Auto merge of #128301 - matthiaskrgr:rollup-9fyf587, r=matthiaskrgr

Rollup of 3 pull requests

Successful merges:

 - #125889 (Add migration lint for 2024 prelude additions)
 - #128215 (Update the reference)
 - #128263 (rustdoc: use strategic ThinVec/Box to shrink `clean::ItemKind`)

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

compiler/rustc_hir_typeck/src/method/prelude_edition_lints.rs

@@ -9,7 +9,7 @@ use rustc_hir as hir;
 use rustc_lint::{ARRAY_INTO_ITER, BOXED_SLICE_INTO_ITER};
 use rustc_middle::span_bug;
 use rustc_middle::ty::{self, Ty};
-use rustc_session::lint::builtin::RUST_2021_PRELUDE_COLLISIONS;
+use rustc_session::lint::builtin::{RUST_2021_PRELUDE_COLLISIONS, RUST_2024_PRELUDE_COLLISIONS};
 use rustc_span::symbol::kw::{Empty, Underscore};
 use rustc_span::symbol::{sym, Ident};
 use rustc_span::Span;
@@ -35,6 +35,21 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         let (prelude_or_array_lint, edition) = match segment.ident.name {
             // `try_into` was added to the prelude in Rust 2021.
             sym::try_into if !span.at_least_rust_2021() => (RUST_2021_PRELUDE_COLLISIONS, "2021"),
+            // `Future::poll` was added to the prelude in Rust 2024.
+            sym::poll
+                // We check that the self type is `Pin<&mut _>` to avoid false positives for this common name.
+                if !span.at_least_rust_2024()
+                    && let ty::Adt(adt_def, args) = self_ty.kind()
+                    && self.tcx.is_lang_item(adt_def.did(), hir::LangItem::Pin)
+                    && let ty::Ref(_, _, ty::Mutability::Mut) =
+                        args[0].as_type().unwrap().kind() =>
+            {
+                (RUST_2024_PRELUDE_COLLISIONS, "2024")
+            }
+            // `IntoFuture::into_future` was added to the prelude in Rust 2024.
+            sym::into_future if !span.at_least_rust_2024() => {
+                (RUST_2024_PRELUDE_COLLISIONS, "2024")
+            }
             // `into_iter` wasn't added to the prelude,
             // but `[T; N].into_iter()` doesn't resolve to IntoIterator::into_iter
             // before Rust 2021, which results in the same problem.

compiler/rustc_lint_defs/src/builtin.rs

@@ -91,6 +91,7 @@ declare_lint_pass! {
         RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX,
         RUST_2021_PRELUDE_COLLISIONS,
         RUST_2024_INCOMPATIBLE_PAT,
+        RUST_2024_PRELUDE_COLLISIONS,
         SELF_CONSTRUCTOR_FROM_OUTER_ITEM,
         SEMICOLON_IN_EXPRESSIONS_FROM_MACROS,
         SINGLE_USE_LIFETIMES,
@@ -3754,6 +3755,46 @@ declare_lint! {
     };
 }
 
+declare_lint! {
+    /// The `rust_2024_prelude_collisions` lint detects the usage of trait methods which are ambiguous
+    /// with traits added to the prelude in future editions.
+    ///
+    /// ### Example
+    ///
+    /// ```rust,edition2021,compile_fail
+    /// #![deny(rust_2024_prelude_collisions)]
+    /// trait Meow {
+    ///     fn poll(&self) {}
+    /// }
+    /// impl<T> Meow for T {}
+    ///
+    /// fn main() {
+    ///     core::pin::pin!(async {}).poll();
+    ///     //                        ^^^^^^
+    ///     // This call to try_into matches both Future::poll and Meow::poll as
+    ///     // `Future` has been added to the Rust prelude in 2024 edition.
+    /// }
+    /// ```
+    ///
+    /// {{produces}}
+    ///
+    /// ### Explanation
+    ///
+    /// Rust 2024, introduces two new additions to the standard library's prelude:
+    /// `Future` and `IntoFuture`. This results in an ambiguity as to which method/function
+    /// to call when an existing `poll`/`into_future` method is called via dot-call syntax or
+    /// a `poll`/`into_future` associated function is called directly on a type.
+    ///
+    pub RUST_2024_PRELUDE_COLLISIONS,
+    Allow,
+    "detects the usage of trait methods which are ambiguous with traits added to the \
+        prelude in future editions",
+    @future_incompatible = FutureIncompatibleInfo {
+        reason: FutureIncompatibilityReason::EditionError(Edition::Edition2024),
+        reference: "<https://doc.rust-lang.org/nightly/edition-guide/rust-2024/prelude.html>",
+    };
+}
+
 declare_lint! {
     /// The `rust_2021_prefixes_incompatible_syntax` lint detects identifiers that will be parsed as a
     /// prefix instead in Rust 2021.

src/bootstrap/src/core/build_steps/check.rs

@@ -9,7 +9,7 @@ use crate::core::builder::{
 };
 use crate::core::config::TargetSelection;
 use crate::{Compiler, Mode, Subcommand};
-use std::path::{Path, PathBuf};
+use std::path::PathBuf;
 
 pub fn cargo_subcommand(kind: Kind) -> &'static str {
     match kind {
@@ -52,7 +52,7 @@ impl Step for Std {
     }
 
     fn run(self, builder: &Builder<'_>) {
-        builder.update_submodule(&Path::new("library").join("stdarch"));
+        builder.require_submodule("library/stdarch", None);
 
         let target = self.target;
         let compiler = builder.compiler(builder.top_stage, builder.config.build);

src/bootstrap/src/core/build_steps/clippy.rs

@@ -1,7 +1,5 @@
 //! Implementation of running clippy on the compiler, standard library and various tools.
 
-use std::path::Path;
-
 use crate::builder::Builder;
 use crate::builder::ShouldRun;
 use crate::core::builder;
@@ -127,7 +125,7 @@ impl Step for Std {
     }
 
     fn run(self, builder: &Builder<'_>) {
-        builder.update_submodule(&Path::new("library").join("stdarch"));
+        builder.require_submodule("library/stdarch", None);
 
         let target = self.target;
         let compiler = builder.compiler(builder.top_stage, builder.config.build);

src/bootstrap/src/core/build_steps/compile.rs

@@ -182,11 +182,16 @@ impl Step for Std {
             return;
         }
 
-        builder.update_submodule(&Path::new("library").join("stdarch"));
+        builder.require_submodule("library/stdarch", None);
 
         // Profiler information requires LLVM's compiler-rt
         if builder.config.profiler {
-            builder.update_submodule(Path::new("src/llvm-project"));
+            builder.require_submodule(
+                "src/llvm-project",
+                Some(
+                    "The `build.profiler` config option requires `compiler-rt` sources from LLVM.",
+                ),
+            );
         }
 
         let mut target_deps = builder.ensure(StartupObjects { compiler, target });
@@ -456,13 +461,15 @@ pub fn std_cargo(builder: &Builder<'_>, target: TargetSelection, stage: u32, car
         // That's probably ok? At least, the difference wasn't enforced before. There's a comment in
         // the compiler_builtins build script that makes me nervous, though:
         // https://github.com/rust-lang/compiler-builtins/blob/31ee4544dbe47903ce771270d6e3bea8654e9e50/build.rs#L575-L579
-        builder.update_submodule(&Path::new("src").join("llvm-project"));
+        builder.require_submodule(
+            "src/llvm-project",
+            Some(
+                "The `build.optimized-compiler-builtins` config option \
+                 requires `compiler-rt` sources from LLVM.",
+            ),
+        );
         let compiler_builtins_root = builder.src.join("src/llvm-project/compiler-rt");
-        if !compiler_builtins_root.exists() {
-            panic!(
-                "need LLVM sources available to build `compiler-rt`, but they weren't present; consider enabling `build.submodules = true` or disabling `optimized-compiler-builtins`"
-            );
-        }
+        assert!(compiler_builtins_root.exists());
         // Note that `libprofiler_builtins/build.rs` also computes this so if
         // you're changing something here please also change that.
         cargo.env("RUST_COMPILER_RT_ROOT", &compiler_builtins_root);

src/bootstrap/src/core/build_steps/dist.rs

@@ -907,7 +907,7 @@ impl Step for Src {
     /// Creates the `rust-src` installer component
     fn run(self, builder: &Builder<'_>) -> GeneratedTarball {
         if !builder.config.dry_run() {
-            builder.update_submodule(Path::new("src/llvm-project"));
+            builder.require_submodule("src/llvm-project", None);
         }
 
         let tarball = Tarball::new_targetless(builder, "rust-src");
@@ -1022,10 +1022,7 @@ impl Step for PlainSourceTarball {
             // FIXME: This code looks _very_ similar to what we have in `src/core/build_steps/vendor.rs`
             // perhaps it should be removed in favor of making `dist` perform the `vendor` step?
 
-            // Ensure we have all submodules from src and other directories checked out.
-            for submodule in build_helper::util::parse_gitmodules(&builder.src) {
-                builder.update_submodule(Path::new(submodule));
-            }
+            builder.require_and_update_all_submodules();
 
             // Vendor all Cargo dependencies
             let mut cmd = command(&builder.initial_cargo);

src/bootstrap/src/core/build_steps/doc.rs

@@ -9,14 +9,14 @@
 
 use std::io::{self, Write};
 use std::path::{Path, PathBuf};
-use std::{fs, mem};
+use std::{env, fs, mem};
 
 use crate::core::build_steps::compile;
 use crate::core::build_steps::tool::{self, prepare_tool_cargo, SourceType, Tool};
 use crate::core::builder::{self, crate_description};
 use crate::core::builder::{Alias, Builder, Compiler, Kind, RunConfig, ShouldRun, Step};
 use crate::core::config::{Config, TargetSelection};
-use crate::utils::helpers::{dir_is_empty, symlink_dir, t, up_to_date};
+use crate::utils::helpers::{symlink_dir, t, up_to_date};
 use crate::Mode;
 
 macro_rules! submodule_helper {
@@ -53,15 +53,16 @@ macro_rules! book {
 
             fn run(self, builder: &Builder<'_>) {
                 $(
-                    let path = Path::new(submodule_helper!( $path, submodule $( = $submodule )? ));
-                    builder.update_submodule(&path);
+                    let path = submodule_helper!( $path, submodule $( = $submodule )? );
+                    builder.require_submodule(path, None);
                 )?
                 builder.ensure(RustbookSrc {
                     target: self.target,
                     name: $book_name.to_owned(),
                     src: builder.src.join($path),
                     parent: Some(self),
                     languages: $lang.into(),
+                    rustdoc: None,
                 })
             }
         }
@@ -80,7 +81,6 @@ book!(
     EditionGuide, "src/doc/edition-guide", "edition-guide", &[], submodule;
     EmbeddedBook, "src/doc/embedded-book", "embedded-book", &[], submodule;
     Nomicon, "src/doc/nomicon", "nomicon", &[], submodule;
-    Reference, "src/doc/reference", "reference", &[], submodule;
     RustByExample, "src/doc/rust-by-example", "rust-by-example", &["ja"], submodule;
     RustdocBook, "src/doc/rustdoc", "rustdoc", &[];
     StyleGuide, "src/doc/style-guide", "style-guide", &[];
@@ -112,6 +112,7 @@ impl Step for UnstableBook {
             src: builder.md_doc_out(self.target).join("unstable-book"),
             parent: Some(self),
             languages: vec![],
+            rustdoc: None,
         })
     }
 }
@@ -123,6 +124,7 @@ struct RustbookSrc<P: Step> {
     src: PathBuf,
     parent: Option<P>,
     languages: Vec<&'static str>,
+    rustdoc: Option<PathBuf>,
 }
 
 impl<P: Step> Step for RustbookSrc<P> {
@@ -153,13 +155,18 @@ impl<P: Step> Step for RustbookSrc<P> {
             builder.info(&format!("Rustbook ({target}) - {name}"));
             let _ = fs::remove_dir_all(&out);
 
-            builder
-                .tool_cmd(Tool::Rustbook)
-                .arg("build")
-                .arg(&src)
-                .arg("-d")
-                .arg(&out)
-                .run(builder);
+            let mut rustbook_cmd = builder.tool_cmd(Tool::Rustbook);
+            if let Some(mut rustdoc) = self.rustdoc {
+                rustdoc.pop();
+                let old_path = env::var_os("PATH").unwrap_or_default();
+                let new_path =
+                    env::join_paths(std::iter::once(rustdoc).chain(env::split_paths(&old_path)))
+                        .expect("could not add rustdoc to PATH");
+
+                rustbook_cmd.env("PATH", new_path);
+            }
+
+            rustbook_cmd.arg("build").arg(&src).arg("-d").arg(&out).run(builder);
 
             for lang in &self.languages {
                 let out = out.join(lang);
@@ -217,29 +224,22 @@ impl Step for TheBook {
     /// * Index page
     /// * Redirect pages
     fn run(self, builder: &Builder<'_>) {
-        let relative_path = Path::new("src").join("doc").join("book");
-        builder.update_submodule(&relative_path);
+        builder.require_submodule("src/doc/book", None);
 
         let compiler = self.compiler;
         let target = self.target;
 
-        let absolute_path = builder.src.join(&relative_path);
+        let absolute_path = builder.src.join("src/doc/book");
         let redirect_path = absolute_path.join("redirects");
-        if !absolute_path.exists()
-            || !redirect_path.exists()
-            || dir_is_empty(&absolute_path)
-            || dir_is_empty(&redirect_path)
-        {
-            eprintln!("Please checkout submodule: {}", relative_path.display());
-            crate::exit!(1);
-        }
+
         // build book
         builder.ensure(RustbookSrc {
             target,
             name: "book".to_owned(),
             src: absolute_path.clone(),
             parent: Some(self),
             languages: vec![],
+            rustdoc: None,
         });
 
         // building older edition redirects
@@ -252,6 +252,7 @@ impl Step for TheBook {
                 // treat the other editions as not having a parent.
                 parent: Option::<Self>::None,
                 languages: vec![],
+                rustdoc: None,
             });
         }
 
@@ -932,8 +933,8 @@ macro_rules! tool_doc {
                     let _ = source_type; // silence the "unused variable" warning
                     let source_type = SourceType::Submodule;
 
-                    let path = Path::new(submodule_helper!( $path, submodule $( = $submodule )? ));
-                    builder.update_submodule(&path);
+                    let path = submodule_helper!( $path, submodule $( = $submodule )? );
+                    builder.require_submodule(path, None);
                 )?
 
                 let stage = builder.top_stage;
@@ -1172,12 +1173,6 @@ impl Step for RustcBook {
     /// in the "md-doc" directory in the build output directory. Then
     /// "rustbook" is used to convert it to HTML.
     fn run(self, builder: &Builder<'_>) {
-        // These submodules are required to be checked out to build rustbook
-        // because they have Cargo dependencies that are needed.
-        #[allow(clippy::single_element_loop)] // This will change soon.
-        for path in ["src/doc/book"] {
-            builder.update_submodule(Path::new(path));
-        }
         let out_base = builder.md_doc_out(self.target).join("rustc");
         t!(fs::create_dir_all(&out_base));
         let out_listing = out_base.join("src/lints");
@@ -1228,6 +1223,50 @@ impl Step for RustcBook {
             src: out_base,
             parent: Some(self),
             languages: vec![],
+            rustdoc: None,
+        });
+    }
+}
+
+#[derive(Ord, PartialOrd, Debug, Clone, Hash, PartialEq, Eq)]
+pub struct Reference {
+    pub compiler: Compiler,
+    pub target: TargetSelection,
+}
+
+impl Step for Reference {
+    type Output = ();
+    const DEFAULT: bool = true;
+
+    fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
+        let builder = run.builder;
+        run.path("src/doc/reference").default_condition(builder.config.docs)
+    }
+
+    fn make_run(run: RunConfig<'_>) {
+        run.builder.ensure(Reference {
+            compiler: run.builder.compiler(run.builder.top_stage, run.builder.config.build),
+            target: run.target,
+        });
+    }
+
+    /// Builds the reference book.
+    fn run(self, builder: &Builder<'_>) {
+        builder.require_submodule("src/doc/reference", None);
+
+        // This is needed for generating links to the standard library using
+        // the mdbook-spec plugin.
+        builder.ensure(compile::Std::new(self.compiler, builder.config.build));
+        let rustdoc = builder.rustdoc(self.compiler);
+
+        // Run rustbook/mdbook to generate the HTML pages.
+        builder.ensure(RustbookSrc {
+            target: self.target,
+            name: "reference".to_owned(),
+            src: builder.src.join("src/doc/reference"),
+            parent: Some(self),
+            languages: vec![],
+            rustdoc: Some(rustdoc),
         });
     }
 }