diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8d965ae8fc..cb47588535 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -275,3 +275,28 @@ see <https://rustc-dev-guide.rust-lang.org/building/how-to-build-and-run.html>.
 
 With this, you should now have a working development setup! See
 [above](#building-and-testing-miri) for how to proceed working on Miri.
+
+
+### Fetching the latest changes from the rustc repo
+
+Run the josh proxy locally
+
+```
+docker run -p 8000:8000 -e JOSH_REMOTE=https://github.com -v josh-vol:/data/git joshproject/josh-proxy:latest
+```
+
+Register the josh proxy as a remote
+
+```
+git remote add josh http://localhost:8000/rust-lang/rust.git:/src/tools/miri.git
+```
+
+Fetch (takes ca 5-10 min the first time)
+
+```
+git fetch josh
+git checkout josh/master
+git switch -c josh_sync
+```
+
+Now push `josh_sync` to your own miri fork and open a PR with it.
diff --git a/cargo-miri/src/main.rs b/cargo-miri/src/main.rs
index 331c4c9c2b..da891ef077 100644
--- a/cargo-miri/src/main.rs
+++ b/cargo-miri/src/main.rs
@@ -1,3 +1,4 @@
+#![cfg_attr(bootstrap, feature(let_else))]
 #![allow(clippy::useless_format, clippy::derive_partial_eq_without_eq, rustc::internal)]
 
 #[macro_use]
diff --git a/rust-version b/rust-version
index 78b9a110aa..7a76ff7339 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-acb8934fd57b3c2740c4abac0a5728c2c9b1423b
+21265dd0d209e7b682f249a3a45034f02d32650b
diff --git a/src/lib.rs b/src/lib.rs
index 0fe21c9243..401b03fe7b 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -10,6 +10,7 @@
 #![feature(is_some_with)]
 #![feature(nonzero_ops)]
 #![feature(local_key_cell_methods)]
+#![cfg_attr(bootstrap, feature(let_else))]
 // Configure clippy and other lints
 #![allow(
     clippy::collapsible_else_if,
diff --git a/tests/fail/concurrency/windows_join_detached.stderr b/tests/fail/concurrency/windows_join_detached.stderr
index 78c75611d3..20f34cf104 100644
--- a/tests/fail/concurrency/windows_join_detached.stderr
+++ b/tests/fail/concurrency/windows_join_detached.stderr
@@ -8,7 +8,7 @@ LL |         let rc = unsafe { c::WaitForSingleObject(self.handle.as_raw_handle(
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
    = note: BACKTRACE:
    = note: inside `std::sys::PLATFORM::thread::Thread::join` at RUSTLIB/std/src/sys/PLATFORM/thread.rs:LL:CC
-   = note: inside `std::thread::JoinInner::<()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
+   = note: inside `std::thread::JoinInner::<'_, ()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
    = note: inside `std::thread::JoinHandle::<()>::join` at RUSTLIB/std/src/thread/mod.rs:LL:CC
 note: inside `main` at $DIR/windows_join_detached.rs:LL:CC
   --> $DIR/windows_join_detached.rs:LL:CC
diff --git a/tests/pass/issues/issue-miri-2433.rs b/tests/pass/issues/issue-miri-2433.rs
new file mode 100644
index 0000000000..a8281d30ba
--- /dev/null
+++ b/tests/pass/issues/issue-miri-2433.rs
@@ -0,0 +1,24 @@
+#![feature(type_alias_impl_trait)]
+
+trait T {
+    type Item;
+}
+
+type Alias<'a> = impl T<Item = &'a ()>;
+
+struct S;
+impl<'a> T for &'a S {
+    type Item = &'a ();
+}
+
+fn filter_positive<'a>() -> Alias<'a> {
+    &S
+}
+
+fn with_positive(fun: impl Fn(Alias<'_>)) {
+    fun(filter_positive());
+}
+
+fn main() {
+    with_positive(|_| ());
+}