Auto merge of rust-lang#90661 - matthiaskrgr:rollup-1umbdlx, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - rust-lang#90487 (Add a chapter on reading Rustdoc output)
 - rust-lang#90508 (Apply adjustments for field expression even if inaccessible)
 - rust-lang#90627 (Suggest dereference of `Box` when inner type is expected)
 - rust-lang#90642 (use matches!() macro in more places)
 - rust-lang#90646 (type error go brrrrrrrr)
 - rust-lang#90649 (Run reveal_all on MIR when inlining is activated.)

Failed merges:

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

Author: bors

compiler/rustc_ast/src/util/parser.rs

@@ -212,7 +212,8 @@ impl AssocOp {
     /// parentheses while having a high degree of confidence on the correctness of the suggestion.
     pub fn can_continue_expr_unambiguously(&self) -> bool {
         use AssocOp::*;
-        match self {
+        matches!(
+            self,
             BitXor | // `{ 42 } ^ 3`
             Assign | // `{ 42 } = { 42 }`
             Divide | // `{ 42 } / 42`
@@ -225,9 +226,8 @@ impl AssocOp {
             As | // `{ 42 } as usize`
             // Equal | // `{ 42 } == { 42 }`    Accepting these here would regress incorrect
             // NotEqual | // `{ 42 } != { 42 }  struct literals parser recovery.
-            Colon => true, // `{ 42 }: usize`
-            _ => false,
-        }
+            Colon, // `{ 42 }: usize`
+        )
     }
 }
 

compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs

@@ -53,10 +53,7 @@ pub(crate) enum LaterUseKind {
 
 impl BorrowExplanation {
     pub(crate) fn is_explained(&self) -> bool {
-        match self {
-            BorrowExplanation::Unexplained => false,
-            _ => true,
-        }
+        !matches!(self, BorrowExplanation::Unexplained)
     }
     pub(crate) fn add_explanation_to_diagnostic<'tcx>(
         &self,

compiler/rustc_borrowck/src/region_infer/mod.rs

@@ -2110,14 +2110,14 @@ impl<'tcx> RegionInferenceContext<'tcx> {
                     _ => constraint_sup_scc != target_scc,
                 }
             } else {
-                match categorized_path[*i].category {
+                !matches!(
+                    categorized_path[*i].category,
                     ConstraintCategory::OpaqueType
-                    | ConstraintCategory::Boring
-                    | ConstraintCategory::BoringNoLocation
-                    | ConstraintCategory::Internal
-                    | ConstraintCategory::Predicate(_) => false,
-                    _ => true,
-                }
+                        | ConstraintCategory::Boring
+                        | ConstraintCategory::BoringNoLocation
+                        | ConstraintCategory::Internal
+                        | ConstraintCategory::Predicate(_)
+                )
             }
         };
 

compiler/rustc_borrowck/src/universal_regions.rs

@@ -138,17 +138,11 @@ impl<'tcx> DefiningTy<'tcx> {
     }
 
     pub fn is_fn_def(&self) -> bool {
-        match *self {
-            DefiningTy::FnDef(..) => true,
-            _ => false,
-        }
+        matches!(*self, DefiningTy::FnDef(..))
     }
 
     pub fn is_const(&self) -> bool {
-        match *self {
-            DefiningTy::Const(..) => true,
-            _ => false,
-        }
+        matches!(*self, DefiningTy::Const(..))
     }
 
     pub fn def_id(&self) -> DefId {

compiler/rustc_codegen_ssa/src/debuginfo/type_names.rs

@@ -124,10 +124,7 @@ fn push_debuginfo_type_name<'tcx>(
             // info for MSVC debugger. However, wrapping these types' names in a synthetic type
             // causes the .natvis engine for WinDbg to fail to display their data, so we opt these
             // types out to aid debugging in MSVC.
-            let is_slice_or_str = match *inner_type.kind() {
-                ty::Slice(_) | ty::Str => true,
-                _ => false,
-            };
+            let is_slice_or_str = matches!(*inner_type.kind(), ty::Slice(_) | ty::Str);
 
             if !cpp_like_names {
                 output.push('&');

compiler/rustc_const_eval/src/const_eval/error.rs

@@ -25,10 +25,7 @@ pub enum ConstEvalErrKind {
 
 impl MachineStopType for ConstEvalErrKind {
     fn is_hard_err(&self) -> bool {
-        match self {
-            Self::Panic { .. } => true,
-            _ => false,
-        }
+        matches!(self, Self::Panic { .. })
     }
 }
 

compiler/rustc_const_eval/src/const_eval/fn_queries.rs

@@ -51,10 +51,8 @@ fn is_const_fn_raw(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
         // If the function itself is not annotated with `const`, it may still be a `const fn`
         // if it resides in a const trait impl.
         is_parent_const_impl_raw(tcx, hir_id)
-    } else if let hir::Node::Ctor(_) = node {
-        true
     } else {
-        false
+        matches!(node, hir::Node::Ctor(_))
     }
 }
 

compiler/rustc_const_eval/src/interpret/intrinsics/type_name.rs

@@ -138,10 +138,8 @@ impl<'tcx> Printer<'tcx> for AbsolutePathPrinter<'tcx> {
         args: &[GenericArg<'tcx>],
     ) -> Result<Self::Path, Self::Error> {
         self = print_prefix(self)?;
-        let args = args.iter().cloned().filter(|arg| match arg.unpack() {
-            GenericArgKind::Lifetime(_) => false,
-            _ => true,
-        });
+        let args =
+            args.iter().cloned().filter(|arg| !matches!(arg.unpack(), GenericArgKind::Lifetime(_)));
         if args.clone().next().is_some() {
             self.generic_delimiters(|cx| cx.comma_sep(args))
         } else {

compiler/rustc_const_eval/src/interpret/terminator.rs

@@ -345,10 +345,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
 
                     // Figure out how to pass which arguments.
                     // The Rust ABI is special: ZST get skipped.
-                    let rust_abi = match caller_abi {
-                        Abi::Rust | Abi::RustCall => true,
-                        _ => false,
-                    };
+                    let rust_abi = matches!(caller_abi, Abi::Rust | Abi::RustCall);
+
                     // We have two iterators: Where the arguments come from,
                     // and where they go to.
 

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -131,10 +131,7 @@ impl Qualifs<'mir, 'tcx> {
             .body
             .basic_blocks()
             .iter_enumerated()
-            .find(|(_, block)| match block.terminator().kind {
-                TerminatorKind::Return => true,
-                _ => false,
-            })
+            .find(|(_, block)| matches!(block.terminator().kind, TerminatorKind::Return))
             .map(|(bb, _)| bb);
 
         let return_block = match return_block {

compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs

@@ -170,11 +170,12 @@ impl Qualif for NeedsNonConstDrop {
             let mut selcx = SelectionContext::with_constness(&infcx, hir::Constness::Const);
             selcx.select(&obligation)
         });
-        match implsrc {
-            Ok(Some(ImplSource::ConstDrop(_)))
-            | Ok(Some(ImplSource::Param(_, ty::BoundConstness::ConstIfConst))) => false,
-            _ => true,
-        }
+        !matches!(
+            implsrc,
+            Ok(Some(
+                ImplSource::ConstDrop(_) | ImplSource::Param(_, ty::BoundConstness::ConstIfConst)
+            ))
+        )
     }
 
     fn in_adt_inherently(cx: &ConstCx<'_, 'tcx>, adt: &'tcx AdtDef, _: SubstsRef<'tcx>) -> bool {

compiler/rustc_lexer/src/unescape.rs

@@ -68,11 +68,10 @@ pub enum EscapeError {
 impl EscapeError {
     /// Returns true for actual errors, as opposed to warnings.
     pub fn is_fatal(&self) -> bool {
-        match self {
-            EscapeError::UnskippedWhitespaceWarning => false,
-            EscapeError::MultipleSkippedLinesWarning => false,
-            _ => true,
-        }
+        !matches!(
+            self,
+            EscapeError::UnskippedWhitespaceWarning | EscapeError::MultipleSkippedLinesWarning
+        )
     }
 }
 

compiler/rustc_middle/src/mir/interpret/error.rs

@@ -538,12 +538,12 @@ impl InterpError<'_> {
     /// To avoid performance issues, there are places where we want to be sure to never raise these formatting errors,
     /// so this method lets us detect them and `bug!` on unexpected errors.
     pub fn formatted_string(&self) -> bool {
-        match self {
+        matches!(
+            self,
             InterpError::Unsupported(UnsupportedOpInfo::Unsupported(_))
-            | InterpError::UndefinedBehavior(UndefinedBehaviorInfo::ValidationFailure { .. })
-            | InterpError::UndefinedBehavior(UndefinedBehaviorInfo::Ub(_)) => true,
-            _ => false,
-        }
+                | InterpError::UndefinedBehavior(UndefinedBehaviorInfo::ValidationFailure { .. })
+                | InterpError::UndefinedBehavior(UndefinedBehaviorInfo::Ub(_))
+        )
     }
 
     /// Should this error be reported as a hard error, preventing compilation, or a soft error,

compiler/rustc_middle/src/ty/relate.rs

@@ -187,8 +187,12 @@ impl<'tcx> Relate<'tcx> for ty::FnSig<'tcx> {
             })
             .enumerate()
             .map(|(i, r)| match r {
-                Err(TypeError::Sorts(exp_found)) => Err(TypeError::ArgumentSorts(exp_found, i)),
-                Err(TypeError::Mutability) => Err(TypeError::ArgumentMutability(i)),
+                Err(TypeError::Sorts(exp_found) | TypeError::ArgumentSorts(exp_found, _)) => {
+                    Err(TypeError::ArgumentSorts(exp_found, i))
+                }
+                Err(TypeError::Mutability | TypeError::ArgumentMutability(_)) => {
+                    Err(TypeError::ArgumentMutability(i))
+                }
                 r => r,
             });
         Ok(ty::FnSig {

compiler/rustc_mir_transform/src/coverage/mod.rs

@@ -485,7 +485,7 @@ fn inject_statement(
 
 // Non-code expressions are injected into the coverage map, without generating executable code.
 fn inject_intermediate_expression(mir_body: &mut mir::Body<'tcx>, expression: CoverageKind) {
-    debug_assert!(if let CoverageKind::Expression { .. } = expression { true } else { false });
+    debug_assert!(matches!(expression, CoverageKind::Expression { .. }));
     debug!("  injecting non-code expression {:?}", expression);
     let inject_in_bb = mir::START_BLOCK;
     let data = &mut mir_body[inject_in_bb];

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -94,10 +94,9 @@ impl CoverageSpan {
         stmt_index: usize,
     ) -> Self {
         let is_closure = match statement.kind {
-            StatementKind::Assign(box (_, Rvalue::Aggregate(box ref kind, _))) => match kind {
-                AggregateKind::Closure(_, _) | AggregateKind::Generator(_, _, _) => true,
-                _ => false,
-            },
+            StatementKind::Assign(box (_, Rvalue::Aggregate(box ref kind, _))) => {
+                matches!(kind, AggregateKind::Closure(_, _) | AggregateKind::Generator(_, _, _))
+            }
             _ => false,
         };
 

compiler/rustc_mir_transform/src/reveal_all.rs

@@ -11,7 +11,7 @@ impl<'tcx> MirPass<'tcx> for RevealAll {
     fn run_pass(&self, tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         // This pass must run before inlining, since we insert callee bodies in RevealAll mode.
         // Do not apply this transformation to generators.
-        if (tcx.sess.mir_opt_level() >= 3 || !super::inline::is_enabled(tcx))
+        if (tcx.sess.mir_opt_level() >= 3 || super::inline::is_enabled(tcx))
             && body.generator.is_none()
         {
             let param_env = tcx.param_env_reveal_all_normalized(body.source.def_id());

compiler/rustc_mir_transform/src/unreachable_prop.rs

@@ -27,9 +27,8 @@ impl MirPass<'_> for UnreachablePropagation {
             // This is a temporary solution that handles possibly diverging asm statements.
             // Accompanying testcases: mir-opt/unreachable_asm.rs and mir-opt/unreachable_asm_2.rs
             let asm_stmt_in_block = || {
-                bb_data.statements.iter().any(|stmt: &Statement<'_>| match stmt.kind {
-                    StatementKind::LlvmInlineAsm(..) => true,
-                    _ => false,
+                bb_data.statements.iter().any(|stmt: &Statement<'_>| {
+                    matches!(stmt.kind, StatementKind::LlvmInlineAsm(..))
                 })
             };
 

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

@@ -320,10 +320,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
 
     /// Returns `true` if the trait predicate is considerd `const` to this selection context.
     pub fn is_trait_predicate_const(&self, pred: ty::TraitPredicate<'_>) -> bool {
-        match pred.constness {
-            ty::BoundConstness::ConstIfConst if self.is_in_const_context => true,
-            _ => false,
-        }
+        matches!(pred.constness, ty::BoundConstness::ConstIfConst) && self.is_in_const_context
     }
 
     /// Returns `true` if the predicate is considered `const` to

compiler/rustc_typeck/src/check/cast.rs

@@ -436,11 +436,8 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                     // Very crude check to see whether the expression must be wrapped
                     // in parentheses for the suggestion to work (issue #89497).
                     // Can/should be extended in the future.
-                    let needs_parens = !has_parens
-                        && match self.expr.kind {
-                            hir::ExprKind::Cast(..) => true,
-                            _ => false,
-                        };
+                    let needs_parens =
+                        !has_parens && matches!(self.expr.kind, hir::ExprKind::Cast(..));
 
                     let mut suggestion = vec![(self.expr.span.shrink_to_lo(), sugg)];
                     if needs_parens {

compiler/rustc_typeck/src/check/compare_method.rs

@@ -453,6 +453,7 @@ fn check_region_bounds_on_impl_item<'tcx>(
     Ok(())
 }
 
+#[instrument(level = "debug", skip(infcx))]
 fn extract_spans_for_error_reporting<'a, 'tcx>(
     infcx: &infer::InferCtxt<'a, 'tcx>,
     terr: &TypeError<'_>,

compiler/rustc_typeck/src/check/demand.rs

@@ -29,6 +29,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
     ) {
         self.annotate_expected_due_to_let_ty(err, expr);
+        self.suggest_box_deref(err, expr, expected, expr_ty);
         self.suggest_compatible_variants(err, expr, expected, expr_ty);
         self.suggest_deref_ref_or_into(err, expr, expected, expr_ty, expected_ty_expr);
         if self.suggest_calling_boxed_future_when_appropriate(err, expr, expected, expr_ty) {
@@ -167,6 +168,23 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    fn suggest_box_deref(
+        &self,
+        err: &mut DiagnosticBuilder<'_>,
+        expr: &hir::Expr<'_>,
+        expected: Ty<'tcx>,
+        expr_ty: Ty<'tcx>,
+    ) {
+        if expr_ty.is_box() && expr_ty.boxed_ty() == expected {
+            err.span_suggestion_verbose(
+                expr.span.shrink_to_lo(),
+                "try dereferencing the `Box`",
+                "*".to_string(),
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+
     /// If the expected type is an enum (Issue #55250) with any variants whose
     /// sole field is of the found type, suggest such variants. (Issue #42764)
     fn suggest_compatible_variants(

compiler/rustc_typeck/src/check/expr.rs

@@ -1698,15 +1698,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         // Save the index of all fields regardless of their visibility in case
                         // of error recovery.
                         self.write_field_index(expr.hir_id, index);
+                        let adjustments = self.adjust_steps(&autoderef);
                         if field.vis.is_accessible_from(def_scope, self.tcx) {
-                            let adjustments = self.adjust_steps(&autoderef);
                             self.apply_adjustments(base, adjustments);
                             self.register_predicates(autoderef.into_obligations());
 
                             self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span, None);
                             return field_ty;
                         }
-                        private_candidate = Some((base_def.did, field_ty));
+                        private_candidate = Some((adjustments, base_def.did, field_ty));
                     }
                 }
                 ty::Tuple(tys) => {
@@ -1729,7 +1729,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
         self.structurally_resolved_type(autoderef.span(), autoderef.final_ty(false));
 
-        if let Some((did, field_ty)) = private_candidate {
+        if let Some((adjustments, did, field_ty)) = private_candidate {
+            // (#90483) apply adjustments to avoid ExprUseVisitor from
+            // creating erroneous projection.
+            self.apply_adjustments(base, adjustments);
             self.ban_private_field_access(expr, expr_t, field, did);
             return field_ty;
         }

compiler/rustc_typeck/src/structured_errors/wrong_number_of_generic_args.rs

@@ -300,7 +300,7 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
                     hir::TyKind::Path(hir::QPath::Resolved(
                         None,
                         hir::Path { res: hir::def::Res::Def(_, id), .. },
-                    )) if *id == def_id => true,
+                    )) => *id == def_id,
                     _ => false,
                 })
             })

library/std/src/net/ip.rs

@@ -878,12 +878,7 @@ impl Ipv4Addr {
     #[must_use]
     #[inline]
     pub const fn is_documentation(&self) -> bool {
-        match self.octets() {
-            [192, 0, 2, _] => true,
-            [198, 51, 100, _] => true,
-            [203, 0, 113, _] => true,
-            _ => false,
-        }
+        matches!(self.octets(), [192, 0, 2, _] | [198, 51, 100, _] | [203, 0, 113, _])
     }
 
     /// Converts this address to an [IPv4-compatible] [`IPv6` address].

library/std/src/os/unix/net/addr.rs

@@ -159,7 +159,7 @@ impl SocketAddr {
     #[must_use]
     #[stable(feature = "unix_socket", since = "1.10.0")]
     pub fn is_unnamed(&self) -> bool {
-        if let AddressKind::Unnamed = self.address() { true } else { false }
+        matches!(self.address(), AddressKind::Unnamed)
     }
 
     /// Returns the contents of this address if it is a `pathname` address.

src/doc/rustdoc/src/SUMMARY.md

@@ -1,6 +1,7 @@
 # The Rustdoc Book
 
 - [What is rustdoc?](what-is-rustdoc.md)
+- [How to read rustdoc output](how-to-read-rustdoc.md)
 - [How to write documentation](how-to-write-documentation.md)
 - [What to include (and exclude)](what-to-include.md)
 - [Command-line arguments](command-line-arguments.md)