From 72b7ee586677e3d6f0a9b24c12a0abc8b3f98729 Mon Sep 17 00:00:00 2001
From: Choongwoo Han <cwhan.tunz@gmail.com>
Date: Fri, 28 Jul 2023 09:19:28 -0700
Subject: [PATCH] Re-enable must_use clippy rule (#3180)

---
 boa_engine/src/builtins/function/mod.rs       |  5 +
 boa_engine/src/builtins/iterable/mod.rs       | 11 +++
 boa_engine/src/builtins/map/ordered_map.rs    |  1 +
 boa_engine/src/builtins/promise/mod.rs        |  2 +
 boa_engine/src/builtins/set/ordered_set.rs    |  1 +
 .../typed_array/integer_indexed_object.rs     |  4 +
 boa_engine/src/context/intrinsics.rs          | 69 +++++++++++++
 boa_engine/src/context/mod.rs                 | 10 ++
 boa_engine/src/error.rs                       | 13 +++
 boa_engine/src/job.rs                         |  3 +
 boa_engine/src/lib.rs                         |  1 -
 boa_engine/src/module/mod.rs                  |  1 +
 boa_engine/src/object/builtins/jsfunction.rs  |  1 +
 boa_engine/src/object/jsobject.rs             | 42 ++++++++
 boa_engine/src/object/mod.rs                  | 97 +++++++++++++++++++
 boa_engine/src/object/shape/mod.rs            |  5 +
 boa_engine/src/object/shape/root_shape.rs     |  1 +
 .../src/object/shape/shared_shape/mod.rs      |  4 +
 boa_engine/src/property/mod.rs                | 19 ++++
 boa_engine/src/realm.rs                       |  1 +
 boa_engine/src/script.rs                      |  1 +
 boa_engine/src/value/display.rs               |  1 +
 boa_engine/src/value/equality.rs              |  3 +
 boa_engine/src/value/mod.rs                   | 26 +++++
 boa_engine/src/value/type.rs                  |  1 +
 boa_engine/src/vm/call_frame/mod.rs           |  1 +
 26 files changed, 323 insertions(+), 1 deletion(-)

diff --git a/boa_engine/src/builtins/function/mod.rs b/boa_engine/src/builtins/function/mod.rs
index 6e32a459fc1..68bb0761a2e 100644
--- a/boa_engine/src/builtins/function/mod.rs
+++ b/boa_engine/src/builtins/function/mod.rs
@@ -316,6 +316,7 @@ pub struct Function {
 
 impl Function {
     /// Returns the codeblock of the function, or `None` if the function is a [`NativeFunction`].
+    #[must_use]
     pub fn codeblock(&self) -> Option<&CodeBlock> {
         match &self.kind {
             FunctionKind::Native { .. } => None,
@@ -438,6 +439,7 @@ impl Function {
     }
 
     /// Gets the `Realm` from where this function originates.
+    #[must_use]
     pub const fn realm(&self) -> &Realm {
         &self.realm
     }
@@ -1128,16 +1130,19 @@ impl BoundFunction {
     }
 
     /// Get a reference to the bound function's this.
+    #[must_use]
     pub const fn this(&self) -> &JsValue {
         &self.this
     }
 
     /// Get a reference to the bound function's target function.
+    #[must_use]
     pub const fn target_function(&self) -> &JsObject {
         &self.target_function
     }
 
     /// Get a reference to the bound function's args.
+    #[must_use]
     pub fn args(&self) -> &[JsValue] {
         self.args.as_slice()
     }
diff --git a/boa_engine/src/builtins/iterable/mod.rs b/boa_engine/src/builtins/iterable/mod.rs
index 13a31260252..2db05486df9 100644
--- a/boa_engine/src/builtins/iterable/mod.rs
+++ b/boa_engine/src/builtins/iterable/mod.rs
@@ -77,60 +77,70 @@ pub struct IteratorPrototypes {
 impl IteratorPrototypes {
     /// Returns the `ArrayIteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn array(&self) -> JsObject {
         self.array.clone()
     }
 
     /// Returns the `IteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn iterator(&self) -> JsObject {
         self.iterator.clone()
     }
 
     /// Returns the `AsyncIteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn async_iterator(&self) -> JsObject {
         self.async_iterator.clone()
     }
 
     /// Returns the `AsyncFromSyncIteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn async_from_sync_iterator(&self) -> JsObject {
         self.async_from_sync_iterator.clone()
     }
 
     /// Returns the `SetIteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn set(&self) -> JsObject {
         self.set.clone()
     }
 
     /// Returns the `StringIteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn string(&self) -> JsObject {
         self.string.clone()
     }
 
     /// Returns the `RegExpStringIteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn regexp_string(&self) -> JsObject {
         self.regexp_string.clone()
     }
 
     /// Returns the `MapIteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn map(&self) -> JsObject {
         self.map.clone()
     }
 
     /// Returns the `ForInIteratorPrototype` object.
     #[inline]
+    #[must_use]
     pub fn for_in(&self) -> JsObject {
         self.for_in.clone()
     }
 
     /// Returns the `%SegmentIteratorPrototype%` object.
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub fn segment(&self) -> JsObject {
         self.segment.clone()
@@ -378,6 +388,7 @@ pub struct IteratorRecord {
 impl IteratorRecord {
     /// Creates a new `IteratorRecord` with the given iterator object, next method and `done` flag.
     #[inline]
+    #[must_use]
     pub fn new(iterator: JsObject, next_method: JsValue) -> Self {
         Self {
             iterator,
diff --git a/boa_engine/src/builtins/map/ordered_map.rs b/boa_engine/src/builtins/map/ordered_map.rs
index 9ee5e7036bf..2c2884bccd3 100644
--- a/boa_engine/src/builtins/map/ordered_map.rs
+++ b/boa_engine/src/builtins/map/ordered_map.rs
@@ -191,6 +191,7 @@ impl<V> OrderedMap<V> {
     /// Return `true` if an equivalent to `key` exists in the map.
     ///
     /// Computes in **O(1)** time (average).
+    #[must_use]
     pub fn contains_key(&self, key: &JsValue) -> bool {
         self.map.contains_key(key)
     }
diff --git a/boa_engine/src/builtins/promise/mod.rs b/boa_engine/src/builtins/promise/mod.rs
index f74b01494bd..c9eb2e32554 100644
--- a/boa_engine/src/builtins/promise/mod.rs
+++ b/boa_engine/src/builtins/promise/mod.rs
@@ -51,6 +51,7 @@ unsafe impl Trace for PromiseState {
 impl PromiseState {
     /// Gets the inner `JsValue` of a fulfilled promise state, or returns `None` if
     /// the state is not `Fulfilled`.
+    #[must_use]
     pub const fn as_fulfilled(&self) -> Option<&JsValue> {
         match self {
             Self::Fulfilled(v) => Some(v),
@@ -60,6 +61,7 @@ impl PromiseState {
 
     /// Gets the inner `JsValue` of a rejected promise state, or returns `None` if
     /// the state is not `Rejected`.
+    #[must_use]
     pub const fn as_rejected(&self) -> Option<&JsValue> {
         match self {
             Self::Rejected(v) => Some(v),
diff --git a/boa_engine/src/builtins/set/ordered_set.rs b/boa_engine/src/builtins/set/ordered_set.rs
index 6eb5ae78c3a..137896f3caf 100644
--- a/boa_engine/src/builtins/set/ordered_set.rs
+++ b/boa_engine/src/builtins/set/ordered_set.rs
@@ -122,6 +122,7 @@ impl OrderedSet {
     /// Return `true` if `value` is present in set, false otherwise.
     ///
     /// Computes in **O(n)** time (average).
+    #[must_use]
     pub fn contains(&self, value: &JsValue) -> bool {
         self.inner.contains(value)
     }
diff --git a/boa_engine/src/builtins/typed_array/integer_indexed_object.rs b/boa_engine/src/builtins/typed_array/integer_indexed_object.rs
index b7049bddc11..28736df3c67 100644
--- a/boa_engine/src/builtins/typed_array/integer_indexed_object.rs
+++ b/boa_engine/src/builtins/typed_array/integer_indexed_object.rs
@@ -66,6 +66,7 @@ impl IntegerIndexed {
     }
 
     /// Get the integer indexed object's byte offset.
+    #[must_use]
     pub const fn byte_offset(&self) -> u64 {
         self.byte_offset
     }
@@ -81,6 +82,7 @@ impl IntegerIndexed {
     }
 
     /// Get a reference to the integer indexed object's viewed array buffer.
+    #[must_use]
     pub const fn viewed_array_buffer(&self) -> Option<&JsObject> {
         self.viewed_array_buffer.as_ref()
     }
@@ -91,6 +93,7 @@ impl IntegerIndexed {
     }
 
     /// Get the integer indexed object's byte length.
+    #[must_use]
     pub const fn byte_length(&self) -> u64 {
         self.byte_length
     }
@@ -101,6 +104,7 @@ impl IntegerIndexed {
     }
 
     /// Get the integer indexed object's array length.
+    #[must_use]
     pub const fn array_length(&self) -> u64 {
         self.array_length
     }
diff --git a/boa_engine/src/context/intrinsics.rs b/boa_engine/src/context/intrinsics.rs
index 92d3c825d5c..1ed9da96fd8 100644
--- a/boa_engine/src/context/intrinsics.rs
+++ b/boa_engine/src/context/intrinsics.rs
@@ -40,12 +40,14 @@ impl Intrinsics {
 
     /// Return the cached intrinsic objects.
     #[inline]
+    #[must_use]
     pub const fn objects(&self) -> &IntrinsicObjects {
         &self.objects
     }
 
     /// Return the cached standard constructors.
     #[inline]
+    #[must_use]
     pub const fn constructors(&self) -> &StandardConstructors {
         &self.constructors
     }
@@ -84,6 +86,7 @@ impl StandardConstructor {
     ///
     /// This is the same as `Object.prototype`, `Array.prototype`, etc
     #[inline]
+    #[must_use]
     pub fn prototype(&self) -> JsObject {
         self.prototype.clone()
     }
@@ -92,6 +95,7 @@ impl StandardConstructor {
     ///
     /// This is the same as `Object`, `Array`, etc.
     #[inline]
+    #[must_use]
     pub fn constructor(&self) -> JsObject {
         self.constructor.clone().into()
     }
@@ -237,6 +241,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-asyncgeneratorfunction-constructor
     #[inline]
+    #[must_use]
     pub const fn async_generator_function(&self) -> &StandardConstructor {
         &self.async_generator_function
     }
@@ -248,6 +253,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-object-constructor
     #[inline]
+    #[must_use]
     pub const fn object(&self) -> &StandardConstructor {
         &self.object
     }
@@ -259,6 +265,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-proxy-constructor
     #[inline]
+    #[must_use]
     pub const fn proxy(&self) -> &StandardConstructor {
         &self.proxy
     }
@@ -270,6 +277,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-date-constructor
     #[inline]
+    #[must_use]
     pub const fn date(&self) -> &StandardConstructor {
         &self.date
     }
@@ -281,6 +289,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-function-constructor
     #[inline]
+    #[must_use]
     pub const fn function(&self) -> &StandardConstructor {
         &self.function
     }
@@ -292,6 +301,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-async-function-constructor
     #[inline]
+    #[must_use]
     pub const fn async_function(&self) -> &StandardConstructor {
         &self.async_function
     }
@@ -303,6 +313,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-generatorfunction-constructor
     #[inline]
+    #[must_use]
     pub const fn generator_function(&self) -> &StandardConstructor {
         &self.generator_function
     }
@@ -314,6 +325,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-array-constructor
     #[inline]
+    #[must_use]
     pub const fn array(&self) -> &StandardConstructor {
         &self.array
     }
@@ -325,6 +337,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-bigint-constructor
     #[inline]
+    #[must_use]
     pub const fn bigint(&self) -> &StandardConstructor {
         &self.bigint
     }
@@ -336,6 +349,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-number-constructor
     #[inline]
+    #[must_use]
     pub const fn number(&self) -> &StandardConstructor {
         &self.number
     }
@@ -347,6 +361,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-boolean-constructor
     #[inline]
+    #[must_use]
     pub const fn boolean(&self) -> &StandardConstructor {
         &self.boolean
     }
@@ -358,6 +373,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-string-constructor
     #[inline]
+    #[must_use]
     pub const fn string(&self) -> &StandardConstructor {
         &self.string
     }
@@ -369,6 +385,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-regexp-constructor
     #[inline]
+    #[must_use]
     pub const fn regexp(&self) -> &StandardConstructor {
         &self.regexp
     }
@@ -380,6 +397,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-symbol-constructor
     #[inline]
+    #[must_use]
     pub const fn symbol(&self) -> &StandardConstructor {
         &self.symbol
     }
@@ -391,6 +409,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-error-constructor
     #[inline]
+    #[must_use]
     pub const fn error(&self) -> &StandardConstructor {
         &self.error
     }
@@ -402,6 +421,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-native-error-types-used-in-this-standard-referenceerror
     #[inline]
+    #[must_use]
     pub const fn reference_error(&self) -> &StandardConstructor {
         &self.reference_error
     }
@@ -413,6 +433,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-native-error-types-used-in-this-standard-typeerror
     #[inline]
+    #[must_use]
     pub const fn type_error(&self) -> &StandardConstructor {
         &self.type_error
     }
@@ -424,6 +445,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-native-error-types-used-in-this-standard-rangeerror
     #[inline]
+    #[must_use]
     pub const fn range_error(&self) -> &StandardConstructor {
         &self.range_error
     }
@@ -435,6 +457,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-native-error-types-used-in-this-standard-syntaxerror
     #[inline]
+    #[must_use]
     pub const fn syntax_error(&self) -> &StandardConstructor {
         &self.syntax_error
     }
@@ -446,6 +469,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-native-error-types-used-in-this-standard-evalerror
     #[inline]
+    #[must_use]
     pub const fn eval_error(&self) -> &StandardConstructor {
         &self.eval_error
     }
@@ -457,6 +481,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-native-error-types-used-in-this-standard-urierror
     #[inline]
+    #[must_use]
     pub const fn uri_error(&self) -> &StandardConstructor {
         &self.uri_error
     }
@@ -468,6 +493,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-aggregate-error-constructor
     #[inline]
+    #[must_use]
     pub const fn aggregate_error(&self) -> &StandardConstructor {
         &self.aggregate_error
     }
@@ -479,6 +505,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-map-constructor
     #[inline]
+    #[must_use]
     pub const fn map(&self) -> &StandardConstructor {
         &self.map
     }
@@ -490,6 +517,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-set-constructor
     #[inline]
+    #[must_use]
     pub const fn set(&self) -> &StandardConstructor {
         &self.set
     }
@@ -501,6 +529,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_array(&self) -> &StandardConstructor {
         &self.typed_array
     }
@@ -512,6 +541,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_int8_array(&self) -> &StandardConstructor {
         &self.typed_int8_array
     }
@@ -523,6 +553,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_uint8_array(&self) -> &StandardConstructor {
         &self.typed_uint8_array
     }
@@ -534,6 +565,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_uint8clamped_array(&self) -> &StandardConstructor {
         &self.typed_uint8clamped_array
     }
@@ -545,6 +577,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_int16_array(&self) -> &StandardConstructor {
         &self.typed_int16_array
     }
@@ -556,6 +589,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_uint16_array(&self) -> &StandardConstructor {
         &self.typed_uint16_array
     }
@@ -567,6 +601,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_uint32_array(&self) -> &StandardConstructor {
         &self.typed_uint32_array
     }
@@ -578,6 +613,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_int32_array(&self) -> &StandardConstructor {
         &self.typed_int32_array
     }
@@ -589,6 +625,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_bigint64_array(&self) -> &StandardConstructor {
         &self.typed_bigint64_array
     }
@@ -600,6 +637,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_biguint64_array(&self) -> &StandardConstructor {
         &self.typed_biguint64_array
     }
@@ -611,6 +649,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_float32_array(&self) -> &StandardConstructor {
         &self.typed_float32_array
     }
@@ -622,6 +661,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typedarray-constructors
     #[inline]
+    #[must_use]
     pub const fn typed_float64_array(&self) -> &StandardConstructor {
         &self.typed_float64_array
     }
@@ -633,6 +673,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-arraybuffer-constructor
     #[inline]
+    #[must_use]
     pub const fn array_buffer(&self) -> &StandardConstructor {
         &self.array_buffer
     }
@@ -644,6 +685,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-dataview-constructor
     #[inline]
+    #[must_use]
     pub const fn data_view(&self) -> &StandardConstructor {
         &self.data_view
     }
@@ -655,6 +697,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma402/#sec-intl-datetimeformat-constructor
     #[inline]
+    #[must_use]
     pub const fn date_time_format(&self) -> &StandardConstructor {
         &self.date_time_format
     }
@@ -666,6 +709,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-promise-constructor
     #[inline]
+    #[must_use]
     pub const fn promise(&self) -> &StandardConstructor {
         &self.promise
     }
@@ -677,6 +721,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-weak-ref-constructor
     #[inline]
+    #[must_use]
     pub const fn weak_ref(&self) -> &StandardConstructor {
         &self.weak_ref
     }
@@ -688,6 +733,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-weakmap-constructor
     #[inline]
+    #[must_use]
     pub const fn weak_map(&self) -> &StandardConstructor {
         &self.weak_map
     }
@@ -699,6 +745,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-weakset-constructor
     #[inline]
+    #[must_use]
     pub const fn weak_set(&self) -> &StandardConstructor {
         &self.weak_set
     }
@@ -710,6 +757,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma402/#sec-intl.collator
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn collator(&self) -> &StandardConstructor {
         &self.collator
@@ -722,6 +770,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma402/#sec-Intl.ListFormat
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn list_format(&self) -> &StandardConstructor {
         &self.list_format
@@ -734,6 +783,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma402/#sec-Intl.Locale
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn locale(&self) -> &StandardConstructor {
         &self.locale
@@ -746,6 +796,7 @@ impl StandardConstructors {
     ///
     /// [spec]: https://tc39.es/ecma402/#sec-intl.segmenter
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn segmenter(&self) -> &StandardConstructor {
         &self.segmenter
@@ -848,6 +899,7 @@ impl IntrinsicObjects {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-%throwtypeerror%
     #[inline]
+    #[must_use]
     pub fn throw_type_error(&self) -> JsFunction {
         self.throw_type_error.clone()
     }
@@ -856,12 +908,14 @@ impl IntrinsicObjects {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-array.prototype.values
     #[inline]
+    #[must_use]
     pub fn array_prototype_values(&self) -> JsFunction {
         self.array_prototype_values.clone()
     }
 
     /// Gets the cached iterator prototypes.
     #[inline]
+    #[must_use]
     pub const fn iterator_prototypes(&self) -> &IteratorPrototypes {
         &self.iterator_prototypes
     }
@@ -870,6 +924,7 @@ impl IntrinsicObjects {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-generator-objects
     #[inline]
+    #[must_use]
     pub fn generator(&self) -> JsObject {
         self.generator.clone()
     }
@@ -878,6 +933,7 @@ impl IntrinsicObjects {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-asyncgenerator-objects
     #[inline]
+    #[must_use]
     pub fn async_generator(&self) -> JsObject {
         self.async_generator.clone()
     }
@@ -885,11 +941,13 @@ impl IntrinsicObjects {
     /// Gets the [`%eval%`][spec] intrinsic function.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-eval-x
+    #[must_use]
     pub fn eval(&self) -> JsFunction {
         self.eval.clone()
     }
 
     /// Gets the URI intrinsic functions.
+    #[must_use]
     pub const fn uri_functions(&self) -> &UriFunctions {
         &self.uri_functions
     }
@@ -897,6 +955,7 @@ impl IntrinsicObjects {
     /// Gets the [`%Reflect%`][spec] intrinsic object.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-reflect
+    #[must_use]
     pub fn reflect(&self) -> JsObject {
         self.reflect.clone()
     }
@@ -904,6 +963,7 @@ impl IntrinsicObjects {
     /// Gets the [`%Math%`][spec] intrinsic object.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-math
+    #[must_use]
     pub fn math(&self) -> JsObject {
         self.math.clone()
     }
@@ -911,6 +971,7 @@ impl IntrinsicObjects {
     /// Gets the [`%JSON%`][spec] intrinsic object.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-json
+    #[must_use]
     pub fn json(&self) -> JsObject {
         self.json.clone()
     }
@@ -918,6 +979,7 @@ impl IntrinsicObjects {
     /// Gets the [`%isFinite%`][spec] intrinsic function.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-isfinite-number
+    #[must_use]
     pub fn is_finite(&self) -> JsFunction {
         self.is_finite.clone()
     }
@@ -925,6 +987,7 @@ impl IntrinsicObjects {
     /// Gets the [`%isNaN%`][spec] intrinsic function.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-isnan-number
+    #[must_use]
     pub fn is_nan(&self) -> JsFunction {
         self.is_nan.clone()
     }
@@ -932,6 +995,7 @@ impl IntrinsicObjects {
     /// Gets the [`%parseFloat%`][spec] intrinsic function.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-parsefloat-string
+    #[must_use]
     pub fn parse_float(&self) -> JsFunction {
         self.parse_float.clone()
     }
@@ -939,6 +1003,7 @@ impl IntrinsicObjects {
     /// Gets the [`%parseInt%`][spec] intrinsic function.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-parseint-string-radix
+    #[must_use]
     pub fn parse_int(&self) -> JsFunction {
         self.parse_int.clone()
     }
@@ -946,6 +1011,7 @@ impl IntrinsicObjects {
     /// Gets the [`%escape%`][spec] intrinsic function.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-escape-string
+    #[must_use]
     #[cfg(feature = "annex-b")]
     pub fn escape(&self) -> JsFunction {
         self.escape.clone()
@@ -954,6 +1020,7 @@ impl IntrinsicObjects {
     /// Gets the [`%unescape%`][spec] intrinsic function.
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-unescape-string
+    #[must_use]
     #[cfg(feature = "annex-b")]
     pub fn unescape(&self) -> JsFunction {
         self.unescape.clone()
@@ -962,6 +1029,7 @@ impl IntrinsicObjects {
     /// Gets the [`%Intl%`][spec] intrinsic object.
     ///
     /// [spec]: https://tc39.es/ecma402/#intl-object
+    #[must_use]
     #[cfg(feature = "intl")]
     pub fn intl(&self) -> JsObject {
         self.intl.clone()
@@ -970,6 +1038,7 @@ impl IntrinsicObjects {
     /// Gets the [`%SegmentsPrototype%`][spec] intrinsic object.
     ///
     /// [spec]: https://tc39.es/ecma402/#sec-%segmentsprototype%-object
+    #[must_use]
     #[cfg(feature = "intl")]
     pub fn segments_prototype(&self) -> JsObject {
         self.segments_prototype.clone()
diff --git a/boa_engine/src/context/mod.rs b/boa_engine/src/context/mod.rs
index 56641c8300f..f57e9ef3c3f 100644
--- a/boa_engine/src/context/mod.rs
+++ b/boa_engine/src/context/mod.rs
@@ -344,6 +344,7 @@ impl<'host> Context<'host> {
 
     /// Gets the string interner.
     #[inline]
+    #[must_use]
     pub const fn interner(&self) -> &Interner {
         &self.interner
     }
@@ -356,18 +357,21 @@ impl<'host> Context<'host> {
 
     /// Returns the global object.
     #[inline]
+    #[must_use]
     pub fn global_object(&self) -> JsObject {
         self.realm.global_object().clone()
     }
 
     /// Returns the currently active intrinsic constructors and objects.
     #[inline]
+    #[must_use]
     pub fn intrinsics(&self) -> &Intrinsics {
         self.realm.intrinsics()
     }
 
     /// Returns the currently active realm.
     #[inline]
+    #[must_use]
     pub const fn realm(&self) -> &Realm {
         &self.realm
     }
@@ -381,6 +385,7 @@ impl<'host> Context<'host> {
 
     /// Get optimizer options.
     #[inline]
+    #[must_use]
     pub const fn optimizer_options(&self) -> OptimizerOptions {
         self.optimizer_options
     }
@@ -452,29 +457,34 @@ impl<'host> Context<'host> {
 
     /// Get the [`RootShape`].
     #[inline]
+    #[must_use]
     pub const fn root_shape(&self) -> &RootShape {
         &self.root_shape
     }
 
     /// Gets the host hooks.
     #[inline]
+    #[must_use]
     pub fn host_hooks(&self) -> MaybeShared<'host, dyn HostHooks> {
         self.host_hooks.clone()
     }
 
     /// Gets the job queue.
     #[inline]
+    #[must_use]
     pub fn job_queue(&self) -> MaybeShared<'host, dyn JobQueue> {
         self.job_queue.clone()
     }
 
     /// Gets the module loader.
+    #[must_use]
     pub fn module_loader(&self) -> MaybeShared<'host, dyn ModuleLoader> {
         self.module_loader.clone()
     }
 
     /// Get the [`RuntimeLimits`].
     #[inline]
+    #[must_use]
     pub const fn runtime_limits(&self) -> RuntimeLimits {
         self.vm.runtime_limits
     }
diff --git a/boa_engine/src/error.rs b/boa_engine/src/error.rs
index 1a66e7caee7..a3d22cddef4 100644
--- a/boa_engine/src/error.rs
+++ b/boa_engine/src/error.rs
@@ -149,6 +149,7 @@ impl JsError {
     ///
     /// assert!(error.as_opaque().is_some());
     /// ```
+    #[must_use]
     pub const fn from_opaque(value: JsValue) -> Self {
         Self {
             inner: Repr::Opaque(value),
@@ -329,6 +330,7 @@ impl JsError {
     ///
     /// assert!(error.as_opaque().is_some());
     /// ```
+    #[must_use]
     pub const fn as_opaque(&self) -> Option<&JsValue> {
         match self.inner {
             Repr::Native(_) => None,
@@ -351,6 +353,7 @@ impl JsError {
     ///
     /// assert!(error.as_native().is_none());
     /// ```
+    #[must_use]
     pub const fn as_native(&self) -> Option<&JsNativeError> {
         match &self.inner {
             Repr::Native(e) => Some(e),
@@ -474,6 +477,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::Aggregate`].
+    #[must_use]
     #[inline]
     pub const fn is_aggregate(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::Aggregate(_))
@@ -496,6 +500,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::Error`].
+    #[must_use]
     #[inline]
     pub const fn is_error(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::Error)
@@ -518,6 +523,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::Eval`].
+    #[must_use]
     #[inline]
     pub const fn is_eval(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::Eval)
@@ -540,6 +546,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::Range`].
+    #[must_use]
     #[inline]
     pub const fn is_range(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::Range)
@@ -562,6 +569,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::Reference`].
+    #[must_use]
     #[inline]
     pub const fn is_reference(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::Reference)
@@ -584,6 +592,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::Syntax`].
+    #[must_use]
     #[inline]
     pub const fn is_syntax(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::Syntax)
@@ -606,6 +615,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::Type`].
+    #[must_use]
     #[inline]
     pub const fn is_type(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::Type)
@@ -628,6 +638,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::Uri`].
+    #[must_use]
     #[inline]
     pub const fn is_uri(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::Uri)
@@ -646,6 +657,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::NoInstructionsRemain`].
+    #[must_use]
     #[inline]
     #[cfg(feature = "fuzz")]
     pub const fn is_no_instructions_remain(&self) -> bool {
@@ -660,6 +672,7 @@ impl JsNativeError {
     }
 
     /// Check if it's a [`JsNativeErrorKind::RuntimeLimit`].
+    #[must_use]
     #[inline]
     pub const fn is_runtime_limit(&self) -> bool {
         matches!(self.kind, JsNativeErrorKind::RuntimeLimit)
diff --git a/boa_engine/src/job.rs b/boa_engine/src/job.rs
index d9049897129..34373bcaf8c 100644
--- a/boa_engine/src/job.rs
+++ b/boa_engine/src/job.rs
@@ -104,6 +104,7 @@ impl NativeJob {
     }
 
     /// Gets a reference to the execution realm of the job.
+    #[must_use]
     pub const fn realm(&self) -> Option<&Realm> {
         self.realm.as_ref()
     }
@@ -167,11 +168,13 @@ impl JobCallback {
     }
 
     /// Gets the inner callback of the job.
+    #[must_use]
     pub const fn callback(&self) -> &JsFunction {
         &self.callback
     }
 
     /// Gets a reference to the host defined additional field as an `Any` trait object.
+    #[must_use]
     pub fn host_defined(&self) -> &dyn Any {
         self.host_defined.as_any()
     }
diff --git a/boa_engine/src/lib.rs b/boa_engine/src/lib.rs
index 97655042bfe..fdb23518e79 100644
--- a/boa_engine/src/lib.rs
+++ b/boa_engine/src/lib.rs
@@ -119,7 +119,6 @@
     clippy::cast_sign_loss,
     clippy::cast_precision_loss,
     clippy::cast_possible_wrap,
-    clippy::must_use_candidate,
 )]
 
 extern crate static_assertions as sa;
diff --git a/boa_engine/src/module/mod.rs b/boa_engine/src/module/mod.rs
index cb5f8693a19..c8082a28e46 100644
--- a/boa_engine/src/module/mod.rs
+++ b/boa_engine/src/module/mod.rs
@@ -383,6 +383,7 @@ impl Module {
 
     /// Gets the realm of this `Module`.
     #[inline]
+    #[must_use]
     pub fn realm(&self) -> &Realm {
         &self.inner.realm
     }
diff --git a/boa_engine/src/object/builtins/jsfunction.rs b/boa_engine/src/object/builtins/jsfunction.rs
index 522242acc69..541873e1651 100644
--- a/boa_engine/src/object/builtins/jsfunction.rs
+++ b/boa_engine/src/object/builtins/jsfunction.rs
@@ -44,6 +44,7 @@ impl JsFunction {
     ///
     /// This does not clone the fields of the function, it only does a shallow clone of the object.
     #[inline]
+    #[must_use]
     pub fn from_object(object: JsObject) -> Option<Self> {
         object
             .is_callable()
diff --git a/boa_engine/src/object/jsobject.rs b/boa_engine/src/object/jsobject.rs
index 2b583a4e758..8d0e56440f6 100644
--- a/boa_engine/src/object/jsobject.rs
+++ b/boa_engine/src/object/jsobject.rs
@@ -156,6 +156,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn borrow(&self) -> Ref<'_, Object> {
         self.try_borrow().expect("Object already mutably borrowed")
@@ -169,6 +170,7 @@ impl JsObject {
     /// # Panics
     /// Panics if the object is currently borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn borrow_mut(&self) -> RefMut<'_, Object, Object> {
         self.try_borrow_mut().expect("Object already borrowed")
@@ -200,6 +202,7 @@ impl JsObject {
     }
 
     /// Checks if the garbage collected memory is the same.
+    #[must_use]
     #[inline]
     pub fn equals(lhs: &Self, rhs: &Self) -> bool {
         std::ptr::eq(lhs.as_ref(), rhs.as_ref())
@@ -285,6 +288,7 @@ impl JsObject {
     /// # Panics
     ///
     /// Panics if the object is currently mutably borrowed.
+    #[must_use]
     #[track_caller]
     pub fn is<T>(&self) -> bool
     where
@@ -299,6 +303,7 @@ impl JsObject {
     /// # Panics
     ///
     /// Panics if the object is currently mutably borrowed.
+    #[must_use]
     #[track_caller]
     pub fn downcast_ref<T>(&self) -> Option<Ref<'_, T>>
     where
@@ -320,6 +325,7 @@ impl JsObject {
     /// # Panics
     ///
     /// Panics if the object is currently borrowed.
+    #[must_use]
     #[track_caller]
     pub fn downcast_mut<T>(&self) -> Option<RefMut<'_, Object, T>>
     where
@@ -342,6 +348,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn prototype(&self) -> JsPrototype {
         self.borrow().prototype()
@@ -363,12 +370,14 @@ impl JsObject {
     /// Panics if the object is currently mutably borrowed
     #[inline]
     #[track_caller]
+    #[allow(clippy::must_use_candidate)]
     pub fn set_prototype(&self, prototype: JsPrototype) -> bool {
         self.borrow_mut().set_prototype(prototype)
     }
 
     /// Checks if it's an `Array` object.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_array(&self) -> bool {
         std::ptr::eq(self.vtable(), &ARRAY_EXOTIC_INTERNAL_METHODS)
@@ -380,6 +389,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_data_view(&self) -> bool {
         self.borrow().is_data_view()
@@ -391,6 +401,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_array_iterator(&self) -> bool {
         self.borrow().is_array_iterator()
@@ -402,6 +413,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_array_buffer(&self) -> bool {
         self.borrow().is_array_buffer()
@@ -413,6 +425,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_map(&self) -> bool {
         self.borrow().is_map()
@@ -424,6 +437,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_map_iterator(&self) -> bool {
         self.borrow().is_map_iterator()
@@ -435,6 +449,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_set(&self) -> bool {
         self.borrow().is_set()
@@ -446,6 +461,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_set_iterator(&self) -> bool {
         self.borrow().is_set_iterator()
@@ -457,6 +473,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_string(&self) -> bool {
         self.borrow().is_string()
@@ -468,6 +485,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_function(&self) -> bool {
         self.borrow().is_function()
@@ -479,6 +497,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_generator(&self) -> bool {
         self.borrow().is_generator()
@@ -490,6 +509,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_symbol(&self) -> bool {
         self.borrow().is_symbol()
@@ -501,6 +521,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_error(&self) -> bool {
         self.borrow().is_error()
@@ -512,6 +533,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_boolean(&self) -> bool {
         self.borrow().is_boolean()
@@ -523,6 +545,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_number(&self) -> bool {
         self.borrow().is_number()
@@ -534,6 +557,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_bigint(&self) -> bool {
         self.borrow().is_bigint()
@@ -545,6 +569,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_date(&self) -> bool {
         self.borrow().is_date()
@@ -556,6 +581,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_regexp(&self) -> bool {
         self.borrow().is_regexp()
@@ -567,6 +593,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_array(&self) -> bool {
         self.borrow().is_typed_array()
@@ -578,6 +605,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_uint8_array(&self) -> bool {
         self.borrow().is_typed_uint8_array()
@@ -589,6 +617,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_int8_array(&self) -> bool {
         self.borrow().is_typed_int8_array()
@@ -600,6 +629,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_uint16_array(&self) -> bool {
         self.borrow().is_typed_uint16_array()
@@ -611,6 +641,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_int16_array(&self) -> bool {
         self.borrow().is_typed_int16_array()
@@ -622,6 +653,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_uint32_array(&self) -> bool {
         self.borrow().is_typed_uint32_array()
@@ -633,6 +665,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_int32_array(&self) -> bool {
         self.borrow().is_typed_int32_array()
@@ -644,6 +677,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_float32_array(&self) -> bool {
         self.borrow().is_typed_float32_array()
@@ -655,6 +689,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_typed_float64_array(&self) -> bool {
         self.borrow().is_typed_float64_array()
@@ -666,6 +701,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_promise(&self) -> bool {
         self.borrow().is_promise()
@@ -677,6 +713,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_ordinary(&self) -> bool {
         self.borrow().is_ordinary()
@@ -688,6 +725,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_proxy(&self) -> bool {
         self.borrow().is_proxy()
@@ -699,6 +737,7 @@ impl JsObject {
     ///
     /// Panics if the object is currently mutably borrowed.
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_native_object(&self) -> bool {
         self.borrow().is_native_object()
@@ -915,6 +954,7 @@ Cannot both specify accessors and a value or writable attribute",
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-iscallable
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_callable(&self) -> bool {
         self.inner.vtable.__call__.is_some()
@@ -927,12 +967,14 @@ Cannot both specify accessors and a value or writable attribute",
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-isconstructor
     #[inline]
+    #[must_use]
     #[track_caller]
     pub fn is_constructor(&self) -> bool {
         self.inner.vtable.__construct__.is_some()
     }
 
     /// Returns true if the `JsObject` is the global for a Realm
+    #[must_use]
     pub fn is_global(&self) -> bool {
         matches!(self.inner.object.borrow().kind, ObjectKind::Global)
     }
diff --git a/boa_engine/src/object/mod.rs b/boa_engine/src/object/mod.rs
index 072693f79a8..a7e4db77fad 100644
--- a/boa_engine/src/object/mod.rs
+++ b/boa_engine/src/object/mod.rs
@@ -420,6 +420,7 @@ impl ObjectData {
     }
 
     /// Create the `AsyncFromSyncIterator` object data
+    #[must_use]
     pub fn async_from_sync_iterator(async_from_sync_iterator: AsyncFromSyncIterator) -> Self {
         Self {
             kind: ObjectKind::AsyncFromSyncIterator(async_from_sync_iterator),
@@ -428,6 +429,7 @@ impl ObjectData {
     }
 
     /// Create the `AsyncGenerator` object data
+    #[must_use]
     pub fn async_generator(async_generator: AsyncGenerator) -> Self {
         Self {
             kind: ObjectKind::AsyncGenerator(async_generator),
@@ -436,6 +438,7 @@ impl ObjectData {
     }
 
     /// Create the `AsyncGeneratorFunction` object data
+    #[must_use]
     pub fn async_generator_function(function: Function) -> Self {
         Self {
             internal_methods: &FUNCTION_INTERNAL_METHODS,
@@ -453,6 +456,7 @@ impl ObjectData {
     }
 
     /// Create the `ArrayIterator` object data
+    #[must_use]
     pub fn array_iterator(array_iterator: ArrayIterator) -> Self {
         Self {
             kind: ObjectKind::ArrayIterator(array_iterator),
@@ -461,6 +465,7 @@ impl ObjectData {
     }
 
     /// Create the `ArrayBuffer` object data
+    #[must_use]
     pub fn array_buffer(array_buffer: ArrayBuffer) -> Self {
         Self {
             kind: ObjectKind::ArrayBuffer(array_buffer),
@@ -478,6 +483,7 @@ impl ObjectData {
     }
 
     /// Create the `MapIterator` object data
+    #[must_use]
     pub fn map_iterator(map_iterator: MapIterator) -> Self {
         Self {
             kind: ObjectKind::MapIterator(map_iterator),
@@ -495,6 +501,7 @@ impl ObjectData {
     }
 
     /// Create the `RegExpStringIterator` object data
+    #[must_use]
     pub fn reg_exp_string_iterator(reg_exp_string_iterator: RegExpStringIterator) -> Self {
         Self {
             kind: ObjectKind::RegExpStringIterator(reg_exp_string_iterator),
@@ -521,6 +528,7 @@ impl ObjectData {
     }
 
     /// Create the `DataView` object data
+    #[must_use]
     pub fn data_view(data_view: DataView) -> Self {
         Self {
             kind: ObjectKind::DataView(data_view),
@@ -529,6 +537,7 @@ impl ObjectData {
     }
 
     /// Create the `Promise` object data
+    #[must_use]
     pub fn promise(promise: Promise) -> Self {
         Self {
             kind: ObjectKind::Promise(promise),
@@ -537,6 +546,7 @@ impl ObjectData {
     }
 
     /// Create the `ForInIterator` object data
+    #[must_use]
     pub fn for_in_iterator(for_in_iterator: ForInIterator) -> Self {
         Self {
             kind: ObjectKind::ForInIterator(for_in_iterator),
@@ -545,6 +555,7 @@ impl ObjectData {
     }
 
     /// Create the `Function` object data
+    #[must_use]
     pub fn function(function: Function, constructor: bool) -> Self {
         Self {
             internal_methods: if constructor {
@@ -557,6 +568,7 @@ impl ObjectData {
     }
 
     /// Create the `BoundFunction` object data
+    #[must_use]
     pub fn bound_function(bound_function: BoundFunction, constructor: bool) -> Self {
         Self {
             kind: ObjectKind::BoundFunction(bound_function),
@@ -569,6 +581,7 @@ impl ObjectData {
     }
 
     /// Create the `Generator` object data
+    #[must_use]
     pub fn generator(generator: Generator) -> Self {
         Self {
             kind: ObjectKind::Generator(generator),
@@ -577,6 +590,7 @@ impl ObjectData {
     }
 
     /// Create the `GeneratorFunction` object data
+    #[must_use]
     pub fn generator_function(function: Function) -> Self {
         Self {
             internal_methods: &FUNCTION_INTERNAL_METHODS,
@@ -594,6 +608,7 @@ impl ObjectData {
     }
 
     /// Create the `SetIterator` object data
+    #[must_use]
     pub fn set_iterator(set_iterator: SetIterator) -> Self {
         Self {
             kind: ObjectKind::SetIterator(set_iterator),
@@ -655,6 +670,7 @@ impl ObjectData {
     }
 
     /// Create the `Proxy` object data
+    #[must_use]
     pub fn proxy(proxy: Proxy, call: bool, construct: bool) -> Self {
         Self {
             kind: ObjectKind::Proxy(proxy),
@@ -678,6 +694,7 @@ impl ObjectData {
     }
 
     /// Create the `Arguments` object data
+    #[must_use]
     pub fn arguments(arguments: Arguments) -> Self {
         Self {
             internal_methods: if matches!(arguments, Arguments::Unmapped) {
@@ -690,6 +707,7 @@ impl ObjectData {
     }
 
     /// Creates the `WeakRef` object data
+    #[must_use]
     pub fn weak_ref(weak_ref: WeakGc<VTableObject>) -> Self {
         Self {
             kind: ObjectKind::WeakRef(weak_ref),
@@ -878,24 +896,28 @@ impl Object {
     }
 
     /// Returns the shape of the object.
+    #[must_use]
     pub const fn shape(&self) -> &Shape {
         &self.properties.shape
     }
 
     /// Returns the kind of the object.
     #[inline]
+    #[must_use]
     pub const fn kind(&self) -> &ObjectKind {
         &self.kind
     }
 
     /// Checks if it's an `AsyncFromSyncIterator` object.
     #[inline]
+    #[must_use]
     pub const fn is_async_from_sync_iterator(&self) -> bool {
         matches!(self.kind, ObjectKind::AsyncFromSyncIterator(_))
     }
 
     /// Returns a reference to the `AsyncFromSyncIterator` data on the object.
     #[inline]
+    #[must_use]
     pub const fn as_async_from_sync_iterator(&self) -> Option<&AsyncFromSyncIterator> {
         match self.kind {
             ObjectKind::AsyncFromSyncIterator(ref async_from_sync_iterator) => {
@@ -907,12 +929,14 @@ impl Object {
 
     /// Checks if it's an `AsyncGenerator` object.
     #[inline]
+    #[must_use]
     pub const fn is_async_generator(&self) -> bool {
         matches!(self.kind, ObjectKind::AsyncGenerator(_))
     }
 
     /// Returns a reference to the async generator data on the object.
     #[inline]
+    #[must_use]
     pub const fn as_async_generator(&self) -> Option<&AsyncGenerator> {
         match self.kind {
             ObjectKind::AsyncGenerator(ref async_generator) => Some(async_generator),
@@ -931,29 +955,34 @@ impl Object {
 
     /// Checks if the object is a `Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_array(&self) -> bool {
         matches!(self.kind, ObjectKind::Array)
     }
 
     #[inline]
+    #[must_use]
     pub(crate) const fn has_viewed_array_buffer(&self) -> bool {
         self.is_typed_array() || self.is_data_view()
     }
 
     /// Checks if the object is a `DataView` object.
     #[inline]
+    #[must_use]
     pub const fn is_data_view(&self) -> bool {
         matches!(self.kind, ObjectKind::DataView(_))
     }
 
     /// Checks if the object is a `ArrayBuffer` object.
     #[inline]
+    #[must_use]
     pub const fn is_array_buffer(&self) -> bool {
         matches!(self.kind, ObjectKind::ArrayBuffer(_))
     }
 
     /// Gets the array buffer data if the object is a `ArrayBuffer`.
     #[inline]
+    #[must_use]
     pub const fn as_array_buffer(&self) -> Option<&ArrayBuffer> {
         match &self.kind {
             ObjectKind::ArrayBuffer(buffer) => Some(buffer),
@@ -972,12 +1001,14 @@ impl Object {
 
     /// Checks if the object is a `ArrayIterator` object.
     #[inline]
+    #[must_use]
     pub const fn is_array_iterator(&self) -> bool {
         matches!(self.kind, ObjectKind::ArrayIterator(_))
     }
 
     /// Gets the array-iterator data if the object is a `ArrayIterator`.
     #[inline]
+    #[must_use]
     pub const fn as_array_iterator(&self) -> Option<&ArrayIterator> {
         match self.kind {
             ObjectKind::ArrayIterator(ref iter) => Some(iter),
@@ -1014,6 +1045,7 @@ impl Object {
 
     /// Gets the for-in-iterator data if the object is a `ForInIterator`.
     #[inline]
+    #[must_use]
     pub const fn as_for_in_iterator(&self) -> Option<&ForInIterator> {
         match &self.kind {
             ObjectKind::ForInIterator(iter) => Some(iter),
@@ -1032,12 +1064,14 @@ impl Object {
 
     /// Checks if the object is a `Map` object.
     #[inline]
+    #[must_use]
     pub const fn is_map(&self) -> bool {
         matches!(self.kind, ObjectKind::Map(_))
     }
 
     /// Gets the map data if the object is a `Map`.
     #[inline]
+    #[must_use]
     pub const fn as_map(&self) -> Option<&OrderedMap<JsValue>> {
         match self.kind {
             ObjectKind::Map(ref map) => Some(map),
@@ -1056,12 +1090,14 @@ impl Object {
 
     /// Checks if the object is a `MapIterator` object.
     #[inline]
+    #[must_use]
     pub const fn is_map_iterator(&self) -> bool {
         matches!(self.kind, ObjectKind::MapIterator(_))
     }
 
     /// Gets the map iterator data if the object is a `MapIterator`.
     #[inline]
+    #[must_use]
     pub const fn as_map_iterator_ref(&self) -> Option<&MapIterator> {
         match &self.kind {
             ObjectKind::MapIterator(iter) => Some(iter),
@@ -1080,12 +1116,14 @@ impl Object {
 
     /// Checks if the object is a `Set` object.
     #[inline]
+    #[must_use]
     pub const fn is_set(&self) -> bool {
         matches!(self.kind, ObjectKind::Set(_))
     }
 
     /// Gets the set data if the object is a `Set`.
     #[inline]
+    #[must_use]
     pub const fn as_set(&self) -> Option<&OrderedSet> {
         match self.kind {
             ObjectKind::Set(ref set) => Some(set),
@@ -1104,6 +1142,7 @@ impl Object {
 
     /// Checks if the object is a `SetIterator` object.
     #[inline]
+    #[must_use]
     pub const fn is_set_iterator(&self) -> bool {
         matches!(self.kind, ObjectKind::SetIterator(_))
     }
@@ -1119,12 +1158,14 @@ impl Object {
 
     /// Checks if the object is a `String` object.
     #[inline]
+    #[must_use]
     pub const fn is_string(&self) -> bool {
         matches!(self.kind, ObjectKind::String(_))
     }
 
     /// Gets the string data if the object is a `String`.
     #[inline]
+    #[must_use]
     pub fn as_string(&self) -> Option<JsString> {
         match self.kind {
             ObjectKind::String(ref string) => Some(string.clone()),
@@ -1134,12 +1175,14 @@ impl Object {
 
     /// Checks if the object is a `Function` object.
     #[inline]
+    #[must_use]
     pub const fn is_function(&self) -> bool {
         matches!(self.kind, ObjectKind::Function(_))
     }
 
     /// Gets the function data if the object is a `Function`.
     #[inline]
+    #[must_use]
     pub const fn as_function(&self) -> Option<&Function> {
         match self.kind {
             ObjectKind::Function(ref function) | ObjectKind::GeneratorFunction(ref function) => {
@@ -1161,6 +1204,7 @@ impl Object {
 
     /// Gets the bound function data if the object is a `BoundFunction`.
     #[inline]
+    #[must_use]
     pub const fn as_bound_function(&self) -> Option<&BoundFunction> {
         match self.kind {
             ObjectKind::BoundFunction(ref bound_function) => Some(bound_function),
@@ -1170,12 +1214,14 @@ impl Object {
 
     /// Checks if the object is a `Generator` object.
     #[inline]
+    #[must_use]
     pub const fn is_generator(&self) -> bool {
         matches!(self.kind, ObjectKind::Generator(_))
     }
 
     /// Gets the generator data if the object is a `Generator`.
     #[inline]
+    #[must_use]
     pub const fn as_generator(&self) -> Option<&Generator> {
         match self.kind {
             ObjectKind::Generator(ref generator) => Some(generator),
@@ -1194,12 +1240,14 @@ impl Object {
 
     /// Checks if the object is a `Symbol` object.
     #[inline]
+    #[must_use]
     pub const fn is_symbol(&self) -> bool {
         matches!(self.kind, ObjectKind::Symbol(_))
     }
 
     /// Gets the error data if the object is a `Symbol`.
     #[inline]
+    #[must_use]
     pub fn as_symbol(&self) -> Option<JsSymbol> {
         match self.kind {
             ObjectKind::Symbol(ref symbol) => Some(symbol.clone()),
@@ -1209,12 +1257,14 @@ impl Object {
 
     /// Checks if the object is a `Error` object.
     #[inline]
+    #[must_use]
     pub const fn is_error(&self) -> bool {
         matches!(self.kind, ObjectKind::Error(_))
     }
 
     /// Gets the error data if the object is a `Error`.
     #[inline]
+    #[must_use]
     pub const fn as_error(&self) -> Option<ErrorKind> {
         match self.kind {
             ObjectKind::Error(e) => Some(e),
@@ -1224,12 +1274,14 @@ impl Object {
 
     /// Checks if the object is a `Boolean` object.
     #[inline]
+    #[must_use]
     pub const fn is_boolean(&self) -> bool {
         matches!(self.kind, ObjectKind::Boolean(_))
     }
 
     /// Gets the boolean data if the object is a `Boolean`.
     #[inline]
+    #[must_use]
     pub const fn as_boolean(&self) -> Option<bool> {
         match self.kind {
             ObjectKind::Boolean(boolean) => Some(boolean),
@@ -1239,12 +1291,14 @@ impl Object {
 
     /// Checks if the object is a `Number` object.
     #[inline]
+    #[must_use]
     pub const fn is_number(&self) -> bool {
         matches!(self.kind, ObjectKind::Number(_))
     }
 
     /// Gets the number data if the object is a `Number`.
     #[inline]
+    #[must_use]
     pub const fn as_number(&self) -> Option<f64> {
         match self.kind {
             ObjectKind::Number(number) => Some(number),
@@ -1254,12 +1308,14 @@ impl Object {
 
     /// Checks if the object is a `BigInt` object.
     #[inline]
+    #[must_use]
     pub const fn is_bigint(&self) -> bool {
         matches!(self.kind, ObjectKind::BigInt(_))
     }
 
     /// Gets the bigint data if the object is a `BigInt`.
     #[inline]
+    #[must_use]
     pub const fn as_bigint(&self) -> Option<&JsBigInt> {
         match self.kind {
             ObjectKind::BigInt(ref bigint) => Some(bigint),
@@ -1269,12 +1325,14 @@ impl Object {
 
     /// Checks if the object is a `Date` object.
     #[inline]
+    #[must_use]
     pub const fn is_date(&self) -> bool {
         matches!(self.kind, ObjectKind::Date(_))
     }
 
     /// Gets the date data if the object is a `Date`.
     #[inline]
+    #[must_use]
     pub const fn as_date(&self) -> Option<&Date> {
         match self.kind {
             ObjectKind::Date(ref date) => Some(date),
@@ -1293,12 +1351,14 @@ impl Object {
 
     /// Checks if it a `RegExp` object.
     #[inline]
+    #[must_use]
     pub const fn is_regexp(&self) -> bool {
         matches!(self.kind, ObjectKind::RegExp(_))
     }
 
     /// Gets the regexp data if the object is a regexp.
     #[inline]
+    #[must_use]
     pub const fn as_regexp(&self) -> Option<&RegExp> {
         match self.kind {
             ObjectKind::RegExp(ref regexp) => Some(regexp),
@@ -1308,12 +1368,14 @@ impl Object {
 
     /// Checks if it a `TypedArray` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_array(&self) -> bool {
         matches!(self.kind, ObjectKind::IntegerIndexed(_))
     }
 
     /// Checks if it a `Uint8Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_uint8_array(&self) -> bool {
         if let ObjectKind::IntegerIndexed(ref int) = self.kind {
             matches!(int.typed_array_name(), TypedArrayKind::Uint8)
@@ -1324,6 +1386,7 @@ impl Object {
 
     /// Checks if it a `Int8Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_int8_array(&self) -> bool {
         if let ObjectKind::IntegerIndexed(ref int) = self.kind {
             matches!(int.typed_array_name(), TypedArrayKind::Int8)
@@ -1334,6 +1397,7 @@ impl Object {
 
     /// Checks if it a `Uint16Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_uint16_array(&self) -> bool {
         if let ObjectKind::IntegerIndexed(ref int) = self.kind {
             matches!(int.typed_array_name(), TypedArrayKind::Uint16)
@@ -1344,6 +1408,7 @@ impl Object {
 
     /// Checks if it a `Int16Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_int16_array(&self) -> bool {
         if let ObjectKind::IntegerIndexed(ref int) = self.kind {
             matches!(int.typed_array_name(), TypedArrayKind::Int16)
@@ -1354,6 +1419,7 @@ impl Object {
 
     /// Checks if it a `Uint32Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_uint32_array(&self) -> bool {
         if let ObjectKind::IntegerIndexed(ref int) = self.kind {
             matches!(int.typed_array_name(), TypedArrayKind::Uint32)
@@ -1364,6 +1430,7 @@ impl Object {
 
     /// Checks if it a `Int32Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_int32_array(&self) -> bool {
         if let ObjectKind::IntegerIndexed(ref int) = self.kind {
             matches!(int.typed_array_name(), TypedArrayKind::Int32)
@@ -1374,6 +1441,7 @@ impl Object {
 
     /// Checks if it a `Float32Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_float32_array(&self) -> bool {
         if let ObjectKind::IntegerIndexed(ref int) = self.kind {
             matches!(int.typed_array_name(), TypedArrayKind::Float32)
@@ -1384,6 +1452,7 @@ impl Object {
 
     /// Checks if it a `Float64Array` object.
     #[inline]
+    #[must_use]
     pub const fn is_typed_float64_array(&self) -> bool {
         if let ObjectKind::IntegerIndexed(ref int) = self.kind {
             matches!(int.typed_array_name(), TypedArrayKind::Float64)
@@ -1394,6 +1463,7 @@ impl Object {
 
     /// Gets the data view data if the object is a `DataView`.
     #[inline]
+    #[must_use]
     pub const fn as_data_view(&self) -> Option<&DataView> {
         match &self.kind {
             ObjectKind::DataView(data_view) => Some(data_view),
@@ -1412,12 +1482,14 @@ impl Object {
 
     /// Checks if it is an `Arguments` object.
     #[inline]
+    #[must_use]
     pub const fn is_arguments(&self) -> bool {
         matches!(self.kind, ObjectKind::Arguments(_))
     }
 
     /// Gets the mapped arguments data if this is a mapped arguments object.
     #[inline]
+    #[must_use]
     pub const fn as_mapped_arguments(&self) -> Option<&ParameterMap> {
         match self.kind {
             ObjectKind::Arguments(Arguments::Mapped(ref args)) => Some(args),
@@ -1436,6 +1508,7 @@ impl Object {
 
     /// Gets the typed array data (integer indexed object) if this is a typed array.
     #[inline]
+    #[must_use]
     pub const fn as_typed_array(&self) -> Option<&IntegerIndexed> {
         match self.kind {
             ObjectKind::IntegerIndexed(ref integer_indexed_object) => Some(integer_indexed_object),
@@ -1456,18 +1529,21 @@ impl Object {
 
     /// Checks if it an ordinary object.
     #[inline]
+    #[must_use]
     pub const fn is_ordinary(&self) -> bool {
         matches!(self.kind, ObjectKind::Ordinary)
     }
 
     /// Checks if it's an proxy object.
     #[inline]
+    #[must_use]
     pub const fn is_proxy(&self) -> bool {
         matches!(self.kind, ObjectKind::Proxy(_))
     }
 
     /// Gets the proxy data if the object is a `Proxy`.
     #[inline]
+    #[must_use]
     pub const fn as_proxy(&self) -> Option<&Proxy> {
         match self.kind {
             ObjectKind::Proxy(ref proxy) => Some(proxy),
@@ -1486,6 +1562,7 @@ impl Object {
 
     /// Gets the weak map data if the object is a `WeakMap`.
     #[inline]
+    #[must_use]
     pub const fn as_weak_map(&self) -> Option<&boa_gc::WeakMap<VTableObject, JsValue>> {
         match self.kind {
             ObjectKind::WeakMap(ref weak_map) => Some(weak_map),
@@ -1504,6 +1581,7 @@ impl Object {
 
     /// Gets the weak set data if the object is a `WeakSet`.
     #[inline]
+    #[must_use]
     pub const fn as_weak_set(&self) -> Option<&boa_gc::WeakMap<VTableObject, ()>> {
         match self.kind {
             ObjectKind::WeakSet(ref weak_set) => Some(weak_set),
@@ -1522,6 +1600,7 @@ impl Object {
 
     /// Gets the prototype instance of this object.
     #[inline]
+    #[must_use]
     pub fn prototype(&self) -> JsPrototype {
         self.properties.shape.prototype()
     }
@@ -1546,12 +1625,14 @@ impl Object {
 
     /// Returns `true` if it holds an Rust type that implements `NativeObject`.
     #[inline]
+    #[must_use]
     pub const fn is_native_object(&self) -> bool {
         matches!(self.kind, ObjectKind::NativeObject(_))
     }
 
     /// Gets the native object data if the object is a `NativeObject`.
     #[inline]
+    #[must_use]
     pub fn as_native_object(&self) -> Option<&dyn NativeObject> {
         match self.kind {
             ObjectKind::NativeObject(ref object) => Some(object.as_ref()),
@@ -1561,12 +1642,14 @@ impl Object {
 
     /// Checks if it is a `Promise` object.
     #[inline]
+    #[must_use]
     pub const fn is_promise(&self) -> bool {
         matches!(self.kind, ObjectKind::Promise(_))
     }
 
     /// Gets the promise data if the object is a `Promise`.
     #[inline]
+    #[must_use]
     pub const fn as_promise(&self) -> Option<&Promise> {
         match self.kind {
             ObjectKind::Promise(ref promise) => Some(promise),
@@ -1585,6 +1668,7 @@ impl Object {
 
     /// Gets the `WeakRef` data if the object is a `WeakRef`.
     #[inline]
+    #[must_use]
     pub const fn as_weak_ref(&self) -> Option<&WeakGc<VTableObject>> {
         match self.kind {
             ObjectKind::WeakRef(ref weak_ref) => Some(weak_ref),
@@ -1594,6 +1678,7 @@ impl Object {
 
     /// Gets a reference to the module namespace if the object is a `ModuleNamespace`.
     #[inline]
+    #[must_use]
     pub const fn as_module_namespace(&self) -> Option<&ModuleNamespace> {
         match &self.kind {
             ObjectKind::ModuleNamespace(ns) => Some(ns),
@@ -1612,6 +1697,7 @@ impl Object {
 
     /// Gets the `Collator` data if the object is a `Collator`.
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn as_collator(&self) -> Option<&Collator> {
         match self.kind {
@@ -1632,6 +1718,7 @@ impl Object {
 
     /// Checks if it is a `Locale` object.
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn is_locale(&self) -> bool {
         matches!(self.kind, ObjectKind::Locale(_))
@@ -1639,6 +1726,7 @@ impl Object {
 
     /// Gets the `Locale` data if the object is a `Locale`.
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn as_locale(&self) -> Option<&icu_locid::Locale> {
         match self.kind {
@@ -1649,6 +1737,7 @@ impl Object {
 
     /// Gets the `ListFormat` data if the object is a `ListFormat`.
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn as_list_format(&self) -> Option<&ListFormat> {
         match self.kind {
@@ -1659,6 +1748,7 @@ impl Object {
 
     /// Checks if it is a `Segmenter` object.
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn is_segmenter(&self) -> bool {
         matches!(self.kind, ObjectKind::Segmenter(_))
@@ -1666,6 +1756,7 @@ impl Object {
 
     /// Gets the `Segmenter` data if the object is a `Segmenter`.
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn as_segmenter(&self) -> Option<&Segmenter> {
         match self.kind {
@@ -1676,6 +1767,7 @@ impl Object {
 
     /// Gets the `Segments` data if the object is a `Segments`.
     #[inline]
+    #[must_use]
     #[cfg(feature = "intl")]
     pub const fn as_segments(&self) -> Option<&Segments> {
         match self.kind {
@@ -1695,6 +1787,7 @@ impl Object {
     }
 
     /// Return `true` if it is a native object and the native type is `T`.
+    #[must_use]
     pub fn is<T>(&self) -> bool
     where
         T: NativeObject,
@@ -1707,6 +1800,7 @@ impl Object {
 
     /// Downcast a reference to the object,
     /// if the object is type native object type `T`.
+    #[must_use]
     pub fn downcast_ref<T>(&self) -> Option<&T>
     where
         T: NativeObject,
@@ -1733,6 +1827,7 @@ impl Object {
 
     /// Returns the properties of the object.
     #[inline]
+    #[must_use]
     pub const fn properties(&self) -> &PropertyMap {
         &self.properties
     }
@@ -1911,6 +2006,7 @@ impl<'ctx, 'host> FunctionObjectBuilder<'ctx, 'host> {
     }
 
     /// Build the function object.
+    #[must_use]
     pub fn build(self) -> JsFunction {
         let function = Function::new(
             FunctionKind::Native {
@@ -2314,6 +2410,7 @@ impl<'ctx, 'host> ConstructorBuilder<'ctx, 'host> {
     }
 
     /// Build the constructor function object.
+    #[must_use]
     pub fn build(mut self) -> JsFunction {
         // Create the native function
         let function = Function::new(
diff --git a/boa_engine/src/object/shape/mod.rs b/boa_engine/src/object/shape/mod.rs
index 352ca91567c..5754e70f9dc 100644
--- a/boa_engine/src/object/shape/mod.rs
+++ b/boa_engine/src/object/shape/mod.rs
@@ -80,12 +80,14 @@ impl Shape {
 
     /// Returns `true` if it's a shared shape, `false` otherwise.
     #[inline]
+    #[must_use]
     pub const fn is_shared(&self) -> bool {
         matches!(self.inner, Inner::Shared(_))
     }
 
     /// Returns `true` if it's a unique shape, `false` otherwise.
     #[inline]
+    #[must_use]
     pub const fn is_unique(&self) -> bool {
         matches!(self.inner, Inner::Unique(_))
     }
@@ -170,6 +172,7 @@ impl Shape {
     }
 
     /// Get the [`JsPrototype`] of the [`Shape`].
+    #[must_use]
     pub fn prototype(&self) -> JsPrototype {
         match &self.inner {
             Inner::Shared(shape) => shape.prototype(),
@@ -188,6 +191,7 @@ impl Shape {
 
     /// Returns the keys of the [`Shape`], in insertion order.
     #[inline]
+    #[must_use]
     pub fn keys(&self) -> Vec<PropertyKey> {
         match &self.inner {
             Inner::Shared(shape) => shape.keys(),
@@ -197,6 +201,7 @@ impl Shape {
 
     /// Return location in memory of the [`Shape`].
     #[inline]
+    #[must_use]
     pub fn to_addr_usize(&self) -> usize {
         match &self.inner {
             Inner::Shared(shape) => shape.to_addr_usize(),
diff --git a/boa_engine/src/object/shape/root_shape.rs b/boa_engine/src/object/shape/root_shape.rs
index da64191ee59..9cc3de38e59 100644
--- a/boa_engine/src/object/shape/root_shape.rs
+++ b/boa_engine/src/object/shape/root_shape.rs
@@ -21,6 +21,7 @@ impl Default for RootShape {
 
 impl RootShape {
     /// Gets the inner [`SharedShape`].
+    #[must_use]
     pub const fn shape(&self) -> &SharedShape {
         &self.shape
     }
diff --git a/boa_engine/src/object/shape/shared_shape/mod.rs b/boa_engine/src/object/shape/shared_shape/mod.rs
index 0eff31474f6..18bb7194096 100644
--- a/boa_engine/src/object/shape/shared_shape/mod.rs
+++ b/boa_engine/src/object/shape/shared_shape/mod.rs
@@ -132,14 +132,17 @@ impl SharedShape {
         self.inner.property_count.saturating_sub(1)
     }
     /// Getter for the transition count field.
+    #[must_use]
     pub fn transition_count(&self) -> u16 {
         self.inner.transition_count
     }
     /// Getter for the previous field.
+    #[must_use]
     pub fn previous(&self) -> Option<&Self> {
         self.inner.previous.as_ref()
     }
     /// Get the prototype of the shape.
+    #[must_use]
     pub fn prototype(&self) -> JsPrototype {
         self.inner.prototype.clone()
     }
@@ -161,6 +164,7 @@ impl SharedShape {
         &self.inner.forward_transitions
     }
     /// Check if the shape has the given prototype.
+    #[must_use]
     pub fn has_prototype(&self, prototype: &JsObject) -> bool {
         self.inner
             .prototype
diff --git a/boa_engine/src/property/mod.rs b/boa_engine/src/property/mod.rs
index 8adcd5a761c..bcfdd7845ac 100644
--- a/boa_engine/src/property/mod.rs
+++ b/boa_engine/src/property/mod.rs
@@ -91,6 +91,7 @@ impl PropertyDescriptor {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-isaccessordescriptor
     #[inline]
+    #[must_use]
     pub const fn is_accessor_descriptor(&self) -> bool {
         matches!(self.kind, DescriptorKind::Accessor { .. })
     }
@@ -102,6 +103,7 @@ impl PropertyDescriptor {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-isdatadescriptor
     #[inline]
+    #[must_use]
     pub const fn is_data_descriptor(&self) -> bool {
         matches!(self.kind, DescriptorKind::Data { .. })
     }
@@ -113,12 +115,14 @@ impl PropertyDescriptor {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-isgenericdescriptor
     #[inline]
+    #[must_use]
     pub const fn is_generic_descriptor(&self) -> bool {
         matches!(self.kind, DescriptorKind::Generic)
     }
 
     /// Returns if the property descriptor is empty.
     #[inline]
+    #[must_use]
     pub const fn is_empty(&self) -> bool {
         self.is_generic_descriptor() && self.enumerable.is_none() && self.configurable.is_none()
     }
@@ -126,6 +130,7 @@ impl PropertyDescriptor {
     /// Returns if the property descriptor is enumerable.
     /// Returns `None` if the `enumerable` field is not set.
     #[inline]
+    #[must_use]
     pub const fn enumerable(&self) -> Option<bool> {
         self.enumerable
     }
@@ -133,6 +138,7 @@ impl PropertyDescriptor {
     /// Returns if the property descriptor is configurable.
     /// Returns `None` if the `configurable` field is not set.
     #[inline]
+    #[must_use]
     pub const fn configurable(&self) -> Option<bool> {
         self.configurable
     }
@@ -140,6 +146,7 @@ impl PropertyDescriptor {
     /// Returns if the property descriptor is writable.
     /// Returns `None` if the `writable` field is not set or the property descriptor is not a data descriptor.
     #[inline]
+    #[must_use]
     pub const fn writable(&self) -> Option<bool> {
         match self.kind {
             DescriptorKind::Data { writable, .. } => writable,
@@ -150,6 +157,7 @@ impl PropertyDescriptor {
     /// Returns the value of the property descriptor.
     /// Returns `None` if the value is not set or the property descriptor is not a data descriptor.
     #[inline]
+    #[must_use]
     pub const fn value(&self) -> Option<&JsValue> {
         match &self.kind {
             DescriptorKind::Data { value, .. } => value.as_ref(),
@@ -160,6 +168,7 @@ impl PropertyDescriptor {
     /// Returns the getter of the property descriptor.
     /// Returns `None` if the getter is not set or the property descriptor is not an accessor descriptor.
     #[inline]
+    #[must_use]
     pub const fn get(&self) -> Option<&JsValue> {
         match &self.kind {
             DescriptorKind::Accessor { get, .. } => get.as_ref(),
@@ -170,6 +179,7 @@ impl PropertyDescriptor {
     /// Returns the setter of the property descriptor.
     /// Returns `None` if the setter is not set or the property descriptor is not an accessor descriptor.
     #[inline]
+    #[must_use]
     pub const fn set(&self) -> Option<&JsValue> {
         match &self.kind {
             DescriptorKind::Accessor { set, .. } => set.as_ref(),
@@ -183,6 +193,7 @@ impl PropertyDescriptor {
     ///
     /// Panics if the `enumerable` field is not set.
     #[inline]
+    #[must_use]
     pub fn expect_enumerable(&self) -> bool {
         self.enumerable
             .expect("[[enumerable]] field not in property descriptor")
@@ -194,6 +205,7 @@ impl PropertyDescriptor {
     ///
     /// Panics if the `configurable` field is not set.
     #[inline]
+    #[must_use]
     pub fn expect_configurable(&self) -> bool {
         self.configurable
             .expect("[[configurable]] field not in property descriptor")
@@ -205,6 +217,7 @@ impl PropertyDescriptor {
     ///
     /// Panics if the `writable` field is not set.
     #[inline]
+    #[must_use]
     pub fn expect_writable(&self) -> bool {
         self.writable()
             .expect("[[writable]] field not in property descriptor")
@@ -216,6 +229,7 @@ impl PropertyDescriptor {
     ///
     /// Panics if the `value` field is not set.
     #[inline]
+    #[must_use]
     pub fn expect_value(&self) -> &JsValue {
         self.value()
             .expect("[[value]] field not in property descriptor")
@@ -227,6 +241,7 @@ impl PropertyDescriptor {
     ///
     /// Panics if the `getter` field is not set.
     #[inline]
+    #[must_use]
     pub fn expect_get(&self) -> &JsValue {
         self.get()
             .expect("[[get]] field not in property descriptor")
@@ -238,6 +253,7 @@ impl PropertyDescriptor {
     ///
     /// Panics if the `setter` field is not set.
     #[inline]
+    #[must_use]
     pub fn expect_set(&self) -> &JsValue {
         self.set()
             .expect("[[set]] field not in property descriptor")
@@ -245,6 +261,7 @@ impl PropertyDescriptor {
 
     /// Returns the kind of the property descriptor.
     #[inline]
+    #[must_use]
     pub const fn kind(&self) -> &DescriptorKind {
         &self.kind
     }
@@ -546,11 +563,13 @@ impl PropertyDescriptorBuilder {
     }
 
     /// Returns a reference to the currently built [`PropertyDescriptor`].
+    #[must_use]
     pub const fn inner(&self) -> &PropertyDescriptor {
         &self.inner
     }
 
     /// Consumes the builder and returns the [`PropertyDescriptor`].
+    #[must_use]
     #[allow(clippy::missing_const_for_fn)]
     pub fn build(self) -> PropertyDescriptor {
         self.inner
diff --git a/boa_engine/src/realm.rs b/boa_engine/src/realm.rs
index 86f5f59fd91..65237b6c049 100644
--- a/boa_engine/src/realm.rs
+++ b/boa_engine/src/realm.rs
@@ -84,6 +84,7 @@ impl Realm {
     }
 
     /// Gets the intrinsics of this `Realm`.
+    #[must_use]
     pub fn intrinsics(&self) -> &Intrinsics {
         &self.inner.intrinsics
     }
diff --git a/boa_engine/src/script.rs b/boa_engine/src/script.rs
index 737337bfeae..d4ce0fd8c97 100644
--- a/boa_engine/src/script.rs
+++ b/boa_engine/src/script.rs
@@ -54,6 +54,7 @@ struct Inner {
 
 impl Script {
     /// Gets the realm of this script.
+    #[must_use]
     pub fn realm(&self) -> &Realm {
         &self.inner.realm
     }
diff --git a/boa_engine/src/value/display.rs b/boa_engine/src/value/display.rs
index 385772202ea..e0b4352f330 100644
--- a/boa_engine/src/value/display.rs
+++ b/boa_engine/src/value/display.rs
@@ -251,6 +251,7 @@ pub(crate) fn log_string_from(x: &JsValue, print_internals: bool, print_children
 
 impl JsValue {
     /// A helper function for specifically printing object values
+    #[must_use]
     pub fn display_obj(&self, print_internals: bool) -> String {
         // A simple helper for getting the address of a value
         // TODO: Find a more general place for this, as it can be used in other situations as well
diff --git a/boa_engine/src/value/equality.rs b/boa_engine/src/value/equality.rs
index 8368ef050f8..7e9255c381d 100644
--- a/boa_engine/src/value/equality.rs
+++ b/boa_engine/src/value/equality.rs
@@ -6,6 +6,7 @@ impl JsValue {
     ///
     /// This method is executed when doing strict equality comparisons with the `===` operator.
     /// For more information, check <https://tc39.es/ecma262/#sec-strict-equality-comparison>.
+    #[must_use]
     pub fn strict_equals(&self, other: &Self) -> bool {
         // 1. If Type(x) is different from Type(y), return false.
         if self.get_type() != other.get_type() {
@@ -131,6 +132,7 @@ impl JsValue {
     ///  - [ECMAScript][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-samevalue
+    #[must_use]
     pub fn same_value(x: &Self, y: &Self) -> bool {
         // 1. If Type(x) is different from Type(y), return false.
         if x.get_type() != y.get_type() {
@@ -160,6 +162,7 @@ impl JsValue {
     ///  - [ECMAScript][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-samevaluezero
+    #[must_use]
     pub fn same_value_zero(x: &Self, y: &Self) -> bool {
         if x.get_type() != y.get_type() {
             return false;
diff --git a/boa_engine/src/value/mod.rs b/boa_engine/src/value/mod.rs
index f302f466b4a..d9d2868033b 100644
--- a/boa_engine/src/value/mod.rs
+++ b/boa_engine/src/value/mod.rs
@@ -133,12 +133,14 @@ impl JsValue {
 
     /// Returns true if the value is an object.
     #[inline]
+    #[must_use]
     pub const fn is_object(&self) -> bool {
         matches!(self, Self::Object(_))
     }
 
     /// Returns the object if the value is object, otherwise `None`.
     #[inline]
+    #[must_use]
     pub const fn as_object(&self) -> Option<&JsObject> {
         match *self {
             Self::Object(ref o) => Some(o),
@@ -153,48 +155,56 @@ impl JsValue {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-iscallable
     #[inline]
+    #[must_use]
     pub fn is_callable(&self) -> bool {
         matches!(self, Self::Object(obj) if obj.is_callable())
     }
 
     /// Returns the callable value if the value is callable, otherwise `None`.
     #[inline]
+    #[must_use]
     pub fn as_callable(&self) -> Option<&JsObject> {
         self.as_object().filter(|obj| obj.is_callable())
     }
 
     /// Returns true if the value is a constructor object.
     #[inline]
+    #[must_use]
     pub fn is_constructor(&self) -> bool {
         matches!(self, Self::Object(obj) if obj.is_constructor())
     }
 
     /// Returns the constructor if the value is a constructor, otherwise `None`.
     #[inline]
+    #[must_use]
     pub fn as_constructor(&self) -> Option<&JsObject> {
         self.as_object().filter(|obj| obj.is_constructor())
     }
 
     /// Returns true if the value is a promise object.
     #[inline]
+    #[must_use]
     pub fn is_promise(&self) -> bool {
         matches!(self, Self::Object(obj) if obj.is_promise())
     }
 
     /// Returns the promise if the value is a promise, otherwise `None`.
     #[inline]
+    #[must_use]
     pub fn as_promise(&self) -> Option<&JsObject> {
         self.as_object().filter(|obj| obj.is_promise())
     }
 
     /// Returns true if the value is a symbol.
     #[inline]
+    #[must_use]
     pub const fn is_symbol(&self) -> bool {
         matches!(self, Self::Symbol(_))
     }
 
     /// Returns the symbol if the value is a symbol, otherwise `None`.
     #[inline]
+    #[must_use]
     pub fn as_symbol(&self) -> Option<JsSymbol> {
         match self {
             Self::Symbol(symbol) => Some(symbol.clone()),
@@ -204,29 +214,34 @@ impl JsValue {
 
     /// Returns true if the value is undefined.
     #[inline]
+    #[must_use]
     pub const fn is_undefined(&self) -> bool {
         matches!(self, Self::Undefined)
     }
 
     /// Returns true if the value is null.
     #[inline]
+    #[must_use]
     pub const fn is_null(&self) -> bool {
         matches!(self, Self::Null)
     }
 
     /// Returns true if the value is null or undefined.
     #[inline]
+    #[must_use]
     pub const fn is_null_or_undefined(&self) -> bool {
         matches!(self, Self::Null | Self::Undefined)
     }
 
     /// Returns true if the value is a 64-bit floating-point number.
     #[inline]
+    #[must_use]
     pub const fn is_double(&self) -> bool {
         matches!(self, Self::Rational(_))
     }
 
     /// Returns true if the value is integer.
+    #[must_use]
     #[allow(clippy::float_cmp)]
     pub fn is_integer(&self) -> bool {
         // If it can fit in a i32 and the truncated version is
@@ -242,12 +257,14 @@ impl JsValue {
 
     /// Returns true if the value is a number.
     #[inline]
+    #[must_use]
     pub const fn is_number(&self) -> bool {
         matches!(self, Self::Rational(_) | Self::Integer(_))
     }
 
     /// Returns the number if the value is a number, otherwise `None`.
     #[inline]
+    #[must_use]
     pub fn as_number(&self) -> Option<f64> {
         match *self {
             Self::Integer(integer) => Some(integer.into()),
@@ -258,12 +275,14 @@ impl JsValue {
 
     /// Returns true if the value is a string.
     #[inline]
+    #[must_use]
     pub const fn is_string(&self) -> bool {
         matches!(self, Self::String(_))
     }
 
     /// Returns the string if the value is a string, otherwise `None`.
     #[inline]
+    #[must_use]
     pub const fn as_string(&self) -> Option<&JsString> {
         match self {
             Self::String(ref string) => Some(string),
@@ -273,12 +292,14 @@ impl JsValue {
 
     /// Returns true if the value is a boolean.
     #[inline]
+    #[must_use]
     pub const fn is_boolean(&self) -> bool {
         matches!(self, Self::Boolean(_))
     }
 
     /// Returns the boolean if the value is a boolean, otherwise `None`.
     #[inline]
+    #[must_use]
     pub const fn as_boolean(&self) -> Option<bool> {
         match self {
             Self::Boolean(boolean) => Some(*boolean),
@@ -288,12 +309,14 @@ impl JsValue {
 
     /// Returns true if the value is a bigint.
     #[inline]
+    #[must_use]
     pub const fn is_bigint(&self) -> bool {
         matches!(self, Self::BigInt(_))
     }
 
     /// Returns an optional reference to a `BigInt` if the value is a `BigInt` primitive.
     #[inline]
+    #[must_use]
     pub const fn as_bigint(&self) -> Option<&JsBigInt> {
         match self {
             Self::BigInt(bigint) => Some(bigint),
@@ -307,6 +330,7 @@ impl JsValue {
     ///  - [ECMAScript][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-toboolean
+    #[must_use]
     pub fn to_boolean(&self) -> bool {
         match *self {
             Self::Symbol(_) | Self::Object(_) => true,
@@ -430,6 +454,7 @@ impl JsValue {
     ///
     /// println!("{}", value.display());
     /// ```
+    #[must_use]
     #[inline]
     pub const fn display(&self) -> ValueDisplay<'_> {
         ValueDisplay {
@@ -929,6 +954,7 @@ impl JsValue {
     /// - [ECMAScript reference][spec]
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-typeof-operator
+    #[must_use]
     pub fn type_of(&self) -> &'static str {
         match *self {
             Self::Rational(_) | Self::Integer(_) => "number",
diff --git a/boa_engine/src/value/type.rs b/boa_engine/src/value/type.rs
index c5cf3486327..74ca4d4141e 100644
--- a/boa_engine/src/value/type.rs
+++ b/boa_engine/src/value/type.rs
@@ -35,6 +35,7 @@ impl JsValue {
     /// <https://tc39.es/ecma262/multipage/ecmascript-data-types-and-values.html#sec-ecmascript-language-types>.
     ///
     /// Check [`JsValue::type_of`] if you need to call the `typeof` operator.
+    #[must_use]
     pub const fn get_type(&self) -> Type {
         match *self {
             Self::Rational(_) | Self::Integer(_) => Type::Number,
diff --git a/boa_engine/src/vm/call_frame/mod.rs b/boa_engine/src/vm/call_frame/mod.rs
index de97c2cb118..506e5f4b9b9 100644
--- a/boa_engine/src/vm/call_frame/mod.rs
+++ b/boa_engine/src/vm/call_frame/mod.rs
@@ -57,6 +57,7 @@ pub struct CallFrame {
 impl CallFrame {
     /// Retrieves the [`CodeBlock`] of this call frame.
     #[inline]
+    #[must_use]
     pub const fn code_block(&self) -> &Gc<CodeBlock> {
         &self.code_block
     }