Rollup of 5 pull requests

compiler/rustc_lint/src/context.rs

@@ -370,7 +370,7 @@ impl LintStore {
                 match level {
                     Level::Allow => "-A",
                     Level::Warn => "-W",
-                    Level::ForceWarn => "--force-warns",
+                    Level::ForceWarn => "--force-warn",
                     Level::Deny => "-D",
                     Level::Forbid => "-F",
                 },

compiler/rustc_lint_defs/src/lib.rs

@@ -64,7 +64,7 @@ impl Level {
         match self {
             Level::Allow => "allow",
             Level::Warn => "warn",
-            Level::ForceWarn => "force-warns",
+            Level::ForceWarn => "force-warn",
             Level::Deny => "deny",
             Level::Forbid => "forbid",
         }

compiler/rustc_middle/src/lint.rs

@@ -288,7 +288,7 @@ pub fn struct_lint_level<'s, 'd>(
                     Level::Deny => "-D",
                     Level::Forbid => "-F",
                     Level::Allow => "-A",
-                    Level::ForceWarn => "--force-warns",
+                    Level::ForceWarn => "--force-warn",
                 };
                 let hyphen_case_lint_name = name.replace("_", "-");
                 if lint_flag_val.as_str() == name {

compiler/rustc_session/src/config.rs

@@ -1101,7 +1101,7 @@ pub fn rustc_short_optgroups() -> Vec<RustcOptGroup> {
         ),
         opt::multi_s(
             "",
-            "force-warns",
+            "force-warn",
             "Specifiy lints that should warn even if \
              they are allowed somewhere else",
             "LINT",
@@ -1175,11 +1175,11 @@ pub fn get_cmd_lint_options(
     let mut lint_opts_with_position = vec![];
     let mut describe_lints = false;
 
-    if !debugging_opts.unstable_options && matches.opt_present("force-warns") {
+    if !debugging_opts.unstable_options && matches.opt_present("force-warn") {
         early_error(
             error_format,
             "the `-Z unstable-options` flag must also be passed to enable \
-            the flag `--force-warns=lints`",
+            the flag `--force-warn=lints`",
         );
     }
 

library/core/src/alloc/global.rs

@@ -20,24 +20,69 @@ use crate::ptr;
 ///
 /// # Example
 ///
-/// ```no_run
-/// use std::alloc::{GlobalAlloc, Layout, alloc};
+/// ```
+/// use std::alloc::{GlobalAlloc, Layout};
+/// use std::cell::UnsafeCell;
 /// use std::ptr::null_mut;
+/// use std::sync::atomic::{
+///     AtomicUsize,
+///     Ordering::{Acquire, SeqCst},
+/// };
 ///
-/// struct MyAllocator;
-///
-/// unsafe impl GlobalAlloc for MyAllocator {
-///     unsafe fn alloc(&self, _layout: Layout) -> *mut u8 { null_mut() }
-///     unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
+/// const ARENA_SIZE: usize = 128 * 1024;
+/// const MAX_SUPPORTED_ALIGN: usize = 4096;
+/// #[repr(C, align(4096))] // 4096 == MAX_SUPPORTED_ALIGN
+/// struct SimpleAllocator {
+///     arena: UnsafeCell<[u8; ARENA_SIZE]>,
+///     remaining: AtomicUsize, // we allocate from the top, counting down
 /// }
 ///
 /// #[global_allocator]
-/// static A: MyAllocator = MyAllocator;
+/// static ALLOCATOR: SimpleAllocator = SimpleAllocator {
+///     arena: UnsafeCell::new([0x55; ARENA_SIZE]),
+///     remaining: AtomicUsize::new(ARENA_SIZE),
+/// };
 ///
-/// fn main() {
-///     unsafe {
-///         assert!(alloc(Layout::new::<u32>()).is_null())
+/// unsafe impl Sync for SimpleAllocator {}
+///
+/// unsafe impl GlobalAlloc for SimpleAllocator {
+///     unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+///         let size = layout.size();
+///         let align = layout.align();
+///
+///         // `Layout` contract forbids making a `Layout` with align=0, or align not power of 2.
+///         // So we can safely use a mask to ensure alignment without worrying about UB.
+///         let align_mask_to_round_down = !(align - 1);
+///
+///         if align > MAX_SUPPORTED_ALIGN {
+///             return null_mut();
+///         }
+///
+///         let mut allocated = 0;
+///         if self
+///             .remaining
+///             .fetch_update(SeqCst, SeqCst, |mut remaining| {
+///                 if size > remaining {
+///                     return None;
+///                 }
+///                 remaining -= size;
+///                 remaining &= align_mask_to_round_down;
+///                 allocated = remaining;
+///                 Some(remaining)
+///             })
+///             .is_err()
+///         {
+///             return null_mut();
+///         };
+///         (self.arena.get() as *mut u8).add(allocated)
 ///     }
+///     unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout) {}
+/// }
+///
+/// fn main() {
+///     let _s = format!("allocating a string!");
+///     let currently = ALLOCATOR.remaining.load(Acquire);
+///     println!("allocated so far: {}", ARENA_SIZE - currently);
 /// }
 /// ```
 ///

src/doc/unstable-book/src/compiler-flags/force-warns.md → src/doc/unstable-book/src/compiler-flags/force-warn.md

@@ -1,10 +1,10 @@
-# `force-warns`
+# `force-warn`
 
 The tracking issue for this feature is: [#85512](https://github.com/rust-lang/rust/issues/85512).
 
 ------------------------
 
-This feature allows you to cause any lint to produce a warning even if the lint has a different level by default or another level is set somewhere else. For instance, the `force-warns` option can be used to make a lint (e.g., `dead_code`) produce a warning even if that lint is allowed in code with `#![allow(dead_code)]`.
+This feature allows you to cause any lint to produce a warning even if the lint has a different level by default or another level is set somewhere else. For instance, the `force-warn` option can be used to make a lint (e.g., `dead_code`) produce a warning even if that lint is allowed in code with `#![allow(dead_code)]`.
 
 ## Example
 
@@ -18,4 +18,4 @@ fn dead_function() {}
 fn main() {}
 ```
 
-We can force a warning to be produced by providing `--force-warns dead_code` to rustc.
+We can force a warning to be produced by providing `--force-warn dead_code` to rustc.

src/librustdoc/html/render/print_item.rs

@@ -1,6 +1,7 @@
 use clean::AttributesExt;
 
 use std::cmp::Ordering;
+use std::fmt;
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir as hir;
@@ -155,7 +156,7 @@ fn should_hide_fields(n_fields: usize) -> bool {
     n_fields > 12
 }
 
-fn toggle_open(w: &mut Buffer, text: &str) {
+fn toggle_open(w: &mut Buffer, text: impl fmt::Display) {
     write!(
         w,
         "<details class=\"rustdoc-toggle type-contents-toggle\">\
@@ -481,6 +482,9 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
     let consts = t.items.iter().filter(|m| m.is_associated_const()).collect::<Vec<_>>();
     let required = t.items.iter().filter(|m| m.is_ty_method()).collect::<Vec<_>>();
     let provided = t.items.iter().filter(|m| m.is_method()).collect::<Vec<_>>();
+    let count_types = types.len();
+    let count_consts = consts.len();
+    let count_methods = required.len() + provided.len();
 
     // Output the trait definition
     wrap_into_docblock(w, |w| {
@@ -511,9 +515,12 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
             let mut toggle = false;
 
             // If there are too many associated types, hide _everything_
-            if should_hide_fields(types.len()) {
+            if should_hide_fields(count_types) {
                 toggle = true;
-                toggle_open(w, "associated items");
+                toggle_open(
+                    w,
+                    format_args!("{} associated items", count_types + count_consts + count_methods),
+                );
             }
             for t in &types {
                 render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait, cx);
@@ -523,9 +530,18 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
             // We also do this if the types + consts is large because otherwise we could
             // render a bunch of types and _then_ a bunch of consts just because both were
             // _just_ under the limit
-            if !toggle && should_hide_fields(types.len() + consts.len()) {
+            if !toggle && should_hide_fields(count_types + count_consts) {
                 toggle = true;
-                toggle_open(w, "associated constants and methods");
+                toggle_open(
+                    w,
+                    format_args!(
+                        "{} associated constant{} and {} method{}",
+                        count_consts,
+                        pluralize(count_consts),
+                        count_methods,
+                        pluralize(count_methods),
+                    ),
+                );
             }
             if !types.is_empty() && !consts.is_empty() {
                 w.write_str("\n");
@@ -534,9 +550,9 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
                 render_assoc_item(w, t, AssocItemLink::Anchor(None), ItemType::Trait, cx);
                 w.write_str(";\n");
             }
-            if !toggle && should_hide_fields(required.len() + provided.len()) {
+            if !toggle && should_hide_fields(count_methods) {
                 toggle = true;
-                toggle_open(w, "methods");
+                toggle_open(w, format_args!("{} methods", count_methods));
             }
             if !consts.is_empty() && !required.is_empty() {
                 w.write_str("\n");
@@ -933,9 +949,10 @@ fn item_enum(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, e: &clean::Enum
             w.write_str(" {}");
         } else {
             w.write_str(" {\n");
-            let toggle = should_hide_fields(e.variants.len());
+            let count_variants = e.variants.len();
+            let toggle = should_hide_fields(count_variants);
             if toggle {
-                toggle_open(w, "variants");
+                toggle_open(w, format_args!("{} variants", count_variants));
             }
             for v in &e.variants {
                 w.write_str("    ");
@@ -1012,7 +1029,8 @@ fn item_enum(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, e: &clean::Enum
 
             use crate::clean::Variant;
             if let clean::VariantItem(Variant::Struct(ref s)) = *variant.kind {
-                toggle_open(w, "fields");
+                let count_fields = s.fields.len();
+                toggle_open(w, format_args!("{} field{}", count_fields, pluralize(count_fields)));
                 let variant_id = cx.derive_id(format!(
                     "{}.{}.fields",
                     ItemType::Variant,
@@ -1385,7 +1403,7 @@ fn render_union(
         fields.iter().filter(|f| matches!(*f.kind, clean::StructFieldItem(..))).count();
     let toggle = should_hide_fields(count_fields);
     if toggle {
-        toggle_open(w, "fields");
+        toggle_open(w, format_args!("{} fields", count_fields));
     }
 
     for field in fields {
@@ -1441,7 +1459,7 @@ fn render_struct(
             let has_visible_fields = count_fields > 0;
             let toggle = should_hide_fields(count_fields);
             if toggle {
-                toggle_open(w, "fields");
+                toggle_open(w, format_args!("{} fields", count_fields));
             }
             for field in fields {
                 if let clean::StructFieldItem(ref ty) = *field.kind {
@@ -1618,3 +1636,7 @@ fn document_type_layout(w: &mut Buffer, cx: &Context<'_>, ty_def_id: DefId) {
 
     writeln!(w, "</div>");
 }
+
+fn pluralize(count: usize) -> &'static str {
+    if count > 1 { "s" } else { "" }
+}

src/librustdoc/lib.rs

@@ -511,10 +511,10 @@ fn opts() -> Vec<RustcOptGroup> {
                 "LEVEL",
             )
         }),
-        unstable("force-warns", |o| {
+        unstable("force-warn", |o| {
             o.optopt(
                 "",
-                "force-warns",
+                "force-warn",
                 "Lints that will warn even if allowed somewhere else",
                 "LINTS",
             )

src/test/run-make/unstable-flag-required/Makefile

@@ -2,4 +2,4 @@
 
 all:
 	$(RUSTDOC) --output-format=json x.html 2>&1 | diff - output-format-json.stderr
-	$(RUSTC) --force-warns dead_code x.rs 2>&1 | diff - force-warns.stderr
+	$(RUSTC) --force-warn dead_code x.rs 2>&1 | diff - force-warn.stderr

src/test/run-make/unstable-flag-required/force-warns.stderr → src/test/run-make/unstable-flag-required/force-warn.stderr

@@ -1,2 +1,2 @@
-error: the `-Z unstable-options` flag must also be passed to enable the flag `--force-warns=lints`
+error: the `-Z unstable-options` flag must also be passed to enable the flag `--force-warn=lints`
 

src/test/rustdoc/toggle-item-contents.rs

@@ -9,7 +9,7 @@ pub struct PubStruct {
 
 // @has 'toggle_item_contents/struct.BigPubStruct.html'
 // @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
-// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show fields'
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 13 fields'
 pub struct BigPubStruct {
     pub a: usize,
     pub b: usize,
@@ -28,7 +28,7 @@ pub struct BigPubStruct {
 
 // @has 'toggle_item_contents/union.BigUnion.html'
 // @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
-// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show fields'
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 13 fields'
 pub union BigUnion {
     pub a: usize,
     pub b: usize,
@@ -63,7 +63,7 @@ pub struct PrivStruct {
 
 // @has 'toggle_item_contents/enum.Enum.html'
 // @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
-// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show fields'
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 2 fields'
 pub enum Enum {
     A, B, C,
     D {
@@ -72,9 +72,19 @@ pub enum Enum {
     }
 }
 
+// @has 'toggle_item_contents/enum.EnumStructVariant.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 1 field'
+pub enum EnumStructVariant {
+    A, B, C,
+    D {
+        a: u8,
+    }
+}
+
 // @has 'toggle_item_contents/enum.LargeEnum.html'
 // @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
-// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show variants'
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 13 variants'
 pub enum LargeEnum {
     A, B, C, D, E, F(u8), G, H, I, J, K, L, M
 }
@@ -90,7 +100,7 @@ pub trait Trait {
 
 // @has 'toggle_item_contents/trait.GinormousTrait.html'
 // @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
-// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show associated items'
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 16 associated items'
 pub trait GinormousTrait {
     type A;
     type B;
@@ -113,7 +123,7 @@ pub trait GinormousTrait {
 
 // @has 'toggle_item_contents/trait.HugeTrait.html'
 // @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
-// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show associated constants and methods'
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 12 associated constants and 2 methods'
 pub trait HugeTrait {
     type A;
     const M: usize = 1;
@@ -133,9 +143,30 @@ pub trait HugeTrait {
     fn bar();
 }
 
+// @has 'toggle_item_contents/trait.GiganticTrait.html'
+// @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 1 associated constant and 1 method'
+pub trait GiganticTrait {
+    type A;
+    type B;
+    type C;
+    type D;
+    type E;
+    type F;
+    type G;
+    type H;
+    type I;
+    type J;
+    type K;
+    type L;
+    const M: usize = 1;
+    #[must_use]
+    fn foo();
+}
+
 // @has 'toggle_item_contents/trait.BigTrait.html'
 // @count - '//details[@class="rustdoc-toggle type-contents-toggle"]' 1
-// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show methods'
+// @has - '//details[@class="rustdoc-toggle type-contents-toggle"]' 'Show 14 methods'
 pub trait BigTrait {
     type A;
     #[must_use]