diff --git a/vmkit/src/mm.rs b/vmkit/src/mm.rs
index 9c4c61b..67c8faf 100644
--- a/vmkit/src/mm.rs
+++ b/vmkit/src/mm.rs
@@ -7,7 +7,6 @@ use crate::{
     threading::Thread,
     VirtualMachine,
 };
-use easy_bitfield::{AtomicBitfieldContainer, ToBitfield};
 use mmtk::{
     util::{
         alloc::{AllocatorSelector, BumpAllocator, ImmixAllocator},
diff --git a/vmkit/src/object_model/header.rs b/vmkit/src/object_model/header.rs
index 5a250e9..dd7128f 100644
--- a/vmkit/src/object_model/header.rs
+++ b/vmkit/src/object_model/header.rs
@@ -1,6 +1,6 @@
 use std::marker::PhantomData;
 
-use crate::{define_vm_metadata_spec, VirtualMachine};
+use crate::VirtualMachine;
 use easy_bitfield::*;
 
 use super::object::ADDRESS_BASED_HASHING;
@@ -11,17 +11,11 @@ pub const OBJECT_REF_OFFSET: isize = 8;
 pub const OBJECT_HEADER_OFFSET: isize = -OBJECT_REF_OFFSET;
 pub const HASHCODE_OFFSET: isize = -(OBJECT_REF_OFFSET + size_of::<usize>() as isize);
 
-
-pub const METADATA_BIT_LIMIT: usize = if ADDRESS_BASED_HASHING {
-    60
-} else {
-    63
-};
+pub const METADATA_BIT_LIMIT: usize = if ADDRESS_BASED_HASHING { 60 } else { 63 };
 
 pub type MetadataField = BitField<u64, usize, 0, METADATA_BIT_LIMIT, false>;
 pub type HashStateField = BitField<u64, HashState, { MetadataField::NEXT_BIT }, 2, false>;
 
-
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum HashState {
     Unhashed,
@@ -89,14 +83,14 @@ impl<VM: VirtualMachine> HeapObjectHeader<VM> {
 
     pub fn set_hash_state(&self, state: HashState) {
         self.metadata.update_synchronized::<HashStateField>(state);
-    }   
+    }
 
     pub fn metadata(&self) -> VM::Metadata {
         VM::Metadata::from_bitfield(self.metadata.read::<MetadataField>() as _)
     }
 
     pub fn set_metadata(&self, metadata: VM::Metadata) {
-        self.metadata.update_synchronized::<MetadataField>(metadata.to_bitfield() as _);
+        self.metadata
+            .update_synchronized::<MetadataField>(metadata.to_bitfield() as _);
     }
-
-}
\ No newline at end of file
+}