Initial implementation of declarative macros 2.0
Implement declarative macros 2.0 (rust-lang/rfcs#1584) behind `#![feature(decl_macro)]`.
Differences from `macro_rules!` include:
- new syntax: `macro m(..) { .. }` instead of `macro_rules! m { (..) => { .. } }`
- declarative macros are items:
```rust
// crate A:
pub mod foo {
m!(); // use before definition; declaration order is irrelevant
pub macro m() {} // `pub`, `pub(super)`, etc. work
}
fn main() {
foo::m!(); // named like other items
{ use foo::m as n; n!(); } // imported like other items
}
pub use foo::m; // re-exported like other items
// crate B:
extern crate A; // no need for `#[macro_use]`
A::foo::m!(); A::m!();
```
- Racket-like hygiene for items, imports, methods, fields, type parameters, privacy, etc.
- Intuitively, names in a macro definition are resolved in the macro definition's scope, not the scope in which the macro is used.
- This [explaination](http://beautifulracket.com/explainer/hygiene.html) of hygiene for Racket applies here (except for the "Breaking Hygiene" section). I wrote a similar [explanation](https://github.com/jseyfried/rfcs/blob/hygiene/text/0000-hygiene.md) for Rust.
- Generally speaking, if `fn f() { <body> }` resolves, `pub macro m() { <body> } ... m!()` also resolves, even if `m!()` is in a separate crate.
- `::foo::bar` in a `macro` behaves like `$crate::foo::bar` in a `macro_rules!`, except it can access everything visible from the `macro` (thus more permissive).
- See [`src/test/{run-pass, compile-fail}/hygiene`](afe7d89858) for examples. Small example:
```rust
mod foo {
fn f() { println!("hello world"); }
pub macro m() { f(); }
}
fn main() { foo::m!(); }
```
Limitations:
- This does not address planned changes to matchers (`expr`,`ty`, etc.), c.f. #26361.
- Lints (including stability and deprecation) and `unsafe` are not hygienic.
- adding hygiene here will be mostly or entirely backwards compatible
- Nested macro definitions (a `macro` inside another `macro`) don't always work correctly when invoked from external crates.
- pending improvements in how we encode macro definitions in crate metadata
- There is no way to "escape" hygiene without using a procedural macro.
r? @nrc
Update OpenSSL download location
In rustbuild itself we download from our mirror but in the containers we don't
do this yet. The OpenSSL download url changes from time to time (it breaks when
they release a new version) so let's download from our mirror instead.
In rustbuild itself we download from our mirror but in the containers we don't
do this yet. The OpenSSL download url changes from time to time (it breaks when
they release a new version) so let's download from our mirror instead.
Refactor: Move the mutable parts out of LintStore. Fix#42007.
* #42007 happens because the `Session` `LintStore` is emptied when linting.
* The `Session` `LintStore` is emptied because the checker (`Early`/`LateContext`) wants ownership.
* The checker wants ownership because it wants to mutate the pass objects and lint levels.
The ownership of the whole store is not essential, only the lint levels and pass objects need to be owned. Therefore, these parts are extracted out of the `LintStore` into a separate structure `LintSession`. The "check crates" methods can operate on `&mut LintSession` instead of `&mut LintStore`.
This is a minor *breaking change* for lint writers since the `LintContext` trait is changed: the `mut_lints` and `level_stack` methods are removed. But no one outside of `librustc/lint/context.rs` is using these functions, so it should be safe.
Remove some needless // gate-test- comments
Also, add detection to treat such comments as tidy errors.
We also remove the found_lib_feature code because it
was just repeating the found_feature code. Originally it
was intended to allow for gate-test lines for
lib features, but apparently nobody missed it.
libstd/sync/mpsc: relicense under rust license
These files are licensed under a different license
than the rest of the codebase. This causes potential
issues and inconveniences.
Relicense these files under the standard license.
I hold original copyright on that code.
Fixes#36556
