diff --git a/RELEASES.md b/RELEASES.md
index c4b36ed988bd2..d8d284ca1fa87 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -359,7 +359,7 @@ Language
 - [`addr_of(_mut)!` macros and the newly stabilized `&raw (const|mut)` are now safe to use with all static items](https://github.com/rust-lang/rust/pull/125834)
 - [size_of_val_raw: for length 0 this is safe to call](https://github.com/rust-lang/rust/pull/126152/)
 - [Reorder trait bound modifiers *after* `for<...>` binder in trait bounds](https://github.com/rust-lang/rust/pull/127054/)
-- [Stabilize opaque type precise capturing (RFC 3617)](https://github.com/rust-lang/rust/pull/127672)
+- [Stabilize `+ use<'lt>` opaque type precise capturing (RFC 3617)](https://github.com/rust-lang/rust/pull/127672)
 - [Stabilize `&raw const` and `&raw mut` operators (RFC 2582)](https://github.com/rust-lang/rust/pull/127679)
 - [Stabilize unsafe extern blocks (RFC 3484)](https://github.com/rust-lang/rust/pull/127921)
 - [Stabilize nested field access in `offset_of!`](https://github.com/rust-lang/rust/pull/128284)
diff --git a/library/std/src/os/fd/raw.rs b/library/std/src/os/fd/raw.rs
index 22f5528248a32..03dff94350dad 100644
--- a/library/std/src/os/fd/raw.rs
+++ b/library/std/src/os/fd/raw.rs
@@ -19,11 +19,9 @@ use crate::sys_common::{AsInner, IntoInner};
 use crate::{fs, io};
 
 /// Raw file descriptors.
-#[rustc_allowed_through_unstable_modules]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg(not(target_os = "hermit"))]
 pub type RawFd = raw::c_int;
-#[rustc_allowed_through_unstable_modules]
 #[stable(feature = "rust1", since = "1.0.0")]
 #[cfg(target_os = "hermit")]
 pub type RawFd = i32;
@@ -33,7 +31,6 @@ pub type RawFd = i32;
 /// This is only available on unix and WASI platforms and must be imported in
 /// order to call the method. Windows platforms have a corresponding
 /// `AsRawHandle` and `AsRawSocket` set of traits.
-#[rustc_allowed_through_unstable_modules]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub trait AsRawFd {
     /// Extracts the raw file descriptor.
@@ -67,7 +64,6 @@ pub trait AsRawFd {
 
 /// A trait to express the ability to construct an object from a raw file
 /// descriptor.
-#[rustc_allowed_through_unstable_modules]
 #[stable(feature = "from_raw_os", since = "1.1.0")]
 pub trait FromRawFd {
     /// Constructs a new instance of `Self` from the given raw file
@@ -112,7 +108,6 @@ pub trait FromRawFd {
 
 /// A trait to express the ability to consume an object and acquire ownership of
 /// its raw file descriptor.
-#[rustc_allowed_through_unstable_modules]
 #[stable(feature = "into_raw_os", since = "1.4.0")]
 pub trait IntoRawFd {
     /// Consumes this object, returning the raw underlying file descriptor.
diff --git a/library/std/src/os/wasi/io/fd.rs b/library/std/src/os/wasi/io/fd.rs
deleted file mode 100644
index 930aca887e3c4..0000000000000
--- a/library/std/src/os/wasi/io/fd.rs
+++ /dev/null
@@ -1,9 +0,0 @@
-//! Owned and borrowed file descriptors.
-
-#![unstable(feature = "wasi_ext", issue = "71213")]
-
-// Tests for this module
-#[cfg(test)]
-mod tests;
-
-pub use crate::os::fd::owned::*;
diff --git a/library/std/src/os/wasi/io/mod.rs b/library/std/src/os/wasi/io/mod.rs
index 4e123a1eec8ae..5f9a735db085e 100644
--- a/library/std/src/os/wasi/io/mod.rs
+++ b/library/std/src/os/wasi/io/mod.rs
@@ -4,3 +4,7 @@
 
 #[stable(feature = "io_safety_wasi", since = "1.65.0")]
 pub use crate::os::fd::*;
+
+// Tests for this module
+#[cfg(test)]
+mod tests;
diff --git a/library/std/src/os/wasi/io/raw.rs b/library/std/src/os/wasi/io/raw.rs
deleted file mode 100644
index da3b36adad409..0000000000000
--- a/library/std/src/os/wasi/io/raw.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-//! WASI-specific extensions to general I/O primitives.
-
-#![unstable(feature = "wasi_ext", issue = "71213")]
-
-// NOTE: despite the fact that this module is unstable,
-// stable Rust had the capability to access the stable
-// re-exported items from os::fd::raw through this
-// unstable module.
-// In PR #95956 the stability checker was changed to check
-// all path segments of an item rather than just the last,
-// which caused the aforementioned stable usage to regress
-// (see issue #99502).
-// As a result, the items in os::fd::raw were given the
-// rustc_allowed_through_unstable_modules attribute.
-// No regression tests were added to ensure this property,
-// as CI is not configured to test wasm32-wasi.
-// If this module is stabilized,
-// you may want to remove those attributes
-// (assuming no other unstable modules need them).
-pub use crate::os::fd::raw::*;
diff --git a/library/std/src/os/wasi/io/fd/tests.rs b/library/std/src/os/wasi/io/tests.rs
similarity index 100%
rename from library/std/src/os/wasi/io/fd/tests.rs
rename to library/std/src/os/wasi/io/tests.rs
diff --git a/library/std/src/rt.rs b/library/std/src/rt.rs
index 384369b0012b5..3a22a16cb165e 100644
--- a/library/std/src/rt.rs
+++ b/library/std/src/rt.rs
@@ -32,9 +32,14 @@ use crate::{mem, panic, sys};
 // - nothing (so this macro is a no-op)
 macro_rules! rtprintpanic {
     ($($t:tt)*) => {
+        #[cfg(not(feature = "panic_immediate_abort"))]
         if let Some(mut out) = crate::sys::stdio::panic_output() {
             let _ = crate::io::Write::write_fmt(&mut out, format_args!($($t)*));
         }
+        #[cfg(feature = "panic_immediate_abort")]
+        {
+            let _ = format_args!($($t)*);
+        }
     }
 }
 
diff --git a/src/bootstrap/defaults/config.compiler.toml b/src/bootstrap/defaults/config.compiler.toml
index a737de3bd0856..269b90106e3aa 100644
--- a/src/bootstrap/defaults/config.compiler.toml
+++ b/src/bootstrap/defaults/config.compiler.toml
@@ -8,6 +8,8 @@ compiler-docs = true
 # where adding `debug!()` appears to do nothing.
 # However, it makes running the compiler slightly slower.
 debug-logging = true
+# Enables debug assertions, which guard from many mistakes when working on the compiler.
+debug-assertions = true
 # Get actually-useful information from backtraces, profiling, etc. with minimal added bytes
 debuginfo-level = "line-tables-only"
 # This greatly increases the speed of rebuilds, especially when there are only minor changes. However, it makes the initial build slightly slower.
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index 1c49063ef5c66..b5310108dbf70 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -2875,21 +2875,26 @@ impl Config {
             allowed_paths.push(":!library");
         }
 
-        // Look for a version to compare to based on the current commit.
-        // Only commits merged by bors will have CI artifacts.
-        let commit = match self.last_modified_commit(&allowed_paths, "download-rustc", if_unchanged)
-        {
-            Some(commit) => commit,
-            None => {
-                if if_unchanged {
-                    return None;
+        let commit = if self.rust_info.is_managed_git_subrepository() {
+            // Look for a version to compare to based on the current commit.
+            // Only commits merged by bors will have CI artifacts.
+            match self.last_modified_commit(&allowed_paths, "download-rustc", if_unchanged) {
+                Some(commit) => commit,
+                None => {
+                    if if_unchanged {
+                        return None;
+                    }
+                    println!("ERROR: could not find commit hash for downloading rustc");
+                    println!("HELP: maybe your repository history is too shallow?");
+                    println!("HELP: consider setting `rust.download-rustc=false` in config.toml");
+                    println!("HELP: or fetch enough history to include one upstream commit");
+                    crate::exit!(1);
                 }
-                println!("ERROR: could not find commit hash for downloading rustc");
-                println!("HELP: maybe your repository history is too shallow?");
-                println!("HELP: consider setting `rust.download-rustc=false` in config.toml");
-                println!("HELP: or fetch enough history to include one upstream commit");
-                crate::exit!(1);
             }
+        } else {
+            channel::read_commit_info_file(&self.src)
+                .map(|info| info.sha.trim().to_owned())
+                .expect("git-commit-info is missing in the project root")
         };
 
         if CiEnv::is_ci() && {
@@ -2971,6 +2976,11 @@ impl Config {
         option_name: &str,
         if_unchanged: bool,
     ) -> Option<String> {
+        assert!(
+            self.rust_info.is_managed_git_subrepository(),
+            "Can't run `Config::last_modified_commit` on a non-git source."
+        );
+
         // Look for a version to compare to based on the current commit.
         // Only commits merged by bors will have CI artifacts.
         let commit = get_closest_merge_commit(Some(&self.src), &self.git_config(), &[]).unwrap();
diff --git a/src/bootstrap/src/utils/change_tracker.rs b/src/bootstrap/src/utils/change_tracker.rs
index 85d17c8fa5077..a3eb781f1476a 100644
--- a/src/bootstrap/src/utils/change_tracker.rs
+++ b/src/bootstrap/src/utils/change_tracker.rs
@@ -335,4 +335,9 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         severity: ChangeSeverity::Warning,
         summary: "Some stamp names in the build artifacts may have changed slightly (e.g., from `llvm-finished-building` to `.llvm-stamp`).",
     },
+    ChangeInfo {
+        change_id: 135729,
+        severity: ChangeSeverity::Info,
+        summary: "Change the compiler profile to default to rust.debug-assertions = true",
+    },
 ];
diff --git a/tests/rustdoc-ui/doctest/doctest-no-run-invalid-langstring-124577.rs b/tests/rustdoc-ui/doctest/doctest-no-run-invalid-langstring-124577.rs
index 571bc94e30f98..db2ccefb0fb1f 100644
--- a/tests/rustdoc-ui/doctest/doctest-no-run-invalid-langstring-124577.rs
+++ b/tests/rustdoc-ui/doctest/doctest-no-run-invalid-langstring-124577.rs
@@ -1,4 +1,5 @@
 //@ compile-flags:--test
+//@ normalize-stdout: "finished in \d+\.\d+s" -> "finished in $$TIME"
 //@ check-pass
 #![allow(rustdoc::invalid_codeblock_attributes)]
 
diff --git a/tests/rustdoc-ui/doctest/doctest-no-run-invalid-langstring-124577.stdout b/tests/rustdoc-ui/doctest/doctest-no-run-invalid-langstring-124577.stdout
index e5c27bebbdb23..7326c0a25a069 100644
--- a/tests/rustdoc-ui/doctest/doctest-no-run-invalid-langstring-124577.stdout
+++ b/tests/rustdoc-ui/doctest/doctest-no-run-invalid-langstring-124577.stdout
@@ -1,5 +1,5 @@
 
 running 0 tests
 
-test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
+test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in $TIME