Remove an outdated assertion

Author: qinsoon

src/policy/marksweepspace/native_ms/global.rs

@@ -288,7 +288,7 @@ impl<VM: VMBinding> MarkSweepSpace<VM> {
         let vm_map = args.vm_map;
         let is_discontiguous = args.vmrequest.is_discontiguous();
         let local_specs = {
-            metadata::extract_side_metadata(&vec![
+            metadata::extract_side_metadata(&[
                 MetadataSpec::OnSide(Block::NEXT_BLOCK_TABLE),
                 MetadataSpec::OnSide(Block::PREV_BLOCK_TABLE),
                 MetadataSpec::OnSide(Block::FREE_LIST_TABLE),

src/util/heap/chunk_map.rs

@@ -52,11 +52,14 @@ impl Chunk {
 pub struct ChunkState(u8);
 
 impl ChunkState {
+    const ALLOC_BIT_MASK: u8 = 0x80;
+    const SPACE_INDEX_MASK: u8 = 0x0F;
+
     /// Create a new ChunkState that represents being allocated in the given space
     pub fn allocated(space_index: usize) -> ChunkState {
         debug_assert!(space_index < crate::util::heap::layout::heap_parameters::MAX_SPACES);
         let mut encode = space_index as u8;
-        encode |= 0x80;
+        encode |= Self::ALLOC_BIT_MASK;
         ChunkState(encode)
     }
     /// Create a new ChunkState that represents being free in the given space
@@ -66,16 +69,15 @@ impl ChunkState {
     }
     /// Is the chunk free?
     pub fn is_free(&self) -> bool {
-        self.0 & 0x80 == 0
+        self.0 & Self::ALLOC_BIT_MASK == 0
     }
     /// Is the chunk allocated?
     pub fn is_allocated(&self) -> bool {
         !self.is_free()
     }
     /// Get the space index of the chunk
     pub fn get_space_index(&self) -> usize {
-        debug_assert!(self.is_allocated());
-        let index = (self.0 & 0x0F) as usize;
+        let index = (self.0 & Self::SPACE_INDEX_MASK) as usize;
         debug_assert!(index < crate::util::heap::layout::heap_parameters::MAX_SPACES);
         index
     }