1 files changed, 2 insertions, 2 deletions
diff --git a/src/libsyntax/ext/deriving/mod.rs b/src/libsyntax/ext/deriving/mod.rs
index edf29e670eb..75f763b5c38 100644
--- a/src/libsyntax/ext/deriving/mod.rs
+++ b/src/libsyntax/ext/deriving/mod.rs
@@ -45,7 +45,7 @@ pub fn expand_meta_deriving(cx: &mut ExtCtxt,
                             _span: Span,
                             mitem: &MetaItem,
                             item: &Item,
-                            push: |P<Item>|) {
+                            mut push: Box<FnMut(P<Item>)>) {
     match mitem.node {
         MetaNameValue(_, ref l) => {
             cx.span_err(l.span, "unexpected value in `deriving`");
@@ -64,7 +64,7 @@ pub fn expand_meta_deriving(cx: &mut ExtCtxt,
                     MetaWord(ref tname) => {
                         macro_rules! expand(($func:path) => ($func(cx, titem.span,
                                                                    &**titem, item,
-                                                                   |i| push(i))));
+                                                                   |i| push.call_mut((i,)))));
                         match tname.get() {
                             "Clone" => expand!(clone::expand_deriving_clone),