Opaque` behavior to coherence check
Fixes#99663.
This broke in 84c3fcd2a0. I'm not exactly certain that adding this behavior back is necessarily correct, but at least the UI test I provided may stimulate some thoughts.
I think delaying a bug here is certainly not correct in the case of opaques -- if we want to change coherence behavior for opaques, then we should at least be emitting a new error.
r? ``@lcnr``
handle consts with param/infer in `const_eval_resolve` better
This PR addresses [this thread here](https://github.com/rust-lang/rust/pull/99449#discussion_r924141230). Was this the change you were looking for ``@lcnr?``
Interestingly, one test has begun to pass. Was that expected?
r? ``@lcnr``
Remove reachable coverage without counters
Remove reachable coverage without counters to maintain invariant that
either there is no coverage at all or there is a live coverage counter
left that provides the function source hash.
The motivating example would be a following closure:
```rust
let f = |x: bool| {
debug_assert!(x);
};
```
Which, with span changes from #93967, with disabled debug assertions,
after the final CFG simplifications but before removal of dead blocks,
gives rise to MIR:
```rust
fn main::{closure#0}(_1: &[closure@a.rs:2:13: 2:22], _2: bool) -> () {
debug x => _2;
let mut _0: ();
bb0: {
Coverage::Expression(4294967295) = 1 - 2;
return;
}
...
}
```
Which also makes the initial instrumentation quite suspect, although
this pull request doesn't attempt to address that aspect directly.
Fixes#98833.
r? ``@wesleywiser`` ``@richkadel``
Slightly improve mismatched GAT where clause error
This makes the error reporting a bit more standardized between `where` on GATs and functions.
cc #99206 (`@BoxyUwU),` don't want to mark this as as "fixed" because they're still not perfect, but this is still an improvement IMO so I want to land it incrementally.
regarding "consider adding where clause to trait definition", we don't actually do that for methods as far as i can tell? i could file an issue to look into that maybe.
Enable raw-dylib for bin crates
Fixes#93842
When `raw-dylib` is used in a `bin` crate, we need to collect all of the `raw-dylib` functions, generate the import library and add that to the linker command line.
I also changed the tests so that 1) the C++ dlls are created after the Rust dlls, thus there is no chance of accidentally using them in the Rust linking process and 2) disabled generating import libraries when building with MSVC.
Rollup of 9 pull requests
Successful merges:
- #92390 (Constify a few `(Partial)Ord` impls)
- #97077 (Simplify some code that depend on Deref)
- #98710 (correct the output of a `capacity` method example)
- #99084 (clarify how write_bytes can lead to UB due to invalid values)
- #99178 (Lighten up const_prop_lint, reusing const_prop)
- #99673 (don't ICE on invalid dyn calls)
- #99703 (Expose size_hint() for TokenStream's iterator)
- #99709 (`Inherited` always has `TypeckResults` available)
- #99713 (Fix sidebar background)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Resolve function lifetime elision on the AST
~Based on https://github.com/rust-lang/rust/pull/97720~
Lifetime elision for functions is purely syntactic in nature, so can be resolved on the AST.
This PR replicates the elision logic and diagnostics on the AST, and replaces HIR-based resolution by a `delay_span_bug`.
This refactor allows for more consistent diagnostics, which don't have to guess the original code from HIR.
r? `@petrochenkov`
Remove reachable coverage without counters to maintain invariant that
either there is no coverage at all or there is a live coverage counter
left that provides the function source hash.
The motivating example would be a following closure:
```rust
let f = |x: bool| {
debug_assert!(x);
};
```
Which, with span changes from #93967, with disabled debug assertions,
after the final CFG simplifications but before removal of dead blocks,
gives rise to MIR:
```rust
fn main::{closure#0}(_1: &[closure@a.rs:2:13: 2:22], _2: bool) -> () {
debug x => _2;
let mut _0: ();
bb0: {
Coverage::Expression(4294967295) = 1 - 2;
return;
}
...
}
```
Improve error messages involving `derive` and `packed`.
There are two errors involving `derive` and `packed`.
```
`#[derive]` can't be derived on a `#[repr(packed)]` struct with type or const parameters
`#[derive]` can't be derived on a `#[repr(packed)]` struct that does not derive Copy
```
The second one overstates things. It is possible to use derive on a
repr(packed) struct that doesn't derive Copy in two cases.
- If all the fields within the struct meet the required alignment: 1 for
`repr(packed)`, or `N` for `repr(packed(N))`.
- If `Default` is the only trait derived.
This commit improves things in a few ways.
- Changes the errors to say `this trait can't be derived on this ...`.
This is more accurate, because it's just *this* trait and *this*
packed struct that are a problem, not *all* derived traits on *all*
packed structs.
- Adds more details to the "ERROR" lines in the test case, enough to
distinguish between the two error messages.
- Adds more cases to the test case that don't cause errors, e.g. `Default`
derives.
- Uses a wider variety of builtin traits in the test case, for better coverage.
r? `@estebank`
