Rollup of 5 pull requests

compiler/rustc_errors/src/lib.rs

@@ -1655,11 +1655,11 @@ impl HandlerInner {
         let backtrace = std::env::var_os("RUST_BACKTRACE").map_or(true, |x| &x != "0");
         for bug in bugs {
             if let Some(file) = self.ice_file.as_ref()
-                && let Ok(mut out) = std::fs::File::options().append(true).open(file)
+                && let Ok(mut out) = std::fs::File::options().create(true).append(true).open(file)
             {
                 let _ = write!(
                     &mut out,
-                    "\n\ndelayed span bug: {}\n{}",
+                    "delayed span bug: {}\n{}\n",
                     bug.inner.styled_message().iter().filter_map(|(msg, _)| msg.as_str()).collect::<String>(),
                     &bug.note
                 );

compiler/rustc_hir_typeck/src/callee.rs

@@ -531,8 +531,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 return;
             }
 
-            let up_to_rcvr_span = segment.ident.span.until(callee_expr.span);
-            let rest_span = callee_expr.span.shrink_to_hi().to(call_expr.span.shrink_to_hi());
+            let Some(callee_expr_span) = callee_expr.span.find_ancestor_inside(call_expr.span)
+            else {
+                return;
+            };
+            let up_to_rcvr_span = segment.ident.span.until(callee_expr_span);
+            let rest_span = callee_expr_span.shrink_to_hi().to(call_expr.span.shrink_to_hi());
             let rest_snippet = if let Some(first) = rest.first() {
                 self.tcx
                     .sess

compiler/rustc_lint/messages.ftl

@@ -155,8 +155,6 @@ lint_builtin_unused_doc_comment = unused doc comment
 lint_builtin_while_true = denote infinite loops with `loop {"{"} ... {"}"}`
     .suggestion = use `loop`
 
-lint_cast_ref_to_mut = casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
-
 lint_check_name_deprecated = lint name `{$lint_name}` is deprecated and does not have an effect anymore. Use: {$new_name}
 
 lint_check_name_unknown = unknown lint: `{$lint_name}`
@@ -320,6 +318,8 @@ lint_invalid_nan_comparisons_eq_ne = incorrect NaN comparison, NaN cannot be dir
 
 lint_invalid_nan_comparisons_lt_le_gt_ge = incorrect NaN comparison, NaN is not orderable
 
+lint_invalid_reference_casting = casting `&T` to `&mut T` is undefined behavior, even if the reference is unused, consider instead using an `UnsafeCell`
+
 lint_lintpass_by_hand = implementing `LintPass` by hand
     .help = try using `declare_lint_pass!` or `impl_lint_pass!` instead
 

compiler/rustc_lint/src/lib.rs

@@ -50,7 +50,6 @@ extern crate tracing;
 
 mod array_into_iter;
 pub mod builtin;
-mod cast_ref_to_mut;
 mod context;
 mod deref_into_dyn_supertrait;
 mod drop_forget_useless;
@@ -78,6 +77,7 @@ mod opaque_hidden_inferred_bound;
 mod pass_by_value;
 mod passes;
 mod redundant_semicolon;
+mod reference_casting;
 mod traits;
 mod types;
 mod unused;
@@ -99,7 +99,6 @@ use rustc_span::Span;
 
 use array_into_iter::ArrayIntoIter;
 use builtin::*;
-use cast_ref_to_mut::*;
 use deref_into_dyn_supertrait::*;
 use drop_forget_useless::*;
 use enum_intrinsics_non_enums::EnumIntrinsicsNonEnums;
@@ -119,6 +118,7 @@ use noop_method_call::*;
 use opaque_hidden_inferred_bound::*;
 use pass_by_value::*;
 use redundant_semicolon::*;
+use reference_casting::*;
 use traits::*;
 use types::*;
 use unused::*;
@@ -218,7 +218,7 @@ late_lint_methods!(
             BoxPointers: BoxPointers,
             PathStatements: PathStatements,
             LetUnderscore: LetUnderscore,
-            CastRefToMut: CastRefToMut,
+            InvalidReferenceCasting: InvalidReferenceCasting,
             // Depends on referenced function signatures in expressions
             UnusedResults: UnusedResults,
             NonUpperCaseGlobals: NonUpperCaseGlobals,

compiler/rustc_lint/src/lints.rs

@@ -743,10 +743,10 @@ pub enum InvalidFromUtf8Diag {
     },
 }
 
-// cast_ref_to_mut.rs
+// reference_casting.rs
 #[derive(LintDiagnostic)]
-#[diag(lint_cast_ref_to_mut)]
-pub struct CastRefToMutDiag;
+#[diag(lint_invalid_reference_casting)]
+pub struct InvalidReferenceCastingDiag;
 
 // hidden_unicode_codepoints.rs
 #[derive(LintDiagnostic)]

compiler/rustc_lint/src/cast_ref_to_mut.rs → compiler/rustc_lint/src/reference_casting.rs

@@ -3,15 +3,16 @@ use rustc_hir::{Expr, ExprKind, MutTy, TyKind, UnOp};
 use rustc_middle::ty;
 use rustc_span::sym;
 
-use crate::{lints::CastRefToMutDiag, LateContext, LateLintPass, LintContext};
+use crate::{lints::InvalidReferenceCastingDiag, LateContext, LateLintPass, LintContext};
 
 declare_lint! {
-    /// The `cast_ref_to_mut` lint checks for casts of `&T` to `&mut T`
+    /// The `invalid_reference_casting` lint checks for casts of `&T` to `&mut T`
     /// without using interior mutability.
     ///
     /// ### Example
     ///
     /// ```rust,compile_fail
+    /// # #![deny(invalid_reference_casting)]
     /// fn x(r: &i32) {
     ///     unsafe {
     ///         *(r as *const i32 as *mut i32) += 1;
@@ -28,14 +29,14 @@ declare_lint! {
     ///
     /// `UnsafeCell` is the only way to obtain aliasable data that is considered
     /// mutable.
-    CAST_REF_TO_MUT,
-    Deny,
+    INVALID_REFERENCE_CASTING,
+    Allow,
     "casts of `&T` to `&mut T` without interior mutability"
 }
 
-declare_lint_pass!(CastRefToMut => [CAST_REF_TO_MUT]);
+declare_lint_pass!(InvalidReferenceCasting => [INVALID_REFERENCE_CASTING]);
 
-impl<'tcx> LateLintPass<'tcx> for CastRefToMut {
+impl<'tcx> LateLintPass<'tcx> for InvalidReferenceCasting {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'tcx>) {
         let ExprKind::Unary(UnOp::Deref, e) = &expr.kind else {
             return;
@@ -68,7 +69,7 @@ impl<'tcx> LateLintPass<'tcx> for CastRefToMut {
 
         let e = e.peel_blocks();
         if let ty::Ref(..) = cx.typeck_results().node_type(e.hir_id).kind() {
-            cx.emit_spanned_lint(CAST_REF_TO_MUT, expr.span, CastRefToMutDiag);
+            cx.emit_spanned_lint(INVALID_REFERENCE_CASTING, expr.span, InvalidReferenceCastingDiag);
         }
     }
 }

compiler/rustc_mir_transform/src/coverage/spans.rs

@@ -11,7 +11,7 @@ use rustc_middle::ty::TyCtxt;
 use rustc_span::source_map::original_sp;
 use rustc_span::{BytePos, ExpnKind, MacroKind, Span, Symbol};
 
-use std::cell::RefCell;
+use std::cell::OnceCell;
 use std::cmp::Ordering;
 
 #[derive(Debug, Copy, Clone)]
@@ -67,7 +67,7 @@ impl CoverageStatement {
 pub(super) struct CoverageSpan {
     pub span: Span,
     pub expn_span: Span,
-    pub current_macro_or_none: RefCell<Option<Option<Symbol>>>,
+    pub current_macro_or_none: OnceCell<Option<Symbol>>,
     pub bcb: BasicCoverageBlock,
     pub coverage_statements: Vec<CoverageStatement>,
     pub is_closure: bool,
@@ -175,8 +175,7 @@ impl CoverageSpan {
     /// If the span is part of a macro, returns the macro name symbol.
     pub fn current_macro(&self) -> Option<Symbol> {
         self.current_macro_or_none
-            .borrow_mut()
-            .get_or_insert_with(|| {
+            .get_or_init(|| {
                 if let ExpnKind::Macro(MacroKind::Bang, current_macro) =
                     self.expn_span.ctxt().outer_expn_data().kind
                 {

library/std/src/panicking.rs

@@ -300,7 +300,7 @@ pub fn panic_hook_with_disk_dump(info: &PanicInfo<'_>, path: Option<&crate::path
     };
 
     if let Some(path) = path
-        && let Ok(mut out) = crate::fs::File::options().create(true).write(true).open(&path)
+        && let Ok(mut out) = crate::fs::File::options().create(true).append(true).open(&path)
     {
         write(&mut out, BacktraceStyle::full());
     }

src/librustdoc/clean/mod.rs

@@ -2818,7 +2818,7 @@ fn clean_use_statement_inner<'tcx>(
     cx: &mut DocContext<'tcx>,
     inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
 ) -> Vec<Item> {
-    if let Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..) = path.res {
+    if should_ignore_res(path.res) {
         return Vec::new();
     }
     // We need this comparison because some imports (for std types for example)

src/librustdoc/clean/utils.rs

@@ -13,7 +13,7 @@ use rustc_ast as ast;
 use rustc_ast::tokenstream::TokenTree;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::{DefId, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, LocalDefId, LOCAL_CRATE};
 use rustc_middle::mir;
 use rustc_middle::mir::interpret::ConstValue;
 use rustc_middle::ty::{self, GenericArgKind, GenericArgsRef, TyCtxt};
@@ -629,3 +629,35 @@ pub(super) fn display_macro_source(
         }
     }
 }
+
+pub(crate) fn inherits_doc_hidden(
+    tcx: TyCtxt<'_>,
+    mut def_id: LocalDefId,
+    stop_at: Option<LocalDefId>,
+) -> bool {
+    let hir = tcx.hir();
+    while let Some(id) = tcx.opt_local_parent(def_id) {
+        if let Some(stop_at) = stop_at && id == stop_at {
+            return false;
+        }
+        def_id = id;
+        if tcx.is_doc_hidden(def_id.to_def_id()) {
+            return true;
+        } else if let Some(node) = hir.find_by_def_id(def_id) &&
+            matches!(
+                node,
+                hir::Node::Item(hir::Item { kind: hir::ItemKind::Impl(_), .. }),
+            )
+        {
+            // `impl` blocks stand a bit on their own: unless they have `#[doc(hidden)]` directly
+            // on them, they don't inherit it from the parent context.
+            return false;
+        }
+    }
+    false
+}
+
+#[inline]
+pub(crate) fn should_ignore_res(res: Res) -> bool {
+    matches!(res, Res::Def(DefKind::Ctor(..), _) | Res::SelfCtor(..))
+}