Remove some Serialize trait bounds

Containers for the most part do not have any trait requirements for
iterating over them. So these bounds are unnecessary when Serializing
only.

serde/src/ser/impls.rs

@@ -184,11 +184,10 @@ where
 
 #[cfg(any(feature = "std", feature = "alloc"))]
 macro_rules! seq_impl {
-    ($ty:ident < T $(: $tbound1:ident $(+ $tbound2:ident)*)* $(, $typaram:ident : $bound:ident)* >) => {
+    ($ty:ident < T $(, $typaram:ident)* >) => {
         impl<T $(, $typaram)*> Serialize for $ty<T $(, $typaram)*>
         where
-            T: Serialize $(+ $tbound1 $(+ $tbound2)*)*,
-            $($typaram: $bound,)*
+            T: Serialize,
         {
             #[inline]
             fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
@@ -202,13 +201,13 @@ macro_rules! seq_impl {
 }
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-seq_impl!(BinaryHeap<T: Ord>);
+seq_impl!(BinaryHeap<T>);
 
 #[cfg(any(feature = "std", feature = "alloc"))]
-seq_impl!(BTreeSet<T: Ord>);
+seq_impl!(BTreeSet<T>);
 
 #[cfg(feature = "std")]
-seq_impl!(HashSet<T: Eq + Hash, H: BuildHasher>);
+seq_impl!(HashSet<T, H>);
 
 #[cfg(any(feature = "std", feature = "alloc"))]
 seq_impl!(LinkedList<T>);