2 files changed, 7 insertions, 13 deletions
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index 636c26bcde0..3c231be20dc 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -57,7 +57,9 @@ impl TokenTree {
         match (self, other) {
             (TokenTree::Token(token, _), TokenTree::Token(token2, _)) => token.kind == token2.kind,
             (TokenTree::Delimited(.., delim, tts), TokenTree::Delimited(.., delim2, tts2)) => {
-                delim == delim2 && tts.eq_unspanned(tts2)
+                delim == delim2
+                    && tts.len() == tts2.len()
+                    && tts.iter().zip(tts2.iter()).all(|(a, b)| a.eq_unspanned(b))
             }
             _ => false,
         }
@@ -694,18 +696,6 @@ impl TokenStream {
         TokenStreamIter::new(self)
     }
 
-    /// Compares two `TokenStream`s, checking equality without regarding span information.
-    pub fn eq_unspanned(&self, other: &TokenStream) -> bool {
-        let mut iter1 = self.iter();
-        let mut iter2 = other.iter();
-        for (tt1, tt2) in iter::zip(&mut iter1, &mut iter2) {
-            if !tt1.eq_unspanned(tt2) {
-                return false;
-            }
-        }
-        iter1.next().is_none() && iter2.next().is_none()
-    }
-
     /// Create a token stream containing a single token with alone spacing. The
     /// spacing used for the final token in a constructed stream doesn't matter
     /// because it's never used. In practice we arbitrarily use
diff --git a/compiler/rustc_ast/src/visit.rs b/compiler/rustc_ast/src/visit.rs
index 908d9fd4bda..1f7c97380dc 100644
--- a/compiler/rustc_ast/src/visit.rs
+++ b/compiler/rustc_ast/src/visit.rs
@@ -121,6 +121,10 @@ pub enum LifetimeCtxt {
 /// explicitly, you need to override each method. (And you also need
 /// to monitor future changes to `Visitor` in case a new method with a
 /// new default implementation gets introduced.)
+///
+/// Every `walk_*` method uses deconstruction to access fields of structs and
+/// enums. This will result in a compile error if a field is added, which makes
+/// it more likely the appropriate visit call will be added for it.
 pub trait Visitor<'ast>: Sized {
     /// The result type of the `visit_*` methods. Can be either `()`,
     /// or `ControlFlow<T>`.