From fab206bf5852c532f85b9ad30f9eea8fc952e8e1 Mon Sep 17 00:00:00 2001
From: cyrgani <ansgar.w.zielke@gmail.com>
Date: Sat, 24 May 2025 22:33:11 +0200
Subject: [PATCH] make `OsString::new` and `PathBuf::new` unstably const

---
 library/std/src/ffi/os_str.rs       | 3 ++-
 library/std/src/path.rs             | 3 ++-
 library/std/src/sys/os_str/bytes.rs | 2 +-
 library/std/src/sys/os_str/wtf8.rs  | 2 +-
 library/std/src/sys_common/wtf8.rs  | 2 +-
 5 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/library/std/src/ffi/os_str.rs b/library/std/src/ffi/os_str.rs
index ead4877512727..22308224a2f86 100644
--- a/library/std/src/ffi/os_str.rs
+++ b/library/std/src/ffi/os_str.rs
@@ -137,7 +137,8 @@ impl OsString {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
     #[inline]
-    pub fn new() -> OsString {
+    #[rustc_const_unstable(feature = "const_pathbuf_osstring_new", issue = "141520")]
+    pub const fn new() -> OsString {
         OsString { inner: Buf::from_string(String::new()) }
     }
 
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index 7959c63385816..3e347798ab998 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -1191,7 +1191,8 @@ impl PathBuf {
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
     #[inline]
-    pub fn new() -> PathBuf {
+    #[rustc_const_unstable(feature = "const_pathbuf_osstring_new", issue = "141520")]
+    pub const fn new() -> PathBuf {
         PathBuf { inner: OsString::new() }
     }
 
diff --git a/library/std/src/sys/os_str/bytes.rs b/library/std/src/sys/os_str/bytes.rs
index 4a8808c923045..f8ab4543a3a52 100644
--- a/library/std/src/sys/os_str/bytes.rs
+++ b/library/std/src/sys/os_str/bytes.rs
@@ -115,7 +115,7 @@ impl Buf {
     }
 
     #[inline]
-    pub fn from_string(s: String) -> Buf {
+    pub const fn from_string(s: String) -> Buf {
         Buf { inner: s.into_bytes() }
     }
 
diff --git a/library/std/src/sys/os_str/wtf8.rs b/library/std/src/sys/os_str/wtf8.rs
index 5174ea65d0cd9..4207a2db635fa 100644
--- a/library/std/src/sys/os_str/wtf8.rs
+++ b/library/std/src/sys/os_str/wtf8.rs
@@ -92,7 +92,7 @@ impl Buf {
     }
 
     #[inline]
-    pub fn from_string(s: String) -> Buf {
+    pub const fn from_string(s: String) -> Buf {
         Buf { inner: Wtf8Buf::from_string(s) }
     }
 
diff --git a/library/std/src/sys_common/wtf8.rs b/library/std/src/sys_common/wtf8.rs
index f9ec112b19747..50bde88b5a4c3 100644
--- a/library/std/src/sys_common/wtf8.rs
+++ b/library/std/src/sys_common/wtf8.rs
@@ -209,7 +209,7 @@ impl Wtf8Buf {
     ///
     /// Since WTF-8 is a superset of UTF-8, this always succeeds.
     #[inline]
-    pub fn from_string(string: String) -> Wtf8Buf {
+    pub const fn from_string(string: String) -> Wtf8Buf {
         Wtf8Buf { bytes: string.into_bytes(), is_known_utf8: true }
     }