Rollup of 8 pull requests

compiler/rustc_ast_lowering/src/lib.rs

@@ -2068,7 +2068,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
         hir::GenericParam {
             hir_id,
             name,
-            span: self.lower_span(param.ident.span),
+            span: self.lower_span(param.span()),
             pure_wrt_drop: self.sess.contains_name(&param.attrs, sym::may_dangle),
             bounds: self.arena.alloc_from_iter(bounds),
             kind,

compiler/rustc_borrowck/src/diagnostics/region_errors.rs

@@ -330,14 +330,14 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                     ty::RawPtr(ty_mut) => {
                         assert_eq!(ty_mut.mutbl, rustc_hir::Mutability::Mut);
                         (
-                            format!("a mutable pointer to {}", ty_mut.ty),
+                            format!("a mutable pointer to `{}`", ty_mut.ty),
                             "mutable pointers are invariant over their type parameter".to_string(),
                         )
                     }
                     ty::Ref(_, inner_ty, mutbl) => {
                         assert_eq!(*mutbl, rustc_hir::Mutability::Mut);
                         (
-                            format!("a mutable reference to {}", inner_ty),
+                            format!("a mutable reference to `{}`", inner_ty),
                             "mutable references are invariant over their type parameter"
                                 .to_string(),
                         )
@@ -351,10 +351,21 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         let adt_desc = adt.descr();
 
                         let desc = format!(
-                            "the type {ty}, which makes the generic argument {generic_arg} invariant"
+                            "the type `{ty}`, which makes the generic argument `{generic_arg}` invariant"
                         );
                         let note = format!(
-                            "the {adt_desc} {base_ty} is invariant over the parameter {base_generic_arg}"
+                            "the {adt_desc} `{base_ty}` is invariant over the parameter `{base_generic_arg}`"
+                        );
+                        (desc, note)
+                    }
+                    ty::FnDef(def_id, _) => {
+                        let name = self.infcx.tcx.item_name(*def_id);
+                        let identity_substs =
+                            InternalSubsts::identity_for_item(self.infcx.tcx, *def_id);
+                        let desc = format!("a function pointer to `{name}`");
+                        let note = format!(
+                            "the function `{name}` is invariant over the parameter `{}`",
+                            identity_substs[param_index as usize]
                         );
                         (desc, note)
                     }

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -540,6 +540,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
                         );
                         self.note_version_mismatch(&mut err, &trait_ref);
                         self.suggest_remove_await(&obligation, &mut err);
+                        self.suggest_derive(&obligation, &mut err, trait_predicate);
 
                         if Some(trait_ref.def_id()) == tcx.lang_items().try_trait() {
                             self.suggest_await_before_try(

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -189,6 +189,13 @@ pub trait InferCtxtExt<'tcx> {
         err: &mut Diagnostic,
         trait_ref: &ty::PolyTraitRef<'tcx>,
     );
+
+    fn suggest_derive(
+        &self,
+        obligation: &PredicateObligation<'tcx>,
+        err: &mut Diagnostic,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
+    );
 }
 
 fn predicate_constraint(generics: &hir::Generics<'_>, pred: String) -> (Span, String) {
@@ -2650,6 +2657,68 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
             _ => {}
         }
     }
+
+    fn suggest_derive(
+        &self,
+        obligation: &PredicateObligation<'tcx>,
+        err: &mut Diagnostic,
+        trait_pred: ty::PolyTraitPredicate<'tcx>,
+    ) {
+        let Some(diagnostic_name) = self.tcx.get_diagnostic_name(trait_pred.def_id()) else {
+            return;
+        };
+        let (adt, substs) = match trait_pred.skip_binder().self_ty().kind() {
+            ty::Adt(adt, substs) if adt.did().is_local() => (adt, substs),
+            _ => return,
+        };
+        let can_derive = {
+            let is_derivable_trait = match diagnostic_name {
+                sym::Default => !adt.is_enum(),
+                sym::PartialEq | sym::PartialOrd => {
+                    let rhs_ty = trait_pred.skip_binder().trait_ref.substs.type_at(1);
+                    trait_pred.skip_binder().self_ty() == rhs_ty
+                }
+                sym::Eq | sym::Ord | sym::Clone | sym::Copy | sym::Hash | sym::Debug => true,
+                _ => false,
+            };
+            is_derivable_trait &&
+                // Ensure all fields impl the trait.
+                adt.all_fields().all(|field| {
+                    let field_ty = field.ty(self.tcx, substs);
+                    let trait_substs = match diagnostic_name {
+                        sym::PartialEq | sym::PartialOrd => {
+                            self.tcx.mk_substs_trait(field_ty, &[field_ty.into()])
+                        }
+                        _ => self.tcx.mk_substs_trait(field_ty, &[]),
+                    };
+                    let trait_pred = trait_pred.map_bound_ref(|tr| ty::TraitPredicate {
+                        trait_ref: ty::TraitRef {
+                            substs: trait_substs,
+                            ..trait_pred.skip_binder().trait_ref
+                        },
+                        ..*tr
+                    });
+                    let field_obl = Obligation::new(
+                        obligation.cause.clone(),
+                        obligation.param_env,
+                        trait_pred.to_predicate(self.tcx),
+                    );
+                    self.predicate_must_hold_modulo_regions(&field_obl)
+                })
+        };
+        if can_derive {
+            err.span_suggestion_verbose(
+                self.tcx.def_span(adt.did()).shrink_to_lo(),
+                &format!(
+                    "consider annotating `{}` with `#[derive({})]`",
+                    trait_pred.skip_binder().self_ty(),
+                    diagnostic_name.to_string(),
+                ),
+                format!("#[derive({})]\n", diagnostic_name.to_string()),
+                Applicability::MaybeIncorrect,
+            );
+        }
+    }
 }
 
 /// Collect all the returned expressions within the input expression.

library/core/src/macros/panic.md

@@ -1,8 +1,7 @@
 Panics the current thread.
 
 This allows a program to terminate immediately and provide feedback
-to the caller of the program. `panic!` should be used when a program reaches
-an unrecoverable state.
+to the caller of the program.
 
 This macro is the perfect way to assert conditions in example code and in
 tests. `panic!` is closely tied with the `unwrap` method of both
@@ -21,13 +20,25 @@ Inside the hook a panic can be accessed as a `&dyn Any + Send`,
 which contains either a `&str` or `String` for regular `panic!()` invocations.
 To panic with a value of another other type, [`panic_any`] can be used.
 
-[`Result`] enum is often a better solution for recovering from errors than
-using the `panic!` macro. This macro should be used to avoid proceeding using
-incorrect values, such as from external sources. Detailed information about
-error handling is found in the [book].
-
 See also the macro [`compile_error!`], for raising errors during compilation.
 
+# When to use `panic!` vs `Result`
+
+The Rust model of error handling groups errors into two major categories:
+recoverable and unrecoverable errors. For a recoverable error, such as a file
+not found error, it’s reasonable to report the problem to the user and retry
+the operation. Unrecoverable errors are always symptoms of bugs, like trying to
+access a location beyond the end of an array.
+
+The Rust language and standard library provides `Result` and `panic!` as parts
+of two complementary systems for representing, reporting, propagating, reacting
+to, and discarding errors for in these two categories.
+
+The `panic!` macro is provided to represent unrecoverable errors, whereas the
+`Result` enum is provided to represent recoverable errors. For more detailed
+information about error handling check out the [book] or the [`std::result`]
+module docs.
+
 [ounwrap]: Option::unwrap
 [runwrap]: Result::unwrap
 [`std::panic::set_hook()`]: ../std/panic/fn.set_hook.html
@@ -36,6 +47,7 @@ See also the macro [`compile_error!`], for raising errors during compilation.
 [`Any`]: crate::any::Any
 [`format!`]: ../std/macro.format.html
 [book]: ../book/ch09-00-error-handling.html
+[`std::result`]: ../std/result/index.html
 
 # Current implementation
 

library/unwind/build.rs

@@ -40,8 +40,6 @@ fn main() {
         // This is handled in the target spec with late_link_args_[static|dynamic]
     } else if target.contains("uwp-windows-gnu") {
         println!("cargo:rustc-link-lib=unwind");
-    } else if target.contains("fuchsia") {
-        println!("cargo:rustc-link-lib=unwind");
     } else if target.contains("haiku") {
         println!("cargo:rustc-link-lib=gcc_s");
     } else if target.contains("redox") {

src/bootstrap/bin/rustdoc.rs

@@ -15,6 +15,10 @@ fn main() {
     let libdir = env::var_os("RUSTDOC_LIBDIR").expect("RUSTDOC_LIBDIR was not set");
     let sysroot = env::var_os("RUSTC_SYSROOT").expect("RUSTC_SYSROOT was not set");
 
+    // Detect whether or not we're a build script depending on whether --target
+    // is passed (a bit janky...)
+    let target = args.windows(2).find(|w| &*w[0] == "--target").and_then(|w| w[1].to_str());
+
     use std::str::FromStr;
 
     let verbose = match env::var("RUSTC_VERBOSE") {
@@ -26,10 +30,18 @@ fn main() {
     dylib_path.insert(0, PathBuf::from(libdir.clone()));
 
     let mut cmd = Command::new(rustdoc);
-    cmd.args(&args)
-        .arg("--sysroot")
-        .arg(&sysroot)
-        .env(dylib_path_var(), env::join_paths(&dylib_path).unwrap());
+
+    if target.is_some() {
+        // The stage0 compiler has a special sysroot distinct from what we
+        // actually downloaded, so we just always pass the `--sysroot` option,
+        // unless one is already set.
+        if !args.iter().any(|arg| arg == "--sysroot") {
+            cmd.arg("--sysroot").arg(&sysroot);
+        }
+    }
+
+    cmd.args(&args);
+    cmd.env(dylib_path_var(), env::join_paths(&dylib_path).unwrap());
 
     // Force all crates compiled by this compiler to (a) be unstable and (b)
     // allow the `rustc_private` feature to link to other unstable crates

src/bootstrap/bootstrap.py

@@ -678,7 +678,7 @@ def fix_bin_or_dylib(self, fname):
             # The latter one does not exist on NixOS when using tmpfs as root.
             try:
                 with open("/etc/os-release", "r") as f:
-                    if not any(line.strip() == "ID=nixos" for line in f):
+                    if not any(l.strip() in ["ID=nixos", "ID='nixos'", 'ID="nixos"'] for l in f):
                         return
             except FileNotFoundError:
                 return

src/librustdoc/lib.rs

@@ -771,6 +771,7 @@ fn main_options(options: config::Options) -> MainResult {
     let externs = options.externs.clone();
     let render_options = options.render_options.clone();
     let scrape_examples_options = options.scrape_examples_options.clone();
+    let document_private = options.render_options.document_private;
     let config = core::create_config(options);
 
     interface::create_compiler_and_run(config, |compiler| {
@@ -791,7 +792,12 @@ fn main_options(options: config::Options) -> MainResult {
             let (resolver, resolver_caches) = {
                 let (krate, resolver, _) = &*abort_on_err(queries.expansion(), sess).peek();
                 let resolver_caches = resolver.borrow_mut().access(|resolver| {
-                    collect_intra_doc_links::early_resolve_intra_doc_links(resolver, krate, externs)
+                    collect_intra_doc_links::early_resolve_intra_doc_links(
+                        resolver,
+                        krate,
+                        externs,
+                        document_private,
+                    )
                 });
                 (resolver.clone(), resolver_caches)
             };

src/librustdoc/passes/collect_intra_doc_links/early.rs

@@ -22,6 +22,7 @@ crate fn early_resolve_intra_doc_links(
     resolver: &mut Resolver<'_>,
     krate: &ast::Crate,
     externs: Externs,
+    document_private_items: bool,
 ) -> ResolverCaches {
     let mut loader = IntraLinkCrateLoader {
         resolver,
@@ -30,6 +31,7 @@ crate fn early_resolve_intra_doc_links(
         traits_in_scope: Default::default(),
         all_traits: Default::default(),
         all_trait_impls: Default::default(),
+        document_private_items,
     };
 
     // Because of the `crate::` prefix, any doc comment can reference
@@ -66,6 +68,7 @@ struct IntraLinkCrateLoader<'r, 'ra> {
     traits_in_scope: DefIdMap<Vec<TraitCandidate>>,
     all_traits: Vec<DefId>,
     all_trait_impls: Vec<DefId>,
+    document_private_items: bool,
 }
 
 impl IntraLinkCrateLoader<'_, '_> {
@@ -175,7 +178,7 @@ impl IntraLinkCrateLoader<'_, '_> {
         }
 
         for child in self.resolver.module_children_or_reexports(module_id) {
-            if child.vis == Visibility::Public {
+            if child.vis == Visibility::Public || self.document_private_items {
                 if let Some(def_id) = child.res.opt_def_id() {
                     self.add_traits_in_parent_scope(def_id);
                 }

src/test/rustdoc/issue-95633.rs

@@ -0,0 +1,7 @@
+// compile-flags: --document-private-items
+
+// This ensures that no ICE is triggered when rustdoc is run on this code.
+
+mod stdlib {
+    pub (crate) use std::i8;
+}

src/test/ui/array-slice-vec/repeat_empty_ok.stderr

@@ -5,6 +5,10 @@ LL |     let headers = [Header{value: &[]}; 128];
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `Header<'_>`
    |
    = note: the `Copy` trait is required because the repeated element will be copied
+help: consider annotating `Header<'_>` with `#[derive(Copy)]`
+   |
+LL | #[derive(Copy)]
+   |
 
 error[E0277]: the trait bound `Header<'_>: Copy` is not satisfied
   --> $DIR/repeat_empty_ok.rs:13:19
@@ -13,6 +17,10 @@ LL |     let headers = [Header{value: &[0]}; 128];
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Copy` is not implemented for `Header<'_>`
    |
    = note: the `Copy` trait is required because the repeated element will be copied
+help: consider annotating `Header<'_>` with `#[derive(Copy)]`
+   |
+LL | #[derive(Copy)]
+   |
 
 error: aborting due to 2 previous errors
 

src/test/ui/associated-types/cache/project-fn-ret-invariant.krisskross.nll.stderr

@@ -10,8 +10,8 @@ LL |     (a, b)
    |     ^^^^^^ function was supposed to return data with lifetime `'b` but it is returning data with lifetime `'a`
    |
    = help: consider adding the following bound: `'a: 'b`
-   = note: requirement occurs because of the type Type<'_>, which makes the generic argument '_ invariant
-   = note: the struct Type<'a> is invariant over the parameter 'a
+   = note: requirement occurs because of the type `Type<'_>`, which makes the generic argument `'_` invariant
+   = note: the struct `Type<'a>` is invariant over the parameter `'a`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
 error: lifetime may not live long enough
@@ -26,8 +26,8 @@ LL |     (a, b)
    |     ^^^^^^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'b`
    |
    = help: consider adding the following bound: `'b: 'a`
-   = note: requirement occurs because of the type Type<'_>, which makes the generic argument '_ invariant
-   = note: the struct Type<'a> is invariant over the parameter 'a
+   = note: requirement occurs because of the type `Type<'_>`, which makes the generic argument `'_` invariant
+   = note: the struct `Type<'a>` is invariant over the parameter `'a`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
 help: `'a` and `'b` must be the same: replace one with the other

src/test/ui/associated-types/cache/project-fn-ret-invariant.oneuse.nll.stderr

@@ -10,8 +10,8 @@ LL |     let a = bar(f, x);
    |             ^^^^^^^^^ argument requires that `'a` must outlive `'b`
    |
    = help: consider adding the following bound: `'a: 'b`
-   = note: requirement occurs because of the type Type<'_>, which makes the generic argument '_ invariant
-   = note: the struct Type<'a> is invariant over the parameter 'a
+   = note: requirement occurs because of the type `Type<'_>`, which makes the generic argument `'_` invariant
+   = note: the struct `Type<'a>` is invariant over the parameter `'a`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
 error: lifetime may not live long enough
@@ -26,8 +26,8 @@ LL |     let b = bar(f, y);
    |             ^^^^^^^^^ argument requires that `'b` must outlive `'a`
    |
    = help: consider adding the following bound: `'b: 'a`
-   = note: requirement occurs because of the type Type<'_>, which makes the generic argument '_ invariant
-   = note: the struct Type<'a> is invariant over the parameter 'a
+   = note: requirement occurs because of the type `Type<'_>`, which makes the generic argument `'_` invariant
+   = note: the struct `Type<'a>` is invariant over the parameter `'a`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
 help: `'a` and `'b` must be the same: replace one with the other

src/test/ui/associated-types/cache/project-fn-ret-invariant.transmute.nll.stderr

@@ -7,8 +7,8 @@ LL | fn baz<'a, 'b>(x: Type<'a>) -> Type<'static> {
 LL |     bar(foo, x)
    |     ^^^^^^^^^^^ returning this value requires that `'a` must outlive `'static`
    |
-   = note: requirement occurs because of the type Type<'_>, which makes the generic argument '_ invariant
-   = note: the struct Type<'a> is invariant over the parameter 'a
+   = note: requirement occurs because of the type `Type<'_>`, which makes the generic argument `'_` invariant
+   = note: the struct `Type<'a>` is invariant over the parameter `'a`
    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
 
 error: aborting due to previous error