Auto merge of #91486 - matthiaskrgr:rollup-699fo18, r=matthiaskrgr

Rollup of 10 pull requests

Successful merges:

 - #88906 (Implement write() method for Box<MaybeUninit<T>>)
 - #90269 (Make `Option::expect` unstably const)
 - #90854 (Type can be unsized and uninhabited)
 - #91170 (rustdoc: preload fonts)
 - #91273 (Fix ICE #91268 by checking that the snippet ends with a `)`)
 - #91381 (Android: -ldl must appear after -lgcc when linking)
 - #91453 (Document Windows TLS drop behaviour)
 - #91462 (Use try_normalize_erasing_regions in needs_drop)
 - #91474 (suppress warning about set_errno being unused on DragonFly)
 - #91483 (Sync rustfmt subtree)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_ast_lowering/src/path.rs

@@ -229,15 +229,19 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         if let Ok(snippet) = self.sess.source_map().span_to_snippet(data.span) {
                             // Do not suggest going from `Trait()` to `Trait<>`
                             if !data.inputs.is_empty() {
-                                if let Some(split) = snippet.find('(') {
-                                    let trait_name = &snippet[0..split];
-                                    let args = &snippet[split + 1..snippet.len() - 1];
-                                    err.span_suggestion(
-                                        data.span,
-                                        "use angle brackets instead",
-                                        format!("{}<{}>", trait_name, args),
-                                        Applicability::MaybeIncorrect,
-                                    );
+                                // Suggest replacing `(` and `)` with `<` and `>`
+                                // The snippet may be missing the closing `)`, skip that case
+                                if snippet.ends_with(')') {
+                                    if let Some(split) = snippet.find('(') {
+                                        let trait_name = &snippet[0..split];
+                                        let args = &snippet[split + 1..snippet.len() - 1];
+                                        err.span_suggestion(
+                                            data.span,
+                                            "use angle brackets instead",
+                                            format!("{}<{}>", trait_name, args),
+                                            Applicability::MaybeIncorrect,
+                                        );
+                                    }
                                 }
                             }
                         };

compiler/rustc_data_structures/src/functor.rs

@@ -23,11 +23,9 @@ impl<T> IdFunctor for Box<T> {
             let value = raw.read();
             // SAFETY: Converts `Box<T>` to `Box<MaybeUninit<T>>` which is the
             // inverse of `Box::assume_init()` and should be safe.
-            let mut raw: Box<mem::MaybeUninit<T>> = Box::from_raw(raw.cast());
+            let raw: Box<mem::MaybeUninit<T>> = Box::from_raw(raw.cast());
             // SAFETY: Write the mapped value back into the `Box`.
-            raw.write(f(value)?);
-            // SAFETY: We just initialized `raw`.
-            raw.assume_init()
+            Box::write(raw, f(value)?)
         })
     }
 }

compiler/rustc_middle/src/ty/layout.rs

@@ -533,7 +533,7 @@ impl<'tcx> LayoutCx<'tcx, TyCtxt<'tcx>> {
             }
         }
 
-        if sized && fields.iter().any(|f| f.abi.is_uninhabited()) {
+        if fields.iter().any(|f| f.abi.is_uninhabited()) {
             abi = Abi::Uninhabited;
         }
 

compiler/rustc_middle/src/ty/util.rs

@@ -788,10 +788,14 @@ impl<'tcx> ty::TyS<'tcx> {
                     [component_ty] => component_ty,
                     _ => self,
                 };
+
                 // This doesn't depend on regions, so try to minimize distinct
                 // query keys used.
-                let erased = tcx.normalize_erasing_regions(param_env, query_ty);
-                tcx.needs_drop_raw(param_env.and(erased))
+                // If normalization fails, we just use `query_ty`.
+                let query_ty =
+                    tcx.try_normalize_erasing_regions(param_env, query_ty).unwrap_or(query_ty);
+
+                tcx.needs_drop_raw(param_env.and(query_ty))
             }
         }
     }

compiler/rustc_ty_utils/src/needs_drop.rs

@@ -147,8 +147,10 @@ where
                             Ok(tys) => tys,
                         };
                         for required_ty in tys {
-                            let required =
-                                tcx.normalize_erasing_regions(self.param_env, required_ty);
+                            let required = tcx
+                                .try_normalize_erasing_regions(self.param_env, required_ty)
+                                .unwrap_or(required_ty);
+
                             queue_type(self, required);
                         }
                     }

library/alloc/src/boxed.rs

@@ -763,6 +763,42 @@ impl<T, A: Allocator> Box<mem::MaybeUninit<T>, A> {
         let (raw, alloc) = Box::into_raw_with_allocator(self);
         unsafe { Box::from_raw_in(raw as *mut T, alloc) }
     }
+
+    /// Writes the value and converts to `Box<T, A>`.
+    ///
+    /// This method converts the box similarly to [`Box::assume_init`] but
+    /// writes `value` into it before conversion thus guaranteeing safety.
+    /// In some scenarios use of this method may improve performance because
+    /// the compiler may be able to optimize copying from stack.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// #![feature(new_uninit)]
+    ///
+    /// let big_box = Box::<[usize; 1024]>::new_uninit();
+    ///
+    /// let mut array = [0; 1024];
+    /// for (i, place) in array.iter_mut().enumerate() {
+    ///     *place = i;
+    /// }
+    ///
+    /// // The optimizer may be able to elide this copy, so previous code writes
+    /// // to heap directly.
+    /// let big_box = Box::write(big_box, array);
+    ///
+    /// for (i, x) in big_box.iter().enumerate() {
+    ///     assert_eq!(*x, i);
+    /// }
+    /// ```
+    #[unstable(feature = "new_uninit", issue = "63291")]
+    #[inline]
+    pub fn write(mut boxed: Self, value: T) -> Box<T, A> {
+        unsafe {
+            (*boxed).write(value);
+            boxed.assume_init()
+        }
+    }
 }
 
 impl<T, A: Allocator> Box<[mem::MaybeUninit<T>], A> {

library/core/src/option.rs

@@ -703,7 +703,8 @@ impl<T> Option<T> {
     #[inline]
     #[track_caller]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn expect(self, msg: &str) -> T {
+    #[rustc_const_unstable(feature = "const_option", issue = "67441")]
+    pub const fn expect(self, msg: &str) -> T {
         match self {
             Some(val) => val,
             None => expect_failed(msg),
@@ -1658,7 +1659,7 @@ impl<T, E> Option<Result<T, E>> {
 #[inline(never)]
 #[cold]
 #[track_caller]
-fn expect_failed(msg: &str) -> ! {
+const fn expect_failed(msg: &str) -> ! {
     panic!("{}", msg)
 }
 

library/std/src/sys/unix/os.rs

@@ -97,6 +97,7 @@ pub fn errno() -> i32 {
 }
 
 #[cfg(target_os = "dragonfly")]
+#[allow(dead_code)]
 pub fn set_errno(e: i32) {
     extern "C" {
         #[thread_local]

library/std/src/thread/local.rs

@@ -76,7 +76,21 @@ use crate::fmt;
 ///    destroyed, but not all platforms have this guard. Those platforms that do
 ///    not guard typically have a synthetic limit after which point no more
 ///    destructors are run.
+/// 3. When the process exits on Windows systems, TLS destructors may only be
+///    run on the thread that causes the process to exit. This is because the
+///    other threads may be forcibly terminated.
 ///
+/// ## Synchronization in thread-local destructors
+///
+/// On Windows, synchronization operations (such as [`JoinHandle::join`]) in
+/// thread local destructors are prone to deadlocks and so should be avoided.
+/// This is because the [loader lock] is held while a destructor is run. The
+/// lock is acquired whenever a thread starts or exits or when a DLL is loaded
+/// or unloaded. Therefore these events are blocked for as long as a thread
+/// local destructor is running.
+///
+/// [loader lock]: https://docs.microsoft.com/en-us/windows/win32/dlls/dynamic-link-library-best-practices
+/// [`JoinHandle::join`]: crate::thread::JoinHandle::join
 /// [`with`]: LocalKey::with
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct LocalKey<T: 'static> {

library/unwind/build.rs

@@ -17,6 +17,9 @@ fn main() {
         } else {
             println!("cargo:rustc-link-lib=gcc");
         }
+
+        // Android's unwinding library depends on dl_iterate_phdr in `libdl`.
+        println!("cargo:rustc-link-lib=dl");
     } else if target.contains("freebsd") {
         println!("cargo:rustc-link-lib=gcc_s");
     } else if target.contains("netbsd") {

src/librustdoc/html/templates/page.html

@@ -7,6 +7,12 @@
     <meta name="description" content="{{page.description}}"> {#- -#}
     <meta name="keywords" content="{{page.keywords}}"> {#- -#}
     <title>{{page.title}}</title> {#- -#}
+    <link rel="preload" as="font" type="font/woff2" crossorigin href="{{static_root_path | safe}}SourceSerif4-Regular.ttf.woff2"> {#- -#}
+    <link rel="preload" as="font" type="font/woff2" crossorigin href="{{static_root_path | safe}}FiraSans-Regular.woff2"> {#- -#}
+    <link rel="preload" as="font" type="font/woff2" crossorigin href="{{static_root_path | safe}}FiraSans-Medium.woff2"> {#- -#}
+    <link rel="preload" as="font" type="font/woff2" crossorigin href="{{static_root_path | safe}}SourceCodePro-Regular.ttf.woff2"> {#- -#}
+    <link rel="preload" as="font" type="font/woff2" crossorigin href="{{static_root_path | safe}}SourceSerif4-Bold.ttf.woff2"> {#- -#}
+    <link rel="preload" as="font" type="font/woff2" crossorigin href="{{static_root_path | safe}}SourceCodePro-Semibold.ttf.woff2"> {#- -#}
     <link rel="stylesheet" type="text/css" {# -#}
           href="{{static_root_path | safe}}normalize{{page.resource_suffix}}.css"> {#- -#}
     <link rel="stylesheet" type="text/css" {# -#}

src/test/ui/issues/issue-88150.rs

@@ -0,0 +1,21 @@
+// run-pass
+// compile-flags:-C debuginfo=2
+// edition:2018
+
+use core::marker::PhantomData;
+
+pub struct Foo<T: ?Sized, A>(
+    PhantomData<(A, T)>,
+);
+
+enum Never {}
+
+impl<T: ?Sized> Foo<T, Never> {
+    fn new_foo() -> Foo<T, Never> {
+        Foo(PhantomData)
+    }
+}
+
+fn main() {
+    let _ = Foo::<[()], Never>::new_foo();
+}

src/test/ui/type/issue-91268.rs

@@ -0,0 +1,9 @@
+// error-pattern: this file contains an unclosed delimiter
+// error-pattern: cannot find type `ţ` in this scope
+// error-pattern: parenthesized type parameters may only be used with a `Fn` trait
+// error-pattern: type arguments are not allowed for this type
+// error-pattern: mismatched types
+// ignore-tidy-trailing-newlines
+// `ţ` must be the last character in this file, it cannot be followed by a newline
+fn main() {
+    0: u8(ţ

src/test/ui/type/issue-91268.stderr

@@ -0,0 +1,50 @@
+error: this file contains an unclosed delimiter
+  --> $DIR/issue-91268.rs:9:12
+   |
+LL | fn main() {
+   |           - unclosed delimiter
+LL |     0: u8(ţ
+   |          - ^
+   |          |
+   |          unclosed delimiter
+
+error: this file contains an unclosed delimiter
+  --> $DIR/issue-91268.rs:9:12
+   |
+LL | fn main() {
+   |           - unclosed delimiter
+LL |     0: u8(ţ
+   |          - ^
+   |          |
+   |          unclosed delimiter
+
+error[E0412]: cannot find type `ţ` in this scope
+  --> $DIR/issue-91268.rs:9:11
+   |
+LL |     0: u8(ţ
+   |           ^ expecting a type here because of type ascription
+
+error[E0214]: parenthesized type parameters may only be used with a `Fn` trait
+  --> $DIR/issue-91268.rs:9:8
+   |
+LL |     0: u8(ţ
+   |        ^^^^ only `Fn` traits may use parentheses
+
+error[E0109]: type arguments are not allowed for this type
+  --> $DIR/issue-91268.rs:9:11
+   |
+LL |     0: u8(ţ
+   |           ^ type argument not allowed
+
+error[E0308]: mismatched types
+  --> $DIR/issue-91268.rs:9:5
+   |
+LL | fn main() {
+   |           - expected `()` because of default return type
+LL |     0: u8(ţ
+   |     ^^^^^^^ expected `()`, found `u8`
+
+error: aborting due to 6 previous errors
+
+Some errors have detailed explanations: E0109, E0214, E0308, E0412.
+For more information about an error, try `rustc --explain E0109`.

src/test/ui/union/issue-81199.rs

@@ -0,0 +1,21 @@
+#[repr(C)]
+union PtrRepr<T: ?Sized> {
+    const_ptr: *const T,
+    mut_ptr: *mut T,
+    components: PtrComponents<T>,
+    //~^ ERROR the trait bound
+}
+
+#[repr(C)]
+struct PtrComponents<T: Pointee + ?Sized> {
+    data_address: *const (),
+    metadata: <T as Pointee>::Metadata,
+}
+
+
+
+pub trait Pointee {
+   type Metadata;
+}
+
+fn main() {}

src/test/ui/union/issue-81199.stderr

@@ -0,0 +1,29 @@
+error[E0277]: the trait bound `T: Pointee` is not satisfied in `PtrComponents<T>`
+  --> $DIR/issue-81199.rs:5:17
+   |
+LL |     components: PtrComponents<T>,
+   |                 ^^^^^^^^^^^^^^^^ within `PtrComponents<T>`, the trait `Pointee` is not implemented for `T`
+   |
+note: required because it appears within the type `PtrComponents<T>`
+  --> $DIR/issue-81199.rs:10:8
+   |
+LL | struct PtrComponents<T: Pointee + ?Sized> {
+   |        ^^^^^^^^^^^^^
+   = note: no field of a union may have a dynamically sized type
+   = help: change the field's type to have a statically known size
+help: consider further restricting this bound
+   |
+LL | union PtrRepr<T: ?Sized + Pointee> {
+   |                         +++++++++
+help: borrowed types always have a statically known size
+   |
+LL |     components: &PtrComponents<T>,
+   |                 +
+help: the `Box` type always has a statically known size and allocates its contents in the heap
+   |
+LL |     components: Box<PtrComponents<T>>,
+   |                 ++++                +
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.

src/tools/rustfmt/.github/workflows/linux.yml

@@ -8,7 +8,9 @@ on:
 jobs:
   test:
     runs-on: ubuntu-latest
-    name: (${{ matrix.target }}, nightly)
+    name: (${{ matrix.target }}, ${{ matrix.cfg_release_channel }})
+    env:
+      CFG_RELEASE_CHANNEL: ${{ matrix.cfg_release_channel }}
     strategy:
       # https://help.github.com/en/actions/getting-started-with-github-actions/about-github-actions#usage-limits
       # There's a limit of 60 concurrent jobs across all repos in the rust-lang organization.
@@ -20,6 +22,7 @@ jobs:
         target: [
           x86_64-unknown-linux-gnu,
         ]
+        cfg_release_channel: [nightly, stable]
 
     steps:
     - name: checkout

src/tools/rustfmt/.github/workflows/mac.yml

@@ -10,13 +10,16 @@ jobs:
     # https://help.github.com/en/actions/automating-your-workflow-with-github-actions/virtual-environments-for-github-hosted-runners#supported-runners-and-hardware-resources
     # macOS Catalina 10.15
     runs-on: macos-latest
-    name: (${{ matrix.target }}, nightly)
+    name: (${{ matrix.target }}, ${{ matrix.cfg_release_channel }})
+    env:
+      CFG_RELEASE_CHANNEL: ${{ matrix.cfg_release_channel }}
     strategy:
       fail-fast: false
       matrix:
         target: [
           x86_64-apple-darwin,
         ]
+        cfg_release_channel: [nightly, stable]
 
     steps:
     - name: checkout

src/tools/rustfmt/.github/workflows/windows.yml

@@ -8,7 +8,9 @@ on:
 jobs:
   test:
     runs-on: windows-latest
-    name: (${{ matrix.target }}, nightly)
+    name: (${{ matrix.target }}, ${{ matrix.cfg_release_channel }})
+    env:
+      CFG_RELEASE_CHANNEL: ${{ matrix.cfg_release_channel }}
     strategy:
       # https://help.github.com/en/actions/getting-started-with-github-actions/about-github-actions#usage-limits
       # There's a limit of 60 concurrent jobs across all repos in the rust-lang organization.
@@ -23,6 +25,7 @@ jobs:
           x86_64-pc-windows-gnu,
           x86_64-pc-windows-msvc,
         ]
+        cfg_release_channel: [nightly, stable]
 
     steps:
     # The Windows runners have autocrlf enabled by default