Auto merge of #106892 - matthiaskrgr:rollup-ohneu8o, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #106072 (fix: misleading "add dyn keyword before derive macro" suggestion)
 - #106859 (Suggestion for type mismatch when we need a u8 but the programmer wrote a char literal)
 - #106863 (Remove various double spaces in compiler source comments.)
 - #106865 (Add explanation comment for GUI test)
 - #106867 (Fix the stability attributes for `std::os::fd`.)
 - #106878 (Add regression test for #92157)
 - #106879 (Add regression test for #42114)
 - #106880 (doc: fix typo)

Failed merges:

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

Author: bors

compiler/rustc_abi/src/lib.rs

@@ -1100,7 +1100,7 @@ pub enum FieldsShape {
         /// named `inverse_memory_index`.
         ///
         // FIXME(eddyb) build a better abstraction for permutations, if possible.
-        // FIXME(camlorn) also consider small vector  optimization here.
+        // FIXME(camlorn) also consider small vector optimization here.
         memory_index: Vec<u32>,
     },
 }

compiler/rustc_borrowck/src/places_conflict.rs

@@ -209,7 +209,7 @@ fn place_components_conflict<'tcx>(
             match (elem, &base_ty.kind(), access) {
                 (_, _, Shallow(Some(ArtificialField::ArrayLength)))
                 | (_, _, Shallow(Some(ArtificialField::ShallowBorrow))) => {
-                    // The array length is like  additional fields on the
+                    // The array length is like additional fields on the
                     // type; it does not overlap any existing data there.
                     // Furthermore, if cannot actually be a prefix of any
                     // borrowed place (at least in MIR as it is currently.)

compiler/rustc_borrowck/src/region_infer/opaque_types.rs

@@ -235,7 +235,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
     /// # Parameters
     ///
     /// - `def_id`, the `impl Trait` type
-    /// - `substs`, the substs  used to instantiate this opaque type
+    /// - `substs`, the substs used to instantiate this opaque type
     /// - `instantiated_ty`, the inferred type C1 -- fully resolved, lifted version of
     ///   `opaque_defn.concrete_ty`
     #[instrument(level = "debug", skip(self))]

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -3305,7 +3305,13 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 let label = "add `dyn` keyword before this trait";
                 let mut diag =
                     rustc_errors::struct_span_err!(tcx.sess, self_ty.span, E0782, "{}", msg);
-                diag.multipart_suggestion_verbose(label, sugg, Applicability::MachineApplicable);
+                if self_ty.span.can_be_used_for_suggestions() {
+                    diag.multipart_suggestion_verbose(
+                        label,
+                        sugg,
+                        Applicability::MachineApplicable,
+                    );
+                }
                 // check if the impl trait that we are considering is a impl of a local trait
                 self.maybe_lint_blanket_trait_impl(&self_ty, &mut diag);
                 diag.emit();

compiler/rustc_hir_typeck/src/expr_use_visitor.rs

@@ -417,7 +417,7 @@ impl<'a, 'tcx> ExprUseVisitor<'a, 'tcx> {
                                 // Named constants have to be equated with the value
                                 // being matched, so that's a read of the value being matched.
                                 //
-                                // FIXME: We don't actually  reads for ZSTs.
+                                // FIXME: We don't actually reads for ZSTs.
                                 needs_to_be_read = true;
                             }
                             _ => {

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -232,7 +232,7 @@ pub type PickResult<'tcx> = Result<Pick<'tcx>, MethodError<'tcx>>;
 pub enum Mode {
     // An expression of the form `receiver.method_name(...)`.
     // Autoderefs are performed on `receiver`, lookup is done based on the
-    // `self` argument  of the method, and static methods aren't considered.
+    // `self` argument of the method, and static methods aren't considered.
     MethodCall,
     // An expression of the form `Type::item` or `<T>::item`.
     // No autoderefs are performed, lookup is done based on the type each

compiler/rustc_infer/src/infer/error_reporting/mod.rs

@@ -1923,6 +1923,22 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
                         (ty::Tuple(fields), _) => {
                             self.emit_tuple_wrap_err(&mut err, span, found, fields)
                         }
+                        // If a byte was expected and the found expression is a char literal
+                        // containing a single ASCII character, perhaps the user meant to write `b'c'` to
+                        // specify a byte literal
+                        (ty::Uint(ty::UintTy::U8), ty::Char) => {
+                            if let Ok(code) = self.tcx.sess().source_map().span_to_snippet(span)
+                                && let Some(code) = code.strip_prefix('\'').and_then(|s| s.strip_suffix('\''))
+                                && code.chars().next().map_or(false, |c| c.is_ascii())
+                            {
+                                err.span_suggestion(
+                                    span,
+                                    "if you meant to write a byte literal, prefix with `b`",
+                                    format!("b'{}'", escape_literal(code)),
+                                    Applicability::MachineApplicable,
+                                );
+                            }
+                        }
                         // If a character was expected and the found expression is a string literal
                         // containing a single character, perhaps the user meant to write `'c'` to
                         // specify a character literal (issue #92479)

compiler/rustc_middle/src/ty/typeck_results.rs

@@ -193,7 +193,7 @@ pub struct TypeckResults<'tcx> {
     pub generator_interior_types: ty::Binder<'tcx, Vec<GeneratorInteriorTypeCause<'tcx>>>,
 
     /// We sometimes treat byte string literals (which are of type `&[u8; N]`)
-    /// as `&[u8]`, depending on the pattern  in which they are used.
+    /// as `&[u8]`, depending on the pattern in which they are used.
     /// This hashset records all instances where we behave
     /// like this to allow `const_to_pat` to reliably handle this situation.
     pub treat_byte_string_as_slice: ItemLocalSet,

compiler/rustc_parse/src/parser/pat.rs

@@ -469,7 +469,7 @@ impl<'a> Parser<'a> {
     /// Try to recover the more general form `intersect ::= $pat_lhs @ $pat_rhs`.
     ///
     /// Allowed binding patterns generated by `binding ::= ref? mut? $ident @ $pat_rhs`
-    /// should already have been parsed by now  at this point,
+    /// should already have been parsed by now at this point,
     /// if the next token is `@` then we can try to parse the more general form.
     ///
     /// Consult `parse_pat_ident` for the `binding` grammar.

compiler/rustc_session/src/config.rs

@@ -2091,7 +2091,7 @@ fn parse_libs(matches: &getopts::Matches, error_format: ErrorOutputType) -> Vec<
         .map(|s| {
             // Parse string of the form "[KIND[:MODIFIERS]=]lib[:new_name]",
             // where KIND is one of "dylib", "framework", "static", "link-arg" and
-            // where MODIFIERS are  a comma separated list of supported modifiers
+            // where MODIFIERS are a comma separated list of supported modifiers
             // (bundle, verbatim, whole-archive, as-needed). Each modifier is prefixed
             // with either + or - to indicate whether it is enabled or disabled.
             // The last value specified for a given modifier wins.