Auto merge of #98457 - japaric:gh98378, r=m-ou-se

make Condvar, Mutex, RwLock const constructors work with the `unsupported` impl

applying this patch locally to the `rust-src` component fixes #98378

however, the solution seems wrong to me because PR #97791 didn't add any `rustc_const_stable` attribute to underlying implementations like `std::sys::unix::futex`, so I must be missing something about how const-stability is checked ... maybe the `restricted_std` feature (gate?) has an effect?

fixes #98378
fixes #98293 (probably)

4 files changed, 4 insertions, 0 deletions

diff --git a/library/std/src/sys_common/condvar.rs b/library/std/src/sys_common/condvar.rs
index f3ac1061b89..8bc5b24115d 100644
--- a/library/std/src/sys_common/condvar.rs
+++ b/library/std/src/sys_common/condvar.rs
@@ -15,6 +15,7 @@ pub struct Condvar {
 impl Condvar {
     /// Creates a new condition variable for use.
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Self {
         Self { inner: imp::MovableCondvar::new(), check: CondvarCheck::new() }
     }
diff --git a/library/std/src/sys_common/condvar/check.rs b/library/std/src/sys_common/condvar/check.rs
index ce8f3670487..4ac9e62bf86 100644
--- a/library/std/src/sys_common/condvar/check.rs
+++ b/library/std/src/sys_common/condvar/check.rs
@@ -50,6 +50,7 @@ pub struct NoCheck;
 
 #[allow(dead_code)]
 impl NoCheck {
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Self {
         Self
     }
diff --git a/library/std/src/sys_common/mutex.rs b/library/std/src/sys_common/mutex.rs
index 48479f5bdb3..7b9f7ef5487 100644
--- a/library/std/src/sys_common/mutex.rs
+++ b/library/std/src/sys_common/mutex.rs
@@ -61,6 +61,7 @@ unsafe impl Sync for MovableMutex {}
 impl MovableMutex {
     /// Creates a new mutex.
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Self {
         Self(imp::MovableMutex::new())
     }
diff --git a/library/std/src/sys_common/rwlock.rs b/library/std/src/sys_common/rwlock.rs
index 36d721fcbcb..042981dac60 100644
--- a/library/std/src/sys_common/rwlock.rs
+++ b/library/std/src/sys_common/rwlock.rs
@@ -15,6 +15,7 @@ pub struct MovableRwLock(imp::MovableRwLock);
 impl MovableRwLock {
     /// Creates a new reader-writer lock for use.
     #[inline]
+    #[rustc_const_stable(feature = "const_locks", since = "1.63.0")]
     pub const fn new() -> Self {
         Self(imp::MovableRwLock::new())
     }