diff --git a/src/iter/macros.rs b/src/iter/macros.rs
index f4282496..18a265d9 100644
--- a/src/iter/macros.rs
+++ b/src/iter/macros.rs
@@ -79,8 +79,15 @@ $fieldname: $innertype,
 .or_else(|| self.$fieldname.next().map(Into::<AstNode>::into))
 ),*
             }
+
+            fn size_hint(&self) -> (usize, Option<usize>) {
+                let size = self.$firstfieldname.len()$( + self.$fieldname.len() ),*;
+                (size, Some(size))
+            }
         }
 
+        impl<'r, 's> ExactSizeIterator for $itertype<'r, 's> {}
+
         impl<'r, 's> IntoIterator for &'r $astnodetype {
             type Item = AstNode<'r, 's>;