diff --git a/compiler/rustc_codegen_cranelift/src/lib.rs b/compiler/rustc_codegen_cranelift/src/lib.rs
index 170750461cace..1480ab2513378 100644
--- a/compiler/rustc_codegen_cranelift/src/lib.rs
+++ b/compiler/rustc_codegen_cranelift/src/lib.rs
@@ -5,8 +5,7 @@
     associated_type_bounds,
     never_type,
     try_blocks,
-    hash_drain_filter,
-    str_split_once
+    hash_drain_filter
 )]
 #![warn(rust_2018_idioms)]
 #![warn(unused_lifetimes)]
diff --git a/compiler/rustc_mir/src/lib.rs b/compiler/rustc_mir/src/lib.rs
index 8b3881ef9de10..508510a81e1fb 100644
--- a/compiler/rustc_mir/src/lib.rs
+++ b/compiler/rustc_mir/src/lib.rs
@@ -28,7 +28,6 @@ Rust MIR: a lowered representation of Rust.
 #![feature(or_patterns)]
 #![feature(once_cell)]
 #![feature(control_flow_enum)]
-#![feature(str_split_once)]
 #![recursion_limit = "256"]
 
 #[macro_use]
diff --git a/compiler/rustc_session/src/lib.rs b/compiler/rustc_session/src/lib.rs
index 36bf8634c6eec..d002f59739166 100644
--- a/compiler/rustc_session/src/lib.rs
+++ b/compiler/rustc_session/src/lib.rs
@@ -1,7 +1,6 @@
 #![feature(crate_visibility_modifier)]
 #![feature(once_cell)]
 #![feature(or_patterns)]
-#![feature(str_split_once)]
 
 #[macro_use]
 extern crate bitflags;
diff --git a/compiler/rustc_span/src/lib.rs b/compiler/rustc_span/src/lib.rs
index 4b03d38ccba5b..4dce029e86b50 100644
--- a/compiler/rustc_span/src/lib.rs
+++ b/compiler/rustc_span/src/lib.rs
@@ -22,7 +22,6 @@
 #![feature(nll)]
 #![feature(min_specialization)]
 #![feature(option_expect_none)]
-#![feature(str_split_once)]
 
 #[macro_use]
 extern crate rustc_macros;
diff --git a/compiler/rustc_target/src/lib.rs b/compiler/rustc_target/src/lib.rs
index 1ad57582ebafb..fb747dfcbd337 100644
--- a/compiler/rustc_target/src/lib.rs
+++ b/compiler/rustc_target/src/lib.rs
@@ -15,7 +15,6 @@
 #![feature(never_type)]
 #![feature(associated_type_bounds)]
 #![feature(exhaustive_patterns)]
-#![feature(str_split_once)]
 
 #[macro_use]
 extern crate rustc_macros;
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index dd98f806451d8..9c92d96dc7059 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -6,7 +6,6 @@
 #![feature(exact_size_is_empty)]
 #![feature(new_uninit)]
 #![feature(pattern)]
-#![feature(str_split_once)]
 #![feature(trusted_len)]
 #![feature(try_reserve)]
 #![feature(unboxed_closures)]
diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs
index 6a35378ca7b50..50ccc2a2eaba1 100644
--- a/library/core/src/str/mod.rs
+++ b/library/core/src/str/mod.rs
@@ -1506,13 +1506,11 @@ impl str {
     /// # Examples
     ///
     /// ```
-    /// #![feature(str_split_once)]
-    ///
     /// assert_eq!("cfg".split_once('='), None);
     /// assert_eq!("cfg=foo".split_once('='), Some(("cfg", "foo")));
     /// assert_eq!("cfg=foo=bar".split_once('='), Some(("cfg", "foo=bar")));
     /// ```
-    #[unstable(feature = "str_split_once", reason = "newly added", issue = "74773")]
+    #[stable(feature = "str_split_once", since = "1.52.0")]
     #[inline]
     pub fn split_once<'a, P: Pattern<'a>>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)> {
         let (start, end) = delimiter.into_searcher(self).next_match()?;
@@ -1525,13 +1523,11 @@ impl str {
     /// # Examples
     ///
     /// ```
-    /// #![feature(str_split_once)]
-    ///
     /// assert_eq!("cfg".rsplit_once('='), None);
     /// assert_eq!("cfg=foo".rsplit_once('='), Some(("cfg", "foo")));
     /// assert_eq!("cfg=foo=bar".rsplit_once('='), Some(("cfg=foo", "bar")));
     /// ```
-    #[unstable(feature = "str_split_once", reason = "newly added", issue = "74773")]
+    #[stable(feature = "str_split_once", since = "1.52.0")]
     #[inline]
     pub fn rsplit_once<'a, P>(&'a self, delimiter: P) -> Option<(&'a str, &'a str)>
     where
diff --git a/library/std/src/lib.rs b/library/std/src/lib.rs
index 32aca8c83924d..63b65d8b41383 100644
--- a/library/std/src/lib.rs
+++ b/library/std/src/lib.rs
@@ -314,7 +314,6 @@
 #![feature(stdsimd)]
 #![feature(stmt_expr_attributes)]
 #![feature(str_internals)]
-#![feature(str_split_once)]
 #![feature(test)]
 #![feature(thread_local)]
 #![feature(thread_local_internals)]
diff --git a/library/test/src/lib.rs b/library/test/src/lib.rs
index f9e65be9b0d40..3415eaa9fb345 100644
--- a/library/test/src/lib.rs
+++ b/library/test/src/lib.rs
@@ -31,7 +31,6 @@
 #![feature(termination_trait_lib)]
 #![feature(test)]
 #![feature(total_cmp)]
-#![feature(str_split_once)]
 
 // Public reexports
 pub use self::bench::{black_box, Bencher};
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index d7978c4a0228d..2342ed3ab670d 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -14,7 +14,6 @@
 #![feature(never_type)]
 #![feature(once_cell)]
 #![feature(type_ascription)]
-#![feature(str_split_once)]
 #![feature(iter_intersperse)]
 #![recursion_limit = "256"]
 #![deny(rustc::internal)]
diff --git a/src/tools/linkchecker/main.rs b/src/tools/linkchecker/main.rs
index 1ab3aead966db..01e067ea0b803 100644
--- a/src/tools/linkchecker/main.rs
+++ b/src/tools/linkchecker/main.rs
@@ -14,7 +14,7 @@
 //! A few exceptions are allowed as there's known bugs in rustdoc, but this
 //! should catch the majority of "broken link" cases.
 
-#![feature(str_split_once)]
+#![cfg_attr(bootstrap, feature(str_split_once))]
 
 use std::collections::hash_map::Entry;
 use std::collections::{HashMap, HashSet};
diff --git a/src/tools/tidy/src/lib.rs b/src/tools/tidy/src/lib.rs
index 27972c4992442..11d36751f67bb 100644
--- a/src/tools/tidy/src/lib.rs
+++ b/src/tools/tidy/src/lib.rs
@@ -3,7 +3,7 @@
 //! This library contains the tidy lints and exposes it
 //! to be used by tools.
 
-#![feature(str_split_once)]
+#![cfg_attr(bootstrap, feature(str_split_once))]
 
 use std::fs::File;
 use std::io::Read;