3 files changed, 7 insertions, 9 deletions
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index b64f7b8ad1b..9e6a186219b 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -2473,9 +2473,7 @@ rustc_index::newtype_index! {
 }
 
 impl<S: Encoder> rustc_serialize::Encodable<S> for AttrId {
-    fn encode(&self, _s: &mut S) -> Result<(), S::Error> {
-        Ok(())
-    }
+    fn encode(&self, _s: &mut S) {}
 }
 
 impl<D: Decoder> rustc_serialize::Decodable<D> for AttrId {
diff --git a/compiler/rustc_ast/src/ptr.rs b/compiler/rustc_ast/src/ptr.rs
index bab85a3019d..30481eddf91 100644
--- a/compiler/rustc_ast/src/ptr.rs
+++ b/compiler/rustc_ast/src/ptr.rs
@@ -121,8 +121,8 @@ impl<D: Decoder, T: 'static + Decodable<D>> Decodable<D> for P<T> {
 }
 
 impl<S: Encoder, T: Encodable<S>> Encodable<S> for P<T> {
-    fn encode(&self, s: &mut S) -> Result<(), S::Error> {
-        (**self).encode(s)
+    fn encode(&self, s: &mut S) {
+        (**self).encode(s);
     }
 }
 
@@ -191,8 +191,8 @@ impl<'a, T> IntoIterator for &'a P<[T]> {
 }
 
 impl<S: Encoder, T: Encodable<S>> Encodable<S> for P<[T]> {
-    fn encode(&self, s: &mut S) -> Result<(), S::Error> {
-        Encodable::encode(&**self, s)
+    fn encode(&self, s: &mut S) {
+        Encodable::encode(&**self, s);
     }
 }
 
diff --git a/compiler/rustc_ast/src/tokenstream.rs b/compiler/rustc_ast/src/tokenstream.rs
index c58fe7287bf..84d8829c398 100644
--- a/compiler/rustc_ast/src/tokenstream.rs
+++ b/compiler/rustc_ast/src/tokenstream.rs
@@ -142,9 +142,9 @@ impl fmt::Debug for LazyTokenStream {
 }
 
 impl<S: Encoder> Encodable<S> for LazyTokenStream {
-    fn encode(&self, s: &mut S) -> Result<(), S::Error> {
+    fn encode(&self, s: &mut S) {
         // Used by AST json printing.
-        Encodable::encode(&self.create_token_stream(), s)
+        Encodable::encode(&self.create_token_stream(), s);
     }
 }