Auto merge of rust-lang#110170 - JohnTitor:rollup-hdramer, r=JohnTitor

Rollup of 8 pull requests

Successful merges:

 - rust-lang#109527 (Set up standard library path substitution in rust-gdb and gdbgui)
 - rust-lang#109752 (Stall auto trait assembly in new solver for int/float vars)
 - rust-lang#109860 (Add support for RISC-V relax target feature)
 - rust-lang#109923 (Update `error [E0449]: unnecessary visibility qualifier` to be more clear)
 - rust-lang#110070 (The `wrapping_neg` example for unsigned types shouldn't use `i8`)
 - rust-lang#110146 (fix(doc): do not parse inline when output is json for external crate)
 - rust-lang#110147 (Add regression test for rust-lang#104916)
 - rust-lang#110149 (Update books)

Failed merges:

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

Author: bors

compiler/rustc_ast_passes/messages.ftl

@@ -17,9 +17,10 @@ ast_passes_keyword_lifetime =
 ast_passes_invalid_label =
     invalid label name `{$name}`
 
-ast_passes_invalid_visibility =
-    unnecessary visibility qualifier
-    .implied = `pub` not permitted here because it's implied
+ast_passes_visibility_not_permitted =
+    visibility qualifiers are not permitted here
+    .enum_variant = enum variants and their fields always share the visibility of the enum they are in
+    .trait_impl = trait items always share the visibility of their trait
     .individual_impl_items = place qualifiers on individual impl items instead
     .individual_foreign_items = place qualifiers on individual foreign items instead
 

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -240,16 +240,12 @@ impl<'a> AstValidator<'a> {
         }
     }
 
-    fn invalid_visibility(&self, vis: &Visibility, note: Option<errors::InvalidVisibilityNote>) {
+    fn visibility_not_permitted(&self, vis: &Visibility, note: errors::VisibilityNotPermittedNote) {
         if let VisibilityKind::Inherited = vis.kind {
             return;
         }
 
-        self.session.emit_err(errors::InvalidVisibility {
-            span: vis.span,
-            implied: vis.kind.is_pub().then_some(vis.span),
-            note,
-        });
+        self.session.emit_err(errors::VisibilityNotPermitted { span: vis.span, note });
     }
 
     fn check_decl_no_pat(decl: &FnDecl, mut report_err: impl FnMut(Span, Option<Ident>, bool)) {
@@ -819,7 +815,10 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                 items,
             }) => {
                 self.with_in_trait_impl(true, Some(*constness), |this| {
-                    this.invalid_visibility(&item.vis, None);
+                    this.visibility_not_permitted(
+                        &item.vis,
+                        errors::VisibilityNotPermittedNote::TraitImpl,
+                    );
                     if let TyKind::Err = self_ty.kind {
                         this.err_handler().emit_err(errors::ObsoleteAuto { span: item.span });
                     }
@@ -866,9 +865,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                         only_trait: only_trait.then_some(()),
                     };
 
-                self.invalid_visibility(
+                self.visibility_not_permitted(
                     &item.vis,
-                    Some(errors::InvalidVisibilityNote::IndividualImplItems),
+                    errors::VisibilityNotPermittedNote::IndividualImplItems,
                 );
                 if let &Unsafe::Yes(span) = unsafety {
                     self.err_handler().emit_err(errors::InherentImplCannotUnsafe {
@@ -924,9 +923,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             }
             ItemKind::ForeignMod(ForeignMod { abi, unsafety, .. }) => {
                 let old_item = mem::replace(&mut self.extern_mod, Some(item));
-                self.invalid_visibility(
+                self.visibility_not_permitted(
                     &item.vis,
-                    Some(errors::InvalidVisibilityNote::IndividualForeignItems),
+                    errors::VisibilityNotPermittedNote::IndividualForeignItems,
                 );
                 if let &Unsafe::Yes(span) = unsafety {
                     self.err_handler().emit_err(errors::UnsafeItem { span, kind: "extern block" });
@@ -940,9 +939,15 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
             }
             ItemKind::Enum(def, _) => {
                 for variant in &def.variants {
-                    self.invalid_visibility(&variant.vis, None);
+                    self.visibility_not_permitted(
+                        &variant.vis,
+                        errors::VisibilityNotPermittedNote::EnumVariant,
+                    );
                     for field in variant.data.fields() {
-                        self.invalid_visibility(&field.vis, None);
+                        self.visibility_not_permitted(
+                            &field.vis,
+                            errors::VisibilityNotPermittedNote::EnumVariant,
+                        );
                     }
                 }
             }
@@ -1301,7 +1306,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
         }
 
         if ctxt == AssocCtxt::Trait || self.in_trait_impl {
-            self.invalid_visibility(&item.vis, None);
+            self.visibility_not_permitted(&item.vis, errors::VisibilityNotPermittedNote::TraitImpl);
             if let AssocItemKind::Fn(box Fn { sig, .. }) = &item.kind {
                 self.check_trait_fn_not_const(sig.header.constness);
             }

compiler/rustc_ast_passes/src/errors.rs

@@ -42,18 +42,20 @@ pub struct InvalidLabel {
 }
 
 #[derive(Diagnostic)]
-#[diag(ast_passes_invalid_visibility, code = "E0449")]
-pub struct InvalidVisibility {
+#[diag(ast_passes_visibility_not_permitted, code = "E0449")]
+pub struct VisibilityNotPermitted {
     #[primary_span]
     pub span: Span,
-    #[label(ast_passes_implied)]
-    pub implied: Option<Span>,
     #[subdiagnostic]
-    pub note: Option<InvalidVisibilityNote>,
+    pub note: VisibilityNotPermittedNote,
 }
 
 #[derive(Subdiagnostic)]
-pub enum InvalidVisibilityNote {
+pub enum VisibilityNotPermittedNote {
+    #[note(ast_passes_enum_variant)]
+    EnumVariant,
+    #[note(ast_passes_trait_impl)]
+    TraitImpl,
     #[note(ast_passes_individual_impl_items)]
     IndividualImplItems,
     #[note(ast_passes_individual_foreign_items)]

compiler/rustc_codegen_ssa/src/target_features.rs

@@ -251,6 +251,7 @@ const RISCV_ALLOWED_FEATURES: &[(&str, Option<Symbol>)] = &[
     ("e", Some(sym::riscv_target_feature)),
     ("f", Some(sym::riscv_target_feature)),
     ("m", Some(sym::riscv_target_feature)),
+    ("relax", Some(sym::riscv_target_feature)),
     ("v", Some(sym::riscv_target_feature)),
     ("zba", Some(sym::riscv_target_feature)),
     ("zbb", Some(sym::riscv_target_feature)),

compiler/rustc_error_codes/src/error_codes/E0449.md

@@ -1,4 +1,6 @@
-A visibility qualifier was used when it was unnecessary.
+A visibility qualifier was used where one is not permitted. Visibility
+qualifiers are not permitted on enum variants, trait items, impl blocks, and
+extern blocks, as they already share the visibility of the parent item.
 
 Erroneous code examples:
 
@@ -9,15 +11,18 @@ trait Foo {
     fn foo();
 }
 
-pub impl Bar {} // error: unnecessary visibility qualifier
+enum Baz {
+    pub Qux, // error: visibility qualifiers are not permitted here
+}
+
+pub impl Bar {} // error: visibility qualifiers are not permitted here
 
-pub impl Foo for Bar { // error: unnecessary visibility qualifier
-    pub fn foo() {} // error: unnecessary visibility qualifier
+pub impl Foo for Bar { // error: visibility qualifiers are not permitted here
+    pub fn foo() {} // error: visibility qualifiers are not permitted here
 }
 ```
 
-To fix this error, please remove the visibility qualifier when it is not
-required. Example:
+To fix this error, simply remove the visibility qualifier. Example:
 
 ```
 struct Bar;
@@ -26,12 +31,18 @@ trait Foo {
     fn foo();
 }
 
+enum Baz {
+    // Enum variants share the visibility of the enum they are in, so
+    // `pub` is not allowed here
+    Qux,
+}
+
 // Directly implemented methods share the visibility of the type itself,
-// so `pub` is unnecessary here
+// so `pub` is not allowed here
 impl Bar {}
 
-// Trait methods share the visibility of the trait, so `pub` is
-// unnecessary in either case
+// Trait methods share the visibility of the trait, so `pub` is not
+// allowed in either case
 impl Foo for Bar {
     fn foo() {}
 }

compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs

@@ -24,21 +24,19 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
         | ty::FnDef(..)
         | ty::FnPtr(_)
         | ty::Error(_)
-        | ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
         | ty::Never
         | ty::Char => Ok(vec![]),
 
-        // Treat this like `struct str([u8]);`
+        // Treat `str` like it's defined as `struct str([u8]);`
         ty::Str => Ok(vec![tcx.mk_slice(tcx.types.u8)]),
 
         ty::Dynamic(..)
         | ty::Param(..)
         | ty::Foreign(..)
         | ty::Alias(ty::Projection, ..)
-        | ty::Placeholder(..) => Err(NoSolution),
-
-        ty::Bound(..)
-        | ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => {
+        | ty::Placeholder(..)
+        | ty::Bound(..)
+        | ty::Infer(_) => {
             bug!("unexpected type `{ty}`")
         }
 

compiler/rustc_trait_selection/src/solve/trait_goals.rs

@@ -147,24 +147,66 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
         ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
     ) -> QueryResult<'tcx> {
-        // This differs from the current stable behavior and
-        // fixes #84857. Due to breakage found via crater, we
-        // currently instead lint patterns which can be used to
-        // exploit this unsoundness on stable, see #93367 for
-        // more details.
-        //
-        // Using `TreatProjections::NextSolverLookup` is fine here because
-        // `instantiate_constituent_tys_for_auto_trait` returns nothing for
-        // projection types anyways. So it doesn't really matter what we do
-        // here, and this is faster.
-        if let Some(def_id) = ecx.tcx().find_map_relevant_impl(
-            goal.predicate.def_id(),
-            goal.predicate.self_ty(),
-            TreatProjections::NextSolverLookup,
-            Some,
-        ) {
-            debug!(?def_id, ?goal, "disqualified auto-trait implementation");
-            return Err(NoSolution);
+        let self_ty = goal.predicate.self_ty();
+        match *self_ty.kind() {
+            // Stall int and float vars until they are resolved to a concrete
+            // numerical type. That's because the check for impls below treats
+            // int vars as matching any impl. Even if we filtered such impls,
+            // we probably don't want to treat an `impl !AutoTrait for i32` as
+            // disqualifying the built-in auto impl for `i64: AutoTrait` either.
+            ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) => {
+                return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS);
+            }
+
+            // These types cannot be structurally decomposed into constitutent
+            // types, and therefore have no builtin impl.
+            ty::Dynamic(..)
+            | ty::Param(..)
+            | ty::Foreign(..)
+            | ty::Alias(ty::Projection, ..)
+            | ty::Placeholder(..) => return Err(NoSolution),
+
+            ty::Infer(_) | ty::Bound(_, _) => bug!("unexpected type `{self_ty}`"),
+
+            // For rigid types, we only register a builtin auto implementation
+            // if there is no implementation that could ever apply to the self
+            // type.
+            //
+            // This differs from the current stable behavior and fixes #84857.
+            // Due to breakage found via crater, we currently instead lint
+            // patterns which can be used to exploit this unsoundness on stable,
+            // see #93367 for more details.
+            ty::Bool
+            | ty::Char
+            | ty::Int(_)
+            | ty::Uint(_)
+            | ty::Float(_)
+            | ty::Str
+            | ty::Array(_, _)
+            | ty::Slice(_)
+            | ty::RawPtr(_)
+            | ty::Ref(_, _, _)
+            | ty::FnDef(_, _)
+            | ty::FnPtr(_)
+            | ty::Closure(_, _)
+            | ty::Generator(_, _, _)
+            | ty::GeneratorWitness(_)
+            | ty::GeneratorWitnessMIR(_, _)
+            | ty::Never
+            | ty::Tuple(_)
+            | ty::Error(_)
+            | ty::Adt(_, _)
+            | ty::Alias(ty::Opaque, _) => {
+                if let Some(def_id) = ecx.tcx().find_map_relevant_impl(
+                    goal.predicate.def_id(),
+                    goal.predicate.self_ty(),
+                    TreatProjections::NextSolverLookup,
+                    Some,
+                ) {
+                    debug!(?def_id, ?goal, "disqualified auto-trait implementation");
+                    return Err(NoSolution);
+                }
+            }
         }
 
         ecx.probe_and_evaluate_goal_for_constituent_tys(

library/core/src/num/uint_macros.rs

@@ -1363,12 +1363,11 @@ macro_rules! uint_impl {
         ///
         /// Basic usage:
         ///
-        /// Please note that this example is shared between integer types.
-        /// Which explains why `i8` is used here.
-        ///
         /// ```
-        /// assert_eq!(100i8.wrapping_neg(), -100);
-        /// assert_eq!((-128i8).wrapping_neg(), -128);
+        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_neg(), 0);")]
+        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_neg(), 1);")]
+        #[doc = concat!("assert_eq!(13_", stringify!($SelfT), ".wrapping_neg(), (!13) + 1);")]
+        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_neg(), !(42 - 1));")]
         /// ```
         #[stable(feature = "num_wrapping", since = "1.2.0")]
         #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]