diff --git a/src/eval/chaining.rs b/src/eval/chaining.rs
index 351df42e..0e6869f9 100644
--- a/src/eval/chaining.rs
+++ b/src/eval/chaining.rs
@@ -989,7 +989,7 @@ impl Engine {
                 } else {
                     let abs_index = index.unsigned_abs();
 
-                    if abs_index as u64 >= usize::MAX as u64 {
+                    if abs_index as u64 > usize::MAX as u64 {
                         return Err(
                             ERR::ErrorStringBounds(s.chars().count(), index, idx_pos).into()
                         );
diff --git a/src/eval/debugger.rs b/src/eval/debugger.rs
index bfdb2af5..e98771e7 100644
--- a/src/eval/debugger.rs
+++ b/src/eval/debugger.rs
@@ -397,7 +397,7 @@ impl Debugger {
     /// Get the custom state.
     #[inline(always)]
     #[must_use]
-    pub fn state(&self) -> &Dynamic {
+    pub const fn state(&self) -> &Dynamic {
         &self.state
     }
     /// Get a mutable reference to the custom state.
diff --git a/src/eval/expr.rs b/src/eval/expr.rs
index ab499a6a..9419e9e9 100644
--- a/src/eval/expr.rs
+++ b/src/eval/expr.rs
@@ -144,11 +144,10 @@ impl Engine {
         let (index, var_pos) = match expr {
             // Check if the variable is `this`
             Expr::Variable(v, None, pos) if v.0.is_none() && v.3 == KEYWORD_THIS => {
-                return if let Some(val) = this_ptr {
-                    Ok(((*val).into(), *pos))
-                } else {
-                    Err(ERR::ErrorUnboundThis(*pos).into())
-                }
+                return this_ptr.as_mut().map_or_else(
+                    || Err(ERR::ErrorUnboundThis(*pos).into()),
+                    |val| Ok(((*val).into(), *pos)),
+                )
             }
             _ if global.always_search_scope => (0, expr.start_position()),
             Expr::Variable(.., Some(i), pos) => (i.get() as usize, *pos),
diff --git a/src/eval/stmt.rs b/src/eval/stmt.rs
index 1003e896..0076102d 100644
--- a/src/eval/stmt.rs
+++ b/src/eval/stmt.rs
@@ -484,12 +484,10 @@ impl Engine {
                         self.eval_expr(scope, global, caches, lib, this_ptr, expr, level)
                     } else if let Ok(None) = expr_result {
                         // Default match clause
-                        if let Some(index) = def_case {
-                            let def_expr = &expressions[*index].expr;
+                        def_case.as_ref().map_or(Ok(Dynamic::UNIT), |&index| {
+                            let def_expr = &expressions[index].expr;
                             self.eval_expr(scope, global, caches, lib, this_ptr, def_expr, level)
-                        } else {
-                            Ok(Dynamic::UNIT)
-                        }
+                        })
                     } else {
                         expr_result.map(|_| Dynamic::UNIT)
                     }
diff --git a/src/eval/target.rs b/src/eval/target.rs
index 0114fa5b..e20f5b07 100644
--- a/src/eval/target.rs
+++ b/src/eval/target.rs
@@ -15,7 +15,12 @@ use std::prelude::v1::*;
 #[allow(dead_code)]
 pub fn calc_offset_len(length: usize, start: crate::INT, len: crate::INT) -> (usize, usize) {
     let start = if start < 0 {
-        length - usize::min(start.unsigned_abs() as usize, length)
+        let abs_start = start.unsigned_abs();
+        if abs_start as u64 > crate::MAX_USIZE_INT as u64 {
+            0
+        } else {
+            length - usize::min(abs_start as usize, length)
+        }
     } else if start > crate::MAX_USIZE_INT || start as usize >= length {
         return (length, 0);
     } else {
diff --git a/src/func/call.rs b/src/func/call.rs
index 071bb5c7..4b1696d8 100644
--- a/src/func/call.rs
+++ b/src/func/call.rs
@@ -1228,13 +1228,11 @@ impl Engine {
 
                 if target_is_shared || target.is_temp_value() {
                     arg_values.insert(0, target.take_or_clone().flatten());
-                    args.extend(arg_values.iter_mut());
                 } else {
                     // Turn it into a method call only if the object is not shared and not a simple value
                     is_ref_mut = true;
                     let obj_ref = target.take_ref().expect("ref");
                     args.push(obj_ref);
-                    args.extend(arg_values.iter_mut());
                 }
             } else {
                 // func(..., ...)
@@ -1246,8 +1244,9 @@ impl Engine {
                             .map(|(value, ..)| arg_values.push(value.flatten()))
                     })?;
                 args.extend(curry.iter_mut());
-                args.extend(arg_values.iter_mut());
             }
+
+            args.extend(arg_values.iter_mut());
         }
 
         self.exec_fn_call(
diff --git a/src/module/mod.rs b/src/module/mod.rs
index 805c821a..672e2cf6 100644
--- a/src/module/mod.rs
+++ b/src/module/mod.rs
@@ -41,7 +41,7 @@ impl FnNamespace {
     /// Is this a module namespace?
     #[inline(always)]
     #[must_use]
-    pub fn is_module_namespace(self) -> bool {
+    pub const fn is_module_namespace(self) -> bool {
         match self {
             Self::Internal => true,
             Self::Global => false,
@@ -50,7 +50,7 @@ impl FnNamespace {
     /// Is this a global namespace?
     #[inline(always)]
     #[must_use]
-    pub fn is_global_namespace(self) -> bool {
+    pub const fn is_global_namespace(self) -> bool {
         match self {
             Self::Internal => false,
             Self::Global => true,
@@ -193,7 +193,6 @@ impl FuncInfo {
                     sig.push_str(", ");
                 }
             }
-            sig.push(')');
         } else {
             let params: StaticVec<_> = self
                 .metadata
@@ -215,8 +214,8 @@ impl FuncInfo {
                 })
                 .collect();
             sig.push_str(&params.join(", "));
-            sig.push(')');
         }
+        sig.push(')');
 
         if !self.func.is_script() && !return_type.is_empty() {
             sig.push_str(" -> ");
diff --git a/src/optimizer.rs b/src/optimizer.rs
index 851628e8..d76fc42c 100644
--- a/src/optimizer.rs
+++ b/src/optimizer.rs
@@ -988,7 +988,7 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
         #[cfg(not(feature = "no_index"))]
         Expr::Index(x, ..) if !_chaining => match (&mut x.lhs, &mut x.rhs) {
             // array[int]
-            (Expr::Array(a, pos), Expr::IntegerConstant(i, ..)) if *i >= 0 && (*i as usize) < a.len() && a.iter().all(Expr::is_pure) => {
+            (Expr::Array(a, pos), Expr::IntegerConstant(i, ..)) if *i >= 0 && *i <= crate::MAX_USIZE_INT && (*i as usize) < a.len() && a.iter().all(Expr::is_pure) => {
                 // Array literal where everything is pure - promote the indexed item.
                 // All other items can be thrown away.
                 state.set_dirty();
@@ -997,7 +997,7 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
                 *expr = result;
             }
             // array[-int]
-            (Expr::Array(a, pos), Expr::IntegerConstant(i, ..)) if *i < 0 && i.unsigned_abs() as usize <= a.len() && a.iter().all(Expr::is_pure) => {
+            (Expr::Array(a, pos), Expr::IntegerConstant(i, ..)) if *i < 0 && i.unsigned_abs() as u64 <= a.len() as u64 && a.iter().all(Expr::is_pure) => {
                 // Array literal where everything is pure - promote the indexed item.
                 // All other items can be thrown away.
                 state.set_dirty();
@@ -1015,25 +1015,25 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
                             .map_or_else(|| Expr::Unit(*pos), |(.., mut expr)| { expr.set_position(*pos); expr });
             }
             // int[int]
-            (Expr::IntegerConstant(n, pos), Expr::IntegerConstant(i, ..)) if *i >= 0 && (*i as usize) < crate::INT_BITS => {
+            (Expr::IntegerConstant(n, pos), Expr::IntegerConstant(i, ..)) if *i >= 0 && *i <= crate::MAX_USIZE_INT && (*i as usize) < crate::INT_BITS => {
                 // Bit-field literal indexing - get the bit
                 state.set_dirty();
                 *expr = Expr::BoolConstant((*n & (1 << (*i as usize))) != 0, *pos);
             }
             // int[-int]
-            (Expr::IntegerConstant(n, pos), Expr::IntegerConstant(i, ..)) if *i < 0 && i.unsigned_abs() as usize <= crate::INT_BITS => {
+            (Expr::IntegerConstant(n, pos), Expr::IntegerConstant(i, ..)) if *i < 0 && i.unsigned_abs() as u64 <= crate::INT_BITS as u64 => {
                 // Bit-field literal indexing - get the bit
                 state.set_dirty();
                 *expr = Expr::BoolConstant((*n & (1 << (crate::INT_BITS - i.unsigned_abs() as usize))) != 0, *pos);
             }
             // string[int]
-            (Expr::StringConstant(s, pos), Expr::IntegerConstant(i, ..)) if *i >= 0 && (*i as usize) < s.chars().count() => {
+            (Expr::StringConstant(s, pos), Expr::IntegerConstant(i, ..)) if *i >= 0 && *i <= crate::MAX_USIZE_INT && (*i as usize) < s.chars().count() => {
                 // String literal indexing - get the character
                 state.set_dirty();
                 *expr = Expr::CharConstant(s.chars().nth(*i as usize).unwrap(), *pos);
             }
             // string[-int]
-            (Expr::StringConstant(s, pos), Expr::IntegerConstant(i, ..)) if *i < 0 && i.unsigned_abs() as usize <= s.chars().count() => {
+            (Expr::StringConstant(s, pos), Expr::IntegerConstant(i, ..)) if *i < 0 && i.unsigned_abs() as u64 <= s.chars().count() as u64 => {
                 // String literal indexing - get the character
                 state.set_dirty();
                 *expr = Expr::CharConstant(s.chars().rev().nth(i.unsigned_abs() as usize - 1).unwrap(), *pos);
diff --git a/src/packages/array_basic.rs b/src/packages/array_basic.rs
index 3b3e9e5a..0751a768 100644
--- a/src/packages/array_basic.rs
+++ b/src/packages/array_basic.rs
@@ -1312,8 +1312,7 @@ pub mod array_functions {
     ///
     /// print(x);       // prints "[1, 2, 3, 4, 3, 2, 1]"
     /// ```
-    #[rhai_fn(return_raw)]
-    pub fn dedup(ctx: NativeCallContext, array: &mut Array) -> RhaiResultOf<()> {
+    pub fn dedup(ctx: NativeCallContext, array: &mut Array) {
         let comparer = FnPtr::new_unchecked(OP_EQUALS, StaticVec::new_const());
         dedup_by_comparer(ctx, array, comparer)
     }
@@ -1340,14 +1339,10 @@ pub mod array_functions {
     ///
     /// print(x);       // prints "[1, 2, 3, 4]"
     /// ```
-    #[rhai_fn(name = "dedup", return_raw)]
-    pub fn dedup_by_comparer(
-        ctx: NativeCallContext,
-        array: &mut Array,
-        comparer: FnPtr,
-    ) -> RhaiResultOf<()> {
+    #[rhai_fn(name = "dedup")]
+    pub fn dedup_by_comparer(ctx: NativeCallContext, array: &mut Array, comparer: FnPtr) {
         if array.is_empty() {
-            return Ok(());
+            return;
         }
 
         array.dedup_by(|x, y| {
@@ -1357,8 +1352,6 @@ pub mod array_functions {
                 .as_bool()
                 .unwrap_or(false)
         });
-
-        Ok(())
     }
     /// Remove duplicated _consecutive_ elements from the array that return `true` when applied a
     /// function named by `comparer`.
@@ -1391,7 +1384,7 @@ pub mod array_functions {
         array: &mut Array,
         comparer: &str,
     ) -> RhaiResultOf<()> {
-        dedup_by_comparer(ctx, array, FnPtr::new(comparer)?)
+        Ok(dedup_by_comparer(ctx, array, FnPtr::new(comparer)?))
     }
     /// Reduce an array by iterating through all elements while applying the `reducer` function.
     ///
diff --git a/src/serde/de.rs b/src/serde/de.rs
index 15c538cd..76c31c11 100644
--- a/src/serde/de.rs
+++ b/src/serde/de.rs
@@ -22,7 +22,7 @@ impl<'de> DynamicDeserializer<'de> {
     /// The reference is necessary because the deserialized type may hold references
     /// (especially `&str`) to the source [`Dynamic`][crate::Dynamic].
     #[must_use]
-    pub fn from_dynamic(value: &'de Dynamic) -> Self {
+    pub const fn from_dynamic(value: &'de Dynamic) -> Self {
         Self { value }
     }
     /// Shortcut for a type conversion error.
@@ -449,21 +449,22 @@ impl<'de> Deserializer<'de> for &mut DynamicDeserializer<'de> {
             visitor.visit_enum(s.as_str().into_deserializer())
         } else {
             #[cfg(not(feature = "no_object"))]
-            if let Some(map) = self.value.downcast_ref::<crate::Map>() {
-                let mut iter = map.iter();
-                let first = iter.next();
-                let second = iter.next();
-                if let (Some((key, value)), None) = (first, second) {
-                    visitor.visit_enum(EnumDeserializer {
-                        tag: key,
-                        content: DynamicDeserializer::from_dynamic(value),
-                    })
-                } else {
-                    self.type_error()
-                }
-            } else {
-                self.type_error()
-            }
+            return self.value.downcast_ref::<crate::Map>().map_or_else(
+                || self.type_error(),
+                |map| {
+                    let mut iter = map.iter();
+                    let first = iter.next();
+                    let second = iter.next();
+                    if let (Some((key, value)), None) = (first, second) {
+                        visitor.visit_enum(EnumDeserializer {
+                            tag: key,
+                            content: DynamicDeserializer::from_dynamic(value),
+                        })
+                    } else {
+                        self.type_error()
+                    }
+                },
+            );
             #[cfg(feature = "no_object")]
             return self.type_error();
         }
@@ -488,7 +489,7 @@ struct IterateDynamicArray<'a, ITER: Iterator<Item = &'a Dynamic>> {
 #[cfg(not(feature = "no_index"))]
 impl<'a, ITER: Iterator<Item = &'a Dynamic>> IterateDynamicArray<'a, ITER> {
     #[must_use]
-    pub fn new(iter: ITER) -> Self {
+    pub const fn new(iter: ITER) -> Self {
         Self { iter }
     }
 }
@@ -525,7 +526,7 @@ struct IterateMap<'a, K: Iterator<Item = &'a str>, V: Iterator<Item = &'a Dynami
 #[cfg(not(feature = "no_object"))]
 impl<'a, K: Iterator<Item = &'a str>, V: Iterator<Item = &'a Dynamic>> IterateMap<'a, K, V> {
     #[must_use]
-    pub fn new(keys: K, values: V) -> Self {
+    pub const fn new(keys: K, values: V) -> Self {
         Self { keys, values }
     }
 }
diff --git a/src/serde/metadata.rs b/src/serde/metadata.rs
index f4d9732f..7a562d5c 100644
--- a/src/serde/metadata.rs
+++ b/src/serde/metadata.rs
@@ -56,7 +56,7 @@ impl PartialOrd for FnMetadata<'_> {
 
 impl Ord for FnMetadata<'_> {
     fn cmp(&self, other: &Self) -> Ordering {
-        match self.name.cmp(&other.name) {
+        match self.name.cmp(other.name) {
             Ordering::Equal => self.num_params.cmp(&other.num_params),
             cmp => cmp,
         }
@@ -79,8 +79,8 @@ impl<'a> From<&'a FuncInfo> for FnMetadata<'a> {
             base_hash,
             full_hash,
             #[cfg(not(feature = "no_module"))]
-            namespace: info.metadata.namespace.into(),
-            access: info.metadata.access.into(),
+            namespace: info.metadata.namespace,
+            access: info.metadata.access,
             name: &info.metadata.name,
             typ,
             num_params: info.metadata.params,
@@ -150,7 +150,7 @@ impl<'a> From<&'a crate::Module> for ModuleMetadata<'a> {
         functions.sort();
 
         Self {
-            doc: module.doc().into(),
+            doc: module.doc(),
             modules: module
                 .iter_sub_modules()
                 .map(|(name, m)| (name, m.as_ref().into()))
@@ -206,7 +206,7 @@ pub fn gen_metadata_to_json(
 
     #[cfg(feature = "metadata")]
     if let Some(ast) = _ast {
-        global.doc = ast.doc().into();
+        global.doc = ast.doc();
     }
 
     serde_json::to_string_pretty(&global)
diff --git a/src/serde/ser.rs b/src/serde/ser.rs
index b7e2d915..1cdc8e28 100644
--- a/src/serde/ser.rs
+++ b/src/serde/ser.rs
@@ -20,7 +20,7 @@ struct DynamicSerializer {
 impl DynamicSerializer {
     /// Create a [`DynamicSerializer`] from a [`Dynamic`][crate::Dynamic] value.
     #[must_use]
-    pub fn new(_value: Dynamic) -> Self {
+    pub const fn new(_value: Dynamic) -> Self {
         Self {
             _key: Dynamic::UNIT,
             _value,
diff --git a/src/serde/str.rs b/src/serde/str.rs
index fd19de8c..df747a42 100644
--- a/src/serde/str.rs
+++ b/src/serde/str.rs
@@ -14,7 +14,7 @@ pub struct StringSliceDeserializer<'a> {
 impl<'a> StringSliceDeserializer<'a> {
     /// Create an `ImmutableStringDeserializer` from an `&str` reference.
     #[must_use]
-    pub fn from_str(value: &'a str) -> Self {
+    pub const fn from_str(value: &'a str) -> Self {
         Self { value }
     }
     /// Shortcut for a type conversion error.
diff --git a/src/tokenizer.rs b/src/tokenizer.rs
index 1eb5bd93..f69f2411 100644
--- a/src/tokenizer.rs
+++ b/src/tokenizer.rs
@@ -1701,11 +1701,11 @@ fn get_next_token_inner(
             // letter or underscore ...
             #[cfg(not(feature = "unicode-xid-ident"))]
             ('a'..='z' | '_' | 'A'..='Z', ..) => {
-                return get_identifier(stream, pos, start_pos, c);
+                return Some(get_identifier(stream, pos, start_pos, c));
             }
             #[cfg(feature = "unicode-xid-ident")]
             (ch, ..) if unicode_xid::UnicodeXID::is_xid_start(ch) || ch == '_' => {
-                return get_identifier(stream, pos, start_pos, c);
+                return Some(get_identifier(stream, pos, start_pos, c));
             }
 
             // " - string literal
@@ -2178,7 +2178,7 @@ fn get_identifier(
     pos: &mut Position,
     start_pos: Position,
     first_char: char,
-) -> Option<(Token, Position)> {
+) -> (Token, Position) {
     let mut result = smallvec::SmallVec::<[char; 8]>::new();
     result.push(first_char);
 
@@ -2197,17 +2197,17 @@ fn get_identifier(
     let identifier: String = result.into_iter().collect();
 
     if let Some(token) = Token::lookup_from_syntax(&identifier) {
-        return Some((token, start_pos));
+        return (token, start_pos);
     }
 
     if !is_valid_identifier {
-        return Some((
+        return (
             Token::LexError(LERR::MalformedIdentifier(identifier).into()),
             start_pos,
-        ));
+        );
     }
 
-    Some((Token::Identifier(identifier.into()), start_pos))
+    (Token::Identifier(identifier.into()), start_pos)
 }
 
 /// Is a keyword allowed as a function?
@@ -2272,7 +2272,7 @@ pub fn is_id_continue(x: char) -> bool {
 #[cfg(not(feature = "unicode-xid-ident"))]
 #[inline(always)]
 #[must_use]
-pub fn is_id_first_alphabetic(x: char) -> bool {
+pub const fn is_id_first_alphabetic(x: char) -> bool {
     x.is_ascii_alphabetic()
 }
 
@@ -2280,7 +2280,7 @@ pub fn is_id_first_alphabetic(x: char) -> bool {
 #[cfg(not(feature = "unicode-xid-ident"))]
 #[inline(always)]
 #[must_use]
-pub fn is_id_continue(x: char) -> bool {
+pub const fn is_id_continue(x: char) -> bool {
     x.is_ascii_alphanumeric() || x == '_'
 }
 
diff --git a/src/types/dynamic.rs b/src/types/dynamic.rs
index 29a88336..5d4803d1 100644
--- a/src/types/dynamic.rs
+++ b/src/types/dynamic.rs
@@ -1166,7 +1166,7 @@ impl Dynamic {
         #[cfg(not(feature = "no_index"))]
         reify!(value, |v: crate::Blob| {
             // don't use blob.into() because it'll be converted into an Array
-            return Dynamic::from_blob(v);
+            return Self::from_blob(v);
         });
         #[cfg(not(feature = "no_object"))]
         reify!(value, |v: crate::Map| return v.into());
@@ -1175,7 +1175,7 @@ impl Dynamic {
         #[cfg(not(feature = "no_std"))]
         reify!(value, |v: Instant| return v.into());
         #[cfg(not(feature = "no_closure"))]
-        reify!(value, |v: crate::Shared<crate::Locked<Dynamic>>| return v
+        reify!(value, |v: crate::Shared<crate::Locked<Self>>| return v
             .into());
 
         Self(Union::Variant(
@@ -1444,7 +1444,7 @@ impl Dynamic {
                 let value = crate::func::locked_read(cell);
 
                 return if (*value).type_id() != TypeId::of::<T>()
-                    && TypeId::of::<Dynamic>() != TypeId::of::<T>()
+                    && TypeId::of::<Self>() != TypeId::of::<T>()
                 {
                     None
                 } else {
@@ -1476,7 +1476,7 @@ impl Dynamic {
                 let guard = crate::func::locked_write(cell);
 
                 return if (*guard).type_id() != TypeId::of::<T>()
-                    && TypeId::of::<Dynamic>() != TypeId::of::<T>()
+                    && TypeId::of::<Self>() != TypeId::of::<T>()
                 {
                     None
                 } else {
@@ -1577,7 +1577,7 @@ impl Dynamic {
                 _ => None,
             };
         }
-        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+        if TypeId::of::<T>() == TypeId::of::<Self>() {
             return self.as_any().downcast_ref::<T>();
         }
 
@@ -1675,7 +1675,7 @@ impl Dynamic {
                 _ => None,
             };
         }
-        if TypeId::of::<T>() == TypeId::of::<Dynamic>() {
+        if TypeId::of::<T>() == TypeId::of::<Self>() {
             return self.as_any_mut().downcast_mut::<T>();
         }
 
@@ -1962,7 +1962,7 @@ impl<T: Variant + Clone> From<Vec<T>> for Dynamic {
     #[inline]
     fn from(value: Vec<T>) -> Self {
         Self(Union::Array(
-            Box::new(value.into_iter().map(Dynamic::from).collect()),
+            Box::new(value.into_iter().map(Self::from).collect()),
             DEFAULT_TAG_VALUE,
             ReadWrite,
         ))
@@ -1973,7 +1973,7 @@ impl<T: Variant + Clone> From<&[T]> for Dynamic {
     #[inline]
     fn from(value: &[T]) -> Self {
         Self(Union::Array(
-            Box::new(value.iter().cloned().map(Dynamic::from).collect()),
+            Box::new(value.iter().cloned().map(Self::from).collect()),
             DEFAULT_TAG_VALUE,
             ReadWrite,
         ))
@@ -1984,7 +1984,7 @@ impl<T: Variant + Clone> std::iter::FromIterator<T> for Dynamic {
     #[inline]
     fn from_iter<X: IntoIterator<Item = T>>(iter: X) -> Self {
         Self(Union::Array(
-            Box::new(iter.into_iter().map(Dynamic::from).collect()),
+            Box::new(iter.into_iter().map(Self::from).collect()),
             DEFAULT_TAG_VALUE,
             ReadWrite,
         ))
@@ -2001,7 +2001,7 @@ impl<K: Into<crate::Identifier>, T: Variant + Clone> From<std::collections::Hash
             Box::new(
                 value
                     .into_iter()
-                    .map(|(k, v)| (k.into(), Dynamic::from(v)))
+                    .map(|(k, v)| (k.into(), Self::from(v)))
                     .collect(),
             ),
             DEFAULT_TAG_VALUE,
@@ -2015,12 +2015,7 @@ impl<K: Into<crate::Identifier>> From<std::collections::HashSet<K>> for Dynamic
     #[inline]
     fn from(value: std::collections::HashSet<K>) -> Self {
         Self(Union::Map(
-            Box::new(
-                value
-                    .into_iter()
-                    .map(|k| (k.into(), Dynamic::UNIT))
-                    .collect(),
-            ),
+            Box::new(value.into_iter().map(|k| (k.into(), Self::UNIT)).collect()),
             DEFAULT_TAG_VALUE,
             ReadWrite,
         ))
@@ -2036,7 +2031,7 @@ impl<K: Into<crate::Identifier>, T: Variant + Clone> From<std::collections::BTre
             Box::new(
                 value
                     .into_iter()
-                    .map(|(k, v)| (k.into(), Dynamic::from(v)))
+                    .map(|(k, v)| (k.into(), Self::from(v)))
                     .collect(),
             ),
             DEFAULT_TAG_VALUE,
@@ -2049,12 +2044,7 @@ impl<K: Into<crate::Identifier>> From<std::collections::BTreeSet<K>> for Dynamic
     #[inline]
     fn from(value: std::collections::BTreeSet<K>) -> Self {
         Self(Union::Map(
-            Box::new(
-                value
-                    .into_iter()
-                    .map(|k| (k.into(), Dynamic::UNIT))
-                    .collect(),
-            ),
+            Box::new(value.into_iter().map(|k| (k.into(), Self::UNIT)).collect()),
             DEFAULT_TAG_VALUE,
             ReadWrite,
         ))
@@ -2074,7 +2064,7 @@ impl From<Instant> for Dynamic {
     }
 }
 #[cfg(not(feature = "no_closure"))]
-impl From<crate::Shared<crate::Locked<Dynamic>>> for Dynamic {
+impl From<crate::Shared<crate::Locked<Self>>> for Dynamic {
     #[inline(always)]
     fn from(value: crate::Shared<crate::Locked<Self>>) -> Self {
         Self(Union::Shared(value, DEFAULT_TAG_VALUE, ReadWrite))
@@ -2084,12 +2074,12 @@ impl From<crate::Shared<crate::Locked<Dynamic>>> for Dynamic {
 impl From<ExclusiveRange> for Dynamic {
     #[inline(always)]
     fn from(value: ExclusiveRange) -> Self {
-        Dynamic::from(value)
+        Self::from(value)
     }
 }
 impl From<InclusiveRange> for Dynamic {
     #[inline(always)]
     fn from(value: InclusiveRange) -> Self {
-        Dynamic::from(value)
+        Self::from(value)
     }
 }
diff --git a/src/types/error.rs b/src/types/error.rs
index 9c0133f4..6e9814cd 100644
--- a/src/types/error.rs
+++ b/src/types/error.rs
@@ -368,9 +368,6 @@ impl EvalAltResult {
                 map.insert("function".into(), f.into());
                 map.insert("source".into(), s.into());
             }
-            Self::ErrorInModule(m, ..) => {
-                map.insert("module".into(), m.into());
-            }
             Self::ErrorMismatchDataType(r, a, ..) | Self::ErrorMismatchOutputType(r, a, ..) => {
                 map.insert("requested".into(), r.into());
                 map.insert("actual".into(), a.into());
@@ -381,9 +378,6 @@ impl EvalAltResult {
                 map.insert("length".into(), (*n as INT).into());
                 map.insert("index".into(), (*i as INT).into());
             }
-            Self::ErrorIndexingType(t, ..) => {
-                map.insert("type".into(), t.into());
-            }
             Self::ErrorVariableExists(v, ..)
             | Self::ErrorForbiddenVariable(v, ..)
             | Self::ErrorVariableNotFound(v, ..)
@@ -395,14 +389,14 @@ impl EvalAltResult {
             Self::ErrorIndexNotFound(v, ..) => {
                 map.insert("index".into(), v.clone());
             }
-            Self::ErrorModuleNotFound(m, ..) => {
+            Self::ErrorInModule(m, ..) | Self::ErrorModuleNotFound(m, ..) => {
                 map.insert("module".into(), m.into());
             }
             Self::ErrorDotExpr(p, ..) => {
                 map.insert("property".into(), p.into());
             }
 
-            Self::ErrorDataTooLarge(t, ..) => {
+            Self::ErrorIndexingType(t, ..) | Self::ErrorDataTooLarge(t, ..) => {
                 map.insert("type".into(), t.into());
             }
             Self::ErrorTerminated(t, ..) => {
diff --git a/src/types/immutable_string.rs b/src/types/immutable_string.rs
index 5b4fefa5..6487efeb 100644
--- a/src/types/immutable_string.rs
+++ b/src/types/immutable_string.rs
@@ -264,9 +264,9 @@ impl Add<ImmutableString> for &ImmutableString {
     }
 }
 
-impl AddAssign<&ImmutableString> for ImmutableString {
+impl AddAssign<&Self> for ImmutableString {
     #[inline]
-    fn add_assign(&mut self, rhs: &ImmutableString) {
+    fn add_assign(&mut self, rhs: &Self) {
         if !rhs.is_empty() {
             if self.is_empty() {
                 self.0 = rhs.0.clone();
@@ -277,9 +277,9 @@ impl AddAssign<&ImmutableString> for ImmutableString {
     }
 }
 
-impl AddAssign<ImmutableString> for ImmutableString {
+impl AddAssign<Self> for ImmutableString {
     #[inline]
-    fn add_assign(&mut self, rhs: ImmutableString) {
+    fn add_assign(&mut self, rhs: Self) {
         if !rhs.is_empty() {
             if self.is_empty() {
                 self.0 = rhs.0;
@@ -431,9 +431,9 @@ impl Sub for &ImmutableString {
     }
 }
 
-impl SubAssign<&ImmutableString> for ImmutableString {
+impl SubAssign<&Self> for ImmutableString {
     #[inline]
-    fn sub_assign(&mut self, rhs: &ImmutableString) {
+    fn sub_assign(&mut self, rhs: &Self) {
         if !rhs.is_empty() {
             if self.is_empty() {
                 self.0 = rhs.0.clone();
@@ -445,9 +445,9 @@ impl SubAssign<&ImmutableString> for ImmutableString {
     }
 }
 
-impl SubAssign<ImmutableString> for ImmutableString {
+impl SubAssign<Self> for ImmutableString {
     #[inline]
-    fn sub_assign(&mut self, rhs: ImmutableString) {
+    fn sub_assign(&mut self, rhs: Self) {
         if !rhs.is_empty() {
             if self.is_empty() {
                 self.0 = rhs.0;
diff --git a/src/types/interner.rs b/src/types/interner.rs
index 90c28461..40df1982 100644
--- a/src/types/interner.rs
+++ b/src/types/interner.rs
@@ -64,7 +64,7 @@ impl StringsInterner<'_> {
     #[inline(always)]
     #[must_use]
     pub fn get<S: AsRef<str> + Into<ImmutableString>>(&mut self, text: S) -> ImmutableString {
-        self.get_with_mapper(|s| s.into(), text)
+        self.get_with_mapper(Into::into, text)
     }
 
     /// Get an identifier from a text string, adding it to the interner if necessary.
diff --git a/src/types/parse_error.rs b/src/types/parse_error.rs
index a80255f0..47e3589a 100644
--- a/src/types/parse_error.rs
+++ b/src/types/parse_error.rs
@@ -302,13 +302,13 @@ impl ParseError {
     /// Get the [type][ParseErrorType] of this parse error.
     #[inline(always)]
     #[must_use]
-    pub fn err_type(&self) -> &ParseErrorType {
+    pub const fn err_type(&self) -> &ParseErrorType {
         &self.0
     }
     /// Get the [position][Position] of this parse error.
     #[inline(always)]
     #[must_use]
-    pub fn position(&self) -> Position {
+    pub const fn position(&self) -> Position {
         self.1
     }
 }
@@ -323,7 +323,7 @@ impl From<ParseErrorType> for RhaiError {
 impl From<ParseErrorType> for ERR {
     #[inline(always)]
     fn from(err: ParseErrorType) -> Self {
-        ERR::ErrorParsing(err, Position::NONE)
+        Self::ErrorParsing(err, Position::NONE)
     }
 }
 
@@ -337,6 +337,6 @@ impl From<ParseError> for RhaiError {
 impl From<ParseError> for ERR {
     #[inline(always)]
     fn from(err: ParseError) -> Self {
-        ERR::ErrorParsing(*err.0, err.1)
+        Self::ErrorParsing(*err.0, err.1)
     }
 }
diff --git a/tests/build_type.rs b/tests/build_type.rs
index 9fbcc1af..05b23bc2 100644
--- a/tests/build_type.rs
+++ b/tests/build_type.rs
@@ -3,7 +3,7 @@ use rhai::{CustomType, Engine, EvalAltResult, Position, TypeBuilder, INT};
 
 #[test]
 fn build_type() -> Result<(), Box<EvalAltResult>> {
-    #[derive(Debug, Clone, PartialEq)]
+    #[derive(Debug, Clone, PartialEq, Eq)]
     struct Vec3 {
         x: INT,
         y: INT,
@@ -60,7 +60,8 @@ fn build_type() -> Result<(), Box<EvalAltResult>> {
                 .with_name("Vec3")
                 .is_iterable()
                 .with_fn("vec3", Self::new)
-                .is_iterable()
+                .with_fn("==", |x: &mut Vec3, y: Vec3| *x == y)
+                .with_fn("!=", |x: &mut Vec3, y: Vec3| *x != y)
                 .with_get_set("x", Self::get_x, Self::set_x)
                 .with_get_set("y", Self::get_y, Self::set_y)
                 .with_get_set("z", Self::get_z, Self::set_z);