This commit stabilizes some of the `proc_macro` language feature as well as a
number of APIs in the `proc_macro` crate as [previously discussed][1]. This
means that on stable Rust you can now define custom procedural macros which
operate as attributes attached to items or `macro_rules!`-like bang-style
invocations. This extends the suite of currently stable procedural macros,
custom derives, with custom attributes and custom bang macros.
Note though that despite the stabilization in this commit procedural macros are
still not usable on stable Rust. To stabilize that we'll need to stabilize at
least part of the `use_extern_macros` feature. Currently you can define a
procedural macro attribute but you can't import it to call it!
A summary of the changes made in this PR (as well as the various consequences)
is:
* The `proc_macro` language and library features are now stable.
* Other APIs not stabilized in the `proc_macro` crate are now named under a
different feature, such as `proc_macro_diagnostic` or `proc_macro_span`.
* A few checks in resolution for `proc_macro` being enabled have switched over
to `use_extern_macros` being enabled. This means that code using
`#![feature(proc_macro)]` today will likely need to move to
`#![feature(use_extern_macros)]`.
It's intended that this PR, once landed, will be followed up with an attempt to
stabilize a small slice of `use_extern_macros` just for procedural macros to
make this feature 100% usable on stable.
[1]: https://internals.rust-lang.org/t/help-stabilize-a-subset-of-macros-2-0/7252
Clarify how the quote macro is loaded
@QuietMisdreavus needed to figure this out for writing a testcase, this should be better documented.
r? @jseyfried
tidy: add a new test for external dependencies
ensure all packages in Cargo.lock will be vendored, and fail if the
source packages isn't whitelisted.
the purpose is to avoid such kind of issues:
- #52029 Rustfmt isn't vendored correctly
- #42719 building beta with vendor=true fail due to network dependencies
as Rust comes with several external dependencies (clippy, miri, rustfmt, rls), it is important to have a way to catch some errors in the update of this submodules.
The new check in tidy quickly reads `Cargo.lock` to search for the `source` of all packages. This attribute is present when the package comes from external source (like `crates.io-index` or some `git` repository). Some sources are whitelisted (like `crates.io-index`) as the crates are vendored.
`Cargo.lock` extract with several cases (git, crates.io, and local).
```
[[package]]
name = "rustfmt-nightly"
version = "0.8.2"
source = "git+https://github.com/rust-lang-nursery/rustfmt?rev=5e5992517d3591e2708d4ca6b155dfcbdf3344b9#5e5992517d3591e2708d4ca6b155dfcbdf3344b9"
dependencies = [
...
]
[[package]]
name = "same-file"
version = "1.0.2"
source = "registry+https://github.com/rust-lang/crates.io-index"
dependencies = [
...
]
[[package]]
name = "rustdoc-themes"
version = "0.1.0"
```
r? @alexcrichton
CTFE: use binary_op to compare integer with match disriminant
This is needed to unblock https://github.com/solson/miri/pull/401: There is code in the Windows initialization functions that uses `match` to test whether a pointer is NULL.
I will add a testcase in miri; I was not sure where to add a testcase in Rust itself.
r? @oli-obk
resolve: Functions introducing procedural macros reserve a slot in the macro namespace as well
Similarly to https://github.com/rust-lang/rust/pull/52234, this gives us symmetry between internal and external views of a crate, but in this case it's always an error to call a procedural macro in the same crate in which it's defined.
Closes https://github.com/rust-lang/rust/issues/52225
Document rounding down in std::time::Durations's subsec_millis etc.
Now also the documentations of `subsec_millis`, `subsec_micros`, `as_millis` and `as_micros` make clear that the fractional nanosecond component is rounded down to whole units.
Fixed#52263
Remove `ty_to_def_id`
fixes https://github.com/rust-lang/rust/issues/52341
The uses were mostly convenience and generally "too powerful" (would also have worked for types that weren't interesting at the use site)
r? @eddyb
rustdoc: don't panic when the cross-re-export handler sees a proc-macro
When i moved the macro cross-re-export inlining code into `clean::inline`, i thought that if a macro had a `Def` that said it was a bang macro, it wouldn't be a proc macro. I thought wrong. Turns out, the `quote!()` in `libproc_macro` is actually a proc-macro, and when the `quote!()` macro is re-exported, this proc-macro is accessed in its place. This causes any `proc_macro::*` glob re-export to pull in this proc-macro, causing the assertion i added to fire, leading to an ICE. This replaces that with an Option that ignores proc-macros for the time being.
Fixes https://github.com/rust-lang/rust/issues/52129
Do not attempt to recompile codegen backend(s) with --keep-stage
Previously we'd attempt to recompile them and that would fail since
we've essentially not built the entire compiler yet, or we're faking
that fact. This commit should make us ignore the codegen backend build
as well.
Unlike the other compile steps, there is no CodegenBackendLink step that
we run here, because that is done later as a part of assembling the
final compiler and as an explicit function call.
r? @alexcrichton
I think this may fix or at least assist with #52174.
cc @RalfJung @tinco -- if you can test this patch locally that'd be
amazing; I don't want to recompile for the next couple hours to test it
locally. I don't think it can make the situation worse, and in fact, if
I've interpreted the cause of the failure correctly then this will fix
your problem.
rustc: Tweak expansion of #[proc_macro] for 2018
The syntactical expansion of `#[proc_macro]` and related attributes currently
contains absolute paths which conflicts with a lint for the 2018 edition,
causing issues like #52214. This commit puts a band-aid on the issue by ensuring
that procedural macros can also migrate to the 2018 edition for now by tweaking
the expansion based on what features are activated. A more long-term solution
would probably tweak the edition hygiene of spans, but this should do the trick
for now.
Closes#52214
Remove most of `PartialEq` and `Hash` impls from AST and HIR structures
Continuation of https://github.com/rust-lang/rust/pull/49326, prerequisite for removing `PartialEq` for `Ident`.
Now also the documentations of `subsec_millis`, `subsec_micros`, `as_millis` and `as_micros` make clear that the fractional nanosecond component is rounded down to whole units.
