Make Caches a struct.

src/eval/cache.rs

@@ -29,40 +29,48 @@ pub type FnResolutionCache = BTreeMap<u64, Option<FnResolutionCacheEntry>>;
 /// The following caches are contained inside this type:
 /// * A stack of [function resolution caches][FnResolutionCache]
 #[derive(Debug, Clone)]
-pub struct Caches<'a>(StaticVec<FnResolutionCache>, PhantomData<&'a ()>);
+pub struct Caches<'a> {
+    /// Stack of [function resolution caches][FnResolutionCache].
+    fn_resolution: StaticVec<FnResolutionCache>,
+    /// Take care of the lifetime parameter.
+    dummy: PhantomData<&'a ()>,
+}
 
 impl Caches<'_> {
     /// Create an empty [`Caches`].
     #[inline(always)]
     #[must_use]
     pub const fn new() -> Self {
-        Self(StaticVec::new_const(), PhantomData)
+        Self {
+            fn_resolution: StaticVec::new_const(),
+            dummy: PhantomData,
+        }
     }
     /// Get the number of function resolution cache(s) in the stack.
     #[inline(always)]
     #[must_use]
     pub fn fn_resolution_caches_len(&self) -> usize {
-        self.0.len()
+        self.fn_resolution.len()
     }
     /// Get a mutable reference to the current function resolution cache.
     #[inline]
     #[must_use]
     pub fn fn_resolution_cache_mut(&mut self) -> &mut FnResolutionCache {
-        if self.0.is_empty() {
+        if self.fn_resolution.is_empty() {
             // Push a new function resolution cache if the stack is empty
             self.push_fn_resolution_cache();
         }
-        self.0.last_mut().unwrap()
+        self.fn_resolution.last_mut().unwrap()
     }
     /// Push an empty function resolution cache onto the stack and make it current.
     #[allow(dead_code)]
     #[inline(always)]
     pub fn push_fn_resolution_cache(&mut self) {
-        self.0.push(BTreeMap::new());
+        self.fn_resolution.push(BTreeMap::new());
     }
     /// Rewind the function resolution caches stack to a particular size.
     #[inline(always)]
     pub fn rewind_fn_resolution_caches(&mut self, len: usize) {
-        self.0.truncate(len);
+        self.fn_resolution.truncate(len);
     }
 }