By default, closures inherit the generic parameters of their scope,
including `Self`. However, in most cases, the closures used to implement
iterators don't need to be generic on the iterator type, only its `Item`
type. We can reduce this genericity by redirecting such closures through
local functions.
This does make the closures more cumbersome to write, but it will
hopefully reduce duplication in their monomorphizations, as well as
their related type lengths.
We now always make fresh lifetimne parameters for all elided
lifetimes, whether they are in the inputs or outputs. But then
we generate `'_` in the case of elided lifetimes from the outputs.
Example:
```rust
async fn foo<'a>(x: &'a u32) -> &u32 { .. }
```
becomes
```rust
type Foo<'a, 'b> = impl Future<Output = &'b u32>;
fn foo<'a>(x: &'a u32) -> Foo<'a, '_>
```
This commit prohibits return position `impl Trait` types that "inherit
lifetimes" from the parent scope. The intent is to forbid cases that are
challenging until they can be addressed properly.
Improve invalid_value lint message
The lint now explains which type is involved and why it cannot be initialized this way. It also points at the innermost struct/enum field that has an offending type, if any.
See https://github.com/erlepereira/x11-rs/issues/99#issuecomment-520311911 for how this helps in some real-world code hitting this lint.
resolve: Remove remaining special cases from built-in macros
Edition and definition sites of the macros are now also taken from the `#[rustc_builtin_macro]` definitions in `libcore`.
---
The edition switch may be a breaking change for `Rustc{Encodable,Decodable}` derives if they are used in combination with the unstable crate `serialize` from sysroot like this
```rust
extern crate serialize;
use serialize as rustc_serialize;
#[derive(RustcEncodable)]
struct S;
```
(see the updated `ui-fulldeps` tests).
Revert "Simplify MIR generation for logical ops"
This reverts commit e38e954a0d.
llvm were not able to optimize the code that well with the simplified mir.
Closes: #62993
Suggest using a qualified path in patterns with inconsistent bindings
A program like the following one:
```rust
enum E { A, B, C }
fn f(x: E) -> bool {
match x {
A | B => false,
C => true
}
}
```
is rejected by the compiler due to `E` variant paths not being in scope.
In this case `A`, `B` are resolved as pattern bindings and consequently
the pattern is considered invalid as the inner or-patterns do not bind
to the same set of identifiers.
This is expected but the compiler errors that follow could be surprising
or confusing to some users. This commit adds a help note explaining that
if the user desired to match against variants or consts, they should use
a qualified path. The help note is restricted to cases where the identifier
starts with an upper-case sequence so as to reduce the false negatives.
Since this happens during resolution, there's no clean way to check what
it is the patterns match against. The syntactic criterium, however, is in line
with the convention that's assumed by the `non-camel-case-types` lint.
Fixes#50831.
Currently mirrors are stored in the rust-lang-ci2 S3 bucket along with
CI toolchains. This is problematic for multiple reasons:
- CI IAM credentials are allowed to both edit and delete those files.
A malicious user gaining access to those credentials would be able to
change our mirrored dependencies, possibly backdooring the compiler.
- Contents of the rust-lang-ci2 bucket are disposable except for the
mirrors' content. When we implement backups for S3 buckets we'd have
to replicate just that part of the bucket, complicating the backup
logic and increasing the chance of mistakes. A standalone bucket will
be way easier to backup.
This commit switches our CI to use the new rust-lang-ci-mirrors bucket.
