Auto merge of #70330 - Centril:rollup-ts0clvx, r=Centril

Rollup of 9 pull requests

Successful merges:

 - #68700 (Add Wake trait for safe construction of Wakers.)
 - #69494 (Stabilize --crate-version option in rustdoc)
 - #70080 (rustc_mir: remove extra space when pretty-printing MIR.)
 - #70195 (Add test for issue #53275)
 - #70199 (Revised span-to-lines conversion to produce an empty vec on DUMMY_SP.)
 - #70299 (add err_machine_stop macro)
 - #70300 (Reword unused variable warning)
 - #70315 (Rename remaining occurences of Void to Opaque.)
 - #70318 (Split long derive lists into two derive attributes.)

Failed merges:

r? @ghost

src/bootstrap/bin/rustdoc.rs

@@ -52,12 +52,7 @@ fn main() {
     // Bootstrap's Cargo-command builder sets this variable to the current Rust version; let's pick
     // it up so we can make rustdoc print this into the docs
     if let Some(version) = env::var_os("RUSTDOC_CRATE_VERSION") {
-        // This "unstable-options" can be removed when `--crate-version` is stabilized
-        if !has_unstable {
-            cmd.arg("-Z").arg("unstable-options");
-        }
         cmd.arg("--crate-version").arg(version);
-        has_unstable = true;
     }
 
     // Needed to be able to run all rustdoc tests.

src/bootstrap/doc.rs

@@ -313,6 +313,9 @@ impl Step for Standalone {
             }
 
             let mut cmd = builder.rustdoc_cmd(compiler);
+            // Needed for --index-page flag
+            cmd.arg("-Z").arg("unstable-options");
+
             cmd.arg("--html-after-content")
                 .arg(&footer)
                 .arg("--html-before-content")
@@ -395,7 +398,7 @@ impl Step for Std {
 
             // Keep a whitelist so we do not build internal stdlib crates, these will be
             // build by the rustc step later if enabled.
-            cargo.arg("-Z").arg("unstable-options").arg("-p").arg(package);
+            cargo.arg("-p").arg(package);
             // Create all crate output directories first to make sure rustdoc uses
             // relative links.
             // FIXME: Cargo should probably do this itself.
@@ -406,6 +409,8 @@ impl Step for Std {
                 .arg("rust.css")
                 .arg("--markdown-no-toc")
                 .arg("--generate-redirect-pages")
+                .arg("-Z")
+                .arg("unstable-options")
                 .arg("--resource-suffix")
                 .arg(crate::channel::CFG_RELEASE_NUM)
                 .arg("--index-page")

src/doc/rustc/src/json.md

@@ -168,7 +168,7 @@ Diagnostics have the following format:
             "rendered": null
         },
         {
-            "message": "consider prefixing with an underscore",
+            "message": "if this is intentional, prefix it with an underscore",
             "code": null,
             "level": "help",
             "spans": [
@@ -201,7 +201,7 @@ Diagnostics have the following format:
     /* Optional string of the rendered version of the diagnostic as displayed
        by rustc. Note that this may be influenced by the `--json` flag.
     */
-    "rendered": "warning: unused variable: `x`\n --> lib.rs:2:9\n  |\n2 |     let x = 123;\n  |         ^ help: consider prefixing with an underscore: `_x`\n  |\n  = note: `#[warn(unused_variables)]` on by default\n\n"
+    "rendered": "warning: unused variable: `x`\n --> lib.rs:2:9\n  |\n2 |     let x = 123;\n  |         ^ help: if this is intentional, prefix it with an underscore: `_x`\n  |\n  = note: `#[warn(unused_variables)]` on by default\n\n"
 }
 ```
 

src/doc/rustdoc/src/command-line-arguments.md

@@ -390,3 +390,15 @@ the same CSS rules as the official `light` theme.
 `--check-theme` is a separate mode in `rustdoc`. When `rustdoc` sees the
 `--check-theme` flag, it discards all other flags and only performs the CSS rule
 comparison operation.
+
+### `--crate-version`: control the crate version
+
+Using this flag looks like this:
+
+```bash
+$ rustdoc src/lib.rs --crate-version 1.3.37
+```
+
+When `rustdoc` receives this flag, it will print an extra "Version (version)" into the sidebar of
+the crate root's docs. You can use this flag to differentiate between different versions of your
+library's documentation.

src/doc/rustdoc/src/unstable-features.md

@@ -248,18 +248,6 @@ Markdown file, the URL given to `--markdown-playground-url` will take precedence
 `--playground-url` and `#![doc(html_playground_url = "url")]` are present when rendering crate docs,
 the attribute will take precedence.
 
-### `--crate-version`: control the crate version
-
-Using this flag looks like this:
-
-```bash
-$ rustdoc src/lib.rs -Z unstable-options --crate-version 1.3.37
-```
-
-When `rustdoc` receives this flag, it will print an extra "Version (version)" into the sidebar of
-the crate root's docs. You can use this flag to differentiate between different versions of your
-library's documentation.
-
 ### `--sort-modules-by-appearance`: control how items on module pages are sorted
 
 Using this flag looks like this:

src/liballoc/lib.rs

@@ -161,6 +161,8 @@ pub mod str;
 pub mod string;
 #[cfg(target_has_atomic = "ptr")]
 pub mod sync;
+#[cfg(target_has_atomic = "ptr")]
+pub mod task;
 #[cfg(test)]
 mod tests;
 pub mod vec;

src/liballoc/task.rs

@@ -0,0 +1,87 @@
+#![unstable(feature = "wake_trait", issue = "69912")]
+//! Types and Traits for working with asynchronous tasks.
+use core::mem::{self, ManuallyDrop};
+use core::task::{RawWaker, RawWakerVTable, Waker};
+
+use crate::sync::Arc;
+
+/// The implementation of waking a task on an executor.
+///
+/// This trait can be used to create a [`Waker`]. An executor can define an
+/// implementation of this trait, and use that to construct a Waker to pass
+/// to the tasks that are executed on that executor.
+///
+/// This trait is a memory-safe and ergonomic alternative to constructing a
+/// [`RawWaker`]. It supports the common executor design in which the data
+/// used to wake up a task is stored in an [`Arc`]. Some executors (especially
+/// those for embedded systems) cannot use this API, which is why [`RawWaker`]
+/// exists as an alternative for those systems.
+#[unstable(feature = "wake_trait", issue = "69912")]
+pub trait Wake {
+    /// Wake this task.
+    #[unstable(feature = "wake_trait", issue = "69912")]
+    fn wake(self: Arc<Self>);
+
+    /// Wake this task without consuming the waker.
+    ///
+    /// If an executor supports a cheaper way to wake without consuming the
+    /// waker, it should override this method. By default, it clones the
+    /// [`Arc`] and calls `wake` on the clone.
+    #[unstable(feature = "wake_trait", issue = "69912")]
+    fn wake_by_ref(self: &Arc<Self>) {
+        self.clone().wake();
+    }
+}
+
+#[unstable(feature = "wake_trait", issue = "69912")]
+impl<W: Wake + Send + Sync + 'static> From<Arc<W>> for Waker {
+    fn from(waker: Arc<W>) -> Waker {
+        // SAFETY: This is safe because raw_waker safely constructs
+        // a RawWaker from Arc<W>.
+        unsafe { Waker::from_raw(raw_waker(waker)) }
+    }
+}
+
+#[unstable(feature = "wake_trait", issue = "69912")]
+impl<W: Wake + Send + Sync + 'static> From<Arc<W>> for RawWaker {
+    fn from(waker: Arc<W>) -> RawWaker {
+        raw_waker(waker)
+    }
+}
+
+// NB: This private function for constructing a RawWaker is used, rather than
+// inlining this into the `From<Arc<W>> for RawWaker` impl, to ensure that
+// the safety of `From<Arc<W>> for Waker` does not depend on the correct
+// trait dispatch - instead both impls call this function directly and
+// explicitly.
+#[inline(always)]
+fn raw_waker<W: Wake + Send + Sync + 'static>(waker: Arc<W>) -> RawWaker {
+    // Increment the reference count of the arc to clone it.
+    unsafe fn clone_waker<W: Wake + Send + Sync + 'static>(waker: *const ()) -> RawWaker {
+        let waker: Arc<W> = Arc::from_raw(waker as *const W);
+        mem::forget(Arc::clone(&waker));
+        raw_waker(waker)
+    }
+
+    // Wake by value, moving the Arc into the Wake::wake function
+    unsafe fn wake<W: Wake + Send + Sync + 'static>(waker: *const ()) {
+        let waker: Arc<W> = Arc::from_raw(waker as *const W);
+        <W as Wake>::wake(waker);
+    }
+
+    // Wake by reference, wrap the waker in ManuallyDrop to avoid dropping it
+    unsafe fn wake_by_ref<W: Wake + Send + Sync + 'static>(waker: *const ()) {
+        let waker: ManuallyDrop<Arc<W>> = ManuallyDrop::new(Arc::from_raw(waker as *const W));
+        <W as Wake>::wake_by_ref(&waker);
+    }
+
+    // Decrement the reference count of the Arc on drop
+    unsafe fn drop_waker<W: Wake + Send + Sync + 'static>(waker: *const ()) {
+        mem::drop(Arc::from_raw(waker as *const W));
+    }
+
+    RawWaker::new(
+        Arc::into_raw(waker) as *const (),
+        &RawWakerVTable::new(clone_waker::<W>, wake::<W>, wake_by_ref::<W>, drop_waker::<W>),
+    )
+}

src/libcore/fmt/mod.rs

@@ -282,10 +282,10 @@ impl<'a> ArgumentV1<'a> {
         // SAFETY: `mem::transmute(x)` is safe because
         //     1. `&'b T` keeps the lifetime it originated with `'b`
         //              (so as to not have an unbounded lifetime)
-        //     2. `&'b T` and `&'b Void` have the same memory layout
+        //     2. `&'b T` and `&'b Opaque` have the same memory layout
         //              (when `T` is `Sized`, as it is here)
         // `mem::transmute(f)` is safe since `fn(&T, &mut Formatter<'_>) -> Result`
-        // and `fn(&Void, &mut Formatter<'_>) -> Result` have the same ABI
+        // and `fn(&Opaque, &mut Formatter<'_>) -> Result` have the same ABI
         // (as long as `T` is `Sized`)
         unsafe { ArgumentV1 { formatter: mem::transmute(f), value: mem::transmute(x) } }
     }

src/librustc/dep_graph/dep_node.rs

@@ -489,19 +489,8 @@ impl<'tcx> DepNodeParams<'tcx> for HirId {
 /// some independent path or string that persists between runs without
 /// the need to be mapped or unmapped. (This ensures we can serialize
 /// them even in the absence of a tcx.)
-#[derive(
-    Clone,
-    Copy,
-    Debug,
-    PartialEq,
-    Eq,
-    PartialOrd,
-    Ord,
-    Hash,
-    RustcEncodable,
-    RustcDecodable,
-    HashStable
-)]
+#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
+#[derive(HashStable)]
 pub struct WorkProductId {
     hash: Fingerprint,
 }

src/librustc/middle/cstore.rs

@@ -40,18 +40,8 @@ impl CrateSource {
     }
 }
 
-#[derive(
-    RustcEncodable,
-    RustcDecodable,
-    Copy,
-    Clone,
-    Ord,
-    PartialOrd,
-    Eq,
-    PartialEq,
-    Debug,
-    HashStable
-)]
+#[derive(RustcEncodable, RustcDecodable, Copy, Clone, Ord, PartialOrd, Eq, PartialEq, Debug)]
+#[derive(HashStable)]
 pub enum DepKind {
     /// A dependency that is only used for its macros.
     MacrosOnly,

src/librustc/middle/region.rs

@@ -80,18 +80,8 @@ use std::fmt;
 // placate the same deriving in `ty::FreeRegion`, but we may want to
 // actually attach a more meaningful ordering to scopes than the one
 // generated via deriving here.
-#[derive(
-    Clone,
-    PartialEq,
-    PartialOrd,
-    Eq,
-    Ord,
-    Hash,
-    Copy,
-    RustcEncodable,
-    RustcDecodable,
-    HashStable
-)]
+#[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, Copy, RustcEncodable, RustcDecodable)]
+#[derive(HashStable)]
 pub struct Scope {
     pub id: hir::ItemLocalId,
     pub data: ScopeData,
@@ -114,19 +104,8 @@ impl fmt::Debug for Scope {
     }
 }
 
-#[derive(
-    Clone,
-    PartialEq,
-    PartialOrd,
-    Eq,
-    Ord,
-    Hash,
-    Debug,
-    Copy,
-    RustcEncodable,
-    RustcDecodable,
-    HashStable
-)]
+#[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, Debug, Copy, RustcEncodable, RustcDecodable)]
+#[derive(HashStable)]
 pub enum ScopeData {
     Node,
 

src/librustc/mir/interpret/allocation.rs

@@ -15,18 +15,8 @@ use std::ops::{Deref, DerefMut, Range};
 
 // NOTE: When adding new fields, make sure to adjust the `Snapshot` impl in
 // `src/librustc_mir/interpret/snapshot.rs`.
-#[derive(
-    Clone,
-    Debug,
-    Eq,
-    PartialEq,
-    PartialOrd,
-    Ord,
-    Hash,
-    RustcEncodable,
-    RustcDecodable,
-    HashStable
-)]
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
+#[derive(HashStable)]
 pub struct Allocation<Tag = (), Extra = ()> {
     /// The actual bytes of the allocation.
     /// Note that the bytes of a pointer represent the offset of the pointer.
@@ -759,18 +749,8 @@ type Block = u64;
 
 /// A bitmask where each bit refers to the byte with the same index. If the bit is `true`, the byte
 /// is defined. If it is `false` the byte is undefined.
-#[derive(
-    Clone,
-    Debug,
-    Eq,
-    PartialEq,
-    PartialOrd,
-    Ord,
-    Hash,
-    RustcEncodable,
-    RustcDecodable,
-    HashStable
-)]
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
+#[derive(HashStable)]
 pub struct UndefMask {
     blocks: Vec<Block>,
     len: Size,

src/librustc/mir/interpret/mod.rs

@@ -46,6 +46,13 @@ macro_rules! err_exhaust {
     };
 }
 
+#[macro_export]
+macro_rules! err_machine_stop {
+    ($($tt:tt)*) => {
+        $crate::mir::interpret::InterpError::MachineStop(Box::new($($tt)*))
+    };
+}
+
 // In the `throw_*` macros, avoid `return` to make them work with `try {}`.
 #[macro_export]
 macro_rules! throw_unsup {
@@ -79,9 +86,7 @@ macro_rules! throw_exhaust {
 
 #[macro_export]
 macro_rules! throw_machine_stop {
-    ($($tt:tt)*) => {
-        Err::<!, _>($crate::mir::interpret::InterpError::MachineStop(Box::new($($tt)*)))?
-    };
+    ($($tt:tt)*) => { Err::<!, _>(err_machine_stop!($($tt)*))? };
 }
 
 mod allocation;

src/librustc/mir/interpret/pointer.rs

@@ -111,18 +111,8 @@ impl<T: layout::HasDataLayout> PointerArithmetic for T {}
 ///
 /// `Pointer` is also generic over the `Tag` associated with each pointer,
 /// which is used to do provenance tracking during execution.
-#[derive(
-    Copy,
-    Clone,
-    Eq,
-    PartialEq,
-    Ord,
-    PartialOrd,
-    RustcEncodable,
-    RustcDecodable,
-    Hash,
-    HashStable
-)]
+#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, RustcEncodable, RustcDecodable, Hash)]
+#[derive(HashStable)]
 pub struct Pointer<Tag = (), Id = AllocId> {
     pub alloc_id: Id,
     pub offset: Size,