diff --git a/Cargo.toml b/Cargo.toml
index 1648e18..63d599a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -34,8 +34,8 @@ default = [
   "num_cpus",
   "pin-project-lite",
 ]
-docs = ["attributes", "unstable"]
-unstable = ["default", "broadcaster"]
+docs = ["attributes", "unstable", "default"]
+unstable = ["std", "broadcaster", "futures-timer"]
 attributes = ["async-attributes"]
 std = [
   "crossbeam-utils",
diff --git a/src/future/future/mod.rs b/src/future/future/mod.rs
index b3efedb..d610096 100644
--- a/src/future/future/mod.rs
+++ b/src/future/future/mod.rs
@@ -7,7 +7,6 @@ cfg_unstable! {
     mod try_join;
 
     use std::time::Duration;
-
     use delay::DelayFuture;
     use flatten::FlattenFuture;
     use crate::future::IntoFuture;
@@ -15,6 +14,9 @@ cfg_unstable! {
     use try_race::TryRace;
     use join::Join;
     use try_join::TryJoin;
+}
+
+cfg_unstable_default! {
     use crate::future::timeout::TimeoutFuture;
 }
 
@@ -149,7 +151,7 @@ extension_trait! {
         /// dbg!(a.await);
         /// # })
         /// ```
-        #[cfg(all(feature = "default", feature = "unstable"))]
+        #[cfg(feature = "unstable")]
         #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
         fn delay(self, dur: Duration) -> impl Future<Output = Self::Output> [DelayFuture<Self>]
         where
@@ -363,13 +365,13 @@ extension_trait! {
 
             # Example
             ```
-            # async_std::task::block_on(async {  
+            # async_std::task::block_on(async {
             #
             use std::time::Duration;
 
             use async_std::prelude::*;
             use async_std::future;
-            
+
             let fut = future::ready(0);
             let dur = Duration::from_millis(100);
             let res = fut.timeout(dur).await;
@@ -383,7 +385,7 @@ extension_trait! {
             # });
             ```
         "#]
-        #[cfg(any(feature = "unstable", feature = "docs"))]
+        #[cfg(any(all(feature = "default", feature = "unstable"), feature = "docs"))]
         #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
         fn timeout(self, dur: Duration) -> impl Future<Output = Self::Output> [TimeoutFuture<Self>]
             where Self: Sized
diff --git a/src/io/mod.rs b/src/io/mod.rs
index 056b05c..51c473d 100644
--- a/src/io/mod.rs
+++ b/src/io/mod.rs
@@ -321,7 +321,7 @@ cfg_default! {
     mod stdout;
 }
 
-cfg_unstable! {
+cfg_unstable_default! {
     pub use stderr::StderrLock;
     pub use stdin::StdinLock;
     pub use stdout::StdoutLock;
diff --git a/src/io/read/bytes.rs b/src/io/read/bytes.rs
index 4224524..ab92596 100644
--- a/src/io/read/bytes.rs
+++ b/src/io/read/bytes.rs
@@ -32,7 +32,7 @@ impl<T: Read + Unpin> Stream for Bytes<T> {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, default))]
 mod tests {
     use crate::io;
     use crate::prelude::*;
diff --git a/src/io/read/chain.rs b/src/io/read/chain.rs
index 335cac2..4fcdb0e 100644
--- a/src/io/read/chain.rs
+++ b/src/io/read/chain.rs
@@ -165,7 +165,7 @@ impl<T: BufRead, U: BufRead> BufRead for Chain<T, U> {
     }
 }
 
-#[cfg(test)]
+#[cfg(all(test, default))]
 mod tests {
     use crate::io;
     use crate::prelude::*;
diff --git a/src/lib.rs b/src/lib.rs
index a698c39..c9d1277 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -266,7 +266,9 @@ cfg_unstable! {
     mod option;
     mod string;
     mod collections;
+}
 
+cfg_unstable_default! {
     #[doc(inline)]
     pub use std::{write, writeln};
 }
diff --git a/src/stream/stream/count.rs b/src/stream/stream/count.rs
index ebf2a2f..1ca8aef 100644
--- a/src/stream/stream/count.rs
+++ b/src/stream/stream/count.rs
@@ -9,7 +9,7 @@ use crate::task::{Context, Poll};
 pin_project! {
     #[doc(hidden)]
     #[allow(missing_debug_implementations)]
-    #[cfg(all(feature = "default", feature = "unstable"))]
+    #[cfg(feature = "unstable")]
     #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
     pub struct CountFuture<S> {
         #[pin]
diff --git a/src/stream/stream/mod.rs b/src/stream/stream/mod.rs
index 25b3745..b98950b 100644
--- a/src/stream/stream/mod.rs
+++ b/src/stream/stream/mod.rs
@@ -355,7 +355,7 @@ extension_trait! {
             # }) }
             ```
         "#]
-        #[cfg(all(feature = "default", feature = "unstable"))]
+        #[cfg(feature = "unstable")]
         #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
         fn throttle(self, d: Duration) -> Throttle<Self>
         where
@@ -1507,7 +1507,7 @@ extension_trait! {
             # }) }
             ```
         "#]
-        #[cfg(all(feature = "default", feature = "unstable"))]
+        #[cfg(feature = "unstable")]
         #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
         fn by_ref(&mut self) -> &mut Self {
             self
diff --git a/src/stream/stream/partition.rs b/src/stream/stream/partition.rs
index 7e2caad..aaf58ac 100644
--- a/src/stream/stream/partition.rs
+++ b/src/stream/stream/partition.rs
@@ -8,7 +8,7 @@ use crate::task::{Context, Poll};
 
 pin_project! {
     #[derive(Debug)]
-    #[cfg(all(feature = "default", feature = "unstable"))]
+    #[cfg(feature = "unstable")]
     #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
     pub struct PartitionFuture<S, F, B> {
         #[pin]
diff --git a/src/stream/stream/unzip.rs b/src/stream/stream/unzip.rs
index e0832ff..cb57578 100644
--- a/src/stream/stream/unzip.rs
+++ b/src/stream/stream/unzip.rs
@@ -8,7 +8,7 @@ use crate::task::{Context, Poll};
 
 pin_project! {
     #[derive(Clone, Debug)]
-    #[cfg(all(feature = "default", feature = "unstable"))]
+    #[cfg(feature = "unstable")]
     #[cfg_attr(feature = "docs", doc(cfg(unstable)))]
     pub struct UnzipFuture<S, FromA, FromB> {
         #[pin]
diff --git a/src/utils.rs b/src/utils.rs
index 7d253b4..ef50ed0 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -19,7 +19,7 @@ pub fn abort_on_panic<T>(f: impl FnOnce() -> T) -> T {
 }
 
 /// Generates a random number in `0..n`.
-#[cfg(feature = "default")]
+#[cfg(any(feature = "unstable", feature = "default"))]
 pub fn random(n: u32) -> u32 {
     use std::cell::Cell;
     use std::num::Wrapping;
@@ -90,6 +90,18 @@ macro_rules! cfg_unstable {
     }
 }
 
+/// Declares unstable and default items.
+#[doc(hidden)]
+macro_rules! cfg_unstable_default {
+    ($($item:item)*) => {
+        $(
+            #[cfg(all(feature = "default", feature = "unstable"))]
+            #[cfg_attr(feature = "docs", doc(unstable))]
+            $item
+        )*
+    }
+}
+
 /// Declares Unix-specific items.
 #[doc(hidden)]
 macro_rules! cfg_unix {