diff --git a/container/src/lib.rs b/container/src/lib.rs
index c11340026..8323b72ae 100644
--- a/container/src/lib.rs
+++ b/container/src/lib.rs
@@ -50,7 +50,7 @@ pub trait Container: Default + Clone + 'static {
     type DrainIter<'a>: Iterator<Item=Self::Item<'a>>;
 
     /// Returns an iterator that drains the contents of this container.
-    // TODO: What invariants should hold after `drain` returns?
+    /// Drain leaves the container in an undefined state.
     fn drain<'a>(&'a mut self) -> Self::DrainIter<'a>;
 }
 
@@ -63,6 +63,10 @@ pub trait PushInto<C> {
 /// A type that has the necessary infrastructure to push elements, without specifying how pushing
 /// itself works. For this, pushable types should implement [`PushInto`].
 pub trait PushContainer: Container {
+    /// Push `item` into self
+    fn push<T: PushInto<Self>>(&mut self, item: T) {
+        item.push_into(self)
+    }
     /// Return the capacity of the container.
     fn capacity(&self) -> usize;
     /// Return the preferred capacity of the container.
@@ -91,10 +95,10 @@ impl<T: Clone + 'static> Container for Vec<T> {
         self.as_slice().iter()
     }
 
-    type DrainIter<'a> = <Vec<T> as IntoIterator>::IntoIter;
+    type DrainIter<'a> = std::vec::Drain<'a, T>;
 
-    fn drain<'a>(&'a mut self) -> Self::DrainIter<'a> {
-        IntoIterator::into_iter(std::mem::take(self))
+    fn drain(&mut self) -> Self::DrainIter<'_> {
+        self.drain(..)
     }
 }
 
@@ -235,7 +239,7 @@ impl<T: PushContainer + 'static> PushPartitioned for T where for<'a> T::Item<'a>
         for datum in self.drain() {
             let index = index(&datum);
             ensure_capacity(&mut buffers[index]);
-            datum.push_into(&mut buffers[index]);
+            buffers[index].push(datum);
             if buffers[index].len() == buffers[index].capacity() {
                 flush(index, &mut buffers[index]);
             }
diff --git a/timely/examples/wordcount_flatcontainer.rs b/timely/examples/wordcount_flatcontainer.rs
index ef4f34557..1b81d9305 100644
--- a/timely/examples/wordcount_flatcontainer.rs
+++ b/timely/examples/wordcount_flatcontainer.rs
@@ -3,7 +3,7 @@ extern crate timely;
 use std::collections::HashMap;
 
 use timely::dataflow::{InputHandle, ProbeHandle};
-use timely::dataflow::operators::containers::Map;
+use timely::dataflow::operators::core::Map;
 use timely::dataflow::operators::{Operator, Inspect, Probe};
 use timely::dataflow::channels::pact::ExchangeCore;
 use timely_container::flatcontainer::{Containerized, FlatStack};
diff --git a/timely/src/dataflow/channels/pact.rs b/timely/src/dataflow/channels/pact.rs
index cfce8bbc2..b73076c7c 100644
--- a/timely/src/dataflow/channels/pact.rs
+++ b/timely/src/dataflow/channels/pact.rs
@@ -75,7 +75,7 @@ where
 // Exchange uses a `Box<Pushable>` because it cannot know what type of pushable will return from the allocator.
 impl<T: Timestamp, C, H: 'static> ParallelizationContractCore<T, C> for ExchangeCore<C, H>
 where
-    C: Data + Container + PushPartitioned,
+    C: Data + PushPartitioned,
     for<'a> H: FnMut(&C::Item<'a>) -> u64
 {
     type Pusher = ExchangePusher<T, C, LogPusher<T, C, Box<dyn Push<BundleCore<T, C>>>>, H>;
diff --git a/timely/src/dataflow/channels/pushers/buffer.rs b/timely/src/dataflow/channels/pushers/buffer.rs
index 21da8e610..4ec5c9bb2 100644
--- a/timely/src/dataflow/channels/pushers/buffer.rs
+++ b/timely/src/dataflow/channels/pushers/buffer.rs
@@ -82,7 +82,7 @@ impl<T, C: Container, P: Push<BundleCore<T, C>>> BufferCore<T, C, P> where T: Eq
     }
 }
 
-impl<T, C: Container + PushContainer, P: Push<BundleCore<T, C>>> BufferCore<T, C, P> where T: Eq+Clone {
+impl<T, C: PushContainer, P: Push<BundleCore<T, C>>> BufferCore<T, C, P> where T: Eq+Clone {
     // internal method for use by `Session`.
     #[inline]
     fn give<D: PushInto<C>>(&mut self, data: D) {
@@ -124,7 +124,7 @@ impl<'a, T, C: Container, P: Push<BundleCore<T, C>>+'a> Session<'a, T, C, P>  wh
     }
 }
 
-impl<'a, T, C: Container + PushContainer, P: Push<BundleCore<T, C>>+'a> Session<'a, T, C, P>  where T: Eq+Clone+'a, C: 'a {
+impl<'a, T, C: PushContainer, P: Push<BundleCore<T, C>>+'a> Session<'a, T, C, P>  where T: Eq+Clone+'a, C: 'a {
     /// Provides one record at the time specified by the `Session`.
     #[inline]
     pub fn give<D: PushInto<C>>(&mut self, data: D) {
diff --git a/timely/src/dataflow/operators/broadcast.rs b/timely/src/dataflow/operators/broadcast.rs
index a1d6f2378..4013f332f 100644
--- a/timely/src/dataflow/operators/broadcast.rs
+++ b/timely/src/dataflow/operators/broadcast.rs
@@ -2,8 +2,7 @@
 
 use crate::ExchangeData;
 use crate::dataflow::{Scope, Stream};
-use crate::dataflow::operators::containers::Map;
-use crate::dataflow::operators::{Exchange};
+use crate::dataflow::operators::{Map, Exchange};
 
 /// Broadcast records to all workers.
 pub trait Broadcast<C: ExchangeData> {
diff --git a/timely/src/dataflow/operators/containers/map.rs b/timely/src/dataflow/operators/core/map.rs
similarity index 96%
rename from timely/src/dataflow/operators/containers/map.rs
rename to timely/src/dataflow/operators/core/map.rs
index 2f50b91f5..d7d467a33 100644
--- a/timely/src/dataflow/operators/containers/map.rs
+++ b/timely/src/dataflow/operators/core/map.rs
@@ -11,7 +11,7 @@ pub trait Map<S: Scope, C: Container> {
     ///
     /// # Examples
     /// ```
-    /// use timely::dataflow::operators::containers::Map;
+    /// use timely::dataflow::operators::core::Map;
     /// use timely::dataflow::operators::{ToStream, Inspect};
     ///
     /// timely::example(|scope| {
@@ -27,7 +27,7 @@ pub trait Map<S: Scope, C: Container> {
     ///
     /// # Examples
     /// ```
-    /// use timely::dataflow::operators::containers::Map;
+    /// use timely::dataflow::operators::core::Map;
     /// use timely::dataflow::operators::{ToStream, Inspect};
     ///
     /// timely::example(|scope| {
diff --git a/timely/src/dataflow/operators/containers/mod.rs b/timely/src/dataflow/operators/core/mod.rs
similarity index 100%
rename from timely/src/dataflow/operators/containers/mod.rs
rename to timely/src/dataflow/operators/core/mod.rs
diff --git a/timely/src/dataflow/operators/mod.rs b/timely/src/dataflow/operators/mod.rs
index 99ac633a2..adf4e4a30 100644
--- a/timely/src/dataflow/operators/mod.rs
+++ b/timely/src/dataflow/operators/mod.rs
@@ -34,7 +34,7 @@ pub use self::generic::{Notificator, FrontierNotificator};
 pub use self::reclock::Reclock;
 pub use self::count::Accumulate;
 
-pub mod containers;
+pub mod core;
 
 pub mod enterleave;
 pub mod input;