Auto merge of #457 - serde-rs:phantom, r=oli-obk

Impl Deserialize for PhantomData<T> for all T

serde/src/de/impls.rs

@@ -356,7 +356,7 @@ pub struct PhantomDataVisitor<T> {
     marker: PhantomData<T>,
 }
 
-impl<T> Visitor for PhantomDataVisitor<T> where T: Deserialize {
+impl<T> Visitor for PhantomDataVisitor<T> {
     type Value = PhantomData<T>;
 
     #[inline]
@@ -367,7 +367,7 @@ impl<T> Visitor for PhantomDataVisitor<T> where T: Deserialize {
     }
 }
 
-impl<T> Deserialize for PhantomData<T> where T: Deserialize {
+impl<T> Deserialize for PhantomData<T> {
     fn deserialize<D>(deserializer: &mut D) -> Result<PhantomData<T>, D::Error>
         where D: Deserializer,
     {

testing/tests/test_gen.rs

@@ -6,6 +6,8 @@ extern crate serde;
 use self::serde::ser::{Serialize, Serializer};
 use self::serde::de::{Deserialize, Deserializer};
 
+use std::marker::PhantomData;
+
 //////////////////////////////////////////////////////////////////////////
 
 #[derive(Serialize, Deserialize)]
@@ -23,6 +25,11 @@ struct WithRef<'a, T: 'a> {
     x: X,
 }
 
+#[derive(Serialize, Deserialize)]
+struct PhantomX {
+    x: PhantomData<X>,
+}
+
 #[derive(Serialize, Deserialize)]
 struct Bounds<T: Serialize + Deserialize> {
     t: T,