Rollup of 9 pull requests

compiler/rustc_attr_parsing/src/attributes/inline.rs

@@ -47,8 +47,8 @@ impl<S: Stage> SingleAttributeParser<S> for InlineParser {
                 }
             }
             ArgParser::NameValue(_) => {
-                let suggestions =
-                    <Self as SingleAttributeParser<S>>::TEMPLATE.suggestions(false, "inline");
+                let suggestions = <Self as SingleAttributeParser<S>>::TEMPLATE
+                    .suggestions(cx.attr_style, "inline");
                 let span = cx.attr_span;
                 cx.emit_lint(AttributeLintKind::IllFormedAttributeInput { suggestions }, span);
                 return None;

compiler/rustc_attr_parsing/src/attributes/macro_attrs.rs

@@ -99,7 +99,7 @@ impl<S: Stage> AttributeParser<S> for MacroUseParser {
                     }
                 }
                 ArgParser::NameValue(_) => {
-                    let suggestions = MACRO_USE_TEMPLATE.suggestions(false, sym::macro_use);
+                    let suggestions = MACRO_USE_TEMPLATE.suggestions(cx.attr_style, sym::macro_use);
                     cx.emit_err(session_diagnostics::IllFormedAttributeInputLint {
                         num_suggestions: suggestions.len(),
                         suggestions: DiagArgValue::StrListSepByAnd(

compiler/rustc_attr_parsing/src/attributes/must_use.rs

@@ -35,8 +35,8 @@ impl<S: Stage> SingleAttributeParser<S> for MustUseParser {
                     Some(value_str)
                 }
                 ArgParser::List(_) => {
-                    let suggestions =
-                        <Self as SingleAttributeParser<S>>::TEMPLATE.suggestions(false, "must_use");
+                    let suggestions = <Self as SingleAttributeParser<S>>::TEMPLATE
+                        .suggestions(cx.attr_style, "must_use");
                     cx.emit_err(session_diagnostics::IllFormedAttributeInputLint {
                         num_suggestions: suggestions.len(),
                         suggestions: DiagArgValue::StrListSepByAnd(

compiler/rustc_attr_parsing/src/attributes/test_attrs.rs

@@ -26,7 +26,7 @@ impl<S: Stage> SingleAttributeParser<S> for IgnoreParser {
                 ArgParser::NameValue(name_value) => {
                     let Some(str_value) = name_value.value_as_str() else {
                         let suggestions = <Self as SingleAttributeParser<S>>::TEMPLATE
-                            .suggestions(false, "ignore");
+                            .suggestions(cx.attr_style, "ignore");
                         let span = cx.attr_span;
                         cx.emit_lint(
                             AttributeLintKind::IllFormedAttributeInput { suggestions },
@@ -37,8 +37,8 @@ impl<S: Stage> SingleAttributeParser<S> for IgnoreParser {
                     Some(str_value)
                 }
                 ArgParser::List(_) => {
-                    let suggestions =
-                        <Self as SingleAttributeParser<S>>::TEMPLATE.suggestions(false, "ignore");
+                    let suggestions = <Self as SingleAttributeParser<S>>::TEMPLATE
+                        .suggestions(cx.attr_style, "ignore");
                     let span = cx.attr_span;
                     cx.emit_lint(AttributeLintKind::IllFormedAttributeInput { suggestions }, span);
                     return None;

compiler/rustc_attr_parsing/src/context.rs

@@ -4,7 +4,7 @@ use std::ops::{Deref, DerefMut};
 use std::sync::LazyLock;
 
 use private::Sealed;
-use rustc_ast::{self as ast, LitKind, MetaItemLit, NodeId};
+use rustc_ast::{self as ast, AttrStyle, LitKind, MetaItemLit, NodeId};
 use rustc_errors::{DiagCtxtHandle, Diagnostic};
 use rustc_feature::{AttributeTemplate, Features};
 use rustc_hir::attrs::AttributeKind;
@@ -305,6 +305,7 @@ pub struct AcceptContext<'f, 'sess, S: Stage> {
     /// The span of the attribute currently being parsed
     pub(crate) attr_span: Span,
 
+    pub(crate) attr_style: AttrStyle,
     /// The expected structure of the attribute.
     ///
     /// Used in reporting errors to give a hint to users what the attribute *should* look like.
@@ -386,6 +387,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                     i.kind.is_bytestr().then(|| self.sess().source_map().start_point(i.span))
                 }),
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -396,6 +398,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedIntegerLiteral,
+            attr_style: self.attr_style,
         })
     }
 
@@ -406,6 +409,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedList,
+            attr_style: self.attr_style,
         })
     }
 
@@ -416,6 +420,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedNoArgs,
+            attr_style: self.attr_style,
         })
     }
 
@@ -427,6 +432,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedIdentifier,
+            attr_style: self.attr_style,
         })
     }
 
@@ -439,6 +445,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedNameValue(name),
+            attr_style: self.attr_style,
         })
     }
 
@@ -450,6 +457,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::DuplicateKey(key),
+            attr_style: self.attr_style,
         })
     }
 
@@ -462,6 +470,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::UnexpectedLiteral,
+            attr_style: self.attr_style,
         })
     }
 
@@ -472,6 +481,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedSingleArgument,
+            attr_style: self.attr_style,
         })
     }
 
@@ -482,6 +492,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
             template: self.template.clone(),
             attribute: self.attr_path.clone(),
             reason: AttributeParseErrorReason::ExpectedAtLeastOneArgument,
+            attr_style: self.attr_style,
         })
     }
 
@@ -500,6 +511,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: false,
                 list: false,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -518,6 +530,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: false,
                 list: true,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -536,6 +549,7 @@ impl<'f, 'sess: 'f, S: Stage> AcceptContext<'f, 'sess, S> {
                 strings: true,
                 list: false,
             },
+            attr_style: self.attr_style,
         })
     }
 
@@ -735,6 +749,7 @@ impl<'sess> AttributeParser<'sess, Early> {
                 },
             },
             attr_span: attr.span,
+            attr_style: attr.style,
             template,
             attr_path: path.get_attribute_path(),
         };
@@ -844,6 +859,7 @@ impl<'sess, S: Stage> AttributeParser<'sess, S> {
                                     emit_lint: &mut emit_lint,
                                 },
                                 attr_span: lower_span(attr.span),
+                                attr_style: attr.style,
                                 template: &accept.template,
                                 attr_path: path.get_attribute_path(),
                             };

compiler/rustc_attr_parsing/src/session_diagnostics.rs

@@ -1,6 +1,6 @@
 use std::num::IntErrorKind;
 
-use rustc_ast as ast;
+use rustc_ast::{self as ast, AttrStyle};
 use rustc_errors::codes::*;
 use rustc_errors::{
     Applicability, Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, EmissionGuarantee, Level,
@@ -556,6 +556,7 @@ pub(crate) enum AttributeParseErrorReason {
 pub(crate) struct AttributeParseError {
     pub(crate) span: Span,
     pub(crate) attr_span: Span,
+    pub(crate) attr_style: AttrStyle,
     pub(crate) template: AttributeTemplate,
     pub(crate) attribute: AttrPath,
     pub(crate) reason: AttributeParseErrorReason,
@@ -694,7 +695,8 @@ impl<'a, G: EmissionGuarantee> Diagnostic<'a, G> for AttributeParseError {
         if let Some(link) = self.template.docs {
             diag.note(format!("for more information, visit <{link}>"));
         }
-        let suggestions = self.template.suggestions(false, &name);
+        let suggestions = self.template.suggestions(self.attr_style, &name);
+
         diag.span_suggestions(
             self.attr_span,
             if suggestions.len() == 1 {

compiler/rustc_feature/src/builtin_attrs.rs

@@ -6,6 +6,7 @@ use AttributeDuplicates::*;
 use AttributeGate::*;
 use AttributeType::*;
 use rustc_data_structures::fx::FxHashMap;
+use rustc_hir::AttrStyle;
 use rustc_hir::attrs::EncodeCrossCrate;
 use rustc_span::edition::Edition;
 use rustc_span::{Symbol, sym};
@@ -132,9 +133,12 @@ pub struct AttributeTemplate {
 }
 
 impl AttributeTemplate {
-    pub fn suggestions(&self, inner: bool, name: impl std::fmt::Display) -> Vec<String> {
+    pub fn suggestions(&self, style: AttrStyle, name: impl std::fmt::Display) -> Vec<String> {
         let mut suggestions = vec![];
-        let inner = if inner { "!" } else { "" };
+        let inner = match style {
+            AttrStyle::Outer => "",
+            AttrStyle::Inner => "!",
+        };
         if self.word {
             suggestions.push(format!("#{inner}[{name}]"));
         }

compiler/rustc_lint/src/context.rs

@@ -24,7 +24,7 @@ use rustc_middle::ty::layout::{LayoutError, LayoutOfHelpers, TyAndLayout};
 use rustc_middle::ty::print::{PrintError, PrintTraitRefExt as _, Printer, with_no_trimmed_paths};
 use rustc_middle::ty::{self, GenericArg, RegisteredTools, Ty, TyCtxt, TypingEnv, TypingMode};
 use rustc_session::lint::{FutureIncompatibleInfo, Lint, LintBuffer, LintExpectationId, LintId};
-use rustc_session::{LintStoreMarker, Session};
+use rustc_session::{DynLintStore, Session};
 use rustc_span::edit_distance::find_best_match_for_names;
 use rustc_span::{Ident, Span, Symbol, sym};
 use tracing::debug;
@@ -62,7 +62,13 @@ pub struct LintStore {
     lint_groups: FxIndexMap<&'static str, LintGroup>,
 }
 
-impl LintStoreMarker for LintStore {}
+impl DynLintStore for LintStore {
+    fn lint_groups_iter(&self) -> Box<dyn Iterator<Item = rustc_session::LintGroup> + '_> {
+        Box::new(self.get_lint_groups().map(|(name, lints, is_externally_loaded)| {
+            rustc_session::LintGroup { name, lints, is_externally_loaded }
+        }))
+    }
+}
 
 /// The target of the `by_name` map, which accounts for renaming/deprecation.
 #[derive(Debug)]

compiler/rustc_middle/src/lint.rs

@@ -211,11 +211,28 @@ impl LintExpectation {
 }
 
 fn explain_lint_level_source(
+    sess: &Session,
     lint: &'static Lint,
     level: Level,
     src: LintLevelSource,
     err: &mut Diag<'_, ()>,
 ) {
+    // Find the name of the lint group that contains the given lint.
+    // Assumes the lint only belongs to one group.
+    let lint_group_name = |lint| {
+        let lint_groups_iter = sess.lint_groups_iter();
+        let lint_id = LintId::of(lint);
+        lint_groups_iter
+            .filter(|lint_group| !lint_group.is_externally_loaded)
+            .find(|lint_group| {
+                lint_group
+                    .lints
+                    .iter()
+                    .find(|lint_group_lint| **lint_group_lint == lint_id)
+                    .is_some()
+            })
+            .map(|lint_group| lint_group.name)
+    };
     let name = lint.name_lower();
     if let Level::Allow = level {
         // Do not point at `#[allow(compat_lint)]` as the reason for a compatibility lint
@@ -224,7 +241,15 @@ fn explain_lint_level_source(
     }
     match src {
         LintLevelSource::Default => {
-            err.note_once(format!("`#[{}({})]` on by default", level.as_str(), name));
+            let level_str = level.as_str();
+            match lint_group_name(lint) {
+                Some(group_name) => {
+                    err.note_once(format!("`#[{level_str}({name})]` (part of `#[{level_str}({group_name})]`) on by default"));
+                }
+                None => {
+                    err.note_once(format!("`#[{level_str}({name})]` on by default"));
+                }
+            }
         }
         LintLevelSource::CommandLine(lint_flag_val, orig_level) => {
             let flag = orig_level.to_cmd_flag();
@@ -427,7 +452,7 @@ pub fn lint_level(
             decorate(&mut err);
         }
 
-        explain_lint_level_source(lint, level, src, &mut err);
+        explain_lint_level_source(sess, lint, level, src, &mut err);
         err.emit()
     }
     lint_level_impl(sess, lint, level, span, Box::new(decorate))

compiler/rustc_parse/src/parser/cfg_select.rs

@@ -1,11 +1,12 @@
 use rustc_ast::token::Token;
 use rustc_ast::tokenstream::{TokenStream, TokenTree};
+use rustc_ast::util::classify;
 use rustc_ast::{MetaItemInner, token};
 use rustc_errors::PResult;
 use rustc_span::Span;
 
 use crate::exp;
-use crate::parser::Parser;
+use crate::parser::{AttrWrapper, ForceCollect, Parser, Restrictions, Trailing, UsePreAttrPos};
 
 pub enum CfgSelectPredicate {
     Cfg(MetaItemInner),
@@ -23,19 +24,26 @@ pub struct CfgSelectBranches {
     pub unreachable: Vec<(CfgSelectPredicate, TokenStream, Span)>,
 }
 
-/// Parses a `TokenTree` that must be of the form `{ /* ... */ }`, and returns a `TokenStream` where
-/// the surrounding braces are stripped.
+/// Parses a `TokenTree` consisting either of `{ /* ... */ }` (and strip the braces) or an
+/// expression followed by a comma (and strip the comma).
 fn parse_token_tree<'a>(p: &mut Parser<'a>) -> PResult<'a, TokenStream> {
-    // Generate an error if the `=>` is not followed by `{`.
-    if p.token != token::OpenBrace {
-        p.expect(exp!(OpenBrace))?;
+    if p.token == token::OpenBrace {
+        // Strip the outer '{' and '}'.
+        match p.parse_token_tree() {
+            TokenTree::Token(..) => unreachable!("because of the expect above"),
+            TokenTree::Delimited(.., tts) => return Ok(tts),
+        }
     }
-
-    // Strip the outer '{' and '}'.
-    match p.parse_token_tree() {
-        TokenTree::Token(..) => unreachable!("because of the expect above"),
-        TokenTree::Delimited(.., tts) => Ok(tts),
+    let expr = p.collect_tokens(None, AttrWrapper::empty(), ForceCollect::Yes, |p, _| {
+        p.parse_expr_res(Restrictions::STMT_EXPR, AttrWrapper::empty())
+            .map(|(expr, _)| (expr, Trailing::No, UsePreAttrPos::No))
+    })?;
+    if !classify::expr_is_complete(&expr) && p.token != token::CloseBrace && p.token != token::Eof {
+        p.expect(exp!(Comma))?;
+    } else {
+        let _ = p.eat(exp!(Comma));
     }
+    Ok(TokenStream::from_ast(&expr))
 }
 
 pub fn parse_cfg_select<'a>(p: &mut Parser<'a>) -> PResult<'a, CfgSelectBranches> {