fix mounted information

packages/core/src/arena.rs

@@ -23,11 +23,6 @@ impl Default for MountId {
 }
 
 impl MountId {
-    pub(crate) fn new(id: usize) -> Self {
-        debug_assert_ne!(id, usize::MAX);
-        Self(id)
-    }
-
     pub(crate) fn as_usize(self) -> Option<usize> {
         if self.0 == usize::MAX {
             None
@@ -35,10 +30,6 @@ impl MountId {
             Some(self.0)
         }
     }
-
-    pub(crate) fn is_none(self) -> bool {
-        self.0 == usize::MAX
-    }
 }
 
 #[derive(Debug, Clone, Copy)]