Introduce new-style attribute parsers for several attributes

Author: jdonszelmann

Cargo.lock

@@ -3478,6 +3478,7 @@ dependencies = [
  "rustc_expand",
  "rustc_feature",
  "rustc_fluent_macro",
+ "rustc_hir",
  "rustc_index",
  "rustc_lexer",
  "rustc_lint_defs",
@@ -3729,6 +3730,7 @@ dependencies = [
  "rustc_abi",
  "rustc_ast",
  "rustc_ast_pretty",
+ "rustc_attr_data_structures",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_error_messages",
@@ -3762,6 +3764,7 @@ dependencies = [
  "rustc_errors",
  "rustc_feature",
  "rustc_fluent_macro",
+ "rustc_hir",
  "rustc_lexer",
  "rustc_lint_defs",
  "rustc_macros",
@@ -4440,6 +4443,7 @@ version = "0.0.0"
 dependencies = [
  "bitflags",
  "rustc_abi",
+ "rustc_ast",
  "rustc_data_structures",
  "rustc_hir",
  "rustc_middle",
@@ -4533,6 +4537,7 @@ dependencies = [
  "punycode",
  "rustc-demangle",
  "rustc_abi",
+ "rustc_ast",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hir",

compiler/rustc_ast_passes/messages.ftl

@@ -207,8 +207,6 @@ ast_passes_precise_capturing_duplicated = duplicate `use<...>` precise capturing
 
 ast_passes_precise_capturing_not_allowed_here = `use<...>` precise capturing syntax not allowed in {$loc}
 
-ast_passes_stability_outside_std = stability attributes may not be used outside of the standard library
-
 ast_passes_static_without_body =
     free static item without body
     .suggestion = provide a definition for the static

compiler/rustc_ast_passes/src/errors.rs

@@ -732,13 +732,6 @@ pub(crate) struct AssociatedSuggestion2 {
     pub potential_assoc: Ident,
 }
 
-#[derive(Diagnostic)]
-#[diag(ast_passes_stability_outside_std, code = E0734)]
-pub(crate) struct StabilityOutsideStd {
-    #[primary_span]
-    pub span: Span,
-}
-
 #[derive(Diagnostic)]
 #[diag(ast_passes_feature_on_non_nightly, code = E0554)]
 pub(crate) struct FeatureOnNonNightly {

compiler/rustc_ast_passes/src/feature_gate.rs

@@ -208,18 +208,6 @@ impl<'a> Visitor<'a> for PostExpansionVisitor<'a> {
                 );
             }
         }
-
-        // Emit errors for non-staged-api crates.
-        if !self.features.staged_api() {
-            if attr.has_name(sym::unstable)
-                || attr.has_name(sym::stable)
-                || attr.has_name(sym::rustc_const_unstable)
-                || attr.has_name(sym::rustc_const_stable)
-                || attr.has_name(sym::rustc_default_body_unstable)
-            {
-                self.sess.dcx().emit_err(errors::StabilityOutsideStd { span: attr.span });
-            }
-        }
     }
 
     fn visit_item(&mut self, i: &'a ast::Item) {

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -2,9 +2,11 @@ use rustc_abi::Align;
 use rustc_ast::token::CommentKind;
 use rustc_ast::{self as ast, AttrStyle};
 use rustc_macros::{Decodable, Encodable, HashStable_Generic};
+use rustc_span::hygiene::Transparency;
 use rustc_span::{Span, Symbol};
+use thin_vec::ThinVec;
 
-use crate::RustcVersion;
+use crate::{DefaultBodyStability, PartialConstStability, RustcVersion, Stability};
 
 #[derive(Copy, Clone, PartialEq, Encodable, Decodable, Debug, HashStable_Generic)]
 pub enum InlineAttr {
@@ -141,6 +143,42 @@ impl Deprecation {
 #[derive(Clone, Debug, HashStable_Generic, Encodable, Decodable)]
 pub enum AttributeKind {
     // tidy-alphabetical-start
-    DocComment { style: AttrStyle, kind: CommentKind, span: Span, comment: Symbol },
+    AllowConstFnUnstable(ThinVec<Symbol>),
+    AllowInternalUnsafe,
+    AllowInternalUnstable(ThinVec<Symbol>),
+    BodyStability {
+        stability: DefaultBodyStability,
+        /// Span of the `#[rustc_default_body_unstable(...)]` attribute
+        span: Span,
+    },
+    Confusables {
+        symbols: ThinVec<Symbol>,
+        // FIXME(jdonszelmann): remove when target validation code is moved
+        first_span: Span,
+    },
+    ConstStability {
+        stability: PartialConstStability,
+        /// Span of the `#[rustc_const_stable(...)]` or `#[rustc_const_unstable(...)]` attribute
+        span: Span,
+    },
+    ConstStabilityIndirect,
+    Deprecation {
+        deprecation: Deprecation,
+        span: Span,
+    },
+    Diagnostic(DiagnosticAttribute),
+    DocComment {
+        style: AttrStyle,
+        kind: CommentKind,
+        span: Span,
+        comment: Symbol,
+    },
+    MacroTransparency(Transparency),
+    Repr(ThinVec<ReprAttr>),
+    Stability {
+        stability: Stability,
+        /// Span of the `#[stable(...)]` or `#[unstable(...)]` attribute
+        span: Span,
+    },
     // tidy-alphabetical-end
 }

compiler/rustc_attr_parsing/messages.ftl

@@ -6,6 +6,8 @@ attr_parsing_deprecated_item_suggestion =
     .help = add `#![feature(deprecated_suggestion)]` to the crate root
     .note = see #94785 for more details
 
+attr_parsing_empty_confusables =
+    expected at least one confusable name
 attr_parsing_expected_one_cfg_pattern =
     expected 1 cfg-pattern
 
@@ -21,8 +23,8 @@ attr_parsing_expects_feature_list =
 attr_parsing_expects_features =
     `{$name}` expects feature names
 
-attr_parsing_incorrect_meta_item =
-    incorrect meta item
+attr_parsing_incorrect_meta_item = expected a quoted string literal
+attr_parsing_incorrect_meta_item_suggestion = consider surrounding this with quotes
 
 attr_parsing_incorrect_repr_format_align_one_arg =
     incorrect `repr(align)` attribute format: `align` takes exactly one argument in parentheses
@@ -93,15 +95,14 @@ attr_parsing_repr_ident =
 attr_parsing_rustc_allowed_unstable_pairing =
     `rustc_allowed_through_unstable_modules` attribute must be paired with a `stable` attribute
 
-attr_parsing_rustc_const_stable_indirect_pairing =
-    `const_stable_indirect` attribute does not make sense on `rustc_const_stable` function, its behavior is already implied
-
 attr_parsing_rustc_promotable_pairing =
     `rustc_promotable` attribute must be paired with either a `rustc_const_unstable` or a `rustc_const_stable` attribute
 
 attr_parsing_soft_no_args =
     `soft` should not have any arguments
 
+attr_parsing_stability_outside_std = stability attributes may not be used outside of the standard library
+
 attr_parsing_unknown_meta_item =
     unknown meta item '{$item}'
     .label = expected one of {$expected}
@@ -128,3 +129,8 @@ attr_parsing_unsupported_literal_generic =
     unsupported literal
 attr_parsing_unsupported_literal_suggestion =
     consider removing the prefix
+
+attr_parsing_unused_multiple =
+    multiple `{$name}` attributes
+    .suggestion = remove this attribute
+    .note = attribute also specified here

compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs

@@ -1,49 +1,65 @@
-use rustc_ast::attr::{AttributeExt, filter_by_name};
-use rustc_session::Session;
+use rustc_attr_data_structures::AttributeKind;
 use rustc_span::{Symbol, sym};
 
+use super::{CombineAttributeParser, ConvertFn};
+use crate::context::AcceptContext;
+use crate::parser::ArgParser;
 use crate::session_diagnostics;
 
-pub fn allow_internal_unstable<'a>(
-    sess: &'a Session,
-    attrs: &'a [impl AttributeExt],
-) -> impl Iterator<Item = Symbol> + 'a {
-    allow_unstable(sess, attrs, sym::allow_internal_unstable)
+pub(crate) struct AllowInternalUnstableParser;
+impl CombineAttributeParser for AllowInternalUnstableParser {
+    const PATH: &'static [rustc_span::Symbol] = &[sym::allow_internal_unstable];
+    type Item = Symbol;
+    const CONVERT: ConvertFn<Self::Item> = AttributeKind::AllowInternalUnstable;
+
+    fn extend<'a>(
+        cx: &'a AcceptContext<'a>,
+        args: &'a ArgParser<'a>,
+    ) -> impl IntoIterator<Item = Self::Item> + 'a {
+        parse_unstable(cx, args, Self::PATH[0])
+    }
 }
 
-pub fn rustc_allow_const_fn_unstable<'a>(
-    sess: &'a Session,
-    attrs: &'a [impl AttributeExt],
-) -> impl Iterator<Item = Symbol> + 'a {
-    allow_unstable(sess, attrs, sym::rustc_allow_const_fn_unstable)
+pub(crate) struct AllowConstFnUnstableParser;
+impl CombineAttributeParser for AllowConstFnUnstableParser {
+    const PATH: &'static [rustc_span::Symbol] = &[sym::rustc_allow_const_fn_unstable];
+    type Item = Symbol;
+    const CONVERT: ConvertFn<Self::Item> = AttributeKind::AllowConstFnUnstable;
+
+    fn extend<'a>(
+        cx: &'a AcceptContext<'a>,
+        args: &'a ArgParser<'a>,
+    ) -> impl IntoIterator<Item = Self::Item> + 'a {
+        parse_unstable(cx, args, Self::PATH[0])
+    }
 }
 
-fn allow_unstable<'a>(
-    sess: &'a Session,
-    attrs: &'a [impl AttributeExt],
+fn parse_unstable<'a>(
+    cx: &AcceptContext<'_>,
+    args: &'a ArgParser<'a>,
     symbol: Symbol,
-) -> impl Iterator<Item = Symbol> + 'a {
-    let attrs = filter_by_name(attrs, symbol);
-    let list = attrs
-        .filter_map(move |attr| {
-            attr.meta_item_list().or_else(|| {
-                sess.dcx().emit_err(session_diagnostics::ExpectsFeatureList {
-                    span: attr.span(),
-                    name: symbol.to_ident_string(),
-                });
-                None
-            })
-        })
-        .flatten();
-
-    list.into_iter().filter_map(move |it| {
-        let name = it.ident().map(|ident| ident.name);
-        if name.is_none() {
-            sess.dcx().emit_err(session_diagnostics::ExpectsFeatures {
-                span: it.span(),
+) -> impl IntoIterator<Item = Symbol> {
+    let mut res = Vec::new();
+
+    let Some(list) = args.list() else {
+        cx.dcx().emit_err(session_diagnostics::ExpectsFeatureList {
+            span: cx.attr_span,
+            name: symbol.to_ident_string(),
+        });
+        return res;
+    };
+
+    for param in list.mixed() {
+        let param_span = param.span();
+        if let Some(ident) = param.meta_item().and_then(|i| i.word_without_args()) {
+            res.push(ident.name);
+        } else {
+            cx.dcx().emit_err(session_diagnostics::ExpectsFeatures {
+                span: param_span,
                 name: symbol.to_ident_string(),
             });
         }
-        name
-    })
+    }
+
+    res
 }

compiler/rustc_attr_parsing/src/attributes/cfg.rs

@@ -1,6 +1,5 @@
-//! Parsing and validation of builtin attributes
-
-use rustc_ast::{self as ast, LitKind, MetaItem, MetaItemInner, MetaItemKind, MetaItemLit, NodeId};
+// TODO: convert cfg properly.... And learn how cfg works I guess
+use rustc_ast::{LitKind, MetaItem, MetaItemInner, MetaItemKind, MetaItemLit, NodeId};
 use rustc_ast_pretty::pprust;
 use rustc_attr_data_structures::RustcVersion;
 use rustc_feature::{Features, GatedCfg, find_gated_cfg};
@@ -9,10 +8,11 @@ use rustc_session::config::ExpectedValues;
 use rustc_session::lint::BuiltinLintDiag;
 use rustc_session::lint::builtin::UNEXPECTED_CFGS;
 use rustc_session::parse::feature_err;
-use rustc_span::{Span, Symbol, kw, sym};
+use rustc_span::symbol::kw;
+use rustc_span::{Span, Symbol, sym};
 
-use crate::util::UnsupportedLiteralReason;
-use crate::{fluent_generated, parse_version, session_diagnostics};
+use crate::session_diagnostics::{self, UnsupportedLiteralReason};
+use crate::{fluent_generated, parse_version};
 
 #[derive(Clone, Debug)]
 pub struct Condition {
@@ -25,7 +25,7 @@ pub struct Condition {
 
 /// Tests if a cfg-pattern matches the cfg set
 pub fn cfg_matches(
-    cfg: &ast::MetaItemInner,
+    cfg: &MetaItemInner,
     sess: &Session,
     lint_node_id: NodeId,
     features: Option<&Features>,
@@ -80,16 +80,16 @@ fn gate_cfg(gated_cfg: &GatedCfg, cfg_span: Span, sess: &Session, features: &Fea
 /// Evaluate a cfg-like condition (with `any` and `all`), using `eval` to
 /// evaluate individual items.
 pub fn eval_condition(
-    cfg: &ast::MetaItemInner,
+    cfg: &MetaItemInner,
     sess: &Session,
     features: Option<&Features>,
     eval: &mut impl FnMut(Condition) -> bool,
 ) -> bool {
     let dcx = sess.dcx();
 
     let cfg = match cfg {
-        ast::MetaItemInner::MetaItem(meta_item) => meta_item,
-        ast::MetaItemInner::Lit(MetaItemLit { kind: LitKind::Bool(b), .. }) => {
+        MetaItemInner::MetaItem(meta_item) => meta_item,
+        MetaItemInner::Lit(MetaItemLit { kind: LitKind::Bool(b), .. }) => {
             if let Some(features) = features {
                 // we can't use `try_gate_cfg` as symbols don't differentiate between `r#true`
                 // and `true`, and we want to keep the former working without feature gate
@@ -118,7 +118,7 @@ pub fn eval_condition(
     };
 
     match &cfg.kind {
-        ast::MetaItemKind::List(mis) if cfg.name_or_empty() == sym::version => {
+        MetaItemKind::List(mis) if cfg.name_or_empty() == sym::version => {
             try_gate_cfg(sym::version, cfg.span, sess, features);
             let (min_version, span) = match &mis[..] {
                 [MetaItemInner::Lit(MetaItemLit { kind: LitKind::Str(sym, ..), span, .. })] => {
@@ -150,7 +150,7 @@ pub fn eval_condition(
                 RustcVersion::CURRENT >= min_version
             }
         }
-        ast::MetaItemKind::List(mis) => {
+        MetaItemKind::List(mis) => {
             for mi in mis.iter() {
                 if mi.meta_item_or_bool().is_none() {
                     dcx.emit_err(session_diagnostics::UnsupportedLiteral {
@@ -209,12 +209,7 @@ pub fn eval_condition(
                             seg.ident.name = Symbol::intern(&format!("target_{}", seg.ident.name));
                         }
 
-                        res & eval_condition(
-                            &ast::MetaItemInner::MetaItem(mi),
-                            sess,
-                            features,
-                            eval,
-                        )
+                        res & eval_condition(&MetaItemInner::MetaItem(mi), sess, features, eval)
                     })
                 }
                 _ => {
@@ -226,7 +221,7 @@ pub fn eval_condition(
                 }
             }
         }
-        ast::MetaItemKind::Word | MetaItemKind::NameValue(..) if cfg.path.segments.len() != 1 => {
+        MetaItemKind::Word | MetaItemKind::NameValue(..) if cfg.path.segments.len() != 1 => {
             dcx.emit_err(session_diagnostics::CfgPredicateIdentifier { span: cfg.path.span });
             true
         }
@@ -239,7 +234,7 @@ pub fn eval_condition(
             });
             true
         }
-        ast::MetaItemKind::Word | ast::MetaItemKind::NameValue(..) => {
+        MetaItemKind::Word | MetaItemKind::NameValue(..) => {
             let ident = cfg.ident().expect("multi-segment cfg predicate");
             eval(Condition {
                 name: ident.name,