Make it more clear what an about async fn's returns when referring to what it returns
see #76547
This is *likely* not the ONLY place that this happens to be unclear, but we can move this fn to rustc_middle or something like that and reuse it if need be, to apply it to more diagnostics
One outstanding question I have is, if the fn returns (), should I make the message more clear (what about `fn f()` vs `fn f() -> ()`, can you tell those apart in the hir?)
R? `@tmandry`
`@rustbot` modify labels +A-diagnostics +T-compiler
If a symbol name can only be imported from one place for a type, and
as long as it was not glob-imported anywhere in the current crate, we
can trim its printed path and print only the name.
This has wide implications on error messages with types, for example,
shortening `std::vec::Vec` to just `Vec`, as long as there is no other
`Vec` importable anywhere.
This adds a new '-Z trim-diagnostic-paths=false' option to control this
feature.
On the good path, with no diagnosis printed, we should try to avoid
issuing this query, so we need to prevent trimmed_def_paths query on
several cases.
This change also relies on a previous commit that differentiates
between `Debug` and `Display` on various rustc types, where the latter
is trimmed and presented to the user and the former is not.
Backport only: avoid ICE on bad placeholder type
#69148 has a proper fix, but it is too big to backport.
This change avoids the ICE by actually emitting an appropriate error. The
output will be duplicated in some cases, but that's better than the
avoidable ICE.
r? @Centril
#69148 has a proper fix, but it is too big to backport.
This change avoids the ICE by actually emitting an appropriate error. The
output will be duplicated in some cases, but that's better than the
avoidable ICE.
Suggest calling method when first argument is `self`
Closes: #66782
I've explored different approaches for this MR but I think the most straightforward is the best one.
I've tried to find out if the methods for given type exist (to maybe have a better suggestion), but we don't collect them anywhere and collecting them is quite problematic. Moreover, collecting all the methods would require rewriting big part of the code and also could potentially include performance degradation, which I don't think is necessary for this simple case.
Suggest adding a lifetime constraint for opaque type
Fixes#67577, where code like this:
```
struct List {
data: Vec<String>,
}
impl List {
fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> {
self.data.iter().filter(|s| s.starts_with(prefix)).map(|s| s.as_ref())
}
}
```
will show this error:
```
Compiling playground v0.0.1 (/playground)
error[E0597]: `prefix` does not live long enough
--> src/lib.rs:6:47
|
5 | fn started_with<'a>(&'a self, prefix: &'a str) -> impl Iterator<Item=&'a str> {
| -- lifetime `'a` defined here --------------------------- opaque type requires that `prefix` is borrowed for `'a`
...
```
but without suggesting the lovely `help: you can add a constraint..`.
r? @estebank
When encountering `_` type placeholder in fn arguments and return type,
suggest using generic type parameters.
Expand what counts as an inferable return type to slice, array and
tuples of `_`.
Previously, only Self, &Self, &mut Self, Arc<Self>, Rc<Self>,
and Box<Self> were available as stable method receivers.
This commit stabilizes nested uses of all the above types.
However, nested receivers remain non-object-safe.
