Remove space after negative sign in Literal to_string
Negative proc macro literal tokens used to be printed with a space between the minus sign and the magnitude. That's because `impl ToString for Literal` used to convert the Literal into a TokenStream, which splits the minus sign into a separate Punct token.
```rust
Literal::isize_unsuffixed(-10).to_string() // "- 10"
```
This PR updates the ToString impl to directly use `rustc_ast::token::Lit`'s ToString, which matches the way Rust negative numbers are idiomatically written without a space.
```rust
Literal::isize_unsuffixed(-10).to_string() // "-10"
```
Test that FFI-safety warnings don't get accidentally dropped on naked
functions. The big picture is that if you implement a naked function
with the Rust ABI you'll get a warning. Further, if you implement a
naked function with a standardized ABI, but use non-FFI-safe types you
will still get a warning.
rust-lang/rfcs#2774rust-lang/rfcs#2972
Polonius also emits the error that NLL doesn't get a chance to: see comment
"Borrowck doesn't get a chance to run, but if it did it should error here."
Remove invalid suggestion involving `Fn` trait bound
This pull request closes#85735. The actual issue is a duplicate of #21974, but #85735 contains a further problem, which is an invalid suggestion if `Fn`/`FnMut`/`FnOnce` trait bounds are involved: The suggestion code checks whether the trait bound ends with `>` to determine whether it has any generic arguments, but the `Fn*` traits have a special syntax for generic arguments that doesn't involve angle brackets. The example given in #85735:
```rust
trait Foo {}
impl<'a, 'b, T> Foo for T
where
T: FnMut(&'a ()),
T: FnMut(&'b ()), {
}
```
currently produces:
```
error[E0283]: type annotations needed
--> src/lib.rs:4:8
|
4 | T: FnMut(&'a ()),
| ^^^^^^^^^^^^^ cannot infer type for type parameter `T`
|
= note: cannot satisfy `T: FnMut<(&'a (),)>`
help: consider specifying the type arguments in the function call
|
4 | T: FnMut(&'a ())::<Self, Args>,
| ^^^^^^^^^^^^^^
error: aborting due to previous error
```
which is incorrect, because there is no function call, and applying the suggestion would lead to a parse error. With my changes, I get:
```
error[E0283]: type annotations needed
--> test.rs:4:8
|
4 | T: FnMut(&'a ()),
| ^^^^^^^^^^^^^ cannot infer type for type parameter `T`
|
::: [...]/library/core/src/ops/function.rs:147:1
|
147 | pub trait FnMut<Args>: FnOnce<Args> {
| ----------------------------------- required by this bound in `FnMut`
|
= note: cannot satisfy `T: FnMut<(&'a (),)>`
error: aborting due to previous error
```
i.e. I have added a check to prevent the invalid suggestion from being issued for `Fn*` bounds, while the underlying issue #21974 remains for now.
This test is ignored in the NLL compare-mode and manually checks the NLL
output. This makes the polonius compare-mode fail, even though the
output is the same as NLL.
The diagnostics are either the same or better than NLLs: an error that
is seen in the compare-mode, but not visible in the NLL output (probably
because of early return in case of error) is visible in the polonius
output.
A duplicate error is emitted because of a suggestion on the universal
regions.
Trait upcasting coercion (part2)
This is the second part of trait upcasting coercion implementation.
Currently this is blocked on #86264 .
The third part might be implemented using unsafety checking
r? `@bjorn3`
This commit intends to fill out some of the remaining pieces of the
C-unwind ABI. This has a number of other changes with it though to move
this design space forward a bit. Notably contained within here is:
* On `panic=unwind`, the `extern "C"` ABI is now considered as "may
unwind". This fixes a longstanding soundness issue where if you
`panic!()` in an `extern "C"` function defined in Rust that's actually
UB because the LLVM representation for the function has the `nounwind`
attribute, but then you unwind.
* Whether or not a function unwinds now mainly considers the ABI of the
function instead of first checking the panic strategy. This fixes a
miscompile of `extern "C-unwind"` with `panic=abort` because that ABI
can still unwind.
* The aborting stub for non-unwinding ABIs with `panic=unwind` has been
reimplemented. Previously this was done as a small tweak during MIR
generation, but this has been moved to a separate and dedicated MIR
pass. This new pass will, for appropriate functions and function
calls, insert a `cleanup` landing pad for any function call that may
unwind within a function that is itself not allowed to unwind. Note
that this subtly changes some behavior from before where previously on
an unwind which was caught-to-abort it would run active destructors in
the function, and now it simply immediately aborts the process.
* The `#[unwind]` attribute has been removed and all users in tests and
such are now using `C-unwind` and `#![feature(c_unwind)]`.
I think this is largely the last piece of the RFC to implement.
Unfortunately I believe this is still not stabilizable as-is because
activating the feature gate changes the behavior of the existing `extern
"C"` ABI in a way that has no replacement. My thinking for how to enable
this is that we add support for the `C-unwind` ABI on stable Rust first,
and then after it hits stable we change the behavior of the `C` ABI.
That way anyone straddling stable/beta/nightly can switch to `C-unwind`
safely.
Rollup of 8 pull requests
Successful merges:
- #87645 (Properly find owner of closure in THIR unsafeck)
- #87646 (Fix a parser ICE on invalid `fn` body)
- #87652 (Validate that naked functions are never inlined)
- #87685 (Write docs for SyncOnceCell From and Default impl)
- #87693 (Add `aarch64-apple-ios-sim` as a possible target to the manifest)
- #87708 (Add convenience method for handling ipv4-mapped addresses by canonicalizing them)
- #87711 (Correct typo)
- #87716 (Allow generic SIMD array element type)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix a parser ICE on invalid `fn` body
Fixes#87635
A better fix would add a check for `fn` body on `expected_one_of_not_found` but I haven't come up with a graceful way. Any idea?
r? ```@oli-obk``` ```@estebank```
Properly find owner of closure in THIR unsafeck
Previously, when encountering a closure in a constant, the THIR unsafeck gets invoked on the owner of the constant instead of the constant itself, producing cycles.
Supersedes #87492. ```@FabianWolff``` thanks for your work on that PR, I copied your test file and added you as a co-author.
Fixes#87414.
r? ```@oli-obk```
Support negative numbers in Literal::from_str
proc_macro::Literal has allowed negative numbers in a single literal token ever since Rust 1.29, using https://doc.rust-lang.org/stable/proc_macro/struct.Literal.html#method.isize_unsuffixed and similar constructors.
```rust
let lit = proc_macro::Literal::isize_unsuffixed(-10);
```
However, the suite of constructors on Literal is not sufficient for all use cases, for example arbitrary precision floats, or custom suffixes in FFI macros.
```rust
let lit = proc_macro::Literal::f64_unsuffixed(0.101001000100001000001000000100000001); // :(
let lit = proc_macro::Literal::i???_suffixed(10ulong); // :(
```
For those, macros construct the literal using from_str instead, which preserves arbitrary precision, custom suffixes, base, and digit grouping.
```rust
let lit = "0.101001000100001000001000000100000001".parse::<Literal>().unwrap();
let lit = "10ulong".parse::<Literal>().unwrap();
let lit = "0b1000_0100_0010_0001".parse::<Literal>().unwrap();
```
However, until this PR it was not possible to construct a literal token that is **both** negative **and** preserving of arbitrary precision etc.
This PR fixes `Literal::from_str` to recognize negative integer and float literals.
Implement a `explicit_generic_args_with_impl_trait` feature gate
Implements #83701
When this gate is enabled, explicit generic arguments can be specified even if `impl Trait` is used in argument position. Generic arguments can only be specified for explicit generic parameters but not for the synthetic type parameters from `impl Trait`
So code like this will be accepted:
```rust
#![feature(explicit_generic_args_with_impl_trait)]
fn foo<T: ?Sized>(_f: impl AsRef<T>) {}
fn main() {
foo::<str>("".to_string());
}
```
CTFE: throw unsupported error when partially overwriting a pointer
Currently, during CTFE, when a write to memory would overwrite parts of a pointer, we make the remaining parts of that pointer "uninitialized". This is probably not what users expect, so if this ever happens they will be quite confused about why some of the data just vanishes for seemingly no good reason.
So I propose we change this to abort CTFE when that happens, to at last avoid silently doing the wrong thing.
Cc https://github.com/rust-lang/rust/issues/87184
Our CTFE test suite still seems to pass. However, we should probably crater this, and I want to do some tests with Miri as well.
After this commit, `unsafe async fn ...` now suggests the `async unsafe` fix
instead of misunderstanding the issue.
This is not perfect for repeated keywords (`const async const`) and for
keywords that are misplaced after `extern "some abi"` because of the way
`check_fn_font_matter` works, but changing it breaks so many tests and
diagnostics it has been judged too high a cost for this PR.
rfc3052 followup: Remove authors field from Cargo manifests
Since RFC 3052 soft deprecated the authors field, hiding it from
crates.io, docs.rs, and making Cargo not add it by default, and it is
not generally up to date/useful information for contributors, we may as well
remove it from crates in this repo.
When this gate is enabled, explicit generic arguments can be specified even
if `impl Trait` is used in argument position. Generic arguments can only be
specified for explicit generic parameters but not for the synthetic type
parameters from `impl Trait`
