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.
This fixes handling default configuration for the `crate_blacklist`
RLS configuration.
Technically this isn't needed, as the VS Code extension can be
configured to accept a predefined blacklist that's equal to the default
one but it's best that it also lands so that we don't need to work
around that.
cc https://github.com/rust-lang/rust/pull/63472
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
