rt: Remove `threaded_scheduler()` and `basic_scheduler()` (#2876)

Co-authored-by: Alice Ryhl <alice@ryhl.io>
Co-authored-by: Carl Lerche <me@carllerche.com>

4 files changed, 34 insertions, 8 deletions

diff --git a/tokio/src/future/block_on.rs b/tokio/src/future/block_on.rs
new file mode 100644
index 00000000..9fc7abc6
--- /dev/null
+++ b/tokio/src/future/block_on.rs
@@ -0,0 +1,15 @@
+use std::future::Future;
+
+cfg_rt_core! {
+    pub(crate) fn block_on<F: Future>(f: F) -> F::Output {
+        let mut e = crate::runtime::enter::enter(false);
+        e.block_on(f).unwrap()
+    }
+}
+
+cfg_not_rt_core! {
+    pub(crate) fn block_on<F: Future>(f: F) -> F::Output {
+        let mut park = crate::park::thread::CachedParkThread::new();
+        park.block_on(f).unwrap()
+    }
+}
diff --git a/tokio/src/future/mod.rs b/tokio/src/future/mod.rs
index 770753f3..f7d93c98 100644
--- a/tokio/src/future/mod.rs
+++ b/tokio/src/future/mod.rs
@@ -1,15 +1,24 @@
-#![allow(unused_imports, dead_code)]
+#![cfg_attr(not(feature = "macros"), allow(unreachable_pub))]
 
 //! Asynchronous values.
 
-mod maybe_done;
-pub use maybe_done::{maybe_done, MaybeDone};
+#[cfg(any(feature = "macros", feature = "process"))]
+pub(crate) mod maybe_done;
 
 mod poll_fn;
 pub use poll_fn::poll_fn;
 
-mod ready;
-pub(crate) use ready::{ok, Ready};
+cfg_not_loom! {
+    mod ready;
+    pub(crate) use ready::{ok, Ready};
+}
 
-mod try_join;
-pub(crate) use try_join::try_join3;
+cfg_process! {
+    mod try_join;
+    pub(crate) use try_join::try_join3;
+}
+
+cfg_sync! {
+    mod block_on;
+    pub(crate) use block_on::block_on;
+}
diff --git a/tokio/src/future/poll_fn.rs b/tokio/src/future/poll_fn.rs
index 9b3d1370..0169bd5f 100644
--- a/tokio/src/future/poll_fn.rs
+++ b/tokio/src/future/poll_fn.rs
@@ -1,3 +1,5 @@
+#![allow(dead_code)]
+
 //! Definition of the `PollFn` adapter combinator
 
 use std::fmt;
diff --git a/tokio/src/future/try_join.rs b/tokio/src/future/try_join.rs
index 5bd80dc8..8943f61a 100644
--- a/tokio/src/future/try_join.rs
+++ b/tokio/src/future/try_join.rs
@@ -1,4 +1,4 @@
-use crate::future::{maybe_done, MaybeDone};
+use crate::future::maybe_done::{maybe_done, MaybeDone};
 
 use pin_project_lite::pin_project;
 use std::future::Future;