Add hint for unresolved associated trait items if the trait has a single item
This PR introduces a special-cased hint for unresolved trait items paths. It is shown if:
- the path was not resolved to any existing trait item
- and no existing trait item's name was reasonably close with regard to edit distance
- and the trait only has a single item in the corresponding namespace
I didn't know where I should put tests, therefore so far I just managed to bless two existing tests. I would be glad for hints where should tests for a hint like this be created, how should they be named (with reference to the original issue?) and what tests should I create (is it enough to test it just for types? or create separate tests also for functions and constants?).
It could also be turned into a machine applicable suggestion I suppose.
This is my first `rustc` PR, so please go easy on me :)
Fixes: https://github.com/rust-lang/rust/issues/87638
permit drop impls with generic constants in where clauses
Fixes#79248
`==` is not sufficient to check for equality between unevaluated consts which causes the above issue because the const in `[(); N - 1]:` on the impl and the const in `[(); N - 1]:` on the struct def are not seen as equal. Any predicate that can contain an unevaluated const cant use `==` here as it will cause us to incorrectly emit an error.
I dont know much about chalk but it seems like we ought to be relating the `TypeWellFormedFromEnv` instead of `==` as it contains a `Ty` so I added that too...
r? ``````@lcnr``````
Validate FFI-safety warnings on naked functions
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
cc ``````@joshtriplett`````` ``````@Amanieu`````` ``````@haraldh``````
explicit_generic_args_with_impl_trait: fix min expected number of generics
Fixes#87718
The problem was that `synth_type_param_count` was already subtracted from `named_type_param_count`, so this ended up being subtracted again. This caused `expected_min` to overflow, and ultimately resulting in weird and wrong behaviour.
I've also added another test not present in the original issue but caused by the same bug.
Disable unused variable lint for naked functions
In most calling conventions, accessing function parameters may require
stack access. However, naked functions have no assembly prelude to set
up stack access. This is why naked functions may only contain a single
`asm!()` block. All parameter access is done inside the `asm!()` block,
so we cannot validate the liveness of the input parameters. Therefore,
we should disable the lint for naked functions.
rust-lang/rfcs#2774rust-lang/rfcs#2972
`@joshtriplett` `@Amanieu` `@haraldh`
rustc: Fill out remaining parts of C-unwind ABI
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.
In most calling conventions, accessing function parameters may require
stack access. However, naked functions have no assembly prelude to set
up stack access. This is why naked functions may only contain a single
`asm!()` block. All parameter access is done inside the `asm!()` block,
so we cannot validate the liveness of the input parameters. Therefore,
we should disable the lint for naked functions.
rust-lang/rfcs#2774rust-lang/rfcs#2972
This test proves that naked functions are treated the same as regular
functions regarding unused function parameters. We will change this
behavior in the next patch.
Remove unnecessary trailing whitespace from error messages
Some error messages currently contain unnecessary trailing whitespace. There are some legitimate reasons for having trailing whitespace in the output, such as for uniform indentation of possibly-empty input lines, but the whitespace I have addressed here occurs in a line used only for spacing, and I see no reason why that should have trailing whitespace (spacing lines inserted in other places also don't have trailing whitespace).
I have also removed a superfluous call to `buffer.putc()`, which has no effect because the same character is already placed there by `draw_col_separator()`.
Use `git diff --ignore-space-at-eol` to see my changes; otherwise the diff is quite large due to the whitespace removed from expected outputs in `src/test/ui/`.
Allow labeled loops as value expressions for `break`
Fixes#86948. This is currently allowed:
```rust
return 'label: loop { break 'label 42; };
break ('label: loop { break 'label 42; });
break 1 + 'label: loop { break 'label 42; };
break 'outer 'inner: loop { break 'inner 42; };
```
But not this:
```rust
break 'label: loop { break 'label 42; };
```
I have fixed this, so that the above now parses as an unlabeled break with a labeled loop as its value expression.
Test dropping union fields more
Now that #87403 is merged, a few more tests can be added for reads/writes to dropping union fields.
r? ``@LeSeulArtichaut``
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
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.
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.
