diff --git a/src/librustc/hir/map/definitions.rs b/src/librustc/hir/map/definitions.rs
index 5993a97c40d..40a51b92473 100644
--- a/src/librustc/hir/map/definitions.rs
+++ b/src/librustc/hir/map/definitions.rs
@@ -53,7 +53,7 @@ impl DefPathTable {
 
     #[inline(always)]
     pub fn def_key(&self, index: DefIndex) -> DefKey {
-        self.index_to_key[index.index()].clone()
+        self.index_to_key[index.index()]
     }
 
     #[inline(always)]
@@ -111,7 +111,7 @@ pub struct Definitions {
 /// A unique identifier that we can use to lookup a definition
 /// precisely. It combines the index of the definition's parent (if
 /// any) with a `DisambiguatedDefPathData`.
-#[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable)]
+#[derive(Copy, Clone, PartialEq, Debug, RustcEncodable, RustcDecodable)]
 pub struct DefKey {
     /// The parent path.
     pub parent: Option<DefIndex>,
@@ -164,7 +164,7 @@ impl DefKey {
 /// between them. This introduces some artificial ordering dependency
 /// but means that if you have, e.g., two impls for the same type in
 /// the same module, they do get distinct `DefId`s.
-#[derive(Clone, PartialEq, Debug, RustcEncodable, RustcDecodable)]
+#[derive(Copy, Clone, PartialEq, Debug, RustcEncodable, RustcDecodable)]
 pub struct DisambiguatedDefPathData {
     pub data: DefPathData,
     pub disambiguator: u32
@@ -277,7 +277,7 @@ impl DefPath {
     }
 }
 
-#[derive(Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
 pub enum DefPathData {
     // Root: these should only be used for the root nodes, because
     // they are treated specially by the `def_path` function.
@@ -472,7 +472,7 @@ impl Definitions {
 
         // Find the next free disambiguator for this key.
         let disambiguator = {
-            let next_disamb = self.next_disambiguator.entry((parent, data.clone())).or_insert(0);
+            let next_disamb = self.next_disambiguator.entry((parent, data)).or_insert(0);
             let disambiguator = *next_disamb;
             *next_disamb = next_disamb.checked_add(1).expect("disambiguator overflow");
             disambiguator