Fine tune hash map sizes.

src/scope.rs

@@ -65,7 +65,7 @@ impl EntryType {
 //
 // Since `Dynamic` is reasonably small, packing it tightly improves cache locality when variables are accessed.
 // The variable type is packed separately into another array because it is even smaller.
-#[derive(Debug, Clone, Default)]
+#[derive(Debug, Clone)]
 pub struct Scope<'a> {
     /// Current value of the entry.
     values: Vec<Dynamic>,
@@ -75,6 +75,16 @@ pub struct Scope<'a> {
     names: Vec<(Cow<'a, str>, Box<StaticVec<String>>)>,
 }
 
+impl Default for Scope<'_> {
+    fn default() -> Self {
+        Self {
+            values: Vec::with_capacity(16),
+            types: Vec::with_capacity(16),
+            names: Vec::with_capacity(16),
+        }
+    }
+}
+
 impl<'a> Scope<'a> {
     /// Create a new Scope.
     ///