diff --git a/src/api/json.rs b/src/api/json.rs
index ce01ca715..378fbe57c 100644
--- a/src/api/json.rs
+++ b/src/api/json.rs
@@ -5,7 +5,7 @@ use crate::func::native::locked_write;
 use crate::parser::{ParseSettingFlags, ParseState};
 use crate::tokenizer::{lex_raw, Token};
 use crate::types::StringsInterner;
-use crate::{Engine, LexError, Map, OptimizationLevel, RhaiResultOf};
+use crate::{Engine, LexError, Map, RhaiResultOf};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 
@@ -134,7 +134,7 @@ impl Engine {
                 state,
                 |s| s.flags |= ParseSettingFlags::DISALLOW_UNQUOTED_MAP_PROPERTIES,
                 #[cfg(not(feature = "no_optimize"))]
-                OptimizationLevel::None,
+                crate::OptimizationLevel::None,
                 #[cfg(feature = "no_optimize")]
                 <_>::default(),
             )?
diff --git a/src/eval/cache.rs b/src/eval/cache.rs
index 2c4e128e9..25302de4a 100644
--- a/src/eval/cache.rs
+++ b/src/eval/cache.rs
@@ -24,7 +24,7 @@ pub struct FnResolutionCacheEntry {
 #[derive(Debug, Clone, Default)]
 pub struct FnResolutionCache {
     /// Hash map containing cached functions.
-    pub map: StraightHashMap<Option<FnResolutionCacheEntry>>,
+    pub dict: StraightHashMap<Option<FnResolutionCacheEntry>>,
     /// Bloom filter to avoid caching "one-hit wonders".
     pub filter: BloomFilterU64,
 }
@@ -34,7 +34,7 @@ impl FnResolutionCache {
     #[inline(always)]
     #[allow(dead_code)]
     pub fn clear(&mut self) {
-        self.map.clear();
+        self.dict.clear();
         self.filter.clear();
     }
 }
@@ -45,39 +45,45 @@ impl FnResolutionCache {
 /// The following caches are contained inside this type:
 /// * A stack of [function resolution caches][FnResolutionCache]
 #[derive(Debug, Clone)]
-pub struct Caches(StaticVec<FnResolutionCache>);
+pub struct Caches {
+    fn_resolution: StaticVec<FnResolutionCache>,
+}
 
 impl Caches {
     /// Create an empty [`Caches`].
     #[inline(always)]
     #[must_use]
     pub const fn new() -> Self {
-        Self(StaticVec::new_const())
+        Self {
+            fn_resolution: StaticVec::new_const(),
+        }
     }
     /// 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.
+    ///
+    /// A new function resolution cache is pushed onto the stack if the stack is empty.
     #[inline]
     #[must_use]
     pub fn fn_resolution_cache_mut(&mut self) -> &mut FnResolutionCache {
         // Push a new function resolution cache if the stack is empty
-        if self.0.is_empty() {
+        if self.fn_resolution.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.
     #[inline(always)]
     pub fn push_fn_resolution_cache(&mut self) {
-        self.0.push(<_>::default());
+        self.fn_resolution.push(<_>::default());
     }
     /// 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);
     }
 }
diff --git a/src/eval/stmt.rs b/src/eval/stmt.rs
index c07b7859b..85bab15ce 100644
--- a/src/eval/stmt.rs
+++ b/src/eval/stmt.rs
@@ -72,7 +72,7 @@ impl Engine {
             let this_ptr = this_ptr.as_deref_mut();
 
             #[cfg(not(feature = "no_module"))]
-            let imports_len = global.num_imports();
+            let orig_imports_len = global.num_imports();
 
             let result =
                 self.eval_stmt(global, caches, scope, this_ptr, stmt, restore_orig_state)?;
@@ -83,7 +83,7 @@ impl Engine {
                 // Without global functions, the extra modules never affect function resolution.
                 if global
                     .scan_imports_raw()
-                    .skip(imports_len)
+                    .skip(orig_imports_len)
                     .any(|(.., m)| m.contains_indexed_global_functions())
                 {
                     // Different scenarios where the cache must be cleared - notice that this is
diff --git a/src/func/call.rs b/src/func/call.rs
index 09beb3ddc..522b2e0a8 100644
--- a/src/func/call.rs
+++ b/src/func/call.rs
@@ -181,7 +181,7 @@ impl Engine {
 
         let cache = caches.fn_resolution_cache_mut();
 
-        match cache.map.entry(hash) {
+        match cache.dict.entry(hash) {
             Entry::Occupied(entry) => entry.into_mut().as_ref(),
             Entry::Vacant(entry) => {
                 let num_args = args.as_deref().map_or(0, FnCallArgs::len);
@@ -190,22 +190,24 @@ impl Engine {
                 let mut bitmask = 1usize; // Bitmask of which parameter to replace with `Dynamic`
 
                 loop {
+                    // First check scripted functions in the AST or embedded environments
                     #[cfg(not(feature = "no_function"))]
                     let func = _global
                         .lib
                         .iter()
                         .rev()
-                        .chain(self.global_modules.iter())
                         .find_map(|m| m.get_fn(hash).map(|f| (f, m.id_raw())));
                     #[cfg(feature = "no_function")]
                     let func = None;
 
+                    // Then check the global namespace
                     let func = func.or_else(|| {
                         self.global_modules
                             .iter()
                             .find_map(|m| m.get_fn(hash).map(|f| (f, m.id_raw())))
                     });
 
+                    // Then check imported modules for global functions, then global sub-modules for global functions
                     #[cfg(not(feature = "no_module"))]
                     let func = func
                         .or_else(|| _global.get_qualified_fn(hash, true))
diff --git a/src/func/script.rs b/src/func/script.rs
index 443e410b1..ed98d39c4 100644
--- a/src/func/script.rs
+++ b/src/func/script.rs
@@ -210,6 +210,10 @@ impl Engine {
     }
 
     // Does a script-defined function exist?
+    ///
+    /// # Note
+    ///
+    /// If the scripted function is not found, this information is cached for future look-ups.
     #[must_use]
     pub(crate) fn has_script_fn(
         &self,
@@ -219,27 +223,27 @@ impl Engine {
     ) -> bool {
         let cache = caches.fn_resolution_cache_mut();
 
-        if let Some(result) = cache.map.get(&hash_script).map(Option::is_some) {
+        if let Some(result) = cache.dict.get(&hash_script).map(Option::is_some) {
             return result;
         }
 
         // First check script-defined functions
-        let r = global.lib.iter().any(|m| m.contains_fn(hash_script))
+        let res = global.lib.iter().any(|m| m.contains_fn(hash_script))
             // Then check the global namespace and packages
             || self.global_modules.iter().any(|m| m.contains_fn(hash_script));
 
         #[cfg(not(feature = "no_module"))]
-        let r = r ||
+        let res = res ||
             // Then check imported modules
             global.contains_qualified_fn(hash_script)
             // Then check sub-modules
             || self.global_sub_modules.values().any(|m| m.contains_qualified_fn(hash_script));
 
-        if !r && !cache.filter.is_absent_and_set(hash_script) {
+        if !res && !cache.filter.is_absent_and_set(hash_script) {
             // Do not cache "one-hit wonders"
-            cache.map.insert(hash_script, None);
+            cache.dict.insert(hash_script, None);
         }
 
-        r
+        res
     }
 }