Add function core::iter::zip
This makes it a little easier to `zip` iterators:
```rust
for (x, y) in zip(xs, ys) {}
// vs.
for (x, y) in xs.into_iter().zip(ys) {}
```
You can `zip(&mut xs, &ys)` for the conventional `iter_mut()` and
`iter()`, respectively. This can also support arbitrary nesting, where
it's easier to see the item layout than with arbitrary `zip` chains:
```rust
for ((x, y), z) in zip(zip(xs, ys), zs) {}
for (x, (y, z)) in zip(xs, zip(ys, zs)) {}
// vs.
for ((x, y), z) in xs.into_iter().zip(ys).zip(xz) {}
for (x, (y, z)) in xs.into_iter().zip((ys.into_iter().zip(xz)) {}
```
It may also format more nicely, especially when the first iterator is a
longer chain of methods -- for example:
```rust
iter::zip(
trait_ref.substs.types().skip(1),
impl_trait_ref.substs.types().skip(1),
)
// vs.
trait_ref
.substs
.types()
.skip(1)
.zip(impl_trait_ref.substs.types().skip(1))
```
This replaces the tuple-pair `IntoIterator` in #78204.
There is prior art for the utility of this in [`itertools::zip`].
[`itertools::zip`]: https://docs.rs/itertools/0.10.0/itertools/fn.zip.html
This currently creates a field which is always false on GenericParamDefKind for future use when
consts are permitted to have defaults
Update const_generics:default locations
Previously just ignored them, now actually do something about them.
Fix using type check instead of value
Add parsing
This adds all the necessary changes to lower const-generics defaults from parsing.
Change P<Expr> to AnonConst
This matches the arguments passed to instantiations of const generics, and makes it specific to
just anonymous constants.
Attempt to fix lowering bugs
Rust contains various size checks conditional on target_arch = "x86_64",
but these checks were never intended to apply to
x86_64-unknown-linux-gnux32. Add target_pointer_width = "64" to the
conditions.
Improve anonymous lifetime note to indicate the target span
Improvement for #81650
Cc #81995
Message after this improvement:
(Improve note in the middle)
```
error[E0311]: the parameter type `T` may not live long enough
--> src/main.rs:25:11
|
24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) {
| -- help: consider adding an explicit lifetime bound...: `T: 'a +`
25 | scope.spawn(move |_| {
| ^^^^^
|
note: the parameter type `T` must be valid for the anonymous lifetime defined on the function body at 24:40...
--> src/main.rs:24:40
|
24 | fn play_with<T: Animal + Send>(scope: &Scope, animal: T) {
| ^^^^^
note: ...so that the type `[closure@src/main.rs:25:17: 27:6]` will meet its required lifetime bounds
--> src/main.rs:25:11
|
25 | scope.spawn(move |_| {
| ^^^^^
```
r? ``````@estebank``````
name async generators something more human friendly in type error diagnostic
fixes#81457
Some details:
1. I opted to load the generator kind from the hir in TyCategory. I also use 1 impl in the hir for the descr
2. I named both the source of the future, in addition to the general type (`future`), not sure what is preferred
3. I am not sure what is required to make sure "generator" is not referred to anywhere. A brief `rg "\"generator\"" showed me that most diagnostics correctly distinguish from generators and async generator, but the `descr` of `DefKind` is pretty general (not sure how thats used)
4. should the descr impl of AsyncGeneratorKind use its display impl instead of copying the string?
Ensure valid TraitRefs are created for GATs
This fixes `ProjectionTy::trait_ref` to use the correct substs. Places that need all of the substs have been updated to not use `trait_ref`.
r? ````@jackh726````
remove useless ?s (clippy::needless_question_marks)
Example code:
```rust
fn opts() -> Option<String> {
let s: Option<String> = Some(String::new());
Some(s?) // this can just be "s"
}
```
Placeholder lifetime error cleanup
- Remove note of trait definition
- Avoid repeating the same self type
- Use original region names when possible
- Use this error kind more often
- Print closure signatures when they are suppose to implement `Fn*` traits
Works towards #57374
r? ```@nikomatsakis```
Only store a LocalDefId in some HIR nodes
Some HIR nodes are guaranteed to be HIR owners: Item, TraitItem, ImplItem, ForeignItem and MacroDef.
As a consequence, we do not need to store the `HirId`'s `local_id`, and we can directly store a `LocalDefId`.
This allows to avoid a bit of the dance with `tcx.hir().local_def_id` and `tcx.hir().local_def_id_to_hir_id` mappings.
avoid full-slicing slices
If we already have a slice, there is no need to get another full-range slice from that, just use the original.
clippy::redundant_slicing
const_generics: Fix incorrect ty::ParamEnv::empty() usage
Fixes#80561
Not sure if I should keep the `debug!(..)`s or not but its the second time I've needed them so they sure seem useful lol
cc ``@lcnr``
r? ``@oli-obk``
If we have a cause containing `ValuePairs::PolyTraitRefs` but neither
TraitRef has any escaping bound regions then we report the same error as
for `ValuePairs::TraitRefs`.
