3 files changed, 25 insertions, 10 deletions

diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index e3ac8a8784a..43b429f6947 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -120,6 +120,12 @@ impl Path {
     pub fn is_global(&self) -> bool {
         !self.segments.is_empty() && self.segments[0].ident.name == kw::PathRoot
     }
+
+    /// If this path is a single identifier with no arguments, does not ensure
+    /// that the path resolves to a const param, the caller should check this.
+    pub fn is_potential_trivial_const_arg(&self) -> bool {
+        self.segments.len() == 1 && self.segments[0].args.is_none()
+    }
 }
 
 /// A segment of a path: an identifier, an optional lifetime, and a set of types.
@@ -1154,7 +1160,9 @@ impl Expr {
     ///
     /// If this is not the case, name resolution does not resolve `N` when using
     /// `min_const_generics` as more complex expressions are not supported.
-    pub fn is_potential_trivial_const_param(&self) -> bool {
+    ///
+    /// Does not ensure that the path resolves to a const param, the caller should check this.
+    pub fn is_potential_trivial_const_arg(&self) -> bool {
         let this = if let ExprKind::Block(block, None) = &self.kind
             && block.stmts.len() == 1
             && let StmtKind::Expr(expr) = &block.stmts[0].kind
@@ -1165,8 +1173,7 @@ impl Expr {
         };
 
         if let ExprKind::Path(None, path) = &this.kind
-            && path.segments.len() == 1
-            && path.segments[0].args.is_none()
+            && path.is_potential_trivial_const_arg()
         {
             true
         } else {
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index f0a6a5e0725..db296aa44db 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -48,14 +48,15 @@ pub enum TokenTree {
     Delimited(DelimSpan, Delimiter, TokenStream),
 }
 
-// Ensure all fields of `TokenTree` is `Send` and `Sync`.
+// Ensure all fields of `TokenTree` are `DynSend` and `DynSync`.
 #[cfg(parallel_compiler)]
 fn _dummy()
 where
-    Token: Send + Sync,
-    DelimSpan: Send + Sync,
-    Delimiter: Send + Sync,
-    TokenStream: Send + Sync,
+    Token: sync::DynSend + sync::DynSync,
+    Spacing: sync::DynSend + sync::DynSync,
+    DelimSpan: sync::DynSend + sync::DynSync,
+    Delimiter: sync::DynSend + sync::DynSync,
+    TokenStream: sync::DynSend + sync::DynSync,
 {
 }
 
@@ -118,7 +119,7 @@ where
     }
 }
 
-pub trait ToAttrTokenStream: sync::Send + sync::Sync {
+pub trait ToAttrTokenStream: sync::DynSend + sync::DynSync {
     fn to_attr_token_stream(&self) -> AttrTokenStream;
 }
 
@@ -550,6 +551,10 @@ impl TokenStream {
             vec_mut.extend(stream_iter);
         }
     }
+
+    pub fn chunks(&self, chunk_size: usize) -> core::slice::Chunks<'_, TokenTree> {
+        self.0.chunks(chunk_size)
+    }
 }
 
 /// By-reference iterator over a [`TokenStream`], that produces `&TokenTree`
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 1526ffa0b03..275692ad5dd 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -188,6 +188,9 @@ pub trait Visitor<'ast>: Sized {
     fn visit_variant(&mut self, v: &'ast Variant) {
         walk_variant(self, v)
     }
+    fn visit_variant_discr(&mut self, discr: &'ast AnonConst) {
+        self.visit_anon_const(discr);
+    }
     fn visit_label(&mut self, label: &'ast Label) {
         walk_label(self, label)
     }
@@ -380,7 +383,7 @@ where
     visitor.visit_ident(variant.ident);
     visitor.visit_vis(&variant.vis);
     visitor.visit_variant_data(&variant.data);
-    walk_list!(visitor, visit_anon_const, &variant.disr_expr);
+    walk_list!(visitor, visit_variant_discr, &variant.disr_expr);
     walk_list!(visitor, visit_attribute, &variant.attrs);
 }