Auto merge of #91288 - matthiaskrgr:rollup-yp5h41r, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #83791 (Weaken guarantee around advancing underlying iterators in zip)
 - #90995 (Document non-guarantees for Hash)
 - #91057 (Expand `available_parallelism` docs in anticipation of cgroup quota support)
 - #91062 (rustdoc: Consolidate static-file replacement mechanism)
 - #91208 (Account for incorrect `where T::Assoc = Ty` bound)
 - #91266 (Use non-generic inner function for pointer formatting)

Failed merges:

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

Author: bors

Diff for: compiler/rustc_ast_passes/src/ast_validation.rs

@@ -23,7 +23,7 @@ use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::Span;
 use rustc_target::spec::abi;
 use std::mem;
-use std::ops::DerefMut;
+use std::ops::{Deref, DerefMut};
 
 const MORE_EXTERN: &str =
     "for more information, visit https://doc.rust-lang.org/std/keyword.extern.html";
@@ -1714,6 +1714,53 @@ fn deny_equality_constraints(
             }
         }
     }
+    // Given `A: Foo, A::Bar = RhsTy`, suggest `A: Foo<Bar = RhsTy>`.
+    if let TyKind::Path(None, full_path) = &predicate.lhs_ty.kind {
+        if let [potential_param, potential_assoc] = &full_path.segments[..] {
+            for param in &generics.params {
+                if param.ident == potential_param.ident {
+                    for bound in &param.bounds {
+                        if let ast::GenericBound::Trait(trait_ref, TraitBoundModifier::None) = bound
+                        {
+                            if let [trait_segment] = &trait_ref.trait_ref.path.segments[..] {
+                                let assoc = pprust::path_to_string(&ast::Path::from_ident(
+                                    potential_assoc.ident,
+                                ));
+                                let ty = pprust::ty_to_string(&predicate.rhs_ty);
+                                let (args, span) = match &trait_segment.args {
+                                    Some(args) => match args.deref() {
+                                        ast::GenericArgs::AngleBracketed(args) => {
+                                            let Some(arg) = args.args.last() else {
+                                                continue;
+                                            };
+                                            (
+                                                format!(", {} = {}", assoc, ty),
+                                                arg.span().shrink_to_hi(),
+                                            )
+                                        }
+                                        _ => continue,
+                                    },
+                                    None => (
+                                        format!("<{} = {}>", assoc, ty),
+                                        trait_segment.span().shrink_to_hi(),
+                                    ),
+                                };
+                                err.multipart_suggestion(
+                                    &format!(
+                                        "if `{}::{}` is an associated type you're trying to set, \
+                                        use the associated type binding syntax",
+                                        trait_segment.ident, potential_assoc.ident,
+                                    ),
+                                    vec![(span, args), (predicate.span, String::new())],
+                                    Applicability::MaybeIncorrect,
+                                );
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
     err.note(
         "see issue #20041 <https://github.com/rust-lang/rust/issues/20041> for more information",
     );

Diff for: compiler/rustc_ast_passes/src/lib.rs

@@ -6,6 +6,7 @@
 
 #![feature(iter_is_partitioned)]
 #![feature(box_patterns)]
+#![feature(let_else)]
 #![recursion_limit = "256"]
 
 pub mod ast_validation;

Diff for: library/core/src/fmt/mod.rs

@@ -2186,28 +2186,34 @@ impl Display for char {
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> Pointer for *const T {
     fn fmt(&self, f: &mut Formatter<'_>) -> Result {
-        let old_width = f.width;
-        let old_flags = f.flags;
-
-        // The alternate flag is already treated by LowerHex as being special-
-        // it denotes whether to prefix with 0x. We use it to work out whether
-        // or not to zero extend, and then unconditionally set it to get the
-        // prefix.
-        if f.alternate() {
-            f.flags |= 1 << (FlagV1::SignAwareZeroPad as u32);
-
-            if f.width.is_none() {
-                f.width = Some((usize::BITS / 4) as usize + 2);
+        /// Since the formatting will be identical for all pointer types, use a non-monomorphized
+        /// implementation for the actual formatting to reduce the amount of codegen work needed
+        fn inner(ptr: *const (), f: &mut Formatter<'_>) -> Result {
+            let old_width = f.width;
+            let old_flags = f.flags;
+
+            // The alternate flag is already treated by LowerHex as being special-
+            // it denotes whether to prefix with 0x. We use it to work out whether
+            // or not to zero extend, and then unconditionally set it to get the
+            // prefix.
+            if f.alternate() {
+                f.flags |= 1 << (FlagV1::SignAwareZeroPad as u32);
+
+                if f.width.is_none() {
+                    f.width = Some((usize::BITS / 4) as usize + 2);
+                }
             }
-        }
-        f.flags |= 1 << (FlagV1::Alternate as u32);
+            f.flags |= 1 << (FlagV1::Alternate as u32);
+
+            let ret = LowerHex::fmt(&(ptr as usize), f);
 
-        let ret = LowerHex::fmt(&(*self as *const () as usize), f);
+            f.width = old_width;
+            f.flags = old_flags;
 
-        f.width = old_width;
-        f.flags = old_flags;
+            ret
+        }
 
-        ret
+        inner(*self as *const (), f)
     }
 }
 

Diff for: library/core/src/hash/mod.rs

@@ -164,6 +164,19 @@ mod sip;
 /// `0xFF` byte to the `Hasher` so that the values `("ab", "c")` and `("a",
 /// "bc")` hash differently.
 ///
+/// ## Portability
+///
+/// Due to differences in endianness and type sizes, data fed by `Hash` to a `Hasher`
+/// should not be considered portable across platforms. Additionally the data passed by most
+/// standard library types should not be considered stable between compiler versions.
+///
+/// This means tests shouldn't probe hard-coded hash values or data fed to a `Hasher` and
+/// instead should check consistency with `Eq`.
+///
+/// Serialization formats intended to be portable between platforms or compiler versions should
+/// either avoid encoding hashes or only rely on `Hash` and `Hasher` implementations that
+/// provide additional guarantees.
+///
 /// [`HashMap`]: ../../std/collections/struct.HashMap.html
 /// [`HashSet`]: ../../std/collections/struct.HashSet.html
 /// [`hash`]: Hash::hash

Diff for: library/core/src/iter/traits/iterator.rs

@@ -458,8 +458,10 @@ pub trait Iterator {
     /// In other words, it zips two iterators together, into a single one.
     ///
     /// If either iterator returns [`None`], [`next`] from the zipped iterator
-    /// will return [`None`]. If the first iterator returns [`None`], `zip` will
-    /// short-circuit and `next` will not be called on the second iterator.
+    /// will return [`None`].
+    /// If the zipped iterator has no more elements to return then each further attempt to advance
+    /// it will first try to advance the first iterator at most one time and if it still yielded an item
+    /// try to advance the second iterator at most one time.
     ///
     /// # Examples
     ///

Diff for: library/std/src/thread/mod.rs

@@ -1460,9 +1460,12 @@ fn _assert_sync_and_send() {
 /// The purpose of this API is to provide an easy and portable way to query
 /// the default amount of parallelism the program should use. Among other things it
 /// does not expose information on NUMA regions, does not account for
-/// differences in (co)processor capabilities, and will not modify the program's
-/// global state in order to more accurately query the amount of available
-/// parallelism.
+/// differences in (co)processor capabilities or current system load,
+/// and will not modify the program's global state in order to more accurately
+/// query the amount of available parallelism.
+///
+/// Where both fixed steady-state and burst limits are available the steady-state
+/// capacity will be used to ensure more predictable latencies.
 ///
 /// Resource limits can be changed during the runtime of a program, therefore the value is
 /// not cached and instead recomputed every time this function is called. It should not be

Diff for: src/librustdoc/config.rs

@@ -552,7 +552,7 @@ impl Options {
                     ))
                     .emit();
                 }
-                themes.push(StylePath { path: theme_file, disabled: true });
+                themes.push(StylePath { path: theme_file });
             }
         }
 

Diff for: src/librustdoc/error.rs

@@ -39,7 +39,10 @@ macro_rules! try_none {
         match $e {
             Some(e) => e,
             None => {
-                return Err(Error::new(io::Error::new(io::ErrorKind::Other, "not found"), $file));
+                return Err(<crate::error::Error as crate::docfs::PathError>::new(
+                    io::Error::new(io::ErrorKind::Other, "not found"),
+                    $file,
+                ));
             }
         }
     }};

Diff for: src/librustdoc/html/layout.rs

@@ -2,8 +2,8 @@ use std::path::PathBuf;
 
 use rustc_data_structures::fx::FxHashMap;
 
+use crate::error::Error;
 use crate::externalfiles::ExternalHtml;
-use crate::html::escape::Escape;
 use crate::html::format::{Buffer, Print};
 use crate::html::render::{ensure_trailing_slash, StylePath};
 
@@ -50,10 +50,11 @@ struct PageLayout<'a> {
     static_root_path: &'a str,
     page: &'a Page<'a>,
     layout: &'a Layout,
-    style_files: String,
+    themes: Vec<String>,
     sidebar: String,
     content: String,
     krate_with_trailing_slash: String,
+    crate rustdoc_version: &'a str,
 }
 
 crate fn render<T: Print, S: Print>(
@@ -66,29 +67,24 @@ crate fn render<T: Print, S: Print>(
 ) -> String {
     let static_root_path = page.get_static_root_path();
     let krate_with_trailing_slash = ensure_trailing_slash(&layout.krate).to_string();
-    let style_files = style_files
+    let mut themes: Vec<String> = style_files
         .iter()
-        .filter_map(|t| t.path.file_stem().map(|stem| (stem, t.disabled)))
-        .filter_map(|t| t.0.to_str().map(|path| (path, t.1)))
-        .map(|t| {
-            format!(
-                r#"<link rel="stylesheet" type="text/css" href="{}.css" {} {}>"#,
-                Escape(&format!("{}{}{}", static_root_path, t.0, page.resource_suffix)),
-                if t.1 { "disabled" } else { "" },
-                if t.0 == "light" { "id=\"themeStyle\"" } else { "" }
-            )
-        })
-        .collect::<String>();
+        .map(StylePath::basename)
+        .collect::<Result<_, Error>>()
+        .unwrap_or_default();
+    themes.sort();
+    let rustdoc_version = rustc_interface::util::version_str().unwrap_or("unknown version");
     let content = Buffer::html().to_display(t); // Note: This must happen before making the sidebar.
     let sidebar = Buffer::html().to_display(sidebar);
     let teractx = tera::Context::from_serialize(PageLayout {
         static_root_path,
         page,
         layout,
-        style_files,
+        themes,
         sidebar,
         content,
         krate_with_trailing_slash,
+        rustdoc_version,
     })
     .unwrap();
     templates.render("page.html", &teractx).unwrap()

Diff for: src/librustdoc/html/render/context.rs

@@ -504,9 +504,9 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         // by the browser as the theme stylesheet. The theme system (hackily) works by
         // changing the href to this stylesheet. All other themes are disabled to
         // prevent rule conflicts
-        scx.style_files.push(StylePath { path: PathBuf::from("light.css"), disabled: false });
-        scx.style_files.push(StylePath { path: PathBuf::from("dark.css"), disabled: true });
-        scx.style_files.push(StylePath { path: PathBuf::from("ayu.css"), disabled: true });
+        scx.style_files.push(StylePath { path: PathBuf::from("light.css") });
+        scx.style_files.push(StylePath { path: PathBuf::from("dark.css") });
+        scx.style_files.push(StylePath { path: PathBuf::from("ayu.css") });
 
         let dst = output;
         scx.ensure_dir(&dst)?;
@@ -596,9 +596,13 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
         page.description = "Settings of Rustdoc";
         page.root_path = "./";
 
-        let mut style_files = self.shared.style_files.clone();
         let sidebar = "<h2 class=\"location\">Settings</h2><div class=\"sidebar-elems\"></div>";
-        style_files.push(StylePath { path: PathBuf::from("settings.css"), disabled: false });
+        let theme_names: Vec<String> = self
+            .shared
+            .style_files
+            .iter()
+            .map(StylePath::basename)
+            .collect::<Result<_, Error>>()?;
         let v = layout::render(
             &self.shared.templates,
             &self.shared.layout,
@@ -607,9 +611,9 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             settings(
                 self.shared.static_root_path.as_deref().unwrap_or("./"),
                 &self.shared.resource_suffix,
-                &self.shared.style_files,
+                theme_names,
             )?,
-            &style_files,
+            &self.shared.style_files,
         );
         self.shared.fs.write(settings_file, v)?;
         if let Some(ref redirections) = self.shared.redirections {

Diff for: src/librustdoc/html/render/mod.rs

@@ -64,7 +64,6 @@ use serde::ser::SerializeSeq;
 use serde::{Serialize, Serializer};
 
 use crate::clean::{self, ItemId, RenderedLink, SelfTy};
-use crate::docfs::PathError;
 use crate::error::Error;
 use crate::formats::cache::Cache;
 use crate::formats::item_type::ItemType;
@@ -173,8 +172,12 @@ impl Serialize for TypeWithKind {
 crate struct StylePath {
     /// The path to the theme
     crate path: PathBuf,
-    /// What the `disabled` attribute should be set to in the HTML tag
-    crate disabled: bool,
+}
+
+impl StylePath {
+    pub fn basename(&self) -> Result<String, Error> {
+        Ok(try_none!(try_none!(self.path.file_stem(), &self.path).to_str(), &self.path).to_string())
+    }
 }
 
 fn write_srclink(cx: &Context<'_>, item: &clean::Item, buf: &mut Buffer) {
@@ -353,7 +356,7 @@ enum Setting {
         js_data_name: &'static str,
         description: &'static str,
         default_value: &'static str,
-        options: Vec<(String, String)>,
+        options: Vec<String>,
     },
 }
 
@@ -393,10 +396,9 @@ impl Setting {
                 options
                     .iter()
                     .map(|opt| format!(
-                        "<option value=\"{}\" {}>{}</option>",
-                        opt.0,
-                        if opt.0 == default_value { "selected" } else { "" },
-                        opt.1,
+                        "<option value=\"{name}\" {}>{name}</option>",
+                        if opt == default_value { "selected" } else { "" },
+                        name = opt,
                     ))
                     .collect::<String>(),
                 root_path,
@@ -421,18 +423,7 @@ impl<T: Into<Setting>> From<(&'static str, Vec<T>)> for Setting {
     }
 }
 
-fn settings(root_path: &str, suffix: &str, themes: &[StylePath]) -> Result<String, Error> {
-    let theme_names: Vec<(String, String)> = themes
-        .iter()
-        .map(|entry| {
-            let theme =
-                try_none!(try_none!(entry.path.file_stem(), &entry.path).to_str(), &entry.path)
-                    .to_string();
-
-            Ok((theme.clone(), theme))
-        })
-        .collect::<Result<_, Error>>()?;
-
+fn settings(root_path: &str, suffix: &str, theme_names: Vec<String>) -> Result<String, Error> {
     // (id, explanation, default value)
     let settings: &[Setting] = &[
         (
@@ -469,10 +460,11 @@ fn settings(root_path: &str, suffix: &str, themes: &[StylePath]) -> Result<Strin
             <span class=\"in-band\">Rustdoc settings</span>\
         </h1>\
         <div class=\"settings\">{}</div>\
-        <script src=\"{}settings{}.js\"></script>",
+        <link rel=\"stylesheet\" href=\"{root_path}settings{suffix}.css\">\
+        <script src=\"{root_path}settings{suffix}.js\"></script>",
         settings.iter().map(|s| s.display(root_path, suffix)).collect::<String>(),
-        root_path,
-        suffix
+        root_path = root_path,
+        suffix = suffix
     ))
 }