Rollup of 10 pull requests

compiler/rustc_ast/src/ast.rs

@@ -1533,11 +1533,10 @@ impl Expr {
             // then type of result is trait object.
             // Otherwise we don't assume the result type.
             ExprKind::Binary(binop, lhs, rhs) if binop.node == BinOpKind::Add => {
-                if let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) {
-                    TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
-                } else {
+                let (Some(lhs), Some(rhs)) = (lhs.to_bound(), rhs.to_bound()) else {
                     return None;
-                }
+                };
+                TyKind::TraitObject(vec![lhs, rhs], TraitObjectSyntax::None)
             }
 
             ExprKind::Underscore => TyKind::Infer,

compiler/rustc_ast/src/attr/mod.rs

@@ -447,20 +447,17 @@ impl MetaItem {
                     thin_vec![PathSegment::path_root(span)]
                 };
                 loop {
-                    if let Some(&TokenTree::Token(Token { kind: token::Ident(name, _), span }, _)) =
+                    let Some(&TokenTree::Token(Token { kind: token::Ident(name, _), span }, _)) =
                         iter.next().map(|tt| TokenTree::uninterpolate(tt)).as_deref()
-                    {
-                        segments.push(PathSegment::from_ident(Ident::new(name, span)));
-                    } else {
+                    else {
                         return None;
-                    }
-                    if let Some(TokenTree::Token(Token { kind: token::PathSep, .. }, _)) =
-                        iter.peek()
-                    {
-                        iter.next();
-                    } else {
+                    };
+                    segments.push(PathSegment::from_ident(Ident::new(name, span)));
+                    let Some(TokenTree::Token(Token { kind: token::PathSep, .. }, _)) = iter.peek()
+                    else {
                         break;
-                    }
+                    };
+                    iter.next();
                 }
                 let span = span.with_hi(segments.last().unwrap().ident.span.hi());
                 Path { span, segments, tokens: None }

compiler/rustc_ast/src/lib.rs

@@ -6,6 +6,7 @@
 
 // tidy-alphabetical-start
 #![cfg_attr(bootstrap, feature(array_windows))]
+#![deny(clippy::manual_let_else)]
 #![doc(test(attr(deny(warnings), allow(internal_features))))]
 #![feature(associated_type_defaults)]
 #![feature(box_patterns)]

compiler/rustc_ast_lowering/src/delegation.rs

@@ -43,13 +43,15 @@ use hir::def::{DefKind, PartialRes, Res};
 use hir::{BodyId, HirId};
 use rustc_abi::ExternAbi;
 use rustc_ast::*;
+use rustc_attr_parsing::{AttributeParser, ShouldEmit};
 use rustc_errors::ErrorGuaranteed;
+use rustc_hir::Target;
 use rustc_hir::attrs::{AttributeKind, InlineAttr};
 use rustc_hir::def_id::DefId;
 use rustc_middle::span_bug;
-use rustc_middle::ty::{Asyncness, ResolverAstLowering};
+use rustc_middle::ty::{Asyncness, DelegationFnSigAttrs, ResolverAstLowering};
 use rustc_span::symbol::kw;
-use rustc_span::{Ident, Span, Symbol};
+use rustc_span::{DUMMY_SP, Ident, Span, Symbol};
 use {rustc_ast as ast, rustc_hir as hir};
 
 use super::{GenericArgsMode, ImplTraitContext, LoweringContext, ParamMode};
@@ -62,6 +64,41 @@ pub(crate) struct DelegationResults<'hir> {
     pub generics: &'hir hir::Generics<'hir>,
 }
 
+struct AttributeAdditionInfo {
+    pub equals: fn(&hir::Attribute) -> bool,
+    pub kind: AttributeAdditionKind,
+}
+
+enum AttributeAdditionKind {
+    Default { factory: fn(Span) -> hir::Attribute },
+    Inherit { flag: DelegationFnSigAttrs, factory: fn(Span, &hir::Attribute) -> hir::Attribute },
+}
+
+const PARENT_ID: hir::ItemLocalId = hir::ItemLocalId::ZERO;
+
+static ATTRIBUTES_ADDITIONS: &[AttributeAdditionInfo] = &[
+    AttributeAdditionInfo {
+        equals: |a| matches!(a, hir::Attribute::Parsed(AttributeKind::MustUse { .. })),
+        kind: AttributeAdditionKind::Inherit {
+            factory: |span, original_attribute| {
+                let reason = match original_attribute {
+                    hir::Attribute::Parsed(AttributeKind::MustUse { reason, .. }) => *reason,
+                    _ => None,
+                };
+
+                hir::Attribute::Parsed(AttributeKind::MustUse { span, reason })
+            },
+            flag: DelegationFnSigAttrs::MUST_USE,
+        },
+    },
+    AttributeAdditionInfo {
+        equals: |a| matches!(a, hir::Attribute::Parsed(AttributeKind::Inline(..))),
+        kind: AttributeAdditionKind::Default {
+            factory: |span| hir::Attribute::Parsed(AttributeKind::Inline(InlineAttr::Hint, span)),
+        },
+    },
+];
+
 impl<'hir> LoweringContext<'_, 'hir> {
     fn is_method(&self, def_id: DefId, span: Span) -> bool {
         match self.tcx.def_kind(def_id) {
@@ -88,7 +125,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
         let sig_id = self.get_delegation_sig_id(item_id, delegation.id, span, is_in_trait_impl);
         match sig_id {
             Ok(sig_id) => {
-                self.add_inline_attribute_if_needed(span);
+                self.add_attributes_if_needed(span, sig_id);
 
                 let is_method = self.is_method(sig_id, span);
                 let (param_count, c_variadic) = self.param_count(sig_id);
@@ -103,29 +140,100 @@ impl<'hir> LoweringContext<'_, 'hir> {
         }
     }
 
-    fn add_inline_attribute_if_needed(&mut self, span: Span) {
-        const PARENT_ID: hir::ItemLocalId = hir::ItemLocalId::ZERO;
-        let create_inline_attr_slice =
-            || [hir::Attribute::Parsed(AttributeKind::Inline(InlineAttr::Hint, span))];
-
-        let new_attributes = match self.attrs.get(&PARENT_ID) {
-            Some(attrs) => {
-                // Check if reuse already specifies any inline attribute, if so, do nothing
-                if attrs
-                    .iter()
-                    .any(|a| matches!(a, hir::Attribute::Parsed(AttributeKind::Inline(..))))
+    fn add_attributes_if_needed(&mut self, span: Span, sig_id: DefId) {
+        let new_attributes = self.create_new_attributes(
+            ATTRIBUTES_ADDITIONS,
+            span,
+            sig_id,
+            self.attrs.get(&PARENT_ID),
+        );
+
+        if new_attributes.is_empty() {
+            return;
+        }
+
+        let new_arena_allocated_attributes = match self.attrs.get(&PARENT_ID) {
+            Some(existing_attrs) => self.arena.alloc_from_iter(
+                existing_attrs.iter().map(|a| a.clone()).chain(new_attributes.into_iter()),
+            ),
+            None => self.arena.alloc_from_iter(new_attributes.into_iter()),
+        };
+
+        self.attrs.insert(PARENT_ID, new_arena_allocated_attributes);
+    }
+
+    fn create_new_attributes(
+        &self,
+        candidate_additions: &[AttributeAdditionInfo],
+        span: Span,
+        sig_id: DefId,
+        existing_attrs: Option<&&[hir::Attribute]>,
+    ) -> Vec<hir::Attribute> {
+        let local_original_attributes = self.parse_local_original_attributes(sig_id);
+
+        candidate_additions
+            .iter()
+            .filter_map(|addition_info| {
+                if let Some(existing_attrs) = existing_attrs
+                    && existing_attrs
+                        .iter()
+                        .any(|existing_attr| (addition_info.equals)(existing_attr))
                 {
-                    return;
+                    return None;
                 }
 
-                self.arena.alloc_from_iter(
-                    attrs.into_iter().map(|a| a.clone()).chain(create_inline_attr_slice()),
-                )
-            }
-            None => self.arena.alloc_from_iter(create_inline_attr_slice()),
-        };
+                match addition_info.kind {
+                    AttributeAdditionKind::Default { factory } => Some(factory(span)),
+                    AttributeAdditionKind::Inherit { flag, factory } => {
+                        let original_attribute = match sig_id.as_local() {
+                            Some(local_id) => self
+                                .resolver
+                                .delegation_fn_sigs
+                                .get(&local_id)
+                                .is_some_and(|sig| sig.attrs_flags.contains(flag))
+                                .then(|| {
+                                    local_original_attributes
+                                        .as_ref()
+                                        .map(|attrs| {
+                                            attrs
+                                                .iter()
+                                                .find(|base_attr| (addition_info.equals)(base_attr))
+                                        })
+                                        .flatten()
+                                })
+                                .flatten(),
+                            None => self
+                                .tcx
+                                .get_all_attrs(sig_id)
+                                .iter()
+                                .find(|base_attr| (addition_info.equals)(base_attr)),
+                        };
 
-        self.attrs.insert(PARENT_ID, new_attributes);
+                        original_attribute.map(|a| factory(span, a))
+                    }
+                }
+            })
+            .collect::<Vec<_>>()
+    }
+
+    fn parse_local_original_attributes(&self, sig_id: DefId) -> Option<Vec<hir::Attribute>> {
+        if let Some(local_id) = sig_id.as_local()
+            && let Some(info) = self.resolver.delegation_fn_sigs.get(&local_id)
+            && !info.to_inherit_attrs.is_empty()
+        {
+            Some(AttributeParser::parse_limited_all(
+                self.tcx.sess,
+                info.to_inherit_attrs.as_slice(),
+                None,
+                Target::Fn,
+                DUMMY_SP,
+                DUMMY_NODE_ID,
+                Some(self.tcx.features()),
+                ShouldEmit::Nothing,
+            ))
+        } else {
+            None
+        }
     }
 
     fn get_delegation_sig_id(
@@ -220,7 +328,9 @@ impl<'hir> LoweringContext<'_, 'hir> {
                     // We are not forwarding the attributes, as the delegation fn sigs are collected on the ast,
                     // and here we need the hir attributes.
                     let default_safety =
-                        if sig.target_feature || self.tcx.def_kind(parent) == DefKind::ForeignMod {
+                        if sig.attrs_flags.contains(DelegationFnSigAttrs::TARGET_FEATURE)
+                            || self.tcx.def_kind(parent) == DefKind::ForeignMod
+                        {
                             hir::Safety::Unsafe
                         } else {
                             hir::Safety::Safe

compiler/rustc_attr_parsing/messages.ftl

@@ -6,9 +6,6 @@ attr_parsing_bundle_needs_static =
 
 attr_parsing_cfg_attr_bad_delim = wrong `cfg_attr` delimiters
 
-attr_parsing_cfg_predicate_identifier =
-    `cfg` predicate key must be an identifier
-
 attr_parsing_deprecated_item_suggestion =
     suggestions on deprecated items are unstable
     .help = add `#![feature(deprecated_suggestion)]` to the crate root
@@ -41,9 +38,6 @@ attr_parsing_empty_link_name =
     link name must not be empty
     .label = empty link name
 
-attr_parsing_expected_one_cfg_pattern =
-    expected 1 cfg-pattern
-
 attr_parsing_expected_single_version_literal =
     expected single version literal
 
@@ -241,12 +235,6 @@ attr_parsing_unstable_cfg_target_compact =
 attr_parsing_unstable_feature_bound_incompatible_stability = item annotated with `#[unstable_feature_bound]` should not be stable
     .help = If this item is meant to be stable, do not use any functions annotated with `#[unstable_feature_bound]`. Otherwise, mark this item as unstable with `#[unstable]`
 
-attr_parsing_unsupported_literal_cfg_boolean =
-    literal in `cfg` predicate value must be a boolean
-attr_parsing_unsupported_literal_cfg_string =
-    literal in `cfg` predicate value must be a string
-attr_parsing_unsupported_literal_generic =
-    unsupported literal
 attr_parsing_unsupported_literal_suggestion =
     consider removing the prefix
 

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -4,7 +4,9 @@ use rustc_ast::token::Delimiter;
 use rustc_ast::tokenstream::DelimSpan;
 use rustc_ast::{AttrItem, Attribute, CRATE_NODE_ID, LitKind, ast, token};
 use rustc_errors::{Applicability, PResult};
-use rustc_feature::{AttrSuggestionStyle, AttributeTemplate, Features, template};
+use rustc_feature::{
+    AttrSuggestionStyle, AttributeTemplate, Features, GatedCfg, find_gated_cfg, template,
+};
 use rustc_hir::attrs::CfgEntry;
 use rustc_hir::lints::AttributeLintKind;
 use rustc_hir::{AttrPath, RustcVersion};
@@ -23,7 +25,7 @@ use crate::session_diagnostics::{
     AttributeParseError, AttributeParseErrorReason, CfgAttrBadDelim, MetaBadDelimSugg,
     ParsedDescription,
 };
-use crate::{AttributeParser, fluent_generated, parse_version, session_diagnostics, try_gate_cfg};
+use crate::{AttributeParser, fluent_generated, parse_version, session_diagnostics};
 
 pub const CFG_TEMPLATE: AttributeTemplate = template!(
     List: &["predicate"],
@@ -410,3 +412,19 @@ fn parse_cfg_attr_internal<'a>(
 
     Ok((cfg_predicate, expanded_attrs))
 }
+
+fn try_gate_cfg(name: Symbol, span: Span, sess: &Session, features: Option<&Features>) {
+    let gate = find_gated_cfg(|sym| sym == name);
+    if let (Some(feats), Some(gated_cfg)) = (features, gate) {
+        gate_cfg(gated_cfg, span, sess, feats);
+    }
+}
+
+#[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
+fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &Session, features: &Features) {
+    let (cfg, feature, has_feature) = gated_cfg;
+    if !has_feature(features) && !cfg_span.allows_unstable(*feature) {
+        let explain = format!("`cfg({cfg})` is experimental and subject to change");
+        feature_err(sess, *feature, cfg_span, explain).emit();
+    }
+}