1 files changed, 5 insertions, 3 deletions
diff --git a/src/libsyntax_ext/deriving/custom.rs b/src/libsyntax_ext/deriving/custom.rs
index a7e2d82bb97..b01ef65e5fe 100644
--- a/src/libsyntax_ext/deriving/custom.rs
+++ b/src/libsyntax_ext/deriving/custom.rs
@@ -23,9 +23,11 @@ struct MarkAttrs<'a>(&'a [ast::Name]);
 
 impl<'a> Visitor<'a> for MarkAttrs<'a> {
     fn visit_attribute(&mut self, attr: &Attribute) {
-        if self.0.contains(&attr.name()) {
-            mark_used(attr);
-            mark_known(attr);
+        if let Some(name) = attr.name() {
+            if self.0.contains(&name) {
+                mark_used(attr);
+                mark_known(attr);
+            }
         }
     }