diff --git a/library/std/src/thread/mod.rs b/library/std/src/thread/mod.rs
index e7944c715ed6..2a155ce31173 100644
--- a/library/std/src/thread/mod.rs
+++ b/library/std/src/thread/mod.rs
@@ -1407,6 +1407,15 @@ impl<T> JoinHandle<T> {
     pub fn join(mut self) -> Result<T> {
         self.0.join()
     }
+
+    /// Checks if the the associated thread is still running its main function.
+    ///
+    /// This might return `false` for a brief moment after the thread's main
+    /// function has returned, but before the thread itself has stopped running.
+    #[unstable(feature = "thread_is_running", issue = "90470")]
+    pub fn is_running(&self) -> bool {
+        Arc::strong_count(&self.0.packet.0) > 1
+    }
 }
 
 impl<T> AsInner<imp::Thread> for JoinHandle<T> {
diff --git a/library/std/src/thread/tests.rs b/library/std/src/thread/tests.rs
index 16ad366fc126..ca0d88135a5d 100644
--- a/library/std/src/thread/tests.rs
+++ b/library/std/src/thread/tests.rs
@@ -2,9 +2,13 @@ use super::Builder;
 use crate::any::Any;
 use crate::mem;
 use crate::result;
-use crate::sync::mpsc::{channel, Sender};
+use crate::sync::{
+    mpsc::{channel, Sender},
+    Arc, Barrier,
+};
 use crate::thread::{self, ThreadId};
 use crate::time::Duration;
+use crate::time::Instant;
 
 // !!! These tests are dangerous. If something is buggy, they will hang, !!!
 // !!! instead of exiting cleanly. This might wedge the buildbots.       !!!
@@ -46,6 +50,36 @@ fn test_run_basic() {
     rx.recv().unwrap();
 }
 
+#[test]
+fn test_is_running() {
+    let b = Arc::new(Barrier::new(2));
+    let t = thread::spawn({
+        let b = b.clone();
+        move || {
+            b.wait();
+            1234
+        }
+    });
+
+    // Thread is definitely running here, since it's still waiting for the barrier.
+    assert_eq!(t.is_running(), true);
+
+    // Unblock the barrier.
+    b.wait();
+
+    // Now check that t.is_running() becomes false within a reasonable time.
+    let start = Instant::now();
+    while t.is_running() {
+        assert!(start.elapsed() < Duration::from_secs(2));
+        thread::sleep(Duration::from_millis(15));
+    }
+
+    // Joining the thread should not block for a significant time now.
+    let join_time = Instant::now();
+    assert_eq!(t.join().unwrap(), 1234);
+    assert!(join_time.elapsed() < Duration::from_secs(2));
+}
+
 #[test]
 fn test_join_panic() {
     match thread::spawn(move || panic!()).join() {
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index d5656f0f37e0..6ba1b1b6036e 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -482,6 +482,7 @@ impl<'a> Builder<'a> {
                 doc::RustByExample,
                 doc::RustcBook,
                 doc::CargoBook,
+                doc::Clippy,
                 doc::EmbeddedBook,
                 doc::EditionGuide,
             ),
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index 6f2470b706a6..2804e7119fbc 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -755,6 +755,7 @@ tool_doc!(
     "src/tools/rustfmt",
     ["rustfmt-nightly", "rustfmt-config_proc_macro"],
 );
+tool_doc!(Clippy, "clippy", "src/tools/clippy", ["clippy_utils"]);
 
 #[derive(Ord, PartialOrd, Debug, Copy, Clone, Hash, PartialEq, Eq)]
 pub struct ErrorIndex {
diff --git a/src/doc/unstable-book/src/library-features/asm.md b/src/doc/unstable-book/src/library-features/asm.md
index bd7234522e1f..6bf21e8f58b2 100644
--- a/src/doc/unstable-book/src/library-features/asm.md
+++ b/src/doc/unstable-book/src/library-features/asm.md
@@ -257,7 +257,7 @@ unsafe {
 }
 
 println!(
-    "L1 Cache: {}",
+    "L0 Cache: {}",
     ((ebx >> 22) + 1) * (((ebx >> 12) & 0x3ff) + 1) * ((ebx & 0xfff) + 1) * (ecx + 1)
 );
 ```
diff --git a/src/tools/rust-analyzer b/src/tools/rust-analyzer
index 1f47693e0280..04f03a360ab8 160000
--- a/src/tools/rust-analyzer
+++ b/src/tools/rust-analyzer
@@ -1 +1 @@
-Subproject commit 1f47693e02809c97db61b51247ae4e4d46744c61
+Subproject commit 04f03a360ab8fef3d9c0ff84de2d39b8a196c717