Rollup merge of #87389 - Aaron1011:expand-known-attrs, r=wesleywiser

Rename `known_attrs` to `expanded_inert_attrs` and move to rustc_expand

There's no need for this to be (untracked) global state.

2 files changed, 8 insertions, 2 deletions

diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index 8c6aef80635..3d5bc770c4f 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -1,6 +1,7 @@
 use crate::expand::{self, AstFragment, Invocation};
 use crate::module::DirOwnership;
 
+use rustc_ast::attr::MarkedAttrs;
 use rustc_ast::ptr::P;
 use rustc_ast::token::{self, Nonterminal};
 use rustc_ast::tokenstream::{CanSynthesizeMissingTokens, TokenStream};
@@ -951,6 +952,10 @@ pub struct ExtCtxt<'a> {
     ///
     /// `Ident` is the module name.
     pub(super) extern_mod_loaded: OnExternModLoaded<'a>,
+    /// When we 'expand' an inert attribute, we leave it
+    /// in the AST, but insert it here so that we know
+    /// not to expand it again.
+    pub(super) expanded_inert_attrs: MarkedAttrs,
 }
 
 impl<'a> ExtCtxt<'a> {
@@ -977,6 +982,7 @@ impl<'a> ExtCtxt<'a> {
             },
             force_mode: false,
             expansions: FxHashMap::default(),
+            expanded_inert_attrs: MarkedAttrs::new(),
         }
     }
 
diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs
index 03d2105e5cc..c72b1b33dbc 100644
--- a/compiler/rustc_expand/src/expand.rs
+++ b/compiler/rustc_expand/src/expand.rs
@@ -754,7 +754,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                     }
                 }
                 SyntaxExtensionKind::NonMacroAttr { mark_used } => {
-                    self.cx.sess.mark_attr_known(&attr);
+                    self.cx.expanded_inert_attrs.mark(&attr);
                     if *mark_used {
                         self.cx.sess.mark_attr_used(&attr);
                     }
@@ -1040,7 +1040,7 @@ impl<'a, 'b> InvocationCollector<'a, 'b> {
         item.visit_attrs(|attrs| {
             attr = attrs
                 .iter()
-                .position(|a| !self.cx.sess.is_attr_known(a) && !is_builtin_attr(a))
+                .position(|a| !self.cx.expanded_inert_attrs.is_marked(a) && !is_builtin_attr(a))
                 .map(|attr_pos| {
                     let attr = attrs.remove(attr_pos);
                     let following_derives = attrs[attr_pos..]