Streamline code.

src/ast/expr.rs

@@ -493,6 +493,9 @@ impl fmt::Debug for Expr {
                     }
                 }
                 f.write_str(&x.3)?;
+                if let Some(n) = x.1.index() {
+                    write!(f, " #{}", n)?;
+                }
                 if let Some(n) = i.map_or_else(|| x.0, |n| NonZeroUsize::new(n.get() as usize)) {
                     write!(f, " #{}", n)?;
                 }

src/ast/stmt.rs

@@ -302,6 +302,10 @@ pub struct TryCatchBlock {
     pub catch_block: StmtBlock,
 }
 
+/// Number of items to keep inline for [`StmtBlockContainer`].
+#[cfg(not(feature = "no_std"))]
+const STMT_BLOCK_INLINE_SIZE: usize = 8;
+
 /// _(internals)_ The underlying container type for [`StmtBlock`].
 /// Exported under the `internals` feature only.
 ///
@@ -309,7 +313,7 @@ pub struct TryCatchBlock {
 /// hold a statements block, with the assumption that most program blocks would container fewer than
 /// 8 statements, and those that do have a lot more statements.
 #[cfg(not(feature = "no_std"))]
-pub type StmtBlockContainer = smallvec::SmallVec<[Stmt; 8]>;
+pub type StmtBlockContainer = smallvec::SmallVec<[Stmt; STMT_BLOCK_INLINE_SIZE]>;
 
 /// _(internals)_ The underlying container type for [`StmtBlock`].
 /// Exported under the `internals` feature only.
@@ -491,9 +495,9 @@ impl From<Stmt> for StmtBlock {
 impl IntoIterator for StmtBlock {
     type Item = Stmt;
     #[cfg(not(feature = "no_std"))]
-    type IntoIter = smallvec::IntoIter<[Stmt; 8]>;
+    type IntoIter = smallvec::IntoIter<[Stmt; STMT_BLOCK_INLINE_SIZE]>;
     #[cfg(feature = "no_std")]
-    type IntoIter = smallvec::IntoIter<[Stmt; 3]>;
+    type IntoIter = smallvec::IntoIter<[Stmt; crate::STATIC_VEC_INLINE_SIZE]>;
 
     #[inline(always)]
     fn into_iter(self) -> Self::IntoIter {

src/eval/expr.rs

@@ -24,13 +24,13 @@ impl Engine {
 
         let root = namespace.root();
 
-        // Qualified - check if the root module is directly indexed
         let index = if global.always_search_scope {
             None
         } else {
             namespace.index()
         };
 
+        // Qualified - check if the root module is directly indexed
         if let Some(index) = index {
             let offset = global.num_imports() - index.get();
 

src/lib.rs

@@ -341,6 +341,9 @@ pub use eval::{Caches, FnResolutionCache, FnResolutionCacheEntry, GlobalRuntimeS
 #[cfg(feature = "metadata")]
 pub use api::definitions::Definitions;
 
+/// Number of items to keep inline for [`StaticVec`].
+const STATIC_VEC_INLINE_SIZE: usize = 3;
+
 /// Alias to [`smallvec::SmallVec<[T; 3]>`](https://crates.io/crates/smallvec), which is a
 /// specialized [`Vec`] backed by a small, inline, fixed-size array when there are ≤ 3 items stored.
 ///
@@ -373,7 +376,7 @@ pub use api::definitions::Definitions;
 /// most scripts load fewer than 4 external modules; most module paths contain fewer than 4 levels
 /// (e.g. `std::collections::map::HashMap` is 4 levels and it is just about as long as they get).
 #[cfg(not(feature = "internals"))]
-type StaticVec<T> = smallvec::SmallVec<[T; 3]>;
+type StaticVec<T> = smallvec::SmallVec<[T; STATIC_VEC_INLINE_SIZE]>;
 
 /// _(internals)_ Alias to [`smallvec::SmallVec<[T; 3]>`](https://crates.io/crates/smallvec),
 /// which is a [`Vec`] backed by a small, inline, fixed-size array when there are ≤ 3 items stored.
@@ -408,7 +411,11 @@ type StaticVec<T> = smallvec::SmallVec<[T; 3]>;
 /// most scripts load fewer than 4 external modules; most module paths contain fewer than 4 levels
 /// (e.g. `std::collections::map::HashMap` is 4 levels and it is just about as long as they get).
 #[cfg(feature = "internals")]
-pub type StaticVec<T> = smallvec::SmallVec<[T; 3]>;
+pub type StaticVec<T> = smallvec::SmallVec<[T; STATIC_VEC_INLINE_SIZE]>;
+
+/// Number of items to keep inline for [`FnArgsVec`].
+#[cfg(not(feature = "no_closure"))]
+const FN_ARGS_VEC_INLINE_SIZE: usize = 5;
 
 /// Inline arguments storage for function calls.
 ///
@@ -423,7 +430,7 @@ pub type StaticVec<T> = smallvec::SmallVec<[T; 3]>;
 ///
 /// Under `no_closure`, this type aliases to [`StaticVec`][crate::StaticVec] instead.
 #[cfg(not(feature = "no_closure"))]
-type FnArgsVec<T> = smallvec::SmallVec<[T; 5]>;
+type FnArgsVec<T> = smallvec::SmallVec<[T; FN_ARGS_VEC_INLINE_SIZE]>;
 
 /// Inline arguments storage for function calls.
 /// This type aliases to [`StaticVec`][crate::StaticVec].

src/module/resolvers/collection.rs

@@ -1,7 +1,10 @@
-use crate::{Engine, Module, ModuleResolver, Position, RhaiResultOf, Shared, ERR};
+use crate::{
+    Engine, Module, ModuleResolver, Position, RhaiResultOf, Shared, StaticVec, ERR,
+    STATIC_VEC_INLINE_SIZE,
+};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
-use std::{ops::AddAssign, slice::Iter, vec::IntoIter};
+use std::{ops::AddAssign, slice::Iter};
 
 /// [Module] resolution service that holds a collection of module resolvers,
 /// to be searched in sequential order.
@@ -21,7 +24,7 @@ use std::{ops::AddAssign, slice::Iter, vec::IntoIter};
 /// engine.set_module_resolver(collection);
 /// ```
 #[derive(Default)]
-pub struct ModuleResolversCollection(Vec<Box<dyn ModuleResolver>>);
+pub struct ModuleResolversCollection(StaticVec<Box<dyn ModuleResolver>>);
 
 impl ModuleResolversCollection {
     /// Create a new [`ModuleResolversCollection`].
@@ -43,7 +46,7 @@ impl ModuleResolversCollection {
     #[inline(always)]
     #[must_use]
     pub const fn new() -> Self {
-        Self(Vec::new())
+        Self(StaticVec::new_const())
     }
     /// Append a [module resolver][ModuleResolver] to the end.
     #[inline(always)]
@@ -109,7 +112,7 @@ impl ModuleResolversCollection {
 
 impl IntoIterator for ModuleResolversCollection {
     type Item = Box<dyn ModuleResolver>;
-    type IntoIter = IntoIter<Box<dyn ModuleResolver>>;
+    type IntoIter = smallvec::IntoIter<[Box<dyn ModuleResolver>; STATIC_VEC_INLINE_SIZE]>;
 
     #[inline(always)]
     #[must_use]

src/types/interner.rs

@@ -110,7 +110,7 @@ impl StringsInterner<'_> {
 
         // If the interner is over capacity, remove the longest entry that has the lowest count
         if self.cache.len() > self.capacity {
-            // Leave some buffer to grow when shrinking the cache.
+            // Throttle: leave some buffer to grow when shrinking the cache.
             // We leave at least two entries, one for the empty string, and one for the string
             // that has just been inserted.
             let max = if self.capacity < 5 {