diff --git a/src/librustc_data_structures/indexed_vec.rs b/src/librustc_data_structures/indexed_vec.rs
index 19528a14038..753f12f400b 100644
--- a/src/librustc_data_structures/indexed_vec.rs
+++ b/src/librustc_data_structures/indexed_vec.rs
@@ -327,7 +327,7 @@ macro_rules! newtype_index {
 #[derive(Clone, PartialEq, Eq)]
 pub struct IndexVec<I: Idx, T> {
     pub raw: Vec<T>,
-    _marker: PhantomData<Fn(&I)>
+    _marker: PhantomData<fn(&I)>
 }
 
 // Whether `IndexVec` is `Send` depends only on the data,