diff --git a/compiler/rustc_serialize/src/collection_impls.rs b/compiler/rustc_serialize/src/collection_impls.rs
index 439641400d5..38f6b402fc5 100644
--- a/compiler/rustc_serialize/src/collection_impls.rs
+++ b/compiler/rustc_serialize/src/collection_impls.rs
@@ -82,7 +82,7 @@ fn decode(d: &mut D) -> BTreeMap<K, V> {
             let mut map = BTreeMap::new();
             for _ in 0..len {
                 let key = Decodable::decode(d);
-                let val = d.read_map_elt_val(|d| Decodable::decode(d));
+                let val = Decodable::decode(d);
                 map.insert(key, val);
             }
             map
@@ -148,7 +148,7 @@ fn decode(d: &mut D) -> HashMap<K, V, S> {
             let mut map = HashMap::with_capacity_and_hasher(len, state);
             for _ in 0..len {
                 let key = Decodable::decode(d);
-                let val = d.read_map_elt_val(|d| Decodable::decode(d));
+                let val = Decodable::decode(d);
                 map.insert(key, val);
             }
             map
@@ -227,7 +227,7 @@ fn decode(d: &mut D) -> indexmap::IndexMap<K, V, S> {
             let mut map = indexmap::IndexMap::with_capacity_and_hasher(len, state);
             for _ in 0..len {
                 let key = Decodable::decode(d);
-                let val = d.read_map_elt_val(|d| Decodable::decode(d));
+                let val = Decodable::decode(d);
                 map.insert(key, val);
             }
             map
diff --git a/compiler/rustc_serialize/src/serialize.rs b/compiler/rustc_serialize/src/serialize.rs
index 53ab6eda6f1..3d87bea5868 100644
--- a/compiler/rustc_serialize/src/serialize.rs
+++ b/compiler/rustc_serialize/src/serialize.rs
@@ -225,14 +225,6 @@ fn read_map<T, F>(&mut self, f: F) -> T
         let len = self.read_usize();
         f(self, len)
     }
-
-    #[inline]
-    fn read_map_elt_val<T, F>(&mut self, f: F) -> T
-    where
-        F: FnOnce(&mut Self) -> T,
-    {
-        f(self)
-    }
 }
 
 /// Trait for types that can be serialized