Fix msrv/no_std build errors

src/lib.rs

@@ -340,7 +340,7 @@ impl<T: Unpin> Event<T> {
 
         if let Some(inner) = self.try_inner() {
             let limit = if notify.is_additional() {
-                usize::MAX
+                core::usize::MAX
             } else {
                 notify.count()
             };
@@ -942,6 +942,7 @@ impl<T> State<T> {
     }
 
     /// If this state was notified, return the tag associated with the notification.
+    #[allow(unused)]
     fn notified(self) -> Option<T> {
         match self {
             Self::Notified { tag, .. } => Some(tag),

src/no_std.rs

@@ -31,6 +31,7 @@ use core::num::NonZeroUsize;
 use core::ops;
 use core::pin::Pin;
 
+use alloc::boxed::Box;
 use alloc::vec::Vec;
 
 impl<T: Unpin> crate::Inner<T> {

src/notify.rs

@@ -323,8 +323,8 @@ macro_rules! impl_for_numeric_types {
             type Tag = ();
             type Notify = Notify;
 
+            #[allow(unused_comparisons)]
             fn into_notification(self) -> Self::Notify {
-                #[allow(unused_comparisons)]
                 if self < 0 {
                     panic!("negative notification count");
                 }