Auto merge of #53604 - oli-obk:min_const_fn, r=Centril,varkor

Implement the `min_const_fn` feature gate

cc @RalfJung @eddyb

r? @Centril

implements the feature gate for #53555

I added a hack so the `const_fn` feature gate also enables the `min_const_fn` feature gate. This ensures that nightly users of `const_fn` don't have to touch their code at all.

The `min_const_fn` checks are run first, and if they succeeded, the `const_fn` checks are run additionally to ensure we didn't miss anything.

2 files changed, 10 insertions, 6 deletions

diff --git a/src/libstd/sys/cloudabi/condvar.rs b/src/libstd/sys/cloudabi/condvar.rs
index c05c837ade2..ccf848a9be4 100644
--- a/src/libstd/sys/cloudabi/condvar.rs
+++ b/src/libstd/sys/cloudabi/condvar.rs
@@ -28,11 +28,13 @@ pub struct Condvar {
 unsafe impl Send for Condvar {}
 unsafe impl Sync for Condvar {}
 
+const NEW: Condvar = Condvar {
+    condvar: UnsafeCell::new(AtomicU32::new(abi::CONDVAR_HAS_NO_WAITERS.0)),
+};
+
 impl Condvar {
     pub const fn new() -> Condvar {
-        Condvar {
-            condvar: UnsafeCell::new(AtomicU32::new(abi::CONDVAR_HAS_NO_WAITERS.0)),
-        }
+        NEW
     }
 
     pub unsafe fn init(&mut self) {}
diff --git a/src/libstd/sys/cloudabi/rwlock.rs b/src/libstd/sys/cloudabi/rwlock.rs
index 8539aec5e2c..dc8624ec8a1 100644
--- a/src/libstd/sys/cloudabi/rwlock.rs
+++ b/src/libstd/sys/cloudabi/rwlock.rs
@@ -32,11 +32,13 @@ pub unsafe fn raw(r: &RWLock) -> *mut AtomicU32 {
 unsafe impl Send for RWLock {}
 unsafe impl Sync for RWLock {}
 
+const NEW: RWLock = RWLock {
+    lock: UnsafeCell::new(AtomicU32::new(abi::LOCK_UNLOCKED.0)),
+};
+
 impl RWLock {
     pub const fn new() -> RWLock {
-        RWLock {
-            lock: UnsafeCell::new(AtomicU32::new(abi::LOCK_UNLOCKED.0)),
-        }
+        NEW
     }
 
     pub unsafe fn try_read(&self) -> bool {