diff --git a/src/librustc/middle/expr_use_visitor.rs b/src/librustc/middle/expr_use_visitor.rs
index 0273d1a76e9a..23d1617e5c65 100644
--- a/src/librustc/middle/expr_use_visitor.rs
+++ b/src/librustc/middle/expr_use_visitor.rs
@@ -274,7 +274,7 @@ enum PassArgs {
 }
 
 impl<'d,'t,'a,'tcx> ExprUseVisitor<'d,'t,'a,'tcx> {
-    pub fn new(delegate: &'d mut (Delegate<'tcx>),
+    pub fn new(delegate: &'d mut (Delegate<'tcx>+'d),
                typer: &'t infer::InferCtxt<'a, 'tcx>)
                -> ExprUseVisitor<'d,'t,'a,'tcx> where 'tcx:'a+'d
     {