`unreachable-pub` lint (as authorized by RFC 2126)
To whom it may concern:
RFC 2126 commissions the creation of a lint for `pub` items that are not visible from crate root (#45521). We understand (but seek confirmation from more knowledgable compiler elders) that this can be implemented by linting HIR items that are _not_ ~~`cx.access_levels.is_exported`~~ `cx.access_levels.is_reachable` but have a `vis` (-ibility) field of `hir::Visibility::Public`.
The lint, tentatively called ~~`unexported-pub`~~ `unreachable-pub` (with the understanding that much could be written on the merits of various names, as it is said of the colors of bicycle-sheds), suggests `crate` as a replacement for `pub` if the `crate_visibility_modifier` feature is enabled (see #45388), and `pub(crate)` otherwise. We also use help messaging to suggest the other potential fix of exporting the item; feedback is desired as to whether this may be confusing or could be worded better.
As a preview of what respecting the proposed lint would look like (and to generate confirmatory evidence that this implementation doesn't issue false positives), ~~we take its suggestions for `libcore`~~ (save one, which is deferred to another pull request because it brings up an unrelated technical matter). I remain your obedient servant.
r? @petrochenkov
ci: Fix broken link in `build-powerpc64le-toolchain.sh`
r? @rust-lang/infra
This is just an emergency fix to keep bors running for another week. I think the numbers will be broken soon. Can we verify if this statement is still true later?
> First, download the CentOS7 glibc.ppc64le and relevant header files.
> (upstream ppc64le support wasn't added until 2.19, which el7 backported.)
typeck: suggest use of match_default_bindings feature
Fixes#45383.
Updates #42640.
r? @nikomatsakis
cc @tschottdorf
This needs a UI test, but thought I'd get some early feedback.
Improve display of error E0308
Ref. Forgetting to call a variant constructor causes a confusing error message #35241.
This PR modifies [`note_type_err`](b7041bfab3/src/librustc/infer/error_reporting/mod.rs (L669-L674)) to display a `help` message when a `TyFnPtr` or `TyFnDef` are found and the return type, of the function or function pointer, is the same as the type that is expected.
The output of compiling
```rust
struct Foo(u32);
fn test() -> Foo { Foo }
fn main() {}
```
is now
```bash
$ rustc src/test/ui/issue-35241.rs
error[E0308]: mismatched types
--> src/test/ui/issue-35241.rs:13:20
|
13 | fn test() -> Foo { Foo }
| --- ^^^ expected struct `Foo`, found fn item
| |
| expected `Foo` because of return type
|
= help: did you mean `Foo { /* fields */ }`?
= note: expected type `Foo`
found type `fn(u32) -> Foo {Foo::{{constructor}}}`
error: aborting due to previous error
```
