Point out the known type when field doesn't satisfy bound
For file
```rust
use std::path::Path;
fn f(p: Path) { }
```
provide the following error
```nocode
error[E0277]: the trait bound `[u8]: std::marker::Sized` is not satisfied in `std::path::Path`
--> file.rs:3:6
|
3 | fn f(p: Path) { }
| ^ within `std::path::Path`, the trait `std::marker::Sized` is not implemented for `[u8]`
|
= note: `[u8]` does not have a constant size known at compile-time
= note: required because it appears within the type `std::path::Path`
= note: all local variables must have a statically known size
```
Fix#23286.
After the fix of #37453 in PR #37369, instead of pointing at only the
cast type, point at the full cast span when a cast needs a dereference:
```
error: casting `&{float}` as `f32` is invalid
--> ../../../src/test/ui/mismatched_types/cast-rfc0401.rs:81:30
|
81 | vec![0.0].iter().map(|s| s as f32).collect::<Vec<f32>>();
| ^^^^^^^^ cannot cast `&{float}` as `f32`
|
help: did you mean `*s`?
--> ../../../src/test/ui/mismatched_types/cast-rfc0401.rs:81:30
|
81 | vec![0.0].iter().map(|s| s as f32).collect::<Vec<f32>>();
| ^
```
instead of
```
error: casting `&{float}` as `f32` is invalid
--> ../../../src/test/ui/mismatched_types/cast-rfc0401.rs:81:35
|
81 | vec![0.0].iter().map(|s| s as f32).collect::<Vec<f32>>();
| - ^^^
| |
| |
| did you mean `*s`?
| cannot cast `&{float}` as `f32`
```
For file
```rust
use std::path::Path;
fn f(p: Path) { }
```
provide the following error
```nocode
error[E0277]: the trait bound `[u8]: std::marker::Sized` is not satisfied in `std::path::Path`
--> file.rs:3:6
|
3 | fn f(p: Path) { }
| ^ within `std::path::Path`, the trait `std::marker::Sized` is not implemented for `[u8]`
|
= note: `[u8]` does not have a constant size known at compile-time
= note: required because it appears within the type `std::path::Path`
= note: all local variables must have a statically known size
```
Warn when an import list is empty
For a given file
```rust
use std::*;
use std::{};
```
output the following warnings
```
warning: unused import: `use std::{};`, #[warn(unused_imports)] on by default
--> file.rs:2:1
|
2 | use std::{};
| ^^^^^^^^^^^^
warning: unused import: `std::*;`, #[warn(unused_imports)] on by default
--> file.rs:1:5
|
1 | use std::*;
| ^^^^^^^
```
For a given file
```rust
use std::*;
use std::{};
```
output the following warnings
```
warning: unused import: `use std::{};`, #[warn(unused_imports)] on by default
--> file.rs:2:1
|
2 | use std::{};
| ^^^^^^^^^^^^
warning: unused import: `std::*;`, #[warn(unused_imports)] on by default
--> file.rs:1:5
|
1 | use std::*;
| ^^^^^^^
```
Point arg num mismatch errors back to their definition
This PR updates the arg num errors (like E0061) to point back at the function definition where they were defined.
Before:
```
error[E0061]: this function takes 2 parameters but 1 parameter was supplied
--> E0061.rs:18:7
|
18 | f(0);
| ^
|
= note: the following parameter types were expected:
= note: u16, &str
```
Now:
```
error[E0061]: this function takes 2 parameters but 1 parameter was supplied
--> E0061.rs:18:7
|
11 | fn f(a: u16, b: &str) {}
| ------------------------ defined here
...
18 | f(0);
| ^ expected 2 parameters
```
This is an incremental improvement. We probably want to underline only the function name and also have support for functions defined in crates outside of the current crate.
r? @nikomatsakis
fix stack overflow by enum and cont issue #36163
some paths were skipped while checking for recursion.
I fixed bug reproduces on win64 cargo test. In previous PR #36458 time complexity was exponential in case of linked const values. Now it's linear.
r? @alexcrichton
Add new #[target_feature = "..."] attribute.
This commit adds a new attribute that instructs the compiler to emit
target specific code for a single function. For example, the following
function is permitted to use instructions that are part of SSE 4.2:
#[target_feature = "+sse4.2"]
fn foo() { ... }
In particular, use of this attribute does not require setting the
-C target-feature or -C target-cpu options on rustc.
This attribute does not have any protections built into it. For example,
nothing stops one from calling the above `foo` function on hosts without
SSE 4.2 support. Doing so may result in a SIGILL.
I've also expanded the x86 target feature whitelist.
Refactor TraitObject to Slice<ExistentialPredicate>
For reference, the primary types changes in this PR are shown below. They may add in the understanding of what is discussed below, though they should not be required.
We change `TraitObject` into a list of `ExistentialPredicate`s to allow for a couple of things:
- Principal (ExistentialPredicate::Trait) is now optional.
- Region bounds are moved out of `TraitObject` into `TyDynamic`. This permits wrapping only the `ExistentialPredicate` list in `Binder`.
- `BuiltinBounds` and `BuiltinBound` are removed entirely from the codebase, to permit future non-constrained auto traits. These are replaced with `ExistentialPredicate::AutoTrait`, which only requires a `DefId`. For the time being, only `Send` and `Sync` are supported; this constraint can be lifted in a future pull request.
- Binder-related logic is extracted from `ExistentialPredicate` into the parent (`Binder<Slice<EP>>`), so `PolyX`s are inside `TraitObject` are replaced with `X`.
The code requires a sorting order for `ExistentialPredicate`s in the interned `Slice`. The sort order is asserted to be correct during interning, but the slices are not sorted at that point.
1. `ExistentialPredicate::Trait` are defined as always equal; **This may be wrong; should we be comparing them and sorting them in some way?**
1. `ExistentialPredicate::Projection`: Compared by `ExistentialProjection::sort_key`.
1. `ExistentialPredicate::AutoTrait`: Compared by `TraitDef.def_path_hash`.
Construction of `ExistentialPredicate`s is conducted through `TyCtxt::mk_existential_predicates`, which interns a passed iterator as a `Slice`. There are no convenience functions to construct from a set of separate iterators; callers must pass an iterator chain. The lack of convenience functions is primarily due to few uses and the relative difficulty in defining a nice API due to optional parts and difficulty in recognizing which argument goes where. It is also true that the current situation isn't significantly better than 4 arguments to a constructor function; but the extra work is deemed unnecessary as of this time.
```rust
// before this PR
struct TraitObject<'tcx> {
pub principal: PolyExistentialTraitRef<'tcx>,
pub region_bound: &'tcx ty::Region,
pub builtin_bounds: BuiltinBounds,
pub projection_bounds: Vec<PolyExistentialProjection<'tcx>>,
}
// after
pub enum ExistentialPredicate<'tcx> {
// e.g. Iterator
Trait(ExistentialTraitRef<'tcx>),
// e.g. Iterator::Item = T
Projection(ExistentialProjection<'tcx>),
// e.g. Send
AutoTrait(DefId),
}
```
This commit adds a new attribute that instructs the compiler to emit
target specific code for a single function. For example, the following
function is permitted to use instructions that are part of SSE 4.2:
#[target_feature = "+sse4.2"]
fn foo() { ... }
In particular, use of this attribute does not require setting the
-C target-feature or -C target-cpu options on rustc.
This attribute does not have any protections built into it. For example,
nothing stops one from calling the above `foo` function on hosts without
SSE 4.2 support. Doing so may result in a SIGILL.
This commit also expands the target feature whitelist to include lzcnt,
popcnt and sse4a. Namely, lzcnt and popcnt have their own CPUID bits,
but were introduced with SSE4.
