rustc: Stabilize the `proc_macro` feature
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
This commit transitions definitions of custom sections on the wasm target from
the unstable `#[wasm_custom_section]` attribute to the
already-stable-for-other-targets `#[link_section]` attribute. Mostly the same
restrictions apply as before, except that this now applies only to statics.
Closes#51088
Previously we'd only do so for stage 0 but with keep-stage
improvements it seems likely that we'll see more developers working in
the stage 1, so we should allow enabling incremental for them.
Ideally, the check we probably want is to only enable incremental for
the last compiler build scheduled, but there's no good way to do so
today. Just enabling incremental in all stages should be sufficient;
we may be doing extra work that's needles -- compiling incrementally
something that will never be recompiled in-place -- but that should be
sufficiently unlikely (i.e., users either don't care or won't be
compiling the compiler twice).
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
