Auto merge of #131808 - jdonszelmann:hir-attributes, r=oli-obk,petrochenkov

Hir attributes

This PR needs some explanation, it's somewhat large.

- This is step one as described in https://github.com/rust-lang/compiler-team/issues/796. I've added a new `hir::Attribute` which is a lowered version of `ast::Attribute`. Right now, this has few concrete effects, however every place that after this PR parses a `hir::Attribute` should later get a pre-parsed attribute as described in https://github.com/rust-lang/compiler-team/issues/796 and transitively https://github.com/rust-lang/rust/issues/131229.
- an extension trait `AttributeExt` is added, which is implemented for both `ast::Attribute` and `hir::Atribute`. This makes `hir::Attributes` mostly compatible with code that used to parse `ast::Attribute`. All its methods are also added as inherent methods to avoid having to import the trait everywhere in the compiler.
  - Incremental can not not hash `ast::Attribute` at all.

1 files changed, 10 insertions, 18 deletions

diff --git a/compiler/rustc_query_system/src/ich/impls_syntax.rs b/compiler/rustc_query_system/src/ich/impls_syntax.rs
index 5a72e80a0a5..480fd497728 100644
--- a/compiler/rustc_query_system/src/ich/impls_syntax.rs
+++ b/compiler/rustc_query_system/src/ich/impls_syntax.rs
@@ -1,18 +1,17 @@
 //! This module contains `HashStable` implementations for various data types
-//! from `rustc_ast` in no particular order.
+//! from various crates in no particular order.
 
-use std::assert_matches::assert_matches;
-
-use rustc_ast as ast;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_hir as hir;
 use rustc_span::SourceFile;
 use smallvec::SmallVec;
 
 use crate::ich::StableHashingContext;
 
 impl<'ctx> rustc_target::HashStableContext for StableHashingContext<'ctx> {}
+impl<'ctx> rustc_ast::HashStableContext for StableHashingContext<'ctx> {}
 
-impl<'a> HashStable<StableHashingContext<'a>> for [ast::Attribute] {
+impl<'a> HashStable<StableHashingContext<'a>> for [hir::Attribute] {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
         if self.is_empty() {
             self.len().hash_stable(hcx, hasher);
@@ -20,7 +19,7 @@ impl<'a> HashStable<StableHashingContext<'a>> for [ast::Attribute] {
         }
 
         // Some attributes are always ignored during hashing.
-        let filtered: SmallVec<[&ast::Attribute; 8]> = self
+        let filtered: SmallVec<[&hir::Attribute; 8]> = self
             .iter()
             .filter(|attr| {
                 !attr.is_doc_comment()
@@ -35,30 +34,23 @@ impl<'a> HashStable<StableHashingContext<'a>> for [ast::Attribute] {
     }
 }
 
-impl<'ctx> rustc_ast::HashStableContext for StableHashingContext<'ctx> {
-    fn hash_attr(&mut self, attr: &ast::Attribute, hasher: &mut StableHasher) {
+impl<'ctx> rustc_hir::HashStableContext for StableHashingContext<'ctx> {
+    fn hash_attr(&mut self, attr: &hir::Attribute, hasher: &mut StableHasher) {
         // Make sure that these have been filtered out.
         debug_assert!(!attr.ident().is_some_and(|ident| self.is_ignored_attr(ident.name)));
         debug_assert!(!attr.is_doc_comment());
 
-        let ast::Attribute { kind, id: _, style, span } = attr;
-        if let ast::AttrKind::Normal(normal) = kind {
-            normal.item.hash_stable(self, hasher);
+        let hir::Attribute { kind, id: _, style, span } = attr;
+        if let hir::AttrKind::Normal(item) = kind {
+            item.hash_stable(self, hasher);
             style.hash_stable(self, hasher);
             span.hash_stable(self, hasher);
-            assert_matches!(
-                normal.tokens.as_ref(),
-                None,
-                "Tokens should have been removed during lowering!"
-            );
         } else {
             unreachable!();
         }
     }
 }
 
-impl<'ctx> rustc_hir::HashStableContext for StableHashingContext<'ctx> {}
-
 impl<'a> HashStable<StableHashingContext<'a>> for SourceFile {
     fn hash_stable(&self, hcx: &mut StableHashingContext<'a>, hasher: &mut StableHasher) {
         let SourceFile {