Encode hir attributes cross-crate properly

Cargo.lock

@@ -3724,6 +3724,7 @@ dependencies = [
 name = "rustc_feature"
 version = "0.0.0"
 dependencies = [
+ "rustc_attr_data_structures",
  "rustc_data_structures",
  "rustc_span",
  "serde",

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -0,0 +1,31 @@
+use crate::AttributeKind;
+
+#[derive(PartialEq)]
+pub enum EncodeCrossCrate {
+    Yes,
+    No,
+}
+
+impl AttributeKind {
+    pub fn encode_cross_crate(&self) -> EncodeCrossCrate {
+        use AttributeKind::*;
+        use EncodeCrossCrate::*;
+
+        match self {
+            Align { .. } => No,
+            AllowConstFnUnstable(..) => No,
+            AllowInternalUnstable(..) => Yes,
+            AsPtr(..) => Yes,
+            BodyStability { .. } => No,
+            Confusables { .. } => Yes,
+            ConstStability { .. } => Yes,
+            ConstStabilityIndirect => No,
+            Deprecation { .. } => Yes,
+            DocComment { .. } => Yes,
+            Inline(..) => No,
+            MacroTransparency(..) => Yes,
+            Repr(..) => No,
+            Stability { .. } => Yes,
+        }
+    }
+}

compiler/rustc_attr_data_structures/src/lib.rs

@@ -9,6 +9,7 @@
 // tidy-alphabetical-end
 
 mod attributes;
+mod encode_cross_crate;
 mod stability;
 mod version;
 
@@ -17,6 +18,7 @@ pub mod lints;
 use std::num::NonZero;
 
 pub use attributes::*;
+pub use encode_cross_crate::EncodeCrossCrate;
 use rustc_abi::Align;
 use rustc_ast::token::CommentKind;
 use rustc_ast::{AttrStyle, IntTy, UintTy};

compiler/rustc_feature/Cargo.toml

@@ -5,8 +5,9 @@ edition = "2024"
 
 [dependencies]
 # tidy-alphabetical-start
+rustc_attr_data_structures = { path = "../rustc_attr_data_structures" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_span = { path = "../rustc_span" }
-serde = { version = "1.0.125", features = [ "derive" ] }
+serde = { version = "1.0.125", features = ["derive"] }
 serde_json = "1.0.59"
 # tidy-alphabetical-end

compiler/rustc_feature/src/builtin_attrs.rs

@@ -5,6 +5,7 @@ use std::sync::LazyLock;
 use AttributeDuplicates::*;
 use AttributeGate::*;
 use AttributeType::*;
+use rustc_attr_data_structures::EncodeCrossCrate;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_span::edition::Edition;
 use rustc_span::{Symbol, sym};
@@ -368,12 +369,6 @@ macro_rules! experimental {
     };
 }
 
-#[derive(PartialEq)]
-pub enum EncodeCrossCrate {
-    Yes,
-    No,
-}
-
 pub struct BuiltinAttribute {
     pub name: Symbol,
     /// Whether this attribute is encode cross crate.

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -5,7 +5,7 @@ use std::io::{Read, Seek, Write};
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
 
-use rustc_ast::attr::AttributeExt;
+use rustc_attr_data_structures::EncodeCrossCrate;
 use rustc_data_structures::fx::{FxIndexMap, FxIndexSet};
 use rustc_data_structures::memmap::{Mmap, MmapMut};
 use rustc_data_structures::sync::{join, par_for_each_in};
@@ -824,9 +824,13 @@ struct AnalyzeAttrState<'a> {
 /// visibility: this is a piece of data that can be computed once per defid, and not once per
 /// attribute. Some attributes would only be usable downstream if they are public.
 #[inline]
-fn analyze_attr(attr: &impl AttributeExt, state: &mut AnalyzeAttrState<'_>) -> bool {
+fn analyze_attr(attr: &hir::Attribute, state: &mut AnalyzeAttrState<'_>) -> bool {
     let mut should_encode = false;
-    if let Some(name) = attr.name()
+    if let hir::Attribute::Parsed(p) = attr
+        && p.encode_cross_crate() == EncodeCrossCrate::No
+    {
+        // Attributes not marked encode-cross-crate don't need to be encoded for downstream crates.
+    } else if let Some(name) = attr.name()
         && !rustc_feature::encode_cross_crate(name)
     {
         // Attributes not marked encode-cross-crate don't need to be encoded for downstream crates.