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authorJana Dönszelmann <jana@donsz.nl>2025-02-09 22:49:33 +0100
committerJana Dönszelmann <jana@donsz.nl>2025-02-24 14:31:17 +0100
commit7e0f5b50168c63bd1879067c043559ef0f01671e (patch)
treeb2f1b1f68ef89985faec8ae287731613e4b520c4
parentdbd3b7928e91758296a0f6093d72f90214888133 (diff)
downloadrust-7e0f5b50168c63bd1879067c043559ef0f01671e.tar.gz
rust-7e0f5b50168c63bd1879067c043559ef0f01671e.zip
Introduce new-style attribute parsers for several attributes
note: compiler compiles but librustdoc and clippy don't
-rw-r--r--Cargo.lock5
-rw-r--r--compiler/rustc_ast_lowering/src/lib.rs16
-rw-r--r--compiler/rustc_ast_passes/messages.ftl2
-rw-r--r--compiler/rustc_ast_passes/src/errors.rs7
-rw-r--r--compiler/rustc_ast_passes/src/feature_gate.rs12
-rw-r--r--compiler/rustc_attr_data_structures/src/attributes.rs44
-rw-r--r--compiler/rustc_attr_parsing/messages.ftl17
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs92
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/cfg.rs34
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/confusables.rs65
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/deprecation.rs214
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/mod.rs8
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/repr.rs381
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/stability.rs471
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/transparency.rs55
-rw-r--r--compiler/rustc_attr_parsing/src/attributes/util.rs24
-rw-r--r--compiler/rustc_attr_parsing/src/context.rs29
-rw-r--r--compiler/rustc_attr_parsing/src/lib.rs49
-rw-r--r--compiler/rustc_attr_parsing/src/session_diagnostics.rs72
-rw-r--r--compiler/rustc_builtin_macros/Cargo.toml1
-rw-r--r--compiler/rustc_builtin_macros/src/deriving/generic/mod.rs15
-rw-r--r--compiler/rustc_codegen_ssa/src/base.rs5
-rw-r--r--compiler/rustc_codegen_ssa/src/codegen_attrs.rs40
-rw-r--r--compiler/rustc_const_eval/src/check_consts/mod.rs6
-rw-r--r--compiler/rustc_errors/Cargo.toml1
-rw-r--r--compiler/rustc_errors/src/diagnostic_impls.rs7
-rw-r--r--compiler/rustc_expand/Cargo.toml1
-rw-r--r--compiler/rustc_expand/src/base.rs33
-rw-r--r--compiler/rustc_expand/src/mbe/macro_rules.rs20
-rw-r--r--compiler/rustc_hir/src/hir.rs4
-rw-r--r--compiler/rustc_hir_analysis/src/check/check.rs35
-rw-r--r--compiler/rustc_hir_typeck/src/method/suggest.rs6
-rw-r--r--compiler/rustc_lint/src/expect.rs1
-rw-r--r--compiler/rustc_lint/src/nonstandard_style.rs11
-rw-r--r--compiler/rustc_lint_defs/src/lib.rs22
-rw-r--r--compiler/rustc_metadata/src/rmeta/decoder.rs1
-rw-r--r--compiler/rustc_middle/src/ty/mod.rs28
-rw-r--r--compiler/rustc_passes/messages.ftl15
-rw-r--r--compiler/rustc_passes/src/check_attr.rs747
-rw-r--r--compiler/rustc_passes/src/errors.rs48
-rw-r--r--compiler/rustc_passes/src/lib_features.rs83
-rw-r--r--compiler/rustc_passes/src/stability.rs47
-rw-r--r--compiler/rustc_privacy/src/lib.rs7
-rw-r--r--compiler/rustc_resolve/src/def_collector.rs14
-rw-r--r--compiler/rustc_resolve/src/macros.rs3
-rw-r--r--compiler/rustc_sanitizers/Cargo.toml1
-rw-r--r--compiler/rustc_span/src/hygiene.rs6
-rw-r--r--compiler/rustc_symbol_mangling/Cargo.toml1
-rw-r--r--tests/ui/feature-gates/feature-gate-fn_align.rs2
-rw-r--r--tests/ui/feature-gates/feature-gate-fn_align.stderr19
50 files changed, 1502 insertions, 1325 deletions
diff --git a/Cargo.lock b/Cargo.lock
index fede1204bab..c86351bf78c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3341,6 +3341,7 @@ dependencies = [
  "rustc_expand",
  "rustc_feature",
  "rustc_fluent_macro",
+ "rustc_hir",
  "rustc_index",
  "rustc_lexer",
  "rustc_lint_defs",
@@ -3597,6 +3598,7 @@ dependencies = [
  "rustc_abi",
  "rustc_ast",
  "rustc_ast_pretty",
+ "rustc_attr_data_structures",
  "rustc_data_structures",
  "rustc_error_codes",
  "rustc_error_messages",
@@ -3631,6 +3633,7 @@ dependencies = [
  "rustc_errors",
  "rustc_feature",
  "rustc_fluent_macro",
+ "rustc_hir",
  "rustc_lexer",
  "rustc_lint_defs",
  "rustc_macros",
@@ -4319,6 +4322,7 @@ version = "0.0.0"
 dependencies = [
  "bitflags",
  "rustc_abi",
+ "rustc_ast",
  "rustc_data_structures",
  "rustc_hir",
  "rustc_middle",
@@ -4415,6 +4419,7 @@ dependencies = [
  "punycode",
  "rustc-demangle",
  "rustc_abi",
+ "rustc_ast",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_hashes",
diff --git a/compiler/rustc_ast_lowering/src/lib.rs b/compiler/rustc_ast_lowering/src/lib.rs
index 8b19484b642..6216da078e5 100644
--- a/compiler/rustc_ast_lowering/src/lib.rs
+++ b/compiler/rustc_ast_lowering/src/lib.rs
@@ -874,9 +874,19 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
 
             debug_assert_eq!(id.owner, self.current_hir_id_owner);
             let ret = self.arena.alloc_from_iter(lowered_attrs);
-            debug_assert!(!ret.is_empty());
-            self.attrs.insert(id.local_id, ret);
-            ret
+
+            // this is possible if an item contained syntactical attribute,
+            // but none of them parse succesfully or all of them were ignored
+            // for not being built-in attributes at all. They could be remaining
+            // unexpanded attributes used as markers in proc-macro derives for example.
+            // This will have emitted some diagnostics for the misparse, but will then
+            // not emit the attribute making the list empty.
+            if ret.is_empty() {
+                &[]
+            } else {
+                self.attrs.insert(id.local_id, ret);
+                ret
+            }
         }
     }
 
diff --git a/compiler/rustc_ast_passes/messages.ftl b/compiler/rustc_ast_passes/messages.ftl
index 5a0ec865f9d..25944392a52 100644
--- a/compiler/rustc_ast_passes/messages.ftl
+++ b/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
diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs
index 6eb9bb1c0da..9f0d2325475 100644
--- a/compiler/rustc_ast_passes/src/errors.rs
+++ b/compiler/rustc_ast_passes/src/errors.rs
@@ -733,13 +733,6 @@ pub(crate) struct AssociatedSuggestion2 {
 }
 
 #[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 {
     #[primary_span]
diff --git a/compiler/rustc_ast_passes/src/feature_gate.rs b/compiler/rustc_ast_passes/src/feature_gate.rs
index e5d8013058f..0f80e49320e 100644
--- a/compiler/rustc_ast_passes/src/feature_gate.rs
+++ b/compiler/rustc_ast_passes/src/feature_gate.rs
@@ -178,18 +178,6 @@ 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) {
diff --git a/compiler/rustc_attr_data_structures/src/attributes.rs b/compiler/rustc_attr_data_structures/src/attributes.rs
index d0f2773b7f9..3f1edacf9a7 100644
--- a/compiler/rustc_attr_data_structures/src/attributes.rs
+++ b/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 {
@@ -72,6 +74,8 @@ pub enum ReprAttr {
     ReprSimd,
     ReprTransparent,
     ReprAlign(Align),
+    // this one is just so we can emit a lint for it
+    ReprEmpty,
 }
 pub use ReprAttr::*;
 
@@ -150,10 +154,44 @@ impl Deprecation {
 /// happen.
 ///
 /// For more docs, look in [`rustc_attr`](https://doc.rust-lang.org/stable/nightly-rustc/rustc_attr/index.html)
-// FIXME(jdonszelmann): rename to AttributeKind once hir::AttributeKind is dissolved
 #[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>),
+    AllowInternalUnstable(ThinVec<(Symbol, Span)>),
+    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, Span)>),
+    Stability {
+        stability: Stability,
+        /// Span of the `#[stable(...)]` or `#[unstable(...)]` attribute
+        span: Span,
+    },
     // tidy-alphabetical-end
 }
diff --git a/compiler/rustc_attr_parsing/messages.ftl b/compiler/rustc_attr_parsing/messages.ftl
index d51e24b2b88..45174c9582d 100644
--- a/compiler/rustc_attr_parsing/messages.ftl
+++ b/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
@@ -90,18 +92,18 @@ attr_parsing_non_ident_feature =
 
 attr_parsing_repr_ident =
     meta item in `repr` must be an identifier
+
 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 +130,8 @@ 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
diff --git a/compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs b/compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs
index 13d246b08a8..d37ede86cfd 100644
--- a/compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/allow_unstable.rs
@@ -1,49 +1,67 @@
-use rustc_ast::attr::{AttributeExt, filter_by_name};
-use rustc_session::Session;
-use rustc_span::{Symbol, sym};
+use std::iter;
 
+use rustc_attr_data_structures::AttributeKind;
+use rustc_span::{Span, Symbol, sym};
+
+use super::{CombineAttributeParser, ConvertFn};
+use crate::context::AcceptContext;
+use crate::parser::ArgParser;
 use crate::session_diagnostics;
 
-pub fn allow_internal_unstable(
-    sess: &Session,
-    attrs: &[impl AttributeExt],
-) -> impl Iterator<Item = Symbol> {
-    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, Span);
+    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]).into_iter().zip(iter::repeat(cx.attr_span))
+    }
 }
 
-pub fn rustc_allow_const_fn_unstable(
-    sess: &Session,
-    attrs: &[impl AttributeExt],
-) -> impl Iterator<Item = Symbol> {
-    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(
-    sess: &Session,
-    attrs: &[impl AttributeExt],
+fn parse_unstable<'a>(
+    cx: &AcceptContext<'_>,
+    args: &'a ArgParser<'a>,
     symbol: Symbol,
-) -> impl Iterator<Item = Symbol> {
-    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.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.emit_err(session_diagnostics::ExpectsFeatures {
+                span: param_span,
                 name: symbol.to_ident_string(),
             });
         }
-        name
-    })
+    }
+
+    res
 }
diff --git a/compiler/rustc_attr_parsing/src/attributes/cfg.rs b/compiler/rustc_attr_parsing/src/attributes/cfg.rs
index bb9aaaa2fea..0d6d521b40c 100644
--- a/compiler/rustc_attr_parsing/src/attributes/cfg.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/cfg.rs
@@ -1,6 +1,4 @@
-//! Parsing and validation of builtin attributes
-
-use rustc_ast::{self as ast, LitKind, MetaItem, MetaItemInner, MetaItemKind, MetaItemLit, NodeId};
+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 +7,11 @@ 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 +24,7 @@ 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>,
@@ -80,7 +79,7 @@ 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,
@@ -88,8 +87,8 @@ pub fn eval_condition(
     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 +117,7 @@ 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 +149,7 @@ 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 +208,7 @@ 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 +220,7 @@ 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 +233,7 @@ 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,
diff --git a/compiler/rustc_attr_parsing/src/attributes/confusables.rs b/compiler/rustc_attr_parsing/src/attributes/confusables.rs
index 2ced759fd88..6cff952fcf2 100644
--- a/compiler/rustc_attr_parsing/src/attributes/confusables.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/confusables.rs
@@ -1,21 +1,58 @@
-//! Parsing and validation of builtin attributes
+use rustc_attr_data_structures::AttributeKind;
+use rustc_span::{Span, Symbol, sym};
+use thin_vec::ThinVec;
 
-use rustc_ast::MetaItemInner;
-use rustc_ast::attr::AttributeExt;
-use rustc_span::Symbol;
+use super::{AcceptMapping, AttributeParser};
+use crate::context::FinalizeContext;
+use crate::session_diagnostics;
 
-/// Read the content of a `rustc_confusables` attribute, and return the list of candidate names.
-pub fn parse_confusables(attr: &impl AttributeExt) -> Option<Vec<Symbol>> {
-    let metas = attr.meta_item_list()?;
+#[derive(Default)]
+pub(crate) struct ConfusablesParser {
+    confusables: ThinVec<Symbol>,
+    first_span: Option<Span>,
+}
+
+impl AttributeParser for ConfusablesParser {
+    const ATTRIBUTES: AcceptMapping<Self> = &[(&[sym::rustc_confusables], |this, cx, args| {
+        let Some(list) = args.list() else {
+            // FIXME(jdonszelmann): error when not a list? Bring validation code here.
+            //       NOTE: currently subsequent attributes are silently ignored using
+            //       tcx.get_attr().
+            return;
+        };
+
+        if list.is_empty() {
+            cx.emit_err(session_diagnostics::EmptyConfusables { span: cx.attr_span });
+        }
+
+        for param in list.mixed() {
+            let span = param.span();
 
-    let mut candidates = Vec::new();
+            let Some(lit) = param.lit() else {
+                cx.emit_err(session_diagnostics::IncorrectMetaItem {
+                    span,
+                    suggestion: Some(session_diagnostics::IncorrectMetaItemSuggestion {
+                        lo: span.shrink_to_lo(),
+                        hi: span.shrink_to_hi(),
+                    }),
+                });
+                continue;
+            };
 
-    for meta in metas {
-        let MetaItemInner::Lit(meta_lit) = meta else {
+            this.confusables.push(lit.symbol);
+        }
+
+        this.first_span.get_or_insert(cx.attr_span);
+    })];
+
+    fn finalize(self, _cx: &FinalizeContext<'_>) -> Option<AttributeKind> {
+        if self.confusables.is_empty() {
             return None;
-        };
-        candidates.push(meta_lit.symbol);
-    }
+        }
 
-    Some(candidates)
+        Some(AttributeKind::Confusables {
+            symbols: self.confusables,
+            first_span: self.first_span.unwrap(),
+        })
+    }
 }
diff --git a/compiler/rustc_attr_parsing/src/attributes/deprecation.rs b/compiler/rustc_attr_parsing/src/attributes/deprecation.rs
index d7415a7198f..7d1417446b2 100644
--- a/compiler/rustc_attr_parsing/src/attributes/deprecation.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/deprecation.rs
@@ -1,121 +1,122 @@
-//! Parsing and validation of builtin attributes
-
-use rustc_ast::attr::AttributeExt;
-use rustc_ast::{MetaItem, MetaItemInner};
-use rustc_ast_pretty::pprust;
-use rustc_attr_data_structures::{DeprecatedSince, Deprecation};
-use rustc_feature::Features;
-use rustc_session::Session;
+use rustc_attr_data_structures::{AttributeKind, DeprecatedSince, Deprecation};
+use rustc_span::symbol::Ident;
 use rustc_span::{Span, Symbol, sym};
 
-use super::util::UnsupportedLiteralReason;
-use crate::{parse_version, session_diagnostics};
+use super::SingleAttributeParser;
+use super::util::parse_version;
+use crate::context::AcceptContext;
+use crate::parser::ArgParser;
+use crate::session_diagnostics;
+use crate::session_diagnostics::UnsupportedLiteralReason;
 
-/// Finds the deprecation attribute. `None` if none exists.
-pub fn find_deprecation(
-    sess: &Session,
-    features: &Features,
-    attrs: &[impl AttributeExt],
-) -> Option<(Deprecation, Span)> {
-    let mut depr: Option<(Deprecation, Span)> = None;
-    let is_rustc = features.staged_api();
+pub(crate) struct DeprecationParser;
 
-    'outer: for attr in attrs {
-        if !attr.has_name(sym::deprecated) {
-            continue;
+fn get(
+    cx: &AcceptContext<'_>,
+    ident: Ident,
+    param_span: Span,
+    arg: &ArgParser<'_>,
+    item: &Option<Symbol>,
+) -> Option<Symbol> {
+    if item.is_some() {
+        cx.emit_err(session_diagnostics::MultipleItem {
+            span: param_span,
+            item: ident.to_string(),
+        });
+        return None;
+    }
+    if let Some(v) = arg.name_value() {
+        if let Some(value_str) = v.value_as_str() {
+            Some(value_str)
+        } else {
+            let lit = v.value_as_lit();
+            cx.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: v.value_span,
+                reason: UnsupportedLiteralReason::DeprecatedString,
+                is_bytestr: lit.kind.is_bytestr(),
+                start_point_span: cx.sess().source_map().start_point(lit.span),
+            });
+            None
         }
+    } else {
+        // FIXME(jdonszelmann): suggestion?
+        cx.emit_err(session_diagnostics::IncorrectMetaItem { span: param_span, suggestion: None });
+        None
+    }
+}
+
+impl SingleAttributeParser for DeprecationParser {
+    const PATH: &'static [rustc_span::Symbol] = &[sym::deprecated];
+
+    fn on_duplicate(cx: &AcceptContext<'_>, first_span: rustc_span::Span) {
+        // FIXME(jdonszelmann): merge with errors from check_attrs.rs
+        cx.emit_err(session_diagnostics::UnusedMultiple {
+            this: cx.attr_span,
+            other: first_span,
+            name: sym::deprecated,
+        });
+    }
+
+    fn convert(cx: &AcceptContext<'_>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        let features = cx.features();
 
         let mut since = None;
         let mut note = None;
         let mut suggestion = None;
 
-        if attr.is_doc_comment() {
-            continue;
-        } else if attr.is_word() {
-        } else if let Some(value) = attr.value_str() {
-            note = Some(value)
-        } else if let Some(list) = attr.meta_item_list() {
-            let get = |meta: &MetaItem, item: &mut Option<Symbol>| {
-                if item.is_some() {
-                    sess.dcx().emit_err(session_diagnostics::MultipleItem {
-                        span: meta.span,
-                        item: pprust::path_to_string(&meta.path),
+        let is_rustc = features.staged_api();
+
+        if let Some(value) = args.name_value()
+            && let Some(value_str) = value.value_as_str()
+        {
+            note = Some(value_str)
+        } else if let Some(list) = args.list() {
+            for param in list.mixed() {
+                let param_span = param.span();
+                let Some(param) = param.meta_item() else {
+                    cx.emit_err(session_diagnostics::UnsupportedLiteral {
+                        span: param_span,
+                        reason: UnsupportedLiteralReason::DeprecatedKvPair,
+                        is_bytestr: false,
+                        start_point_span: cx.sess().source_map().start_point(param_span),
                     });
-                    return false;
-                }
-                if let Some(v) = meta.value_str() {
-                    *item = Some(v);
-                    true
-                } else {
-                    if let Some(lit) = meta.name_value_literal() {
-                        sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral {
-                            span: lit.span,
-                            reason: UnsupportedLiteralReason::DeprecatedString,
-                            is_bytestr: lit.kind.is_bytestr(),
-                            start_point_span: sess.source_map().start_point(lit.span),
-                        });
-                    } else {
-                        sess.dcx()
-                            .emit_err(session_diagnostics::IncorrectMetaItem { span: meta.span });
-                    }
-                    false
-                }
-            };
+                    return None;
+                };
 
-            for meta in &list {
-                match meta {
-                    MetaItemInner::MetaItem(mi) => match mi.name_or_empty() {
-                        sym::since => {
-                            if !get(mi, &mut since) {
-                                continue 'outer;
-                            }
-                        }
-                        sym::note => {
-                            if !get(mi, &mut note) {
-                                continue 'outer;
-                            }
-                        }
-                        sym::suggestion => {
-                            if !features.deprecated_suggestion() {
-                                sess.dcx().emit_err(
-                                    session_diagnostics::DeprecatedItemSuggestion {
-                                        span: mi.span,
-                                        is_nightly: sess.is_nightly_build(),
-                                        details: (),
-                                    },
-                                );
-                            }
+                let (ident, arg) = param.word_or_empty();
 
-                            if !get(mi, &mut suggestion) {
-                                continue 'outer;
-                            }
-                        }
-                        _ => {
-                            sess.dcx().emit_err(session_diagnostics::UnknownMetaItem {
-                                span: meta.span(),
-                                item: pprust::path_to_string(&mi.path),
-                                expected: if features.deprecated_suggestion() {
-                                    &["since", "note", "suggestion"]
-                                } else {
-                                    &["since", "note"]
-                                },
+                match ident.name {
+                    sym::since => {
+                        since = Some(get(cx, ident, param_span, arg, &since)?);
+                    }
+                    sym::note => {
+                        note = Some(get(cx, ident, param_span, arg, &note)?);
+                    }
+                    sym::suggestion => {
+                        if !features.deprecated_suggestion() {
+                            cx.emit_err(session_diagnostics::DeprecatedItemSuggestion {
+                                span: param_span,
+                                is_nightly: cx.sess().is_nightly_build(),
+                                details: (),
                             });
-                            continue 'outer;
                         }
-                    },
-                    MetaItemInner::Lit(lit) => {
-                        sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral {
-                            span: lit.span,
-                            reason: UnsupportedLiteralReason::DeprecatedKvPair,
-                            is_bytestr: false,
-                            start_point_span: sess.source_map().start_point(lit.span),
+
+                        suggestion = Some(get(cx, ident, param_span, arg, &suggestion)?);
+                    }
+                    _ => {
+                        cx.emit_err(session_diagnostics::UnknownMetaItem {
+                            span: param_span,
+                            item: ident.to_string(),
+                            expected: if features.deprecated_suggestion() {
+                                &["since", "note", "suggestion"]
+                            } else {
+                                &["since", "note"]
+                            },
                         });
-                        continue 'outer;
+                        return None;
                     }
                 }
             }
-        } else {
-            continue;
         }
 
         let since = if let Some(since) = since {
@@ -126,23 +127,24 @@ pub fn find_deprecation(
             } else if let Some(version) = parse_version(since) {
                 DeprecatedSince::RustcVersion(version)
             } else {
-                sess.dcx().emit_err(session_diagnostics::InvalidSince { span: attr.span() });
+                cx.emit_err(session_diagnostics::InvalidSince { span: cx.attr_span });
                 DeprecatedSince::Err
             }
         } else if is_rustc {
-            sess.dcx().emit_err(session_diagnostics::MissingSince { span: attr.span() });
+            cx.emit_err(session_diagnostics::MissingSince { span: cx.attr_span });
             DeprecatedSince::Err
         } else {
             DeprecatedSince::Unspecified
         };
 
         if is_rustc && note.is_none() {
-            sess.dcx().emit_err(session_diagnostics::MissingNote { span: attr.span() });
-            continue;
+            cx.emit_err(session_diagnostics::MissingNote { span: cx.attr_span });
+            return None;
         }
 
-        depr = Some((Deprecation { since, note, suggestion }, attr.span()));
+        Some(AttributeKind::Deprecation {
+            deprecation: Deprecation { since, note, suggestion },
+            span: cx.attr_span,
+        })
     }
-
-    depr
 }
diff --git a/compiler/rustc_attr_parsing/src/attributes/mod.rs b/compiler/rustc_attr_parsing/src/attributes/mod.rs
index 7d08cf6f0d9..6ecd6b4d7db 100644
--- a/compiler/rustc_attr_parsing/src/attributes/mod.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/mod.rs
@@ -32,14 +32,6 @@ pub(crate) mod stability;
 pub(crate) mod transparency;
 pub(crate) mod util;
 
-pub use allow_unstable::*;
-pub use cfg::*;
-pub use confusables::*;
-pub use deprecation::*;
-pub use repr::*;
-pub use stability::*;
-pub use transparency::*;
-
 type AcceptFn<T> = fn(&mut T, &AcceptContext<'_>, &ArgParser<'_>);
 type AcceptMapping<T> = &'static [(&'static [rustc_span::Symbol], AcceptFn<T>)];
 
diff --git a/compiler/rustc_attr_parsing/src/attributes/repr.rs b/compiler/rustc_attr_parsing/src/attributes/repr.rs
index 28c381160b8..26ca637faec 100644
--- a/compiler/rustc_attr_parsing/src/attributes/repr.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/repr.rs
@@ -1,15 +1,13 @@
-//! Parsing and validation of builtin attributes
-
 use rustc_abi::Align;
-use rustc_ast::attr::AttributeExt;
-use rustc_ast::{self as ast, MetaItemKind};
-use rustc_attr_data_structures::IntType;
-use rustc_attr_data_structures::ReprAttr::*;
-use rustc_session::Session;
-use rustc_span::{Symbol, sym};
+use rustc_ast::{IntTy, LitIntType, LitKind, UintTy};
+use rustc_attr_data_structures::{AttributeKind, IntType, ReprAttr};
+use rustc_span::{Span, Symbol, sym};
 
-use crate::ReprAttr;
-use crate::session_diagnostics::{self, IncorrectReprFormatGenericCause};
+use super::{CombineAttributeParser, ConvertFn};
+use crate::context::AcceptContext;
+use crate::parser::{ArgParser, MetaItemListParser, MetaItemParser};
+use crate::session_diagnostics;
+use crate::session_diagnostics::IncorrectReprFormatGenericCause;
 
 /// Parse #[repr(...)] forms.
 ///
@@ -18,185 +16,216 @@ use crate::session_diagnostics::{self, IncorrectReprFormatGenericCause};
 /// the same discriminant size that the corresponding C enum would or C
 /// structure layout, `packed` to remove padding, and `transparent` to delegate representation
 /// concerns to the only non-ZST field.
-pub fn find_repr_attrs(sess: &Session, attr: &impl AttributeExt) -> Vec<ReprAttr> {
-    if attr.has_name(sym::repr) { parse_repr_attr(sess, attr) } else { Vec::new() }
-}
+// FIXME(jdonszelmann): is a vec the right representation here even? isn't it just a struct?
+pub(crate) struct ReprParser;
 
-pub fn parse_repr_attr(sess: &Session, attr: &impl AttributeExt) -> Vec<ReprAttr> {
-    assert!(attr.has_name(sym::repr), "expected `#[repr(..)]`, found: {attr:?}");
-    let mut acc = Vec::new();
-    let dcx = sess.dcx();
-
-    if let Some(items) = attr.meta_item_list() {
-        for item in items {
-            let mut recognised = false;
-            if item.is_word() {
-                let hint = match item.name_or_empty() {
-                    sym::Rust => Some(ReprRust),
-                    sym::C => Some(ReprC),
-                    sym::packed => Some(ReprPacked(Align::ONE)),
-                    sym::simd => Some(ReprSimd),
-                    sym::transparent => Some(ReprTransparent),
-                    sym::align => {
-                        sess.dcx().emit_err(session_diagnostics::InvalidReprAlignNeedArg {
-                            span: item.span(),
-                        });
-                        recognised = true;
-                        None
-                    }
-                    name => int_type_of_word(name).map(ReprInt),
-                };
-
-                if let Some(h) = hint {
-                    recognised = true;
-                    acc.push(h);
-                }
-            } else if let Some((name, value)) = item.singleton_lit_list() {
-                let mut literal_error = None;
-                let mut err_span = item.span();
-                if name == sym::align {
-                    recognised = true;
-                    match parse_alignment(&value.kind) {
-                        Ok(literal) => acc.push(ReprAlign(literal)),
-                        Err(message) => {
-                            err_span = value.span;
-                            literal_error = Some(message)
-                        }
-                    };
-                } else if name == sym::packed {
-                    recognised = true;
-                    match parse_alignment(&value.kind) {
-                        Ok(literal) => acc.push(ReprPacked(literal)),
-                        Err(message) => {
-                            err_span = value.span;
-                            literal_error = Some(message)
-                        }
-                    };
-                } else if matches!(name, sym::Rust | sym::C | sym::simd | sym::transparent)
-                    || int_type_of_word(name).is_some()
-                {
-                    recognised = true;
-                    sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoParen {
-                        span: item.span(),
-                        name: name.to_ident_string(),
-                    });
-                }
-                if let Some(literal_error) = literal_error {
-                    sess.dcx().emit_err(session_diagnostics::InvalidReprGeneric {
-                        span: err_span,
-                        repr_arg: name.to_ident_string(),
-                        error_part: literal_error,
-                    });
-                }
-            } else if let Some(meta_item) = item.meta_item() {
-                match &meta_item.kind {
-                    MetaItemKind::NameValue(value) => {
-                        if meta_item.has_name(sym::align) || meta_item.has_name(sym::packed) {
-                            let name = meta_item.name_or_empty().to_ident_string();
-                            recognised = true;
-                            sess.dcx().emit_err(session_diagnostics::IncorrectReprFormatGeneric {
-                                span: item.span(),
-                                repr_arg: &name,
-                                cause: IncorrectReprFormatGenericCause::from_lit_kind(
-                                    item.span(),
-                                    &value.kind,
-                                    &name,
-                                ),
-                            });
-                        } else if matches!(
-                            meta_item.name_or_empty(),
-                            sym::Rust | sym::C | sym::simd | sym::transparent
-                        ) || int_type_of_word(meta_item.name_or_empty()).is_some()
-                        {
-                            recognised = true;
-                            sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoValue {
-                                span: meta_item.span,
-                                name: meta_item.name_or_empty().to_ident_string(),
-                            });
-                        }
-                    }
-                    MetaItemKind::List(nested_items) => {
-                        if meta_item.has_name(sym::align) {
-                            recognised = true;
-                            if let [nested_item] = nested_items.as_slice() {
-                                sess.dcx().emit_err(
-                                    session_diagnostics::IncorrectReprFormatExpectInteger {
-                                        span: nested_item.span(),
-                                    },
-                                );
-                            } else {
-                                sess.dcx().emit_err(
-                                    session_diagnostics::IncorrectReprFormatAlignOneArg {
-                                        span: meta_item.span,
-                                    },
-                                );
-                            }
-                        } else if meta_item.has_name(sym::packed) {
-                            recognised = true;
-                            if let [nested_item] = nested_items.as_slice() {
-                                sess.dcx().emit_err(
-                                    session_diagnostics::IncorrectReprFormatPackedExpectInteger {
-                                        span: nested_item.span(),
-                                    },
-                                );
-                            } else {
-                                sess.dcx().emit_err(
-                                    session_diagnostics::IncorrectReprFormatPackedOneOrZeroArg {
-                                        span: meta_item.span,
-                                    },
-                                );
-                            }
-                        } else if matches!(
-                            meta_item.name_or_empty(),
-                            sym::Rust | sym::C | sym::simd | sym::transparent
-                        ) || int_type_of_word(meta_item.name_or_empty()).is_some()
-                        {
-                            recognised = true;
-                            sess.dcx().emit_err(session_diagnostics::InvalidReprHintNoParen {
-                                span: meta_item.span,
-                                name: meta_item.name_or_empty().to_ident_string(),
-                            });
-                        }
-                    }
-                    _ => (),
-                }
-            }
-            if !recognised {
-                // Not a word we recognize. This will be caught and reported by
-                // the `check_mod_attrs` pass, but this pass doesn't always run
-                // (e.g. if we only pretty-print the source), so we have to gate
-                // the `span_delayed_bug` call as follows:
-                if sess.opts.pretty.is_none_or(|pp| pp.needs_analysis()) {
-                    dcx.span_delayed_bug(item.span(), "unrecognized representation hint");
-                }
+impl CombineAttributeParser for ReprParser {
+    type Item = (ReprAttr, Span);
+    const PATH: &'static [rustc_span::Symbol] = &[sym::repr];
+    const CONVERT: ConvertFn<Self::Item> = AttributeKind::Repr;
+
+    fn extend<'a>(
+        cx: &'a AcceptContext<'a>,
+        args: &'a ArgParser<'a>,
+    ) -> impl IntoIterator<Item = Self::Item> + 'a {
+        let mut reprs = Vec::new();
+
+        let Some(list) = args.list() else {
+            return reprs;
+        };
+
+        if list.is_empty() {
+            // this is so validation can emit a lint
+            reprs.push((ReprAttr::ReprEmpty, cx.attr_span));
+        }
+
+        for param in list.mixed() {
+            if let Some(_) = param.lit() {
+                cx.emit_err(session_diagnostics::ReprIdent { span: cx.attr_span });
+                continue;
             }
+
+            reprs.extend(
+                param.meta_item().and_then(|mi| parse_repr(cx, &mi)).map(|r| (r, param.span())),
+            );
         }
+
+        reprs
     }
-    acc
+}
+
+macro_rules! int_pat {
+    () => {
+        sym::i8
+            | sym::u8
+            | sym::i16
+            | sym::u16
+            | sym::i32
+            | sym::u32
+            | sym::i64
+            | sym::u64
+            | sym::i128
+            | sym::u128
+            | sym::isize
+            | sym::usize
+    };
 }
 
 fn int_type_of_word(s: Symbol) -> Option<IntType> {
-    use rustc_attr_data_structures::IntType::*;
+    use IntType::*;
 
     match s {
-        sym::i8 => Some(SignedInt(ast::IntTy::I8)),
-        sym::u8 => Some(UnsignedInt(ast::UintTy::U8)),
-        sym::i16 => Some(SignedInt(ast::IntTy::I16)),
-        sym::u16 => Some(UnsignedInt(ast::UintTy::U16)),
-        sym::i32 => Some(SignedInt(ast::IntTy::I32)),
-        sym::u32 => Some(UnsignedInt(ast::UintTy::U32)),
-        sym::i64 => Some(SignedInt(ast::IntTy::I64)),
-        sym::u64 => Some(UnsignedInt(ast::UintTy::U64)),
-        sym::i128 => Some(SignedInt(ast::IntTy::I128)),
-        sym::u128 => Some(UnsignedInt(ast::UintTy::U128)),
-        sym::isize => Some(SignedInt(ast::IntTy::Isize)),
-        sym::usize => Some(UnsignedInt(ast::UintTy::Usize)),
+        sym::i8 => Some(SignedInt(IntTy::I8)),
+        sym::u8 => Some(UnsignedInt(UintTy::U8)),
+        sym::i16 => Some(SignedInt(IntTy::I16)),
+        sym::u16 => Some(UnsignedInt(UintTy::U16)),
+        sym::i32 => Some(SignedInt(IntTy::I32)),
+        sym::u32 => Some(UnsignedInt(UintTy::U32)),
+        sym::i64 => Some(SignedInt(IntTy::I64)),
+        sym::u64 => Some(UnsignedInt(UintTy::U64)),
+        sym::i128 => Some(SignedInt(IntTy::I128)),
+        sym::u128 => Some(UnsignedInt(UintTy::U128)),
+        sym::isize => Some(SignedInt(IntTy::Isize)),
+        sym::usize => Some(UnsignedInt(UintTy::Usize)),
         _ => None,
     }
 }
 
-pub fn parse_alignment(node: &ast::LitKind) -> Result<Align, &'static str> {
-    if let ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed) = node {
+fn parse_repr(cx: &AcceptContext<'_>, param: &MetaItemParser<'_>) -> Option<ReprAttr> {
+    use ReprAttr::*;
+
+    // FIXME(jdonszelmann): invert the parsing here to match on the word first and then the
+    // structure.
+    let (ident, args) = param.word_or_empty();
+
+    match (ident.name, args) {
+        (sym::align, ArgParser::NoArgs) => {
+            cx.emit_err(session_diagnostics::InvalidReprAlignNeedArg { span: ident.span });
+            None
+        }
+        (sym::align, ArgParser::List(l)) => parse_repr_align(cx, l, param.span(), AlignKind::Align),
+
+        (sym::packed, ArgParser::NoArgs) => Some(ReprPacked(Align::ONE)),
+        (sym::packed, ArgParser::List(l)) => {
+            parse_repr_align(cx, l, param.span(), AlignKind::Packed)
+        }
+
+        (sym::align | sym::packed, ArgParser::NameValue(l)) => {
+            cx.emit_err(session_diagnostics::IncorrectReprFormatGeneric {
+                span: param.span(),
+                // FIXME(jdonszelmann) can just be a string in the diag type
+                repr_arg: &ident.to_string(),
+                cause: IncorrectReprFormatGenericCause::from_lit_kind(
+                    param.span(),
+                    &l.value_as_lit().kind,
+                    ident.name.as_str(),
+                ),
+            });
+            None
+        }
+
+        (sym::Rust, ArgParser::NoArgs) => Some(ReprRust),
+        (sym::C, ArgParser::NoArgs) => Some(ReprC),
+        (sym::simd, ArgParser::NoArgs) => Some(ReprSimd),
+        (sym::transparent, ArgParser::NoArgs) => Some(ReprTransparent),
+        (i @ int_pat!(), ArgParser::NoArgs) => {
+            // int_pat!() should make sure it always parses
+            Some(ReprInt(int_type_of_word(i).unwrap()))
+        }
+
+        (
+            sym::Rust | sym::C | sym::simd | sym::transparent | int_pat!(),
+            ArgParser::NameValue(_),
+        ) => {
+            cx.emit_err(session_diagnostics::InvalidReprHintNoValue {
+                span: param.span(),
+                name: ident.to_string(),
+            });
+            None
+        }
+        (sym::Rust | sym::C | sym::simd | sym::transparent | int_pat!(), ArgParser::List(_)) => {
+            cx.emit_err(session_diagnostics::InvalidReprHintNoParen {
+                span: param.span(),
+                name: ident.to_string(),
+            });
+            None
+        }
+
+        _ => {
+            cx.emit_err(session_diagnostics::UnrecognizedReprHint { span: param.span() });
+            None
+        }
+    }
+}
+
+enum AlignKind {
+    Packed,
+    Align,
+}
+
+fn parse_repr_align(
+    cx: &AcceptContext<'_>,
+    list: &MetaItemListParser<'_>,
+    param_span: Span,
+    align_kind: AlignKind,
+) -> Option<ReprAttr> {
+    use AlignKind::*;
+
+    let Some(align) = list.single() else {
+        match align_kind {
+            Packed => {
+                cx.emit_err(session_diagnostics::IncorrectReprFormatPackedOneOrZeroArg {
+                    span: param_span,
+                });
+            }
+            Align => {
+                cx.dcx().emit_err(session_diagnostics::IncorrectReprFormatAlignOneArg {
+                    span: param_span,
+                });
+            }
+        }
+
+        return None;
+    };
+
+    let Some(lit) = align.lit() else {
+        match align_kind {
+            Packed => {
+                cx.emit_err(session_diagnostics::IncorrectReprFormatPackedExpectInteger {
+                    span: align.span(),
+                });
+            }
+            Align => {
+                cx.emit_err(session_diagnostics::IncorrectReprFormatExpectInteger {
+                    span: align.span(),
+                });
+            }
+        }
+
+        return None;
+    };
+
+    match parse_alignment(&lit.kind) {
+        Ok(literal) => Some(match align_kind {
+            AlignKind::Packed => ReprAttr::ReprPacked(literal),
+            AlignKind::Align => ReprAttr::ReprAlign(literal),
+        }),
+        Err(message) => {
+            cx.emit_err(session_diagnostics::InvalidReprGeneric {
+                span: lit.span,
+                repr_arg: match align_kind {
+                    Packed => "packed".to_string(),
+                    Align => "align".to_string(),
+                },
+                error_part: message,
+            });
+            None
+        }
+    }
+}
+
+fn parse_alignment(node: &LitKind) -> Result<Align, &'static str> {
+    if let LitKind::Int(literal, LitIntType::Unsuffixed) = node {
         // `Align::from_bytes` accepts 0 as an input, check is_power_of_two() first
         if literal.get().is_power_of_two() {
             // Only possible error is larger than 2^29
diff --git a/compiler/rustc_attr_parsing/src/attributes/stability.rs b/compiler/rustc_attr_parsing/src/attributes/stability.rs
index 454b8b5de82..6d76456e83c 100644
--- a/compiler/rustc_attr_parsing/src/attributes/stability.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/stability.rs
@@ -1,266 +1,258 @@
-//! Parsing and validation of builtin attributes
-
 use std::num::NonZero;
 
-use rustc_ast::MetaItem;
-use rustc_ast::attr::AttributeExt;
-use rustc_ast_pretty::pprust;
 use rustc_attr_data_structures::{
-    ConstStability, DefaultBodyStability, Stability, StabilityLevel, StableSince, UnstableReason,
-    VERSION_PLACEHOLDER,
+    AttributeKind, DefaultBodyStability, PartialConstStability, Stability, StabilityLevel,
+    StableSince, UnstableReason, VERSION_PLACEHOLDER,
 };
 use rustc_errors::ErrorGuaranteed;
-use rustc_session::Session;
 use rustc_span::{Span, Symbol, kw, sym};
 
-use crate::attributes::util::UnsupportedLiteralReason;
-use crate::{parse_version, session_diagnostics};
-
-/// Collects stability info from `stable`/`unstable`/`rustc_allowed_through_unstable_modules`
-/// attributes in `attrs`. Returns `None` if no stability attributes are found.
-pub fn find_stability(
-    sess: &Session,
-    attrs: &[impl AttributeExt],
-    item_sp: Span,
-) -> Option<(Stability, Span)> {
-    let mut stab: Option<(Stability, Span)> = None;
-    let mut allowed_through_unstable_modules = None;
-
-    for attr in attrs {
-        match attr.name_or_empty() {
-            sym::rustc_allowed_through_unstable_modules => {
-                // The value is mandatory, but avoid ICEs in case such code reaches this function.
-                allowed_through_unstable_modules = Some(attr.value_str().unwrap_or_else(|| {
-                    sess.dcx().span_delayed_bug(
-                        item_sp,
-                        "`#[rustc_allowed_through_unstable_modules]` without deprecation message",
-                    );
-                    kw::Empty
-                }))
-            }
-            sym::unstable => {
-                if stab.is_some() {
-                    sess.dcx().emit_err(session_diagnostics::MultipleStabilityLevels {
-                        span: attr.span(),
-                    });
-                    break;
-                }
+use super::util::parse_version;
+use super::{AcceptMapping, AttributeParser, SingleAttributeParser};
+use crate::context::{AcceptContext, FinalizeContext};
+use crate::parser::{ArgParser, MetaItemParser};
+use crate::session_diagnostics::{self, UnsupportedLiteralReason};
+
+macro_rules! reject_outside_std {
+    ($cx: ident) => {
+        // Emit errors for non-staged-api crates.
+        if !$cx.features().staged_api() {
+            $cx.emit_err(session_diagnostics::StabilityOutsideStd { span: $cx.attr_span });
+            return;
+        }
+    };
+}
 
-                if let Some((feature, level)) = parse_unstability(sess, attr) {
-                    stab = Some((Stability { level, feature }, attr.span()));
-                }
-            }
-            sym::stable => {
-                if stab.is_some() {
-                    sess.dcx().emit_err(session_diagnostics::MultipleStabilityLevels {
-                        span: attr.span(),
-                    });
-                    break;
-                }
-                if let Some((feature, level)) = parse_stability(sess, attr) {
-                    stab = Some((Stability { level, feature }, attr.span()));
-                }
-            }
-            _ => {}
+#[derive(Default)]
+pub(crate) struct StabilityParser {
+    allowed_through_unstable_modules: Option<Symbol>,
+    stability: Option<(Stability, Span)>,
+}
+
+impl StabilityParser {
+    /// Checks, and emits an error when a stability (or unstability) was already set, which would be a duplicate.
+    fn check_duplicate(&self, cx: &AcceptContext<'_>) -> bool {
+        if let Some((_, _)) = self.stability {
+            cx.emit_err(session_diagnostics::MultipleStabilityLevels { span: cx.attr_span });
+            true
+        } else {
+            false
         }
     }
+}
 
-    if let Some(allowed_through_unstable_modules) = allowed_through_unstable_modules {
-        match &mut stab {
-            Some((
+impl AttributeParser for StabilityParser {
+    const ATTRIBUTES: AcceptMapping<Self> = &[
+        (&[sym::stable], |this, cx, args| {
+            reject_outside_std!(cx);
+            if !this.check_duplicate(cx)
+                && let Some((feature, level)) = parse_stability(cx, args)
+            {
+                this.stability = Some((Stability { level, feature }, cx.attr_span));
+            }
+        }),
+        (&[sym::unstable], |this, cx, args| {
+            reject_outside_std!(cx);
+            if !this.check_duplicate(cx)
+                && let Some((feature, level)) = parse_unstability(cx, args)
+            {
+                this.stability = Some((Stability { level, feature }, cx.attr_span));
+            }
+        }),
+        (&[sym::rustc_allowed_through_unstable_modules], |this, cx, args| {
+            reject_outside_std!(cx);
+            this.allowed_through_unstable_modules =
+                Some(match args.name_value().and_then(|i| i.value_as_str()) {
+                    Some(msg) => msg,
+                    None => kw::Empty,
+                });
+        }),
+    ];
+
+    fn finalize(mut self, cx: &FinalizeContext<'_>) -> Option<AttributeKind> {
+        if let Some(atum) = self.allowed_through_unstable_modules {
+            if let Some((
                 Stability {
-                    level: StabilityLevel::Stable { allowed_through_unstable_modules: in_stab, .. },
+                    level: StabilityLevel::Stable { ref mut allowed_through_unstable_modules, .. },
                     ..
                 },
                 _,
-            )) => *in_stab = Some(allowed_through_unstable_modules),
-            _ => {
-                sess.dcx()
-                    .emit_err(session_diagnostics::RustcAllowedUnstablePairing { span: item_sp });
+            )) = self.stability
+            {
+                *allowed_through_unstable_modules = Some(atum);
+            } else {
+                cx.dcx().emit_err(session_diagnostics::RustcAllowedUnstablePairing {
+                    span: cx.target_span,
+                });
             }
         }
-    }
 
-    stab
+        let (stability, span) = self.stability?;
+
+        Some(AttributeKind::Stability { stability, span })
+    }
 }
 
-/// Collects stability info from `rustc_const_stable`/`rustc_const_unstable`/`rustc_promotable`
-/// attributes in `attrs`. Returns `None` if no stability attributes are found.
-pub fn find_const_stability(
-    sess: &Session,
-    attrs: &[impl AttributeExt],
-    item_sp: Span,
-) -> Option<(ConstStability, Span)> {
-    let mut const_stab: Option<(ConstStability, Span)> = None;
-    let mut promotable = false;
-    let mut const_stable_indirect = false;
-
-    for attr in attrs {
-        match attr.name_or_empty() {
-            sym::rustc_promotable => promotable = true,
-            sym::rustc_const_stable_indirect => const_stable_indirect = true,
-            sym::rustc_const_unstable => {
-                if const_stab.is_some() {
-                    sess.dcx().emit_err(session_diagnostics::MultipleStabilityLevels {
-                        span: attr.span(),
-                    });
-                    break;
-                }
+// FIXME(jdonszelmann) change to Single
+#[derive(Default)]
+pub(crate) struct BodyStabilityParser {
+    stability: Option<(DefaultBodyStability, Span)>,
+}
 
-                if let Some((feature, level)) = parse_unstability(sess, attr) {
-                    const_stab = Some((
-                        ConstStability {
-                            level,
-                            feature,
-                            const_stable_indirect: false,
-                            promotable: false,
-                        },
-                        attr.span(),
-                    ));
-                }
+impl AttributeParser for BodyStabilityParser {
+    const ATTRIBUTES: AcceptMapping<Self> =
+        &[(&[sym::rustc_default_body_unstable], |this, cx, args| {
+            reject_outside_std!(cx);
+            if this.stability.is_some() {
+                cx.dcx()
+                    .emit_err(session_diagnostics::MultipleStabilityLevels { span: cx.attr_span });
+            } else if let Some((feature, level)) = parse_unstability(cx, args) {
+                this.stability = Some((DefaultBodyStability { level, feature }, cx.attr_span));
             }
-            sym::rustc_const_stable => {
-                if const_stab.is_some() {
-                    sess.dcx().emit_err(session_diagnostics::MultipleStabilityLevels {
-                        span: attr.span(),
-                    });
-                    break;
-                }
-                if let Some((feature, level)) = parse_stability(sess, attr) {
-                    const_stab = Some((
-                        ConstStability {
-                            level,
-                            feature,
-                            const_stable_indirect: false,
-                            promotable: false,
-                        },
-                        attr.span(),
-                    ));
-                }
-            }
-            _ => {}
-        }
-    }
+        })];
 
-    // Merge promotable and const_stable_indirect into stability info
-    if promotable {
-        match &mut const_stab {
-            Some((stab, _)) => stab.promotable = promotable,
-            _ => {
-                _ = sess
-                    .dcx()
-                    .emit_err(session_diagnostics::RustcPromotablePairing { span: item_sp })
-            }
-        }
+    fn finalize(self, _cx: &FinalizeContext<'_>) -> Option<AttributeKind> {
+        let (stability, span) = self.stability?;
+
+        Some(AttributeKind::BodyStability { stability, span })
     }
-    if const_stable_indirect {
-        match &mut const_stab {
-            Some((stab, _)) => {
-                if stab.is_const_unstable() {
-                    stab.const_stable_indirect = true;
-                } else {
-                    _ = sess.dcx().emit_err(session_diagnostics::RustcConstStableIndirectPairing {
-                        span: item_sp,
-                    })
-                }
-            }
-            _ => {
-                // This function has no const stability attribute, but has `const_stable_indirect`.
-                // We ignore that; unmarked functions are subject to recursive const stability
-                // checks by default so we do carry out the user's intent.
-            }
-        }
+}
+
+pub(crate) struct ConstStabilityIndirectParser;
+// FIXME(jdonszelmann): single word attribute group when we have these
+impl SingleAttributeParser for ConstStabilityIndirectParser {
+    const PATH: &'static [rustc_span::Symbol] = &[sym::rustc_const_stable_indirect];
+
+    // ignore
+    fn on_duplicate(_cx: &AcceptContext<'_>, _first_span: Span) {}
+
+    fn convert(_cx: &AcceptContext<'_>, _args: &ArgParser<'_>) -> Option<AttributeKind> {
+        Some(AttributeKind::ConstStabilityIndirect)
     }
+}
 
-    const_stab
+#[derive(Default)]
+pub(crate) struct ConstStabilityParser {
+    promotable: bool,
+    stability: Option<(PartialConstStability, Span)>,
 }
 
-/// Calculates the const stability for a const function in a `-Zforce-unstable-if-unmarked` crate
-/// without the `staged_api` feature.
-pub fn unmarked_crate_const_stab(
-    _sess: &Session,
-    attrs: &[impl AttributeExt],
-    regular_stab: Stability,
-) -> ConstStability {
-    assert!(regular_stab.level.is_unstable());
-    // The only attribute that matters here is `rustc_const_stable_indirect`.
-    // We enforce recursive const stability rules for those functions.
-    let const_stable_indirect =
-        attrs.iter().any(|a| a.name_or_empty() == sym::rustc_const_stable_indirect);
-    ConstStability {
-        feature: regular_stab.feature,
-        const_stable_indirect,
-        promotable: false,
-        level: regular_stab.level,
+impl ConstStabilityParser {
+    /// Checks, and emits an error when a stability (or unstability) was already set, which would be a duplicate.
+    fn check_duplicate(&self, cx: &AcceptContext<'_>) -> bool {
+        if let Some((_, _)) = self.stability {
+            cx.emit_err(session_diagnostics::MultipleStabilityLevels { span: cx.attr_span });
+            true
+        } else {
+            false
+        }
     }
 }
 
-/// Collects stability info from `rustc_default_body_unstable` attributes in `attrs`.
-/// Returns `None` if no stability attributes are found.
-pub fn find_body_stability(
-    sess: &Session,
-    attrs: &[impl AttributeExt],
-) -> Option<(DefaultBodyStability, Span)> {
-    let mut body_stab: Option<(DefaultBodyStability, Span)> = None;
-
-    for attr in attrs {
-        if attr.has_name(sym::rustc_default_body_unstable) {
-            if body_stab.is_some() {
-                sess.dcx()
-                    .emit_err(session_diagnostics::MultipleStabilityLevels { span: attr.span() });
-                break;
+impl AttributeParser for ConstStabilityParser {
+    const ATTRIBUTES: AcceptMapping<Self> = &[
+        (&[sym::rustc_const_stable], |this, cx, args| {
+            reject_outside_std!(cx);
+
+            if !this.check_duplicate(cx)
+                && let Some((feature, level)) = parse_stability(cx, args)
+            {
+                this.stability = Some((
+                    PartialConstStability { level, feature, promotable: false },
+                    cx.attr_span,
+                ));
             }
-
-            if let Some((feature, level)) = parse_unstability(sess, attr) {
-                body_stab = Some((DefaultBodyStability { level, feature }, attr.span()));
+        }),
+        (&[sym::rustc_const_unstable], |this, cx, args| {
+            reject_outside_std!(cx);
+            if !this.check_duplicate(cx)
+                && let Some((feature, level)) = parse_unstability(cx, args)
+            {
+                this.stability = Some((
+                    PartialConstStability { level, feature, promotable: false },
+                    cx.attr_span,
+                ));
+            }
+        }),
+        (&[sym::rustc_promotable], |this, cx, _| {
+            reject_outside_std!(cx);
+            this.promotable = true;
+        }),
+    ];
+
+    fn finalize(mut self, cx: &FinalizeContext<'_>) -> Option<AttributeKind> {
+        if self.promotable {
+            if let Some((ref mut stab, _)) = self.stability {
+                stab.promotable = true;
+            } else {
+                cx.dcx()
+                    .emit_err(session_diagnostics::RustcPromotablePairing { span: cx.target_span });
             }
         }
-    }
 
-    body_stab
+        let (stability, span) = self.stability?;
+
+        Some(AttributeKind::ConstStability { stability, span })
+    }
 }
 
-fn insert_or_error(sess: &Session, meta: &MetaItem, item: &mut Option<Symbol>) -> Option<()> {
+/// Tries to insert the value of a `key = value` meta item into an option.
+///
+/// Emits an error when either the option was already Some, or the arguments weren't of form
+/// `name = value`
+fn insert_value_into_option_or_error(
+    cx: &AcceptContext<'_>,
+    param: &MetaItemParser<'_>,
+    item: &mut Option<Symbol>,
+) -> Option<()> {
     if item.is_some() {
-        sess.dcx().emit_err(session_diagnostics::MultipleItem {
-            span: meta.span,
-            item: pprust::path_to_string(&meta.path),
+        cx.emit_err(session_diagnostics::MultipleItem {
+            span: param.span(),
+            item: param.path_without_args().to_string(),
         });
         None
-    } else if let Some(v) = meta.value_str() {
-        *item = Some(v);
+    } else if let Some(v) = param.args().name_value()
+        && let Some(s) = v.value_as_str()
+    {
+        *item = Some(s);
         Some(())
     } else {
-        sess.dcx().emit_err(session_diagnostics::IncorrectMetaItem { span: meta.span });
+        cx.emit_err(session_diagnostics::IncorrectMetaItem {
+            span: param.span(),
+            suggestion: None,
+        });
         None
     }
 }
 
 /// Read the content of a `stable`/`rustc_const_stable` attribute, and return the feature name and
 /// its stability information.
-fn parse_stability(sess: &Session, attr: &impl AttributeExt) -> Option<(Symbol, StabilityLevel)> {
-    let metas = attr.meta_item_list()?;
-
+pub(crate) fn parse_stability(
+    cx: &AcceptContext<'_>,
+    args: &ArgParser<'_>,
+) -> Option<(Symbol, StabilityLevel)> {
     let mut feature = None;
     let mut since = None;
-    for meta in metas {
-        let Some(mi) = meta.meta_item() else {
-            sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral {
-                span: meta.span(),
+
+    for param in args.list()?.mixed() {
+        let param_span = param.span();
+        let Some(param) = param.meta_item() else {
+            cx.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: param_span,
                 reason: UnsupportedLiteralReason::Generic,
                 is_bytestr: false,
-                start_point_span: sess.source_map().start_point(meta.span()),
+                start_point_span: cx.sess().source_map().start_point(param_span),
             });
             return None;
         };
 
-        match mi.name_or_empty() {
-            sym::feature => insert_or_error(sess, mi, &mut feature)?,
-            sym::since => insert_or_error(sess, mi, &mut since)?,
+        match param.word_or_empty_without_args().name {
+            sym::feature => insert_value_into_option_or_error(cx, &param, &mut feature)?,
+            sym::since => insert_value_into_option_or_error(cx, &param, &mut since)?,
             _ => {
-                sess.dcx().emit_err(session_diagnostics::UnknownMetaItem {
-                    span: meta.span(),
-                    item: pprust::path_to_string(&mi.path),
+                cx.emit_err(session_diagnostics::UnknownMetaItem {
+                    span: param_span,
+                    item: param.path_without_args().to_string(),
                     expected: &["feature", "since"],
                 });
                 return None;
@@ -271,9 +263,9 @@ fn parse_stability(sess: &Session, attr: &impl AttributeExt) -> Option<(Symbol,
     let feature = match feature {
         Some(feature) if rustc_lexer::is_ident(feature.as_str()) => Ok(feature),
         Some(_bad_feature) => {
-            Err(sess.dcx().emit_err(session_diagnostics::NonIdentFeature { span: attr.span() }))
+            Err(cx.emit_err(session_diagnostics::NonIdentFeature { span: cx.attr_span }))
         }
-        None => Err(sess.dcx().emit_err(session_diagnostics::MissingFeature { span: attr.span() })),
+        None => Err(cx.emit_err(session_diagnostics::MissingFeature { span: cx.attr_span })),
     };
 
     let since = if let Some(since) = since {
@@ -282,11 +274,11 @@ fn parse_stability(sess: &Session, attr: &impl AttributeExt) -> Option<(Symbol,
         } else if let Some(version) = parse_version(since) {
             StableSince::Version(version)
         } else {
-            sess.dcx().emit_err(session_diagnostics::InvalidSince { span: attr.span() });
+            cx.emit_err(session_diagnostics::InvalidSince { span: cx.attr_span });
             StableSince::Err
         }
     } else {
-        sess.dcx().emit_err(session_diagnostics::MissingSince { span: attr.span() });
+        cx.emit_err(session_diagnostics::MissingSince { span: cx.attr_span });
         StableSince::Err
     };
 
@@ -299,46 +291,48 @@ fn parse_stability(sess: &Session, attr: &impl AttributeExt) -> Option<(Symbol,
     }
 }
 
-/// Read the content of a `unstable`/`rustc_const_unstable`/`rustc_default_body_unstable`
+// Read the content of a `unstable`/`rustc_const_unstable`/`rustc_default_body_unstable`
 /// attribute, and return the feature name and its stability information.
-fn parse_unstability(sess: &Session, attr: &impl AttributeExt) -> Option<(Symbol, StabilityLevel)> {
-    let metas = attr.meta_item_list()?;
-
+pub(crate) fn parse_unstability(
+    cx: &AcceptContext<'_>,
+    args: &ArgParser<'_>,
+) -> Option<(Symbol, StabilityLevel)> {
     let mut feature = None;
     let mut reason = None;
     let mut issue = None;
     let mut issue_num = None;
     let mut is_soft = false;
     let mut implied_by = None;
-    for meta in metas {
-        let Some(mi) = meta.meta_item() else {
-            sess.dcx().emit_err(session_diagnostics::UnsupportedLiteral {
-                span: meta.span(),
+    for param in args.list()?.mixed() {
+        let Some(param) = param.meta_item() else {
+            cx.emit_err(session_diagnostics::UnsupportedLiteral {
+                span: param.span(),
                 reason: UnsupportedLiteralReason::Generic,
                 is_bytestr: false,
-                start_point_span: sess.source_map().start_point(meta.span()),
+                start_point_span: cx.sess().source_map().start_point(param.span()),
             });
             return None;
         };
 
-        match mi.name_or_empty() {
-            sym::feature => insert_or_error(sess, mi, &mut feature)?,
-            sym::reason => insert_or_error(sess, mi, &mut reason)?,
+        let (word, args) = param.word_or_empty();
+        match word.name {
+            sym::feature => insert_value_into_option_or_error(cx, &param, &mut feature)?,
+            sym::reason => insert_value_into_option_or_error(cx, &param, &mut reason)?,
             sym::issue => {
-                insert_or_error(sess, mi, &mut issue)?;
+                insert_value_into_option_or_error(cx, &param, &mut issue)?;
 
-                // These unwraps are safe because `insert_or_error` ensures the meta item
+                // These unwraps are safe because `insert_value_into_option_or_error` ensures the meta item
                 // is a name/value pair string literal.
                 issue_num = match issue.unwrap().as_str() {
                     "none" => None,
-                    issue => match issue.parse::<NonZero<u32>>() {
+                    issue_str => match issue_str.parse::<NonZero<u32>>() {
                         Ok(num) => Some(num),
                         Err(err) => {
-                            sess.dcx().emit_err(
+                            cx.emit_err(
                                 session_diagnostics::InvalidIssueString {
-                                    span: mi.span,
+                                    span: param.span(),
                                     cause: session_diagnostics::InvalidIssueStringCause::from_int_error_kind(
-                                        mi.name_value_literal_span().unwrap(),
+                                        args.name_value().unwrap().value_span,
                                         err.kind(),
                                     ),
                                 },
@@ -349,16 +343,16 @@ fn parse_unstability(sess: &Session, attr: &impl AttributeExt) -> Option<(Symbol
                 };
             }
             sym::soft => {
-                if !mi.is_word() {
-                    sess.dcx().emit_err(session_diagnostics::SoftNoArgs { span: mi.span });
+                if !args.no_args() {
+                    cx.emit_err(session_diagnostics::SoftNoArgs { span: param.span() });
                 }
                 is_soft = true;
             }
-            sym::implied_by => insert_or_error(sess, mi, &mut implied_by)?,
+            sym::implied_by => insert_value_into_option_or_error(cx, &param, &mut implied_by)?,
             _ => {
-                sess.dcx().emit_err(session_diagnostics::UnknownMetaItem {
-                    span: meta.span(),
-                    item: pprust::path_to_string(&mi.path),
+                cx.emit_err(session_diagnostics::UnknownMetaItem {
+                    span: param.span(),
+                    item: param.path_without_args().to_string(),
                     expected: &["feature", "reason", "issue", "soft", "implied_by"],
                 });
                 return None;
@@ -369,14 +363,13 @@ fn parse_unstability(sess: &Session, attr: &impl AttributeExt) -> Option<(Symbol
     let feature = match feature {
         Some(feature) if rustc_lexer::is_ident(feature.as_str()) => Ok(feature),
         Some(_bad_feature) => {
-            Err(sess.dcx().emit_err(session_diagnostics::NonIdentFeature { span: attr.span() }))
+            Err(cx.emit_err(session_diagnostics::NonIdentFeature { span: cx.attr_span }))
         }
-        None => Err(sess.dcx().emit_err(session_diagnostics::MissingFeature { span: attr.span() })),
+        None => Err(cx.emit_err(session_diagnostics::MissingFeature { span: cx.attr_span })),
     };
 
-    let issue = issue.ok_or_else(|| {
-        sess.dcx().emit_err(session_diagnostics::MissingIssue { span: attr.span() })
-    });
+    let issue =
+        issue.ok_or_else(|| cx.emit_err(session_diagnostics::MissingIssue { span: cx.attr_span }));
 
     match (feature, issue) {
         (Ok(feature), Ok(_)) => {
diff --git a/compiler/rustc_attr_parsing/src/attributes/transparency.rs b/compiler/rustc_attr_parsing/src/attributes/transparency.rs
index f4065a77048..ad83a1f7af8 100644
--- a/compiler/rustc_attr_parsing/src/attributes/transparency.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/transparency.rs
@@ -1,36 +1,33 @@
-use rustc_ast::attr::AttributeExt;
-use rustc_attr_data_structures::TransparencyError;
+use rustc_attr_data_structures::AttributeKind;
 use rustc_span::hygiene::Transparency;
 use rustc_span::sym;
 
-pub fn find_transparency(
-    attrs: &[impl AttributeExt],
-    macro_rules: bool,
-) -> (Transparency, Option<TransparencyError>) {
-    let mut transparency = None;
-    let mut error = None;
-    for attr in attrs {
-        if attr.has_name(sym::rustc_macro_transparency) {
-            if let Some((_, old_span)) = transparency {
-                error = Some(TransparencyError::MultipleTransparencyAttrs(old_span, attr.span()));
-                break;
-            } else if let Some(value) = attr.value_str() {
-                transparency = Some((
-                    match value {
-                        sym::transparent => Transparency::Transparent,
-                        sym::semitransparent => Transparency::SemiTransparent,
-                        sym::opaque => Transparency::Opaque,
-                        _ => {
-                            error =
-                                Some(TransparencyError::UnknownTransparency(value, attr.span()));
-                            continue;
-                        }
-                    },
-                    attr.span(),
-                ));
+use super::{AcceptContext, SingleAttributeParser};
+use crate::parser::ArgParser;
+
+pub(crate) struct TransparencyParser;
+
+// FIXME(jdonszelmann): make these proper diagnostics
+#[allow(rustc::untranslatable_diagnostic)]
+#[allow(rustc::diagnostic_outside_of_impl)]
+impl SingleAttributeParser for TransparencyParser {
+    const PATH: &'static [rustc_span::Symbol] = &[sym::rustc_macro_transparency];
+
+    fn on_duplicate(cx: &crate::context::AcceptContext<'_>, first_span: rustc_span::Span) {
+        cx.dcx().span_err(vec![first_span, cx.attr_span], "multiple macro transparency attributes");
+    }
+
+    fn convert(cx: &AcceptContext<'_>, args: &ArgParser<'_>) -> Option<AttributeKind> {
+        match args.name_value().and_then(|nv| nv.value_as_str()) {
+            Some(sym::transparent) => Some(Transparency::Transparent),
+            Some(sym::semitransparent) => Some(Transparency::SemiTransparent),
+            Some(sym::opaque) => Some(Transparency::Opaque),
+            Some(other) => {
+                cx.dcx().span_err(cx.attr_span, format!("unknown macro transparency: `{other}`"));
+                None
             }
+            None => None,
         }
+        .map(AttributeKind::MacroTransparency)
     }
-    let fallback = if macro_rules { Transparency::SemiTransparent } else { Transparency::Opaque };
-    (transparency.map_or(fallback, |t| t.0), error)
 }
diff --git a/compiler/rustc_attr_parsing/src/attributes/util.rs b/compiler/rustc_attr_parsing/src/attributes/util.rs
index e36f7dfff5a..05a9029c59a 100644
--- a/compiler/rustc_attr_parsing/src/attributes/util.rs
+++ b/compiler/rustc_attr_parsing/src/attributes/util.rs
@@ -3,22 +3,6 @@ use rustc_attr_data_structures::RustcVersion;
 use rustc_feature::is_builtin_attr_name;
 use rustc_span::{Symbol, sym};
 
-pub(crate) enum UnsupportedLiteralReason {
-    Generic,
-    CfgString,
-    CfgBoolean,
-    DeprecatedString,
-    DeprecatedKvPair,
-}
-
-pub fn is_builtin_attr(attr: &impl AttributeExt) -> bool {
-    attr.is_doc_comment() || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name))
-}
-
-pub fn find_crate_name(attrs: &[impl AttributeExt]) -> Option<Symbol> {
-    first_attr_value_str_by_name(attrs, sym::crate_name)
-}
-
 /// Parse a rustc version number written inside string literal in an attribute,
 /// like appears in `since = "1.0.0"`. Suffixes like "-dev" and "-nightly" are
 /// not accepted in this position, unlike when parsing CFG_RELEASE.
@@ -34,3 +18,11 @@ pub fn parse_version(s: Symbol) -> Option<RustcVersion> {
     let patch = digits.next().unwrap_or("0").parse().ok()?;
     Some(RustcVersion { major, minor, patch })
 }
+
+pub fn is_builtin_attr(attr: &impl AttributeExt) -> bool {
+    attr.is_doc_comment() || attr.ident().is_some_and(|ident| is_builtin_attr_name(ident.name))
+}
+
+pub fn find_crate_name(attrs: &[impl AttributeExt]) -> Option<Symbol> {
+    first_attr_value_str_by_name(attrs, sym::crate_name)
+}
diff --git a/compiler/rustc_attr_parsing/src/context.rs b/compiler/rustc_attr_parsing/src/context.rs
index a9151696f56..f875ef4fbaa 100644
--- a/compiler/rustc_attr_parsing/src/context.rs
+++ b/compiler/rustc_attr_parsing/src/context.rs
@@ -1,3 +1,4 @@
+use std::cell::RefCell;
 use std::collections::BTreeMap;
 use std::ops::Deref;
 use std::sync::LazyLock;
@@ -11,7 +12,15 @@ use rustc_session::Session;
 use rustc_span::symbol::kw;
 use rustc_span::{DUMMY_SP, ErrorGuaranteed, Span, Symbol, sym};
 
-use crate::attributes::AttributeParser as _;
+use crate::attributes::allow_unstable::{AllowConstFnUnstableParser, AllowInternalUnstableParser};
+use crate::attributes::confusables::ConfusablesParser;
+use crate::attributes::deprecation::DeprecationParser;
+use crate::attributes::repr::ReprParser;
+use crate::attributes::stability::{
+    BodyStabilityParser, ConstStabilityIndirectParser, ConstStabilityParser, StabilityParser,
+};
+use crate::attributes::transparency::TransparencyParser;
+use crate::attributes::{AttributeParser as _, Combine, Single};
 use crate::parser::{ArgParser, MetaItemParser};
 
 macro_rules! attribute_groups {
@@ -52,6 +61,24 @@ macro_rules! attribute_groups {
 
 attribute_groups!(
     pub(crate) static ATTRIBUTE_MAPPING = [
+        // tidy-alphabetical-start
+        BodyStabilityParser,
+        ConfusablesParser,
+        ConstStabilityParser,
+        StabilityParser,
+        // tidy-alphabetical-end
+
+        // tidy-alphabetical-start
+        Combine<AllowConstFnUnstableParser>,
+        Combine<AllowInternalUnstableParser>,
+        Combine<ReprParser>,
+        // tidy-alphabetical-end
+
+        // tidy-alphabetical-start
+        Single<ConstStabilityIndirectParser>,
+        Single<DeprecationParser>,
+        Single<TransparencyParser>,
+        // tidy-alphabetical-end
     ];
 );
 
diff --git a/compiler/rustc_attr_parsing/src/lib.rs b/compiler/rustc_attr_parsing/src/lib.rs
index 74f26e2c06b..9841166b37d 100644
--- a/compiler/rustc_attr_parsing/src/lib.rs
+++ b/compiler/rustc_attr_parsing/src/lib.rs
@@ -83,14 +83,59 @@
 #![warn(unreachable_pub)]
 // tidy-alphabetical-end
 
+#[macro_use]
 mod attributes;
 mod context;
 pub mod parser;
 mod session_diagnostics;
 
-pub use attributes::*;
+pub use attributes::cfg::*;
+pub use attributes::util::{find_crate_name, is_builtin_attr, parse_version};
 pub use context::{AttributeParser, OmitDoc};
 pub use rustc_attr_data_structures::*;
-pub use util::{find_crate_name, is_builtin_attr, parse_version};
 
 rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
+
+/// Finds attributes in sequences of attributes by pattern matching.
+///
+/// A little like `matches` but for attributes.
+///
+/// ```rust,ignore (illustrative)
+/// // finds the repr attribute
+/// if let Some(r) = find_attr!(attrs, AttributeKind::Repr(r) => r) {
+///
+/// }
+///
+/// // checks if one has matched
+/// if find_attr!(attrs, AttributeKind::Repr(_)) {
+///
+/// }
+/// ```
+///
+/// Often this requires you to first end up with a list of attributes.
+/// A common way to get those is through `tcx.get_all_attrs(did)`
+#[macro_export]
+macro_rules! find_attr {
+    ($attributes_list: expr, $pattern: pat $(if $guard: expr)?) => {{
+        $crate::find_attr!($attributes_list, $pattern $(if $guard)? => ()).is_some()
+    }};
+
+    ($attributes_list: expr, $pattern: pat $(if $guard: expr)? => $e: expr) => {{
+        fn check_attribute_iterator<'a>(_: &'_ impl IntoIterator<Item = &'a rustc_hir::Attribute>) {}
+        check_attribute_iterator(&$attributes_list);
+
+        let find_attribute = |iter| {
+            for i in $attributes_list {
+                match i {
+                    rustc_hir::Attribute::Parsed($pattern) $(if $guard)? => {
+                        return Some($e);
+                    }
+                    _ => {}
+                }
+            }
+
+            None
+        };
+        find_attribute($attributes_list)
+    }};
+}
diff --git a/compiler/rustc_attr_parsing/src/session_diagnostics.rs b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
index 92bc2a8aeb0..9d34b807ac2 100644
--- a/compiler/rustc_attr_parsing/src/session_diagnostics.rs
+++ b/compiler/rustc_attr_parsing/src/session_diagnostics.rs
@@ -6,9 +6,16 @@ use rustc_errors::{Applicability, Diag, DiagCtxtHandle, Diagnostic, EmissionGuar
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
-use crate::attributes::util::UnsupportedLiteralReason;
 use crate::fluent_generated as fluent;
 
+pub(crate) enum UnsupportedLiteralReason {
+    Generic,
+    CfgString,
+    CfgBoolean,
+    DeprecatedString,
+    DeprecatedKvPair,
+}
+
 #[derive(Diagnostic)]
 #[diag(attr_parsing_expected_one_cfg_pattern, code = E0536)]
 pub(crate) struct ExpectedOneCfgPattern {
@@ -39,6 +46,21 @@ pub(crate) struct MultipleItem {
 pub(crate) struct IncorrectMetaItem {
     #[primary_span]
     pub span: Span,
+
+    #[subdiagnostic]
+    pub suggestion: Option<IncorrectMetaItemSuggestion>,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(
+    attr_parsing_incorrect_meta_item_suggestion,
+    applicability = "maybe-incorrect"
+)]
+pub(crate) struct IncorrectMetaItemSuggestion {
+    #[suggestion_part(code = "\"")]
+    pub lo: Span,
+    #[suggestion_part(code = "\"")]
+    pub hi: Span,
 }
 
 /// Error code: E0541
@@ -338,13 +360,6 @@ pub(crate) struct RustcPromotablePairing {
 }
 
 #[derive(Diagnostic)]
-#[diag(attr_parsing_rustc_const_stable_indirect_pairing)]
-pub(crate) struct RustcConstStableIndirectPairing {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
 #[diag(attr_parsing_rustc_allowed_unstable_pairing, code = E0789)]
 pub(crate) struct RustcAllowedUnstablePairing {
     #[primary_span]
@@ -423,3 +438,44 @@ pub(crate) struct UnknownVersionLiteral {
     #[primary_span]
     pub span: Span,
 }
+
+// FIXME(jdonszelmann) duplicated from `rustc_passes`, remove once `check_attr` is integrated.
+#[derive(Diagnostic)]
+#[diag(attr_parsing_unused_multiple)]
+pub(crate) struct UnusedMultiple {
+    #[primary_span]
+    #[suggestion(code = "", applicability = "machine-applicable")]
+    pub this: Span,
+    #[note]
+    pub other: Span,
+    pub name: Symbol,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_stability_outside_std, code = E0734)]
+pub(crate) struct StabilityOutsideStd {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_empty_confusables)]
+pub(crate) struct EmptyConfusables {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_repr_ident, code = E0565)]
+pub(crate) struct ReprIdent {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(attr_parsing_unrecognized_repr_hint, code = E0552)]
+#[help]
+pub(crate) struct UnrecognizedReprHint {
+    #[primary_span]
+    pub span: Span,
+}
diff --git a/compiler/rustc_builtin_macros/Cargo.toml b/compiler/rustc_builtin_macros/Cargo.toml
index f29be2ee818..b5f4f2efd1f 100644
--- a/compiler/rustc_builtin_macros/Cargo.toml
+++ b/compiler/rustc_builtin_macros/Cargo.toml
@@ -20,6 +20,7 @@ rustc_errors = { path = "../rustc_errors" }
 rustc_expand = { path = "../rustc_expand" }
 rustc_feature = { path = "../rustc_feature" }
 rustc_fluent_macro = { path = "../rustc_fluent_macro" }
+rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
 rustc_lexer = { path = "../rustc_lexer" }
 rustc_lint_defs = { path = "../rustc_lint_defs" }
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
index 234ec858216..6b59ac25827 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
@@ -185,8 +185,9 @@ use rustc_ast::{
     self as ast, AnonConst, BindingMode, ByRef, EnumDef, Expr, GenericArg, GenericParamKind,
     Generics, Mutability, PatKind, VariantData,
 };
-use rustc_attr_parsing as attr;
+use rustc_attr_parsing::{AttributeKind, AttributeParser, ReprPacked};
 use rustc_expand::base::{Annotatable, ExtCtxt};
+use rustc_hir::Attribute;
 use rustc_span::{DUMMY_SP, Ident, Span, Symbol, kw, sym};
 use thin_vec::{ThinVec, thin_vec};
 use ty::{Bounds, Path, Ref, Self_, Ty};
@@ -480,14 +481,10 @@ impl<'a> TraitDef<'a> {
     ) {
         match item {
             Annotatable::Item(item) => {
-                let is_packed = item.attrs.iter().any(|attr| {
-                    for r in attr::find_repr_attrs(cx.sess, attr) {
-                        if let attr::ReprPacked(_) = r {
-                            return true;
-                        }
-                    }
-                    false
-                });
+                let is_packed = matches!(
+                    AttributeParser::parse_limited(cx.sess, &item.attrs, sym::repr, item.span, true),
+                    Some(Attribute::Parsed(AttributeKind::Repr(r))) if r.iter().any(|(x, _)| matches!(x, ReprPacked(..)))
+                );
 
                 let newitem = match &item.kind {
                     ast::ItemKind::Struct(struct_def, generics) => self.expand_struct_def(
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index 40238f4b491..73a97d32c2d 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -5,7 +5,9 @@ use std::time::{Duration, Instant};
 
 use itertools::Itertools;
 use rustc_abi::FIRST_VARIANT;
+use rustc_ast as ast;
 use rustc_ast::expand::allocator::{ALLOCATOR_METHODS, AllocatorKind, global_fn_name};
+use rustc_attr_parsing::OptimizeAttr;
 use rustc_data_structures::fx::{FxHashMap, FxIndexSet};
 use rustc_data_structures::profiling::{get_resident_set_size, print_time_passes_entry};
 use rustc_data_structures::sync::par_map;
@@ -29,7 +31,6 @@ use rustc_span::{DUMMY_SP, Symbol, sym};
 use rustc_trait_selection::infer::{BoundRegionConversionTime, TyCtxtInferExt};
 use rustc_trait_selection::traits::{ObligationCause, ObligationCtxt};
 use tracing::{debug, info};
-use {rustc_ast as ast, rustc_attr_parsing as attr};
 
 use crate::assert_module_sources::CguReuse;
 use crate::back::link::are_upstream_rust_objects_already_included;
@@ -1061,7 +1062,7 @@ pub(crate) fn provide(providers: &mut Providers) {
 
         let any_for_speed = defids.items().any(|id| {
             let CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
-            matches!(optimize, attr::OptimizeAttr::Speed)
+            matches!(optimize, OptimizeAttr::Speed)
         });
 
         if any_for_speed {
diff --git a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
index 4c422431791..673740b4aab 100644
--- a/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
+++ b/compiler/rustc_codegen_ssa/src/codegen_attrs.rs
@@ -5,7 +5,8 @@ use rustc_ast::expand::autodiff_attrs::{
     AutoDiffAttrs, DiffActivity, DiffMode, valid_input_activity, valid_ret_activity,
 };
 use rustc_ast::{MetaItem, MetaItemInner, attr};
-use rustc_attr_parsing::{InlineAttr, InstructionSetAttr, OptimizeAttr};
+use rustc_attr_parsing::ReprAttr::ReprAlign;
+use rustc_attr_parsing::{AttributeKind, InlineAttr, InstructionSetAttr, OptimizeAttr};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::codes::*;
 use rustc_errors::{DiagMessage, SubdiagMessage, struct_span_code_err};
@@ -112,6 +113,18 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
             }
         };
 
+        if let hir::Attribute::Parsed(p) = attr {
+            match p {
+                AttributeKind::Repr(reprs) => {
+                    codegen_fn_attrs.alignment = reprs
+                        .iter()
+                        .find_map(|(r, _)| if let ReprAlign(x) = r { Some(*x) } else { None });
+                }
+
+                _ => {}
+            }
+        }
+
         let Some(Ident { name, .. }) = attr.ident() else {
             continue;
         };
@@ -426,27 +439,6 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                         }
                     })
             }
-            sym::repr => {
-                codegen_fn_attrs.alignment = if let Some(items) = attr.meta_item_list()
-                    && let [item] = items.as_slice()
-                    && let Some((sym::align, literal)) = item.singleton_lit_list()
-                {
-                    rustc_attr_parsing::parse_alignment(&literal.kind)
-                        .inspect_err(|msg| {
-                            struct_span_code_err!(
-                                tcx.dcx(),
-                                literal.span,
-                                E0589,
-                                "invalid `repr(align)` attribute: {}",
-                                msg
-                            )
-                            .emit();
-                        })
-                        .ok()
-                } else {
-                    None
-                };
-            }
             sym::patchable_function_entry => {
                 codegen_fn_attrs.patchable_function_entry = attr.meta_item_list().and_then(|l| {
                     let mut prefix = None;
@@ -831,7 +823,7 @@ impl<'a> MixedExportNameAndNoMangleState<'a> {
             export_name: Some(export_name),
             no_mangle: Some(no_mangle),
             hir_id: Some(hir_id),
-            no_mangle_attr: Some(no_mangle_attr),
+            no_mangle_attr: Some(_),
         } = self
         {
             tcx.emit_node_span_lint(
@@ -840,7 +832,7 @@ impl<'a> MixedExportNameAndNoMangleState<'a> {
                 no_mangle,
                 errors::MixedExportNameAndNoMangle {
                     no_mangle,
-                    no_mangle_attr: rustc_hir_pretty::attribute_to_string(&tcx, no_mangle_attr),
+                    no_mangle_attr: "#[unsafe(no_mangle)]".to_string(),
                     export_name,
                     removal_span: no_mangle,
                 },
diff --git a/compiler/rustc_const_eval/src/check_consts/mod.rs b/compiler/rustc_const_eval/src/check_consts/mod.rs
index 52e000858b4..659d4a30456 100644
--- a/compiler/rustc_const_eval/src/check_consts/mod.rs
+++ b/compiler/rustc_const_eval/src/check_consts/mod.rs
@@ -4,12 +4,13 @@
 //! has interior mutability or needs to be dropped, as well as the visitor that emits errors when
 //! it finds operations that are invalid in a certain context.
 
+use rustc_attr_parsing::{AttributeKind, find_attr};
 use rustc_errors::DiagCtxtHandle;
+use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_middle::ty::{self, PolyFnSig, TyCtxt};
 use rustc_middle::{bug, mir};
 use rustc_span::Symbol;
-use {rustc_attr_parsing as attr, rustc_hir as hir};
 
 pub use self::qualifs::Qualif;
 
@@ -81,7 +82,8 @@ pub fn rustc_allow_const_fn_unstable(
     feature_gate: Symbol,
 ) -> bool {
     let attrs = tcx.hir().attrs(tcx.local_def_id_to_hir_id(def_id));
-    attr::rustc_allow_const_fn_unstable(tcx.sess, attrs).any(|name| name == feature_gate)
+
+    find_attr!(attrs, AttributeKind::AllowConstFnUnstable(syms) if syms.contains(&feature_gate))
 }
 
 /// Returns `true` if the given `def_id` (trait or function) is "safe to expose on stable".
diff --git a/compiler/rustc_errors/Cargo.toml b/compiler/rustc_errors/Cargo.toml
index c1d8cd9bb9e..b11793c190a 100644
--- a/compiler/rustc_errors/Cargo.toml
+++ b/compiler/rustc_errors/Cargo.toml
@@ -10,6 +10,7 @@ derive_setters = "0.1.6"
 rustc_abi = { path = "../rustc_abi" }
 rustc_ast = { path = "../rustc_ast" }
 rustc_ast_pretty = { path = "../rustc_ast_pretty" }
+rustc_attr_data_structures = { path = "../rustc_attr_data_structures" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_error_codes = { path = "../rustc_error_codes" }
 rustc_error_messages = { path = "../rustc_error_messages" }
diff --git a/compiler/rustc_errors/src/diagnostic_impls.rs b/compiler/rustc_errors/src/diagnostic_impls.rs
index 7f383946c14..db6532f41ea 100644
--- a/compiler/rustc_errors/src/diagnostic_impls.rs
+++ b/compiler/rustc_errors/src/diagnostic_impls.rs
@@ -8,6 +8,7 @@ use std::process::ExitStatus;
 use rustc_abi::TargetDataLayoutErrors;
 use rustc_ast::util::parser::ExprPrecedence;
 use rustc_ast_pretty::pprust;
+use rustc_attr_data_structures::RustcVersion;
 use rustc_macros::Subdiagnostic;
 use rustc_span::edition::Edition;
 use rustc_span::{Ident, MacroRulesNormalizedIdent, Span, Symbol};
@@ -96,6 +97,12 @@ into_diag_arg_using_display!(
     rustc_abi::ExternAbi,
 );
 
+impl IntoDiagArg for RustcVersion {
+    fn into_diag_arg(self) -> DiagArgValue {
+        DiagArgValue::Str(Cow::Owned(self.to_string()))
+    }
+}
+
 impl<I: rustc_type_ir::Interner> IntoDiagArg for rustc_type_ir::TraitRef<I> {
     fn into_diag_arg(self) -> DiagArgValue {
         self.to_string().into_diag_arg()
diff --git a/compiler/rustc_expand/Cargo.toml b/compiler/rustc_expand/Cargo.toml
index 33bada106ca..0ba139ea5cc 100644
--- a/compiler/rustc_expand/Cargo.toml
+++ b/compiler/rustc_expand/Cargo.toml
@@ -17,6 +17,7 @@ rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_feature = { path = "../rustc_feature" }
 rustc_fluent_macro = { path = "../rustc_fluent_macro" }
+rustc_hir = { path = "../rustc_hir" }
 rustc_lexer = { path = "../rustc_lexer" }
 rustc_lint_defs = { path = "../rustc_lint_defs" }
 rustc_macros = { path = "../rustc_macros" }
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index 819694d1cdc..4a250145308 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -11,11 +11,12 @@ use rustc_ast::token::Nonterminal;
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::visit::{AssocCtxt, Visitor};
 use rustc_ast::{self as ast, AttrVec, Attribute, HasAttrs, Item, NodeId, PatKind};
-use rustc_attr_parsing::{self as attr, Deprecation, Stability};
+use rustc_attr_parsing::{AttributeKind, Deprecation, Stability, find_attr};
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::sync;
 use rustc_errors::{DiagCtxtHandle, ErrorGuaranteed, PResult};
 use rustc_feature::Features;
+use rustc_hir as hir;
 use rustc_lint_defs::{BufferedEarlyLint, RegisteredTools};
 use rustc_parse::MACRO_ARGUMENTS;
 use rustc_parse::parser::Parser;
@@ -838,19 +839,23 @@ impl SyntaxExtension {
     /// and other properties converted from attributes.
     pub fn new(
         sess: &Session,
-        features: &Features,
         kind: SyntaxExtensionKind,
         span: Span,
         helper_attrs: Vec<Symbol>,
         edition: Edition,
         name: Symbol,
-        attrs: &[impl AttributeExt],
+        attrs: &[hir::Attribute],
         is_local: bool,
     ) -> SyntaxExtension {
         let allow_internal_unstable =
-            rustc_attr_parsing::allow_internal_unstable(sess, attrs).collect::<Vec<Symbol>>();
+            find_attr!(attrs, AttributeKind::AllowInternalUnstable(i) => i)
+                .map(|i| i.as_slice())
+                .unwrap_or_default();
+        // FIXME(jdonszelman): allow_internal_unsafe isn't yet new-style
+        // let allow_internal_unsafe = find_attr!(attrs, AttributeKind::AllowInternalUnsafe);
+        let allow_internal_unsafe =
+            ast::attr::find_by_name(attrs, sym::allow_internal_unsafe).is_some();
 
-        let allow_internal_unsafe = ast::attr::contains_name(attrs, sym::allow_internal_unsafe);
         let local_inner_macros = ast::attr::find_by_name(attrs, sym::macro_export)
             .and_then(|macro_export| macro_export.meta_item_list())
             .is_some_and(|l| ast::attr::list_contains_name(&l, sym::local_inner_macros));
@@ -867,16 +872,17 @@ impl SyntaxExtension {
                 )
             })
             .unwrap_or_else(|| (None, helper_attrs));
-        let stability = attr::find_stability(sess, attrs, span);
-        let const_stability = attr::find_const_stability(sess, attrs, span);
-        let body_stability = attr::find_body_stability(sess, attrs);
-        if let Some((_, sp)) = const_stability {
+
+        let stability = find_attr!(attrs, AttributeKind::Stability{stability, ..} => *stability);
+
+        // FIXME(jdonszelmann): make it impossible to miss the or_else in the typesystem
+        if let Some(sp) = find_attr!(attrs, AttributeKind::ConstStability{span, ..} => *span) {
             sess.dcx().emit_err(errors::MacroConstStability {
                 span: sp,
                 head_span: sess.source_map().guess_head_span(span),
             });
         }
-        if let Some((_, sp)) = body_stability {
+        if let Some(sp) = find_attr!(attrs, AttributeKind::BodyStability{span, ..} => *span) {
             sess.dcx().emit_err(errors::MacroBodyStability {
                 span: sp,
                 head_span: sess.source_map().guess_head_span(span),
@@ -887,9 +893,10 @@ impl SyntaxExtension {
             kind,
             span,
             allow_internal_unstable: (!allow_internal_unstable.is_empty())
-                .then(|| allow_internal_unstable.into()),
-            stability: stability.map(|(s, _)| s),
-            deprecation: attr::find_deprecation(sess, features, attrs).map(|(d, _)| d),
+                // FIXME(jdonszelmann): avoid the into_iter/collect?
+                .then(|| allow_internal_unstable.iter().map(|i| i.0).collect::<Vec<_>>().into()),
+            stability,
+            deprecation: find_attr!(attrs, AttributeKind::Deprecation{deprecation, ..} => *deprecation),
             helper_attrs,
             edition,
             builtin_name,
diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs
index b02a9b93c8a..cc7e3e65105 100644
--- a/compiler/rustc_expand/src/mbe/macro_rules.rs
+++ b/compiler/rustc_expand/src/mbe/macro_rules.rs
@@ -3,17 +3,17 @@ use std::collections::hash_map::Entry;
 use std::{mem, slice};
 
 use ast::token::IdentIsRaw;
-use rustc_ast::attr::AttributeExt;
 use rustc_ast::token::NtPatKind::*;
 use rustc_ast::token::TokenKind::*;
 use rustc_ast::token::{self, Delimiter, NonterminalKind, Token, TokenKind};
 use rustc_ast::tokenstream::{DelimSpan, TokenStream};
 use rustc_ast::{self as ast, DUMMY_NODE_ID, NodeId};
 use rustc_ast_pretty::pprust;
-use rustc_attr_parsing::{self as attr, TransparencyError};
+use rustc_attr_parsing::{AttributeKind, find_attr};
 use rustc_data_structures::fx::{FxHashMap, FxIndexMap};
 use rustc_errors::{Applicability, ErrorGuaranteed};
 use rustc_feature::Features;
+use rustc_hir as hir;
 use rustc_lint_defs::BuiltinLintDiag;
 use rustc_lint_defs::builtin::{
     RUST_2021_INCOMPATIBLE_OR_PATTERNS, SEMICOLON_IN_EXPRESSIONS_FROM_MACROS,
@@ -371,7 +371,7 @@ pub fn compile_declarative_macro(
     features: &Features,
     macro_def: &ast::MacroDef,
     ident: Ident,
-    attrs: &[impl AttributeExt],
+    attrs: &[hir::Attribute],
     span: Span,
     node_id: NodeId,
     edition: Edition,
@@ -379,7 +379,6 @@ pub fn compile_declarative_macro(
     let mk_syn_ext = |expander| {
         SyntaxExtension::new(
             sess,
-            features,
             SyntaxExtensionKind::LegacyBang(expander),
             span,
             Vec::new(),
@@ -391,7 +390,6 @@ pub fn compile_declarative_macro(
     };
     let dummy_syn_ext = |guar| (mk_syn_ext(Box::new(DummyExpander(guar))), Vec::new());
 
-    let dcx = sess.dcx();
     let lhs_nm = Ident::new(sym::lhs, span);
     let rhs_nm = Ident::new(sym::rhs, span);
     let tt_spec = Some(NonterminalKind::TT);
@@ -542,16 +540,8 @@ pub fn compile_declarative_macro(
 
     check_emission(macro_check::check_meta_variables(&sess.psess, node_id, span, &lhses, &rhses));
 
-    let (transparency, transparency_error) = attr::find_transparency(attrs, macro_rules);
-    match transparency_error {
-        Some(TransparencyError::UnknownTransparency(value, span)) => {
-            dcx.span_err(span, format!("unknown macro transparency: `{value}`"));
-        }
-        Some(TransparencyError::MultipleTransparencyAttrs(old_span, new_span)) => {
-            dcx.span_err(vec![old_span, new_span], "multiple macro transparency attributes");
-        }
-        None => {}
-    }
+    let transparency = find_attr!(attrs, AttributeKind::MacroTransparency(x) => *x)
+        .unwrap_or(Transparency::fallback(macro_rules));
 
     if let Some(guar) = guar {
         // To avoid warning noise, only consider the rules of this
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index d55c644cbc0..06c49366659 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -1151,6 +1151,9 @@ impl AttributeExt for Attribute {
     fn span(&self) -> Span {
         match &self {
             Attribute::Unparsed(u) => u.span,
+            // FIXME: should not be needed anymore when all attrs are parsed
+            Attribute::Parsed(AttributeKind::Deprecation { span, .. }) => *span,
+            Attribute::Parsed(AttributeKind::DocComment { span, .. }) => *span,
             a => panic!("can't get the span of an arbitrary parsed attribute: {a:?}"),
         }
     }
@@ -1193,6 +1196,7 @@ impl AttributeExt for Attribute {
     fn style(&self) -> AttrStyle {
         match &self {
             Attribute::Unparsed(u) => u.style,
+            Attribute::Parsed(AttributeKind::DocComment { style, .. }) => *style,
             _ => panic!(),
         }
     }
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index 0b37bc15d87..09320b86878 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -2,6 +2,8 @@ use std::cell::LazyCell;
 use std::ops::ControlFlow;
 
 use rustc_abi::FieldIdx;
+use rustc_attr_parsing::AttributeKind;
+use rustc_attr_parsing::ReprAttr::ReprPacked;
 use rustc_data_structures::unord::{UnordMap, UnordSet};
 use rustc_errors::MultiSpan;
 use rustc_errors::codes::*;
@@ -1203,11 +1205,13 @@ fn check_simd(tcx: TyCtxt<'_>, sp: Span, def_id: LocalDefId) {
 pub(super) fn check_packed(tcx: TyCtxt<'_>, sp: Span, def: ty::AdtDef<'_>) {
     let repr = def.repr();
     if repr.packed() {
-        for attr in tcx.get_attrs(def.did(), sym::repr) {
-            for r in attr::parse_repr_attr(tcx.sess, attr) {
-                if let attr::ReprPacked(pack) = r
+        if let Some(reprs) =
+            attr::find_attr!(tcx.get_all_attrs(def.did()), AttributeKind::Repr(r) => r)
+        {
+            for (r, _) in reprs {
+                if let ReprPacked(pack) = r
                     && let Some(repr_pack) = repr.pack
-                    && pack != repr_pack
+                    && pack != &repr_pack
                 {
                     struct_span_code_err!(
                         tcx.dcx(),
@@ -1419,16 +1423,19 @@ fn check_enum(tcx: TyCtxt<'_>, def_id: LocalDefId) {
     def.destructor(tcx); // force the destructor to be evaluated
 
     if def.variants().is_empty() {
-        if let Some(attr) = tcx.get_attrs(def_id, sym::repr).next() {
-            struct_span_code_err!(
-                tcx.dcx(),
-                attr.span(),
-                E0084,
-                "unsupported representation for zero-variant enum"
-            )
-            .with_span_label(tcx.def_span(def_id), "zero-variant enum")
-            .emit();
-        }
+        attr::find_attr!(
+            tcx.get_all_attrs(def_id),
+            AttributeKind::Repr(rs) => {
+                struct_span_code_err!(
+                    tcx.dcx(),
+                    rs.first().unwrap().1,
+                    E0084,
+                    "unsupported representation for zero-variant enum"
+                )
+                .with_span_label(tcx.def_span(def_id), "zero-variant enum")
+                .emit();
+            }
+        );
     }
 
     let repr_type_ty = def.repr().discr_type().to_ty(tcx);
diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs
index 8438a92219e..18218a7a0a6 100644
--- a/compiler/rustc_hir_typeck/src/method/suggest.rs
+++ b/compiler/rustc_hir_typeck/src/method/suggest.rs
@@ -9,7 +9,7 @@ use std::path::PathBuf;
 
 use hir::Expr;
 use rustc_ast::ast::Mutability;
-use rustc_attr_parsing::parse_confusables;
+use rustc_attr_parsing::{AttributeKind, find_attr};
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::sorted_map::SortedMap;
 use rustc_data_structures::unord::UnordSet;
@@ -1884,9 +1884,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 for inherent_method in
                     self.tcx.associated_items(inherent_impl_did).in_definition_order()
                 {
-                    if let Some(attr) =
-                        self.tcx.get_attr(inherent_method.def_id, sym::rustc_confusables)
-                        && let Some(candidates) = parse_confusables(attr)
+                    if let Some(candidates) = find_attr!(self.tcx.get_all_attrs(inherent_method.def_id), AttributeKind::Confusables{symbols, ..} => symbols)
                         && candidates.contains(&item_name.name)
                         && let ty::AssocKind::Fn = inherent_method.kind
                     {
diff --git a/compiler/rustc_lint/src/expect.rs b/compiler/rustc_lint/src/expect.rs
index f0742e73d05..9ca148e1f25 100644
--- a/compiler/rustc_lint/src/expect.rs
+++ b/compiler/rustc_lint/src/expect.rs
@@ -39,6 +39,7 @@ fn check_expectations(tcx: TyCtxt<'_>, tool_filter: Option<Symbol>) {
             LintExpectationId::Stable { hir_id, attr_index, lint_index: Some(lint_index) } => {
                 // We are an `eval_always` query, so looking at the attribute's `AttrId` is ok.
                 let attr_id = tcx.hir().attrs(hir_id)[attr_index as usize].id();
+
                 (attr_id, lint_index)
             }
             _ => panic!("fulfilled expectations must have a lint index"),
diff --git a/compiler/rustc_lint/src/nonstandard_style.rs b/compiler/rustc_lint/src/nonstandard_style.rs
index cded5e1b9c8..49f9ad39780 100644
--- a/compiler/rustc_lint/src/nonstandard_style.rs
+++ b/compiler/rustc_lint/src/nonstandard_style.rs
@@ -1,4 +1,5 @@
 use rustc_abi::ExternAbi;
+use rustc_attr_parsing::{AttributeKind, AttributeParser, ReprAttr};
 use rustc_hir::def::{DefKind, Res};
 use rustc_hir::intravisit::FnKind;
 use rustc_hir::{AttrArgs, AttrItem, Attribute, GenericParamKind, PatExprKind, PatKind};
@@ -7,7 +8,7 @@ use rustc_session::config::CrateType;
 use rustc_session::{declare_lint, declare_lint_pass};
 use rustc_span::def_id::LocalDefId;
 use rustc_span::{BytePos, Ident, Span, sym};
-use {rustc_ast as ast, rustc_attr_parsing as attr, rustc_hir as hir};
+use {rustc_ast as ast, rustc_hir as hir};
 
 use crate::lints::{
     NonCamelCaseType, NonCamelCaseTypeSub, NonSnakeCaseDiag, NonSnakeCaseDiagSub,
@@ -161,10 +162,10 @@ impl NonCamelCaseTypes {
 
 impl EarlyLintPass for NonCamelCaseTypes {
     fn check_item(&mut self, cx: &EarlyContext<'_>, it: &ast::Item) {
-        let has_repr_c = it
-            .attrs
-            .iter()
-            .any(|attr| attr::find_repr_attrs(cx.sess(), attr).contains(&attr::ReprC));
+        let has_repr_c = matches!(
+            AttributeParser::parse_limited(cx.sess(), &it.attrs, sym::repr, it.span, true),
+            Some(Attribute::Parsed(AttributeKind::Repr(r))) if r.iter().any(|(r, _)| r == &ReprAttr::ReprC)
+        );
 
         if has_repr_c {
             return;
diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index ff3dae08ffc..e564235c41a 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -251,19 +251,23 @@ impl Level {
 
     /// Converts an `Attribute` to a level.
     pub fn from_attr(attr: &impl AttributeExt) -> Option<Self> {
-        Self::from_symbol(attr.name_or_empty(), Some(attr.id()))
+        Self::from_symbol(attr.name_or_empty(), || Some(attr.id()))
     }
 
     /// Converts a `Symbol` to a level.
-    pub fn from_symbol(s: Symbol, id: Option<AttrId>) -> Option<Self> {
-        match (s, id) {
-            (sym::allow, _) => Some(Level::Allow),
-            (sym::expect, Some(attr_id)) => {
-                Some(Level::Expect(LintExpectationId::Unstable { attr_id, lint_index: None }))
+    pub fn from_symbol(s: Symbol, id: impl FnOnce() -> Option<AttrId>) -> Option<Self> {
+        match s {
+            sym::allow => Some(Level::Allow),
+            sym::expect => {
+                if let Some(attr_id) = id() {
+                    Some(Level::Expect(LintExpectationId::Unstable { attr_id, lint_index: None }))
+                } else {
+                    None
+                }
             }
-            (sym::warn, _) => Some(Level::Warn),
-            (sym::deny, _) => Some(Level::Deny),
-            (sym::forbid, _) => Some(Level::Forbid),
+            sym::warn => Some(Level::Warn),
+            sym::deny => Some(Level::Deny),
+            sym::forbid => Some(Level::Forbid),
             _ => None,
         }
     }
diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index 591c8ed50d5..16149198303 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -1071,7 +1071,6 @@ impl<'a> CrateMetadataRef<'a> {
         let attrs: Vec<_> = self.get_item_attrs(id, sess).collect();
         SyntaxExtension::new(
             sess,
-            tcx.features(),
             kind,
             self.get_span(id, sess),
             helper_attrs,
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 8ed5a118093..0c139e6fcb8 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -27,6 +27,7 @@ pub use intrinsic::IntrinsicDef;
 use rustc_abi::{Align, FieldIdx, Integer, IntegerType, ReprFlags, ReprOptions, VariantIdx};
 use rustc_ast::expand::StrippedCfgItem;
 use rustc_ast::node_id::NodeMap;
+use rustc_attr_parsing::AttributeKind;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
 use rustc_data_structures::intern::Interned;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
@@ -1495,9 +1496,10 @@ impl<'tcx> TyCtxt<'tcx> {
             field_shuffle_seed ^= user_seed;
         }
 
-        for attr in self.get_attrs(did, sym::repr) {
-            for r in attr::parse_repr_attr(self.sess, attr) {
-                flags.insert(match r {
+        if let Some(reprs) = attr::find_attr!(self.get_all_attrs(did), AttributeKind::Repr(r) => r)
+        {
+            for (r, _) in reprs {
+                flags.insert(match *r {
                     attr::ReprRust => ReprFlags::empty(),
                     attr::ReprC => ReprFlags::IS_C,
                     attr::ReprPacked(pack) => {
@@ -1535,6 +1537,10 @@ impl<'tcx> TyCtxt<'tcx> {
                         max_align = max_align.max(Some(align));
                         ReprFlags::empty()
                     }
+                    attr::ReprEmpty => {
+                        /* skip these, they're just for diagnostics */
+                        ReprFlags::empty()
+                    }
                 });
             }
         }
@@ -1757,13 +1763,21 @@ impl<'tcx> TyCtxt<'tcx> {
         did: impl Into<DefId>,
         attr: Symbol,
     ) -> impl Iterator<Item = &'tcx hir::Attribute> {
+        self.get_all_attrs(did).filter(move |a: &&hir::Attribute| a.has_name(attr))
+    }
+
+    /// Gets all attributes.
+    ///
+    /// To see if an item has a specific attribute, you should use [`rustc_attr_parsing::find_attr!`] so you can use matching.
+    pub fn get_all_attrs(
+        self,
+        did: impl Into<DefId>,
+    ) -> impl Iterator<Item = &'tcx hir::Attribute> {
         let did: DefId = did.into();
-        let filter_fn = move |a: &&hir::Attribute| a.has_name(attr);
         if let Some(did) = did.as_local() {
-            self.hir().attrs(self.local_def_id_to_hir_id(did)).iter().filter(filter_fn)
+            self.hir().attrs(self.local_def_id_to_hir_id(did)).iter()
         } else {
-            debug_assert!(rustc_feature::encode_cross_crate(attr));
-            self.attrs_for_def(did).iter().filter(filter_fn)
+            self.attrs_for_def(did).iter()
         }
     }
 
diff --git a/compiler/rustc_passes/messages.ftl b/compiler/rustc_passes/messages.ftl
index 978cb7af242..bc43580a7f0 100644
--- a/compiler/rustc_passes/messages.ftl
+++ b/compiler/rustc_passes/messages.ftl
@@ -311,9 +311,6 @@ passes_duplicate_lang_item_crate_depends =
     .first_definition_path = first definition in `{$orig_crate_name}` loaded from {$orig_path}
     .second_definition_path = second definition in `{$crate_name}` loaded from {$path}
 
-passes_empty_confusables =
-    expected at least one confusable name
-
 passes_export_name =
     attribute should be applied to a free function, impl method or static
     .label = not a free function, impl method or static
@@ -365,9 +362,6 @@ passes_incorrect_do_not_recommend_args =
 passes_incorrect_do_not_recommend_location =
     `#[diagnostic::do_not_recommend]` can only be placed on trait implementations
 
-passes_incorrect_meta_item = expected a quoted string literal
-passes_incorrect_meta_item_suggestion = consider surrounding this with quotes
-
 passes_incorrect_target =
     `{$name}` lang item must be applied to a {$kind} with {$at_least ->
         [true] at least {$num}
@@ -641,13 +635,12 @@ passes_repr_align_greater_than_target_max =
 passes_repr_conflicting =
     conflicting representation hints
 
-passes_repr_ident =
-    meta item in `repr` must be an identifier
-
 passes_rustc_allow_const_fn_unstable =
     attribute should be applied to `const fn`
     .label = not a `const fn`
 
+passes_rustc_const_stable_indirect_pairing =
+    `const_stable_indirect` attribute does not make sense on `rustc_const_stable` function, its behavior is already implied
 passes_rustc_dirty_clean =
     attribute requires -Z query-dep-graph to be enabled
 
@@ -774,10 +767,6 @@ passes_unreachable_due_to_uninhabited = unreachable {$descr}
 passes_unrecognized_field =
     unrecognized field name `{$name}`
 
-passes_unrecognized_repr_hint =
-    unrecognized representation hint
-    .help = valid reprs are `Rust` (default), `C`, `align`, `packed`, `transparent`, `simd`, `i8`, `u8`, `i16`, `u16`, `i32`, `u32`, `i64`, `u64`, `i128`, `u128`, `isize`, `usize`
-
 passes_unstable_attr_for_already_stable_feature =
     can't mark as unstable using an already stable feature
     .label = this feature is already stable
diff --git a/compiler/rustc_passes/src/check_attr.rs b/compiler/rustc_passes/src/check_attr.rs
index 8b783196659..4a61e6dab1b 100644
--- a/compiler/rustc_passes/src/check_attr.rs
+++ b/compiler/rustc_passes/src/check_attr.rs
@@ -1,3 +1,4 @@
+// FIXME(jdonszelmann): should become rustc_attr_validation
 //! This module implements some validity checks for attributes.
 //! In particular it verifies that `#[inline]` and `#[repr]` attributes are
 //! attached to items that actually support them and if there are
@@ -7,8 +8,9 @@
 use std::cell::Cell;
 use std::collections::hash_map::Entry;
 
-use rustc_abi::{ExternAbi, Size};
+use rustc_abi::{Align, ExternAbi, Size};
 use rustc_ast::{AttrStyle, LitKind, MetaItemInner, MetaItemKind, MetaItemLit, ast};
+use rustc_attr_parsing::{AttributeKind, ReprAttr, find_attr};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{Applicability, DiagCtxtHandle, IntoDiagArg, MultiSpan, StashKey};
 use rustc_feature::{AttributeDuplicates, AttributeType, BUILTIN_ATTRIBUTE_MAP, BuiltinAttribute};
@@ -113,190 +115,201 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         let mut seen = FxHashMap::default();
         let attrs = self.tcx.hir().attrs(hir_id);
         for attr in attrs {
-            match attr.path().as_slice() {
-                [sym::diagnostic, sym::do_not_recommend, ..] => {
-                    self.check_do_not_recommend(attr.span(), hir_id, target, attr, item)
-                }
-                [sym::diagnostic, sym::on_unimplemented, ..] => {
-                    self.check_diagnostic_on_unimplemented(attr.span(), hir_id, target)
-                }
-                [sym::inline, ..] => self.check_inline(hir_id, attr, span, target),
-                [sym::coverage, ..] => self.check_coverage(attr, span, target),
-                [sym::optimize, ..] => self.check_optimize(hir_id, attr, span, target),
-                [sym::no_sanitize, ..] => self.check_no_sanitize(attr, span, target),
-                [sym::non_exhaustive, ..] => self.check_non_exhaustive(hir_id, attr, span, target, item),
-                [sym::marker, ..] => self.check_marker(hir_id, attr, span, target),
-                [sym::target_feature, ..] => {
-                    self.check_target_feature(hir_id, attr, span, target, attrs)
-                }
-                [sym::thread_local, ..] => self.check_thread_local(attr, span, target),
-                [sym::track_caller, ..] => {
-                    self.check_track_caller(hir_id, attr.span(), attrs, span, target)
-                }
-                [sym::doc, ..] => self.check_doc_attrs(
-                    attr,
-                    hir_id,
-                    target,
-                    &mut specified_inline,
-                    &mut doc_aliases,
-                ),
-                [sym::no_link, ..] => self.check_no_link(hir_id, attr, span, target),
-                [sym::export_name, ..] => self.check_export_name(hir_id, attr, span, target),
-                [sym::rustc_layout_scalar_valid_range_start, ..]
-                | [sym::rustc_layout_scalar_valid_range_end, ..] => {
-                    self.check_rustc_layout_scalar_valid_range(attr, span, target)
-                }
-                [sym::allow_internal_unstable, ..] => {
-                    self.check_allow_internal_unstable(hir_id, attr, span, target, attrs)
-                }
-                [sym::debugger_visualizer, ..] => self.check_debugger_visualizer(attr, target),
-                [sym::rustc_allow_const_fn_unstable, ..] => {
-                    self.check_rustc_allow_const_fn_unstable(hir_id, attr, span, target)
-                }
-                [sym::rustc_std_internal_symbol, ..] => {
-                    self.check_rustc_std_internal_symbol(attr, span, target)
-                }
-                [sym::naked, ..] => self.check_naked(hir_id, attr, span, target, attrs),
-                [sym::rustc_as_ptr, ..] => {
-                    self.check_applied_to_fn_or_method(hir_id, attr, span, target)
-                }
-                [sym::rustc_never_returns_null_ptr, ..] => {
-                    self.check_applied_to_fn_or_method(hir_id, attr, span, target)
-                }
-                [sym::rustc_legacy_const_generics, ..] => {
-                    self.check_rustc_legacy_const_generics(hir_id, attr, span, target, item)
-                }
-                [sym::rustc_lint_query_instability, ..] => {
-                    self.check_applied_to_fn_or_method(hir_id, attr, span, target)
-                }
-                [sym::rustc_lint_untracked_query_information, ..] => {
-                    self.check_applied_to_fn_or_method(hir_id, attr, span, target)
-                }
-                [sym::rustc_lint_diagnostics, ..] => {
-                    self.check_applied_to_fn_or_method(hir_id, attr, span, target)
-                }
-                [sym::rustc_lint_opt_ty, ..] => self.check_rustc_lint_opt_ty(attr, span, target),
-                [sym::rustc_lint_opt_deny_field_access, ..] => {
-                    self.check_rustc_lint_opt_deny_field_access(attr, span, target)
-                }
-                [sym::rustc_clean, ..]
-                | [sym::rustc_dirty, ..]
-                | [sym::rustc_if_this_changed, ..]
-                | [sym::rustc_then_this_would_need, ..] => self.check_rustc_dirty_clean(attr),
-                [sym::rustc_coinductive, ..]
-                | [sym::rustc_must_implement_one_of, ..]
-                | [sym::rustc_deny_explicit_impl, ..]
-                | [sym::rustc_do_not_implement_via_object, ..]
-                | [sym::const_trait, ..] => self.check_must_be_applied_to_trait(attr, span, target),
-                [sym::collapse_debuginfo, ..] => self.check_collapse_debuginfo(attr, span, target),
-                [sym::must_not_suspend, ..] => self.check_must_not_suspend(attr, span, target),
-                [sym::must_use, ..] => self.check_must_use(hir_id, attr, target),
-                [sym::may_dangle, ..] => self.check_may_dangle(hir_id, attr),
-                [sym::rustc_pass_by_value, ..] => self.check_pass_by_value(attr, span, target),
-                [sym::rustc_allow_incoherent_impl, ..] => {
-                    self.check_allow_incoherent_impl(attr, span, target)
-                }
-                [sym::rustc_has_incoherent_inherent_impls, ..] => {
-                    self.check_has_incoherent_inherent_impls(attr, span, target)
-                }
-                [sym::ffi_pure, ..] => self.check_ffi_pure(attr.span(), attrs, target),
-                [sym::ffi_const, ..] => self.check_ffi_const(attr.span(), target),
-                [sym::rustc_const_unstable, ..]
-                | [sym::rustc_const_stable, ..]
-                | [sym::unstable, ..]
-                | [sym::stable, ..]
-                | [sym::rustc_allowed_through_unstable_modules, ..]
-                | [sym::rustc_promotable, ..] => self.check_stability_promotable(attr, target),
-                [sym::link_ordinal, ..] => self.check_link_ordinal(attr, span, target),
-                [sym::rustc_confusables, ..] => self.check_confusables(attr, target),
-                [sym::cold, ..] => self.check_cold(hir_id, attr, span, target),
-                [sym::link, ..] => self.check_link(hir_id, attr, span, target),
-                [sym::link_name, ..] => self.check_link_name(hir_id, attr, span, target),
-                [sym::link_section, ..] => self.check_link_section(hir_id, attr, span, target),
-                [sym::no_mangle, ..] => self.check_no_mangle(hir_id, attr, span, target),
-                [sym::deprecated, ..] => self.check_deprecated(hir_id, attr, span, target),
-                [sym::macro_use, ..] | [sym::macro_escape, ..] => {
-                    self.check_macro_use(hir_id, attr, target)
-                }
-                [sym::path, ..] => self.check_generic_attr(hir_id, attr, target, Target::Mod),
-                [sym::macro_export, ..] => self.check_macro_export(hir_id, attr, target),
-                [sym::ignore, ..] | [sym::should_panic, ..] => {
-                    self.check_generic_attr(hir_id, attr, target, Target::Fn)
-                }
-                [sym::automatically_derived, ..] => {
-                    self.check_generic_attr(hir_id, attr, target, Target::Impl)
-                }
-                [sym::no_implicit_prelude, ..] => {
-                    self.check_generic_attr(hir_id, attr, target, Target::Mod)
-                }
-                [sym::rustc_object_lifetime_default, ..] => self.check_object_lifetime_default(hir_id),
-                [sym::proc_macro, ..] => {
-                    self.check_proc_macro(hir_id, target, ProcMacroKind::FunctionLike)
-                }
-                [sym::proc_macro_attribute, ..] => {
-                    self.check_proc_macro(hir_id, target, ProcMacroKind::Attribute);
-                }
-                [sym::proc_macro_derive, ..] => {
-                    self.check_generic_attr(hir_id, attr, target, Target::Fn);
-                    self.check_proc_macro(hir_id, target, ProcMacroKind::Derive)
-                }
-                [sym::autodiff, ..] => {
-                    self.check_autodiff(hir_id, attr, span, target)
-                }
-                [sym::coroutine, ..] => {
-                    self.check_coroutine(attr, target);
-                }
-                [sym::linkage, ..] => self.check_linkage(attr, span, target),
-                [sym::rustc_pub_transparent, ..] => self.check_rustc_pub_transparent(attr.span(), span, attrs),
-                [
-                    // ok
-                    sym::allow
-                    | sym::expect
-                    | sym::warn
-                    | sym::deny
-                    | sym::forbid
-                    | sym::cfg
-                    | sym::cfg_attr
-                    // need to be fixed
-                    | sym::cfi_encoding // FIXME(cfi_encoding)
-                    | sym::pointee // FIXME(derive_coerce_pointee)
-                    | sym::omit_gdb_pretty_printer_section // FIXME(omit_gdb_pretty_printer_section)
-                    | sym::used // handled elsewhere to restrict to static items
-                    | sym::repr // handled elsewhere to restrict to type decls items
-                    | sym::instruction_set // broken on stable!!!
-                    | sym::windows_subsystem // broken on stable!!!
-                    | sym::patchable_function_entry // FIXME(patchable_function_entry)
-                    | sym::deprecated_safe // FIXME(deprecated_safe)
-                    // internal
-                    | sym::prelude_import
-                    | sym::panic_handler
-                    | sym::allow_internal_unsafe
-                    | sym::fundamental
-                    | sym::lang
-                    | sym::needs_allocator
-                    | sym::default_lib_allocator
-                    | sym::custom_mir,
-                    ..
-                ] => {}
-                [name, ..] => {
-                    match BUILTIN_ATTRIBUTE_MAP.get(name) {
-                        // checked below
-                        Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) => {}
-                        Some(_) => {
-                            // FIXME: differentiate between unstable and internal attributes just
-                            // like we do with features instead of just accepting `rustc_`
-                            // attributes by name. That should allow trimming the above list, too.
-                            if !name.as_str().starts_with("rustc_") {
-                                span_bug!(
-                                    attr.span(),
-                                    "builtin attribute {name:?} not handled by `CheckAttrVisitor`"
-                                )
+            match attr {
+                Attribute::Parsed(AttributeKind::Confusables { first_span, .. }) => {
+                    self.check_confusables(*first_span, target);
+                }
+                Attribute::Parsed(
+                    AttributeKind::Stability { span, .. }
+                    | AttributeKind::ConstStability { span, .. },
+                ) => self.check_stability_promotable(*span, target),
+                Attribute::Parsed(AttributeKind::AllowInternalUnstable(syms)) => self
+                    .check_allow_internal_unstable(
+                        hir_id,
+                        syms.first().unwrap().1,
+                        span,
+                        target,
+                        attrs,
+                    ),
+                _ => {
+                    match attr.path().as_slice() {
+                        [sym::diagnostic, sym::do_not_recommend, ..] => {
+                            self.check_do_not_recommend(attr.span(), hir_id, target, attr, item)
+                        }
+                        [sym::diagnostic, sym::on_unimplemented, ..] => {
+                            self.check_diagnostic_on_unimplemented(attr.span(), hir_id, target)
+                        }
+                        [sym::inline, ..] => self.check_inline(hir_id, attr, span, target),
+                        [sym::coverage, ..] => self.check_coverage(attr, span, target),
+                        [sym::optimize, ..] => self.check_optimize(hir_id, attr, span, target),
+                        [sym::no_sanitize, ..] => {
+                            self.check_no_sanitize(attr, span, target)
+                        }
+                        [sym::non_exhaustive, ..] => self.check_non_exhaustive(hir_id, attr, span, target, item),
+                        [sym::marker, ..] => self.check_marker(hir_id, attr, span, target),
+                        [sym::target_feature, ..] => {
+                            self.check_target_feature(hir_id, attr, span, target, attrs)
+                        }
+                        [sym::thread_local, ..] => self.check_thread_local(attr, span, target),
+                        [sym::track_caller, ..] => {
+                            self.check_track_caller(hir_id, attr.span(), attrs, span, target)
+                        }
+                        [sym::doc, ..] => self.check_doc_attrs(
+                            attr,
+                            hir_id,
+                            target,
+                            &mut specified_inline,
+                            &mut doc_aliases,
+                        ),
+                        [sym::no_link, ..] => self.check_no_link(hir_id, attr, span, target),
+                        [sym::export_name, ..] => self.check_export_name(hir_id, attr, span, target),
+                        [sym::rustc_layout_scalar_valid_range_start, ..]
+                        | [sym::rustc_layout_scalar_valid_range_end, ..] => {
+                            self.check_rustc_layout_scalar_valid_range(attr, span, target)
+                        }
+                        [sym::debugger_visualizer, ..] => self.check_debugger_visualizer(attr, target),
+                        [sym::rustc_allow_const_fn_unstable, ..] => {
+                            self.check_rustc_allow_const_fn_unstable(hir_id, attr, span, target)
+                        }
+                        [sym::rustc_std_internal_symbol, ..] => {
+                            self.check_rustc_std_internal_symbol(attr, span, target)
+                        }
+                        [sym::naked, ..] => self.check_naked(hir_id, attr, span, target, attrs),
+                        [sym::rustc_as_ptr, ..] => {
+                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                        }
+                        [sym::rustc_never_returns_null_ptr, ..] => {
+                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                        }
+                        [sym::rustc_legacy_const_generics, ..] => {
+                            self.check_rustc_legacy_const_generics(hir_id, attr, span, target, item)
+                        }
+                        [sym::rustc_lint_query_instability, ..] => {
+                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                        }
+                        [sym::rustc_lint_untracked_query_information, ..] => {
+                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                        }
+                        [sym::rustc_lint_diagnostics, ..] => {
+                            self.check_applied_to_fn_or_method(hir_id, attr, span, target)
+                        }
+                        [sym::rustc_lint_opt_ty, ..] => self.check_rustc_lint_opt_ty(attr, span, target),
+                        [sym::rustc_lint_opt_deny_field_access, ..] => {
+                            self.check_rustc_lint_opt_deny_field_access(attr, span, target)
+                        }
+                        [sym::rustc_clean, ..]
+                        | [sym::rustc_dirty, ..]
+                        | [sym::rustc_if_this_changed, ..]
+                        | [sym::rustc_then_this_would_need, ..] => self.check_rustc_dirty_clean(attr),
+                        [sym::rustc_coinductive, ..]
+                        | [sym::rustc_must_implement_one_of, ..]
+                        | [sym::rustc_deny_explicit_impl, ..]
+                        | [sym::rustc_do_not_implement_via_object, ..]
+                        | [sym::const_trait, ..] => self.check_must_be_applied_to_trait(attr, span, target),
+                        [sym::collapse_debuginfo, ..] => self.check_collapse_debuginfo(attr, span, target),
+                        [sym::must_not_suspend, ..] => self.check_must_not_suspend(attr, span, target),
+                        [sym::must_use, ..] => self.check_must_use(hir_id, attr, target),
+                        [sym::may_dangle, ..] => self.check_may_dangle(hir_id, attr),
+                        [sym::rustc_pass_by_value, ..] => self.check_pass_by_value(attr, span, target),
+                        [sym::rustc_allow_incoherent_impl, ..] => {
+                            self.check_allow_incoherent_impl(attr, span, target)
+                        }
+                        [sym::rustc_has_incoherent_inherent_impls, ..] => {
+                            self.check_has_incoherent_inherent_impls(attr, span, target)
+                        }
+                        [sym::ffi_pure, ..] => self.check_ffi_pure(attr.span(), attrs, target),
+                        [sym::ffi_const, ..] => self.check_ffi_const(attr.span(), target),
+                        [sym::link_ordinal, ..] => self.check_link_ordinal(attr, span, target),
+                        [sym::cold, ..] => self.check_cold(hir_id, attr, span, target),
+                        [sym::link, ..] => self.check_link(hir_id, attr, span, target),
+                        [sym::link_name, ..] => self.check_link_name(hir_id, attr, span, target),
+                        [sym::link_section, ..] => self.check_link_section(hir_id, attr, span, target),
+                        [sym::no_mangle, ..] => self.check_no_mangle(hir_id, attr, span, target),
+                        [sym::deprecated, ..] => self.check_deprecated(hir_id, attr, span, target),
+                        [sym::macro_use, ..] | [sym::macro_escape, ..] => {
+                            self.check_macro_use(hir_id, attr, target)
+                        }
+                        [sym::path, ..] => self.check_generic_attr(hir_id, attr, target, Target::Mod),
+                        [sym::macro_export, ..] => self.check_macro_export(hir_id, attr, target),
+                        [sym::ignore, ..] | [sym::should_panic, ..] => {
+                            self.check_generic_attr(hir_id, attr, target, Target::Fn)
+                        }
+                        [sym::automatically_derived, ..] => {
+                            self.check_generic_attr(hir_id, attr, target, Target::Impl)
+                        }
+                        [sym::no_implicit_prelude, ..] => {
+                            self.check_generic_attr(hir_id, attr, target, Target::Mod)
+                        }
+                        [sym::rustc_object_lifetime_default, ..] => self.check_object_lifetime_default(hir_id),
+                        [sym::proc_macro, ..] => {
+                            self.check_proc_macro(hir_id, target, ProcMacroKind::FunctionLike)
+                        }
+                        [sym::proc_macro_attribute, ..] => {
+                            self.check_proc_macro(hir_id, target, ProcMacroKind::Attribute);
+                        }
+                        [sym::proc_macro_derive, ..] => {
+                            self.check_generic_attr(hir_id, attr, target, Target::Fn);
+                            self.check_proc_macro(hir_id, target, ProcMacroKind::Derive)
+                        }
+                        [sym::autodiff, ..] => {
+                            self.check_autodiff(hir_id, attr, span, target)
+                        }
+                        [sym::coroutine, ..] => {
+                            self.check_coroutine(attr, target);
+                        }
+                        [sym::linkage, ..] => self.check_linkage(attr, span, target),
+                        [sym::rustc_pub_transparent, ..] => self.check_rustc_pub_transparent(attr.span(), span, attrs),
+                        [
+                            // ok
+                            sym::allow
+                            | sym::expect
+                            | sym::warn
+                            | sym::deny
+                            | sym::forbid
+                            | sym::cfg
+                            | sym::cfg_attr
+                            // need to be fixed
+                            | sym::cfi_encoding // FIXME(cfi_encoding)
+                            | sym::pointee // FIXME(derive_coerce_pointee)
+                            | sym::omit_gdb_pretty_printer_section // FIXME(omit_gdb_pretty_printer_section)
+                            | sym::used // handled elsewhere to restrict to static items
+                            | sym::repr // handled elsewhere to restrict to type decls items
+                            | sym::instruction_set // broken on stable!!!
+                            | sym::windows_subsystem // broken on stable!!!
+                            | sym::patchable_function_entry // FIXME(patchable_function_entry)
+                            | sym::deprecated_safe // FIXME(deprecated_safe)
+                            // internal
+                            | sym::prelude_import
+                            | sym::panic_handler
+                            | sym::allow_internal_unsafe
+                            | sym::fundamental
+                            | sym::lang
+                            | sym::needs_allocator
+                            | sym::default_lib_allocator
+                            | sym::custom_mir,
+                            ..
+                        ] => {}
+                        [name, ..] => {
+                            match BUILTIN_ATTRIBUTE_MAP.get(name) {
+                                // checked below
+                                Some(BuiltinAttribute { type_: AttributeType::CrateLevel, .. }) => {}
+                                Some(_) => {
+                                    // FIXME: differentiate between unstable and internal attributes just
+                                    // like we do with features instead of just accepting `rustc_`
+                                    // attributes by name. That should allow trimming the above list, too.
+                                    if !name.as_str().starts_with("rustc_") {
+                                        span_bug!(
+                                            attr.span(),
+                                            "builtin attribute {name:?} not handled by `CheckAttrVisitor`"
+                                        )
+                                    }
+                                }
+                                None => (),
                             }
                         }
-                        None => (),
+                        [] => unreachable!(),
                     }
                 }
-                [] => unreachable!(),
             }
 
             let builtin = attr.ident().and_then(|ident| BUILTIN_ATTRIBUTE_MAP.get(&ident.name));
@@ -343,11 +356,11 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         );
     }
 
-    fn inline_attr_str_error_without_macro_def(&self, hir_id: HirId, attr: &Attribute, sym: &str) {
+    fn inline_attr_str_error_without_macro_def(&self, hir_id: HirId, attr_span: Span, sym: &str) {
         self.tcx.emit_node_span_lint(
             UNUSED_ATTRIBUTES,
             hir_id,
-            attr.span(),
+            attr_span,
             errors::IgnoredAttr { sym },
         );
     }
@@ -568,6 +581,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
             sym::warn,
             sym::deny,
             sym::forbid,
+            // FIXME(jdonszelmann): not used, because already a new-style attr (ugh)
             sym::deprecated,
             sym::must_use,
             // abi, linking and FFI
@@ -595,6 +609,17 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         continue;
                     }
 
+                    // FIXME(jdonszelmann): once naked uses new-style parsing,
+                    // this check can be part of the parser and be removed here
+                    match other_attr {
+                        Attribute::Parsed(
+                            AttributeKind::Deprecation { .. } | AttributeKind::Repr { .. },
+                        ) => {
+                            continue;
+                        }
+                        _ => {}
+                    }
+
                     if !ALLOW_LIST.iter().any(|name| other_attr.has_name(*name)) {
                         self.dcx().emit_err(errors::NakedFunctionIncompatibleAttribute {
                             span: other_attr.span(),
@@ -1858,12 +1883,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         // #[repr(foo)]
         // #[repr(bar, align(8))]
         // ```
-        let hints: Vec<_> = attrs
-            .iter()
-            .filter(|attr| attr.has_name(sym::repr))
-            .filter_map(|attr| attr.meta_item_list())
-            .flatten()
-            .collect();
+        let reprs = find_attr!(attrs, AttributeKind::Repr(r) => r.as_slice()).unwrap_or(&[]);
 
         let mut int_reprs = 0;
         let mut is_explicit_rust = false;
@@ -1871,66 +1891,33 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         let mut is_simd = false;
         let mut is_transparent = false;
 
-        // catch `repr()` with no arguments, applied to an item (i.e. not `#![repr()]`)
-        if hints.is_empty() && item.is_some() {
-            for attr in attrs.iter().filter(|attr| attr.has_name(sym::repr)) {
-                match target {
-                    Target::Struct | Target::Union | Target::Enum => {}
-                    Target::Fn | Target::Method(_) => {
-                        feature_err(
-                            &self.tcx.sess,
-                            sym::fn_align,
-                            attr.span(),
-                            fluent::passes_repr_align_function,
-                        )
-                        .emit();
-                    }
-                    _ => {
-                        self.dcx().emit_err(
-                            errors::AttrApplication::StructEnumFunctionMethodUnion {
-                                hint_span: attr.span(),
-                                span,
-                            },
-                        );
-                    }
-                }
-            }
-
-            return;
-        }
-
-        for hint in &hints {
-            if !hint.is_meta_item() {
-                self.dcx().emit_err(errors::ReprIdent { span: hint.span() });
-                continue;
-            }
-
-            match hint.name_or_empty() {
-                sym::Rust => {
+        for (repr, repr_span) in reprs {
+            match repr {
+                ReprAttr::ReprRust => {
                     is_explicit_rust = true;
                     match target {
                         Target::Struct | Target::Union | Target::Enum => continue,
                         _ => {
                             self.dcx().emit_err(errors::AttrApplication::StructEnumUnion {
-                                hint_span: hint.span(),
+                                hint_span: *repr_span,
                                 span,
                             });
                         }
                     }
                 }
-                sym::C => {
+                ReprAttr::ReprC => {
                     is_c = true;
                     match target {
                         Target::Struct | Target::Union | Target::Enum => continue,
                         _ => {
                             self.dcx().emit_err(errors::AttrApplication::StructEnumUnion {
-                                hint_span: hint.span(),
+                                hint_span: *repr_span,
                                 span,
                             });
                         }
                     }
                 }
-                sym::align => {
+                ReprAttr::ReprAlign(align) => {
                     match target {
                         Target::Struct | Target::Union | Target::Enum => {}
                         Target::Fn | Target::Method(_) => {
@@ -1938,7 +1925,7 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                                 feature_err(
                                     &self.tcx.sess,
                                     sym::fn_align,
-                                    hint.span(),
+                                    *repr_span,
                                     fluent::passes_repr_align_function,
                                 )
                                 .emit();
@@ -1947,83 +1934,97 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                         _ => {
                             self.dcx().emit_err(
                                 errors::AttrApplication::StructEnumFunctionMethodUnion {
-                                    hint_span: hint.span(),
+                                    hint_span: *repr_span,
                                     span,
                                 },
                             );
                         }
                     }
 
-                    self.check_align_value(hint);
+                    self.check_align_value(*align, *repr_span);
                 }
-                sym::packed => {
+                ReprAttr::ReprPacked(_) => {
                     if target != Target::Struct && target != Target::Union {
                         self.dcx().emit_err(errors::AttrApplication::StructUnion {
-                            hint_span: hint.span(),
+                            hint_span: *repr_span,
                             span,
                         });
                     } else {
                         continue;
                     }
                 }
-                sym::simd => {
+                ReprAttr::ReprSimd => {
                     is_simd = true;
                     if target != Target::Struct {
                         self.dcx().emit_err(errors::AttrApplication::Struct {
-                            hint_span: hint.span(),
+                            hint_span: *repr_span,
                             span,
                         });
                     } else {
                         continue;
                     }
                 }
-                sym::transparent => {
+                ReprAttr::ReprTransparent => {
                     is_transparent = true;
                     match target {
                         Target::Struct | Target::Union | Target::Enum => continue,
                         _ => {
                             self.dcx().emit_err(errors::AttrApplication::StructEnumUnion {
-                                hint_span: hint.span(),
+                                hint_span: *repr_span,
                                 span,
                             });
                         }
                     }
                 }
-                sym::i8
-                | sym::u8
-                | sym::i16
-                | sym::u16
-                | sym::i32
-                | sym::u32
-                | sym::i64
-                | sym::u64
-                | sym::i128
-                | sym::u128
-                | sym::isize
-                | sym::usize => {
+                ReprAttr::ReprInt(_) => {
                     int_reprs += 1;
                     if target != Target::Enum {
                         self.dcx().emit_err(errors::AttrApplication::Enum {
-                            hint_span: hint.span(),
+                            hint_span: *repr_span,
                             span,
                         });
                     } else {
                         continue;
                     }
                 }
-                _ => {
-                    self.dcx().emit_err(errors::UnrecognizedReprHint { span: hint.span() });
-                    continue;
+                // FIXME(jdonszelmann): move the diagnostic for unused repr attrs here, I think
+                // it's a better place for it.
+                ReprAttr::ReprEmpty => {
+                    // catch `repr()` with no arguments, applied to an item (i.e. not `#![repr()]`)
+                    if item.is_some() {
+                        match target {
+                            Target::Struct | Target::Union | Target::Enum => {}
+                            Target::Fn | Target::Method(_) => {
+                                feature_err(
+                                    &self.tcx.sess,
+                                    sym::fn_align,
+                                    *repr_span,
+                                    fluent::passes_repr_align_function,
+                                )
+                                .emit();
+                            }
+                            _ => {
+                                self.dcx().emit_err(
+                                    errors::AttrApplication::StructEnumFunctionMethodUnion {
+                                        hint_span: *repr_span,
+                                        span,
+                                    },
+                                );
+                            }
+                        }
+                    }
+
+                    return;
                 }
             };
         }
 
         // Just point at all repr hints if there are any incompatibilities.
         // This is not ideal, but tracking precisely which ones are at fault is a huge hassle.
-        let hint_spans = hints.iter().map(|hint| hint.span());
+        let hint_spans = reprs.iter().map(|(_, span)| *span);
 
         // Error on repr(transparent, <anything else>).
-        if is_transparent && hints.len() > 1 {
+        if is_transparent && reprs.len() > 1 {
             let hint_spans = hint_spans.clone().collect();
             self.dcx().emit_err(errors::TransparentIncompatible {
                 hint_spans,
@@ -2052,41 +2053,21 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    fn check_align_value(&self, item: &MetaItemInner) {
-        match item.singleton_lit_list() {
-            Some((
-                _,
-                MetaItemLit {
-                    kind: ast::LitKind::Int(literal, ast::LitIntType::Unsuffixed), ..
-                },
-            )) => {
-                let val = literal.get() as u64;
-                if val > 2_u64.pow(29) {
-                    // for values greater than 2^29, a different error will be emitted, make sure that happens
-                    self.dcx().span_delayed_bug(
-                        item.span(),
-                        "alignment greater than 2^29 should be errored on elsewhere",
-                    );
-                } else {
-                    // only do this check when <= 2^29 to prevent duplicate errors:
-                    // alignment greater than 2^29 not supported
-                    // alignment is too large for the current target
-
-                    let max =
-                        Size::from_bits(self.tcx.sess.target.pointer_width).signed_int_max() as u64;
-                    if val > max {
-                        self.dcx().emit_err(errors::InvalidReprAlignForTarget {
-                            span: item.span(),
-                            size: max,
-                        });
-                    }
-                }
-            }
+    fn check_align_value(&self, align: Align, span: Span) {
+        if align.bytes() > 2_u64.pow(29) {
+            // for values greater than 2^29, a different error will be emitted, make sure that happens
+            self.dcx().span_delayed_bug(
+                span,
+                "alignment greater than 2^29 should be errored on elsewhere",
+            );
+        } else {
+            // only do this check when <= 2^29 to prevent duplicate errors:
+            // alignment greater than 2^29 not supported
+            // alignment is too large for the current target
 
-            // if the attribute is malformed, singleton_lit_list may not be of the expected type or may be None
-            // but an error will have already been emitted, so this code should just skip such attributes
-            Some((_, _)) | None => {
-                self.dcx().span_delayed_bug(item.span(), "malformed repr(align(N))");
+            let max = Size::from_bits(self.tcx.sess.target.pointer_width).signed_int_max() as u64;
+            if align.bytes() > max {
+                self.dcx().emit_err(errors::InvalidReprAlignForTarget { span, size: max });
             }
         }
     }
@@ -2134,41 +2115,44 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
 
     /// Outputs an error for `#[allow_internal_unstable]` which can only be applied to macros.
     /// (Allows proc_macro functions)
+    // FIXME(jdonszelmann): if possible, move to attr parsing
     fn check_allow_internal_unstable(
         &self,
         hir_id: HirId,
-        attr: &Attribute,
+        attr_span: Span,
         span: Span,
         target: Target,
         attrs: &[Attribute],
     ) {
-        debug!("Checking target: {:?}", target);
         match target {
             Target::Fn => {
                 for attr in attrs {
                     if attr.is_proc_macro_attr() {
-                        debug!("Is proc macro attr");
+                        // return on proc macros
                         return;
                     }
                 }
-                debug!("Is not proc macro attr");
+                // continue out of the match
             }
-            Target::MacroDef => {}
+            // return on decl macros
+            Target::MacroDef => return,
             // FIXME(#80564): We permit struct fields and match arms to have an
             // `#[allow_internal_unstable]` attribute with just a lint, because we previously
             // erroneously allowed it and some crates used it accidentally, to be compatible
             // with crates depending on them, we can't throw an error here.
-            Target::Field | Target::Arm => self.inline_attr_str_error_without_macro_def(
-                hir_id,
-                attr,
-                "allow_internal_unstable",
-            ),
-            _ => {
-                self.tcx
-                    .dcx()
-                    .emit_err(errors::AllowInternalUnstable { attr_span: attr.span(), span });
+            Target::Field | Target::Arm => {
+                self.inline_attr_str_error_without_macro_def(
+                    hir_id,
+                    attr_span,
+                    "allow_internal_unstable",
+                );
+                return;
             }
+            // otherwise continue out of the match
+            _ => {}
         }
+
+        self.tcx.dcx().emit_err(errors::AllowInternalUnstable { attr_span, span });
     }
 
     /// Checks if the items on the `#[debugger_visualizer]` attribute are valid.
@@ -2223,10 +2207,10 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    fn check_stability_promotable(&self, attr: &Attribute, target: Target) {
+    fn check_stability_promotable(&self, span: Span, target: Target) {
         match target {
             Target::Expression => {
-                self.dcx().emit_err(errors::StabilityPromotable { attr_span: attr.span() });
+                self.dcx().emit_err(errors::StabilityPromotable { attr_span: span });
             }
             _ => {}
         }
@@ -2241,36 +2225,9 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
         }
     }
 
-    fn check_confusables(&self, attr: &Attribute, target: Target) {
-        match target {
-            Target::Method(MethodKind::Inherent) => {
-                let Some(metas) = attr.meta_item_list() else {
-                    return;
-                };
-
-                let mut candidates = Vec::new();
-
-                for meta in metas {
-                    let MetaItemInner::Lit(meta_lit) = meta else {
-                        self.dcx().emit_err(errors::IncorrectMetaItem {
-                            span: meta.span(),
-                            suggestion: errors::IncorrectMetaItemSuggestion {
-                                lo: meta.span().shrink_to_lo(),
-                                hi: meta.span().shrink_to_hi(),
-                            },
-                        });
-                        return;
-                    };
-                    candidates.push(meta_lit.symbol);
-                }
-
-                if candidates.is_empty() {
-                    self.dcx().emit_err(errors::EmptyConfusables { span: attr.span() });
-                }
-            }
-            _ => {
-                self.dcx().emit_err(errors::Confusables { attr_span: attr.span() });
-            }
+    fn check_confusables(&self, span: Span, target: Target) {
+        if !matches!(target, Target::Method(MethodKind::Inherent)) {
+            self.dcx().emit_err(errors::Confusables { attr_span: span });
         }
     }
 
@@ -2346,8 +2303,32 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     }
 
     fn check_unused_attribute(&self, hir_id: HirId, attr: &Attribute) {
+        // FIXME(jdonszelmann): deduplicate these checks after more attrs are parsed. This is very
+        // ugly now but can 100% be removed later.
+        if let Attribute::Parsed(p) = attr {
+            match p {
+                AttributeKind::Repr(reprs) => {
+                    for (r, span) in reprs {
+                        if let ReprAttr::ReprEmpty = r {
+                            self.tcx.emit_node_span_lint(
+                                UNUSED_ATTRIBUTES,
+                                hir_id,
+                                *span,
+                                errors::Unused {
+                                    attr_span: *span,
+                                    note: errors::UnusedNote::EmptyList { name: sym::repr },
+                                },
+                            );
+                        }
+                    }
+                    return;
+                }
+                _ => {}
+            }
+        }
+
         // Warn on useless empty attributes.
-        let note = if matches!(
+        let note = if (matches!(
             attr.name_or_empty(),
             sym::macro_use
                 | sym::allow
@@ -2356,9 +2337,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
                 | sym::deny
                 | sym::forbid
                 | sym::feature
-                | sym::repr
                 | sym::target_feature
-        ) && attr.meta_item_list().is_some_and(|list| list.is_empty())
+        ) && attr.meta_item_list().is_some_and(|list| list.is_empty()))
         {
             errors::UnusedNote::EmptyList { name: attr.name_or_empty() }
         } else if matches!(
@@ -2552,12 +2532,8 @@ impl<'tcx> CheckAttrVisitor<'tcx> {
     }
 
     fn check_rustc_pub_transparent(&self, attr_span: Span, span: Span, attrs: &[Attribute]) {
-        if !attrs
-            .iter()
-            .filter(|attr| attr.has_name(sym::repr))
-            .filter_map(|attr| attr.meta_item_list())
-            .flatten()
-            .any(|nmi| nmi.has_name(sym::transparent))
+        if !find_attr!(attrs, AttributeKind::Repr(r) => r.iter().any(|(r, _)| r == &ReprAttr::ReprTransparent))
+            .unwrap_or(false)
         {
             self.dcx().emit_err(errors::RustcPubTransparent { span, attr_span });
         }
@@ -2734,7 +2710,6 @@ fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
     // resolution for the attribute macro error.
     const ATTRS_TO_CHECK: &[Symbol] = &[
         sym::macro_export,
-        sym::repr,
         sym::path,
         sym::automatically_derived,
         sym::rustc_main,
@@ -2746,47 +2721,47 @@ fn check_invalid_crate_level_attr(tcx: TyCtxt<'_>, attrs: &[Attribute]) {
     ];
 
     for attr in attrs {
-        // This function should only be called with crate attributes
-        // which are inner attributes always but lets check to make sure
-        if attr.style() == AttrStyle::Inner {
-            for attr_to_check in ATTRS_TO_CHECK {
-                if attr.has_name(*attr_to_check) {
-                    let item = tcx
-                        .hir_free_items()
-                        .map(|id| tcx.hir_item(id))
-                        .find(|item| !item.span.is_dummy()) // Skip prelude `use`s
-                        .map(|item| errors::ItemFollowingInnerAttr {
-                            span: item.ident.span,
-                            kind: item.kind.descr(),
-                        });
-                    let err = tcx.dcx().create_err(errors::InvalidAttrAtCrateLevel {
-                        span: attr.span(),
-                        sugg_span: tcx
-                            .sess
-                            .source_map()
-                            .span_to_snippet(attr.span())
-                            .ok()
-                            .filter(|src| src.starts_with("#!["))
-                            .map(|_| {
-                                attr.span()
-                                    .with_lo(attr.span().lo() + BytePos(1))
-                                    .with_hi(attr.span().lo() + BytePos(2))
-                            }),
-                        name: *attr_to_check,
-                        item,
-                    });
+        // FIXME(jdonszelmann): all attrs should be combined here cleaning this up some day.
+        let (span, name) = if let Some(a) =
+            ATTRS_TO_CHECK.iter().find(|attr_to_check| attr.has_name(**attr_to_check))
+        {
+            (attr.span(), *a)
+        } else if let Attribute::Parsed(AttributeKind::Repr(r)) = attr {
+            (r.first().unwrap().1, sym::repr)
+        } else {
+            continue;
+        };
 
-                    if let Attribute::Unparsed(p) = attr {
-                        tcx.dcx().try_steal_replace_and_emit_err(
-                            p.path.span,
-                            StashKey::UndeterminedMacroResolution,
-                            err,
-                        );
-                    } else {
-                        err.emit();
-                    }
-                }
-            }
+
+        let item = tcx
+            .hir_free_items()
+            .map(|id| tcx.hir_item(id))
+            .find(|item| !item.span.is_dummy()) // Skip prelude `use`s
+            .map(|item| errors::ItemFollowingInnerAttr {
+                span: item.ident.span,
+                kind: item.kind.descr(),
+            });
+        let err = tcx.dcx().create_err(errors::InvalidAttrAtCrateLevel {
+            span,
+            sugg_span: tcx
+                .sess
+                .source_map()
+                .span_to_snippet(span)
+                .ok()
+                .filter(|src| src.starts_with("#!["))
+                .map(|_| span.with_lo(span.lo() + BytePos(1)).with_hi(span.lo() + BytePos(2))),
+            name,
+            item,
+        });
+
+        if let Attribute::Unparsed(p) = attr {
+            tcx.dcx().try_steal_replace_and_emit_err(
+                p.path.span,
+                StashKey::UndeterminedMacroResolution,
+                err,
+            );
+        } else {
+            err.emit();
         }
     }
 }
diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 9bcdd238547..5f686f38bab 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -583,13 +583,6 @@ pub(crate) struct NoMangle {
 }
 
 #[derive(Diagnostic)]
-#[diag(passes_repr_ident, code = E0565)]
-pub(crate) struct ReprIdent {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
 #[diag(passes_repr_conflicting, code = E0566)]
 pub(crate) struct ReprConflicting {
     #[primary_span]
@@ -737,31 +730,6 @@ pub(crate) struct Linkage {
 }
 
 #[derive(Diagnostic)]
-#[diag(passes_empty_confusables)]
-pub(crate) struct EmptyConfusables {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
-#[diag(passes_incorrect_meta_item, code = E0539)]
-pub(crate) struct IncorrectMetaItem {
-    #[primary_span]
-    pub span: Span,
-    #[subdiagnostic]
-    pub suggestion: IncorrectMetaItemSuggestion,
-}
-
-#[derive(Subdiagnostic)]
-#[multipart_suggestion(passes_incorrect_meta_item_suggestion, applicability = "maybe-incorrect")]
-pub(crate) struct IncorrectMetaItemSuggestion {
-    #[suggestion_part(code = "\"")]
-    pub lo: Span,
-    #[suggestion_part(code = "\"")]
-    pub hi: Span,
-}
-
-#[derive(Diagnostic)]
 #[diag(passes_stability_promotable)]
 pub(crate) struct StabilityPromotable {
     #[primary_span]
@@ -1476,14 +1444,6 @@ pub(crate) struct ObjectLifetimeErr {
 }
 
 #[derive(Diagnostic)]
-#[diag(passes_unrecognized_repr_hint, code = E0552)]
-#[help]
-pub(crate) struct UnrecognizedReprHint {
-    #[primary_span]
-    pub span: Span,
-}
-
-#[derive(Diagnostic)]
 pub(crate) enum AttrApplication {
     #[diag(passes_attr_application_enum, code = E0517)]
     Enum {
@@ -1902,3 +1862,11 @@ pub(crate) struct NoSanitize<'a> {
     pub accepted_kind: &'a str,
     pub attr_str: &'a str,
 }
+
+// FIXME(jdonszelmann): move back to rustc_attr
+#[derive(Diagnostic)]
+#[diag(passes_rustc_const_stable_indirect_pairing)]
+pub(crate) struct RustcConstStableIndirectPairing {
+    #[primary_span]
+    pub span: Span,
+}
diff --git a/compiler/rustc_passes/src/lib_features.rs b/compiler/rustc_passes/src/lib_features.rs
index d4403da4f62..7353c1ead5a 100644
--- a/compiler/rustc_passes/src/lib_features.rs
+++ b/compiler/rustc_passes/src/lib_features.rs
@@ -4,7 +4,7 @@
 //! but are not declared in one single location (unlike lang features), which means we need to
 //! collect them instead.
 
-use rustc_attr_parsing::VERSION_PLACEHOLDER;
+use rustc_attr_parsing::{AttributeKind, StabilityLevel, StableSince};
 use rustc_hir::Attribute;
 use rustc_hir::intravisit::Visitor;
 use rustc_middle::hir::nested_filter;
@@ -26,66 +26,29 @@ impl<'tcx> LibFeatureCollector<'tcx> {
     }
 
     fn extract(&self, attr: &Attribute) -> Option<(Symbol, FeatureStability, Span)> {
-        let stab_attrs = [
-            sym::stable,
-            sym::unstable,
-            sym::rustc_const_stable,
-            sym::rustc_const_unstable,
-            sym::rustc_default_body_unstable,
-        ];
-
-        // Find a stability attribute: one of #[stable(…)], #[unstable(…)],
-        // #[rustc_const_stable(…)], #[rustc_const_unstable(…)] or #[rustc_default_body_unstable].
-        if let Some(stab_attr) = stab_attrs.iter().find(|stab_attr| attr.has_name(**stab_attr)) {
-            if let Some(metas) = attr.meta_item_list() {
-                let mut feature = None;
-                let mut since = None;
-                for meta in metas {
-                    if let Some(mi) = meta.meta_item() {
-                        // Find the `feature = ".."` meta-item.
-                        match (mi.name_or_empty(), mi.value_str()) {
-                            (sym::feature, val) => feature = val,
-                            (sym::since, val) => since = val,
-                            _ => {}
-                        }
-                    }
-                }
-
-                if let Some(s) = since
-                    && s.as_str() == VERSION_PLACEHOLDER
-                {
-                    since = Some(sym::env_CFG_RELEASE);
-                }
-
-                if let Some(feature) = feature {
-                    // This additional check for stability is to make sure we
-                    // don't emit additional, irrelevant errors for malformed
-                    // attributes.
-                    let is_unstable = matches!(
-                        *stab_attr,
-                        sym::unstable
-                            | sym::rustc_const_unstable
-                            | sym::rustc_default_body_unstable
-                    );
-                    if is_unstable {
-                        return Some((feature, FeatureStability::Unstable, attr.span()));
-                    }
-                    if let Some(since) = since {
-                        return Some((
-                            feature,
-                            FeatureStability::AcceptedSince(since),
-                            attr.span(),
-                        ));
-                    }
-                }
-                // We need to iterate over the other attributes, because
-                // `rustc_const_unstable` is not mutually exclusive with
-                // the other stability attributes, so we can't just `break`
-                // here.
+        let (feature, level, span) = match attr {
+            Attribute::Parsed(AttributeKind::Stability { stability, span }) => {
+                (stability.feature, stability.level, *span)
             }
-        }
-
-        None
+            Attribute::Parsed(AttributeKind::ConstStability { stability, span }) => {
+                (stability.feature, stability.level, *span)
+            }
+            Attribute::Parsed(AttributeKind::BodyStability { stability, span }) => {
+                (stability.feature, stability.level, *span)
+            }
+            _ => return None,
+        };
+
+        let feature_stability = match level {
+            StabilityLevel::Unstable { .. } => FeatureStability::Unstable,
+            StabilityLevel::Stable { since, .. } => FeatureStability::AcceptedSince(match since {
+                StableSince::Version(v) => Symbol::intern(&v.to_string()),
+                StableSince::Current => sym::env_CFG_RELEASE,
+                StableSince::Err => return None,
+            }),
+        };
+
+        Some((feature, feature_stability, span))
     }
 
     fn collect_feature(&mut self, feature: Symbol, stability: FeatureStability, span: Span) {
diff --git a/compiler/rustc_passes/src/stability.rs b/compiler/rustc_passes/src/stability.rs
index d92edf959af..8a4bdf3875c 100644
--- a/compiler/rustc_passes/src/stability.rs
+++ b/compiler/rustc_passes/src/stability.rs
@@ -6,8 +6,8 @@ use std::num::NonZero;
 
 use rustc_ast_lowering::stability::extern_abi_stability;
 use rustc_attr_parsing::{
-    self as attr, ConstStability, DeprecatedSince, Stability, StabilityLevel, StableSince,
-    UnstableReason, VERSION_PLACEHOLDER,
+    self as attr, AttributeKind, ConstStability, DeprecatedSince, PartialConstStability, Stability,
+    StabilityLevel, StableSince, UnstableReason, VERSION_PLACEHOLDER, find_attr,
 };
 use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::unord::{ExtendUnord, UnordMap, UnordSet};
@@ -121,7 +121,9 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
         let attrs = self.tcx.hir().attrs(self.tcx.local_def_id_to_hir_id(def_id));
         debug!("annotate(id = {:?}, attrs = {:?})", def_id, attrs);
 
-        let depr = attr::find_deprecation(self.tcx.sess, self.tcx.features(), attrs);
+        let depr = attr::find_attr!(attrs, AttributeKind::Deprecation{deprecation, span} => (*deprecation, *span));
+        let const_stability_indirect = find_attr!(attrs, AttributeKind::ConstStabilityIndirect);
+
         let mut is_deprecated = false;
         if let Some((depr, span)) = &depr {
             is_deprecated = true;
@@ -154,9 +156,10 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
                 if inherit_deprecation.yes() && stab.is_unstable() {
                     self.index.stab_map.insert(def_id, stab);
                     if fn_sig.is_some_and(|s| s.header.is_const()) {
-                        let const_stab =
-                            attr::unmarked_crate_const_stab(self.tcx.sess, attrs, stab);
-                        self.index.const_stab_map.insert(def_id, const_stab);
+                        self.index.const_stab_map.insert(
+                            def_id,
+                            ConstStability::unmarked(const_stability_indirect, stab),
+                        );
                     }
                 }
             }
@@ -171,9 +174,9 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
         }
 
         // # Regular and body stability
-
-        let stab = attr::find_stability(self.tcx.sess, attrs, item_sp);
-        let body_stab = attr::find_body_stability(self.tcx.sess, attrs);
+        let stab = attr::find_attr!(attrs, AttributeKind::Stability { stability, span } => (*stability, *span));
+        let body_stab =
+            attr::find_attr!(attrs, AttributeKind::BodyStability { stability, .. } => *stability);
 
         if let Some((depr, span)) = &depr
             && depr.is_since_rustc_version()
@@ -182,7 +185,7 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             self.tcx.dcx().emit_err(errors::DeprecatedAttribute { span: *span });
         }
 
-        if let Some((body_stab, _span)) = body_stab {
+        if let Some(body_stab) = body_stab {
             // FIXME: check that this item can have body stability
 
             self.index.default_body_stab_map.insert(def_id, body_stab);
@@ -260,10 +263,10 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
 
         // # Const stability
 
-        let const_stab = attr::find_const_stability(self.tcx.sess, attrs, item_sp);
+        let const_stab = attr::find_attr!(attrs, AttributeKind::ConstStability { stability, span } => (*stability, *span));
 
         // If the current node is a function with const stability attributes (directly given or
-        // implied), check if the function/method is const.
+        // implied), check if the function/method is const or the parent impl block is const.
         if let Some(fn_sig) = fn_sig
             && !fn_sig.header.is_const()
             && const_stab.is_some()
@@ -285,7 +288,7 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
         // Stable *language* features shouldn't be used as unstable library features.
         // (Not doing this for stable library features is checked by tidy.)
         if let Some((
-            ConstStability { level: StabilityLevel::Unstable { .. }, feature, .. },
+            PartialConstStability { level: StabilityLevel::Unstable { .. }, feature, .. },
             const_span,
         )) = const_stab
         {
@@ -297,9 +300,17 @@ impl<'a, 'tcx> Annotator<'a, 'tcx> {
             }
         }
 
+        if let Some((stab, span)) = &const_stab
+            && stab.is_const_stable()
+            && const_stability_indirect
+        {
+            self.tcx.dcx().emit_err(errors::RustcConstStableIndirectPairing { span: *span });
+        }
+
         // After checking the immediate attributes, get rid of the span and compute implied
         // const stability: inherit feature gate from regular stability.
-        let mut const_stab = const_stab.map(|(stab, _span)| stab);
+        let mut const_stab = const_stab
+            .map(|(stab, _span)| ConstStability::from_partial(stab, const_stability_indirect));
 
         // If this is a const fn but not annotated with stability markers, see if we can inherit regular stability.
         if fn_sig.is_some_and(|s| s.header.is_const())  && const_stab.is_none() &&
@@ -785,8 +796,10 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> {
                 let features = self.tcx.features();
                 if features.staged_api() {
                     let attrs = self.tcx.hir().attrs(item.hir_id());
-                    let stab = attr::find_stability(self.tcx.sess, attrs, item.span);
-                    let const_stab = attr::find_const_stability(self.tcx.sess, attrs, item.span);
+                    let stab = attr::find_attr!(attrs, AttributeKind::Stability{stability, span} => (*stability, *span));
+
+                    // FIXME(jdonszelmann): make it impossible to miss the or_else in the typesystem
+                    let const_stab = attr::find_attr!(attrs, AttributeKind::ConstStability{stability, ..} => *stability);
 
                     // If this impl block has an #[unstable] attribute, give an
                     // error if all involved types and traits are stable, because
@@ -817,7 +830,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'tcx> {
                     // needs to have an error emitted.
                     if features.const_trait_impl()
                         && self.tcx.is_const_trait_impl(item.owner_id.to_def_id())
-                        && const_stab.is_some_and(|(stab, _)| stab.is_const_stable())
+                        && const_stab.is_some_and(|stab| stab.is_const_stable())
                     {
                         self.tcx.dcx().emit_err(errors::TraitImplConstStable { span: item.span });
                     }
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index 41725d0c6a4..5271d03a6f6 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -22,6 +22,7 @@ use errors::{
 };
 use rustc_ast::MacroDef;
 use rustc_ast::visit::{VisitorResult, try_visit};
+use rustc_attr_parsing::AttributeKind;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_data_structures::intern::Interned;
 use rustc_errors::{MultiSpan, listify};
@@ -493,7 +494,11 @@ impl<'tcx> EmbargoVisitor<'tcx> {
         // Non-opaque macros cannot make other items more accessible than they already are.
         let hir_id = self.tcx.local_def_id_to_hir_id(local_def_id);
         let attrs = self.tcx.hir().attrs(hir_id);
-        if attr::find_transparency(attrs, md.macro_rules).0 != Transparency::Opaque {
+
+        if attr::find_attr!(attrs, AttributeKind::MacroTransparency(x) => *x)
+            .unwrap_or(Transparency::fallback(md.macro_rules))
+            != Transparency::Opaque
+        {
             return;
         }
 
diff --git a/compiler/rustc_resolve/src/def_collector.rs b/compiler/rustc_resolve/src/def_collector.rs
index 5eb8e420fa4..b050aabe225 100644
--- a/compiler/rustc_resolve/src/def_collector.rs
+++ b/compiler/rustc_resolve/src/def_collector.rs
@@ -3,6 +3,7 @@ use std::mem;
 use rustc_ast::visit::FnKind;
 use rustc_ast::*;
 use rustc_ast_pretty::pprust;
+use rustc_attr_parsing::{AttributeParser, OmitDoc};
 use rustc_expand::expand::AstFragment;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind};
@@ -132,8 +133,19 @@ impl<'a, 'ra, 'tcx> visit::Visitor<'a> for DefCollector<'a, 'ra, 'tcx> {
             ItemKind::Fn(..) | ItemKind::Delegation(..) => DefKind::Fn,
             ItemKind::MacroDef(def) => {
                 let edition = i.span.edition();
+
+                // FIXME(jdonszelmann) make one of these in the resolver?
+                // FIXME(jdonszelmann) don't care about tools here maybe? Just parse what we can.
+                // Does that prevents errors from happening? maybe
+                let parser = AttributeParser::new(
+                    &self.resolver.tcx.sess,
+                    self.resolver.tcx.features(),
+                    Vec::new(),
+                );
+                let attrs = parser.parse_attribute_list(&i.attrs, i.span, OmitDoc::Skip);
+
                 let macro_data =
-                    self.resolver.compile_macro(def, i.ident, &i.attrs, i.span, i.id, edition);
+                    self.resolver.compile_macro(def, i.ident, &attrs, i.span, i.id, edition);
                 let macro_kind = macro_data.ext.macro_kind();
                 opt_macro_data = Some(macro_data);
                 DefKind::Macro(macro_kind)
diff --git a/compiler/rustc_resolve/src/macros.rs b/compiler/rustc_resolve/src/macros.rs
index a70def2f6c9..984dfff3ea5 100644
--- a/compiler/rustc_resolve/src/macros.rs
+++ b/compiler/rustc_resolve/src/macros.rs
@@ -5,7 +5,6 @@ use std::cell::Cell;
 use std::mem;
 use std::sync::Arc;
 
-use rustc_ast::attr::AttributeExt;
 use rustc_ast::expand::StrippedCfgItem;
 use rustc_ast::{self as ast, Crate, NodeId, attr};
 use rustc_ast_pretty::pprust;
@@ -1112,7 +1111,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
         &mut self,
         macro_def: &ast::MacroDef,
         ident: Ident,
-        attrs: &[impl AttributeExt],
+        attrs: &[rustc_hir::Attribute],
         span: Span,
         node_id: NodeId,
         edition: Edition,
diff --git a/compiler/rustc_sanitizers/Cargo.toml b/compiler/rustc_sanitizers/Cargo.toml
index 66488bc9625..900cd4243b1 100644
--- a/compiler/rustc_sanitizers/Cargo.toml
+++ b/compiler/rustc_sanitizers/Cargo.toml
@@ -8,6 +8,7 @@ bitflags = "2.5.0"
 tracing = "0.1"
 twox-hash = "1.6.3"
 rustc_abi = { path = "../rustc_abi" }
+rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_middle = { path = "../rustc_middle" }
diff --git a/compiler/rustc_span/src/hygiene.rs b/compiler/rustc_span/src/hygiene.rs
index 9bf1d305e54..84e89ff4b7d 100644
--- a/compiler/rustc_span/src/hygiene.rs
+++ b/compiler/rustc_span/src/hygiene.rs
@@ -175,6 +175,12 @@ pub enum Transparency {
     Opaque,
 }
 
+impl Transparency {
+    pub fn fallback(macro_rules: bool) -> Self {
+        if macro_rules { Transparency::SemiTransparent } else { Transparency::Opaque }
+    }
+}
+
 impl LocalExpnId {
     /// The ID of the theoretical expansion that generates freshly parsed, unexpanded AST.
     pub const ROOT: LocalExpnId = LocalExpnId::ZERO;
diff --git a/compiler/rustc_symbol_mangling/Cargo.toml b/compiler/rustc_symbol_mangling/Cargo.toml
index 12fe6b719f9..90ddf4c8a04 100644
--- a/compiler/rustc_symbol_mangling/Cargo.toml
+++ b/compiler/rustc_symbol_mangling/Cargo.toml
@@ -9,6 +9,7 @@ punycode = "0.4.0"
 rustc-demangle = "0.1.21"
 
 rustc_abi = { path = "../rustc_abi" }
+rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
 rustc_hashes = { path = "../rustc_hashes" }
diff --git a/tests/ui/feature-gates/feature-gate-fn_align.rs b/tests/ui/feature-gates/feature-gate-fn_align.rs
index 06784a45d76..744877704dd 100644
--- a/tests/ui/feature-gates/feature-gate-fn_align.rs
+++ b/tests/ui/feature-gates/feature-gate-fn_align.rs
@@ -4,6 +4,6 @@
 fn requires_alignment() {}
 
 trait MyTrait {
-    #[repr(align)] //~ ERROR `repr(align)` attributes on functions are unstable
+    #[repr(align)] //~ ERROR invalid `repr(align)` attribute: `align` needs an argument
     fn myfun();
 }
diff --git a/tests/ui/feature-gates/feature-gate-fn_align.stderr b/tests/ui/feature-gates/feature-gate-fn_align.stderr
index cd9900c6051..ff17c29fe02 100644
--- a/tests/ui/feature-gates/feature-gate-fn_align.stderr
+++ b/tests/ui/feature-gates/feature-gate-fn_align.stderr
@@ -1,3 +1,9 @@
+error[E0589]: invalid `repr(align)` attribute: `align` needs an argument
+  --> $DIR/feature-gate-fn_align.rs:7:12
+   |
+LL |     #[repr(align)]
+   |            ^^^^^ help: supply an argument here: `align(...)`
+
 error[E0658]: `repr(align)` attributes on functions are unstable
   --> $DIR/feature-gate-fn_align.rs:3:8
    |
@@ -8,16 +14,7 @@ LL | #[repr(align(16))]
    = help: add `#![feature(fn_align)]` to the crate attributes to enable
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
 
-error[E0658]: `repr(align)` attributes on functions are unstable
-  --> $DIR/feature-gate-fn_align.rs:7:12
-   |
-LL |     #[repr(align)]
-   |            ^^^^^
-   |
-   = note: see issue #82232 <https://github.com/rust-lang/rust/issues/82232> for more information
-   = help: add `#![feature(fn_align)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0658`.
+Some errors have detailed explanations: E0589, E0658.
+For more information about an error, try `rustc --explain E0589`.