Restructure lint lists in boa_engine (#2455)

This Pull Request restructures the lint deny/warn/allow lists in `boa_engine`. It adds a lot of documentation to pup functions. There are still a few clippy lints that are not fixed, mainly regarding casting of number types. Fixing those lints effectiveley would in some cases probably require bigger refactors.

This should probably wait for #2449 to be merged, because that PR already fixes that lints regarding the `Date` built-in.

boa_engine/Cargo.toml

@@ -33,7 +33,6 @@ flowgraph = []
 console = []
 
 [dependencies]
-boa_unicode.workspace = true
 boa_interner.workspace = true
 boa_gc.workspace = true
 boa_profiler.workspace = true

boa_engine/src/bigint.rs

@@ -25,12 +25,14 @@ pub struct JsBigInt {
 impl JsBigInt {
     /// Create a new [`JsBigInt`].
     #[inline]
+    #[must_use]
     pub fn new<T: Into<Self>>(value: T) -> Self {
         value.into()
     }
 
     /// Create a [`JsBigInt`] with value `0`.
     #[inline]
+    #[must_use]
     pub fn zero() -> Self {
         Self {
             inner: Rc::new(RawBigInt::zero()),
@@ -39,12 +41,14 @@ impl JsBigInt {
 
     /// Check if is zero.
     #[inline]
+    #[must_use]
     pub fn is_zero(&self) -> bool {
         self.inner.is_zero()
     }
 
     /// Create a [`JsBigInt`] with value `1`.
     #[inline]
+    #[must_use]
     pub fn one() -> Self {
         Self {
             inner: Rc::new(RawBigInt::one()),
@@ -53,12 +57,14 @@ impl JsBigInt {
 
     /// Check if is one.
     #[inline]
+    #[must_use]
     pub fn is_one(&self) -> bool {
         self.inner.is_one()
     }
 
     /// Convert bigint to string with radix.
     #[inline]
+    #[must_use]
     pub fn to_string_radix(&self, radix: u32) -> String {
         self.inner.to_str_radix(radix)
     }
@@ -67,12 +73,14 @@ impl JsBigInt {
     ///
     /// Returns `f64::INFINITY` if the `BigInt` is too big.
     #[inline]
+    #[must_use]
     pub fn to_f64(&self) -> f64 {
         self.inner.to_f64().unwrap_or(f64::INFINITY)
     }
 
     /// Converts a string to a `BigInt` with the specified radix.
     #[inline]
+    #[must_use]
     pub fn from_string_radix(buf: &str, radix: u32) -> Option<Self> {
         Some(Self {
             inner: Rc::new(RawBigInt::parse_bytes(buf.as_bytes(), radix)?),
@@ -86,6 +94,7 @@ impl JsBigInt {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-stringtobigint
     #[inline]
+    #[must_use]
     pub fn from_string(mut string: &str) -> Option<Self> {
         string = string.trim();
 
@@ -115,6 +124,7 @@ impl JsBigInt {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-numeric-types-bigint-equal
     #[inline]
+    #[must_use]
     pub fn same_value_zero(x: &Self, y: &Self) -> bool {
         // Return BigInt::equal(x, y)
         Self::equal(x, y)
@@ -128,6 +138,7 @@ impl JsBigInt {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-numeric-types-bigint-sameValue
     #[inline]
+    #[must_use]
     pub fn same_value(x: &Self, y: &Self) -> bool {
         // Return BigInt::equal(x, y)
         Self::equal(x, y)
@@ -143,10 +154,12 @@ impl JsBigInt {
     ///
     /// [spec]: https://tc39.es/ecma262/#sec-numeric-types-bigint-sameValueZero
     #[inline]
+    #[must_use]
     pub fn equal(x: &Self, y: &Self) -> bool {
         x == y
     }
 
+    /// Returns `x` to the power `y`.
     #[inline]
     pub fn pow(x: &Self, y: &Self) -> JsResult<Self> {
         let y = y
@@ -168,37 +181,27 @@ impl JsBigInt {
         Ok(Self::new(x.inner.as_ref().clone().pow(y)))
     }
 
+    /// Performs the `>>` operation.
     #[inline]
     pub fn shift_right(x: &Self, y: &Self) -> JsResult<Self> {
-        if let Some(n) = y.inner.to_i32() {
-            let inner = if n > 0 {
-                x.inner.as_ref().clone().shr(n as usize)
-            } else {
-                x.inner.as_ref().clone().shl(n.unsigned_abs())
-            };
-
-            Ok(Self::new(inner))
-        } else {
-            Err(JsNativeError::range()
+        match y.inner.to_i32() {
+            Some(n) if n > 0 => Ok(Self::new(x.inner.as_ref().clone().shr(n as usize))),
+            Some(n) => Ok(Self::new(x.inner.as_ref().clone().shl(n.unsigned_abs()))),
+            None => Err(JsNativeError::range()
                 .with_message("Maximum BigInt size exceeded")
-                .into())
+                .into()),
         }
     }
 
+    /// Performs the `<<` operation.
     #[inline]
     pub fn shift_left(x: &Self, y: &Self) -> JsResult<Self> {
-        if let Some(n) = y.inner.to_i32() {
-            let inner = if n > 0 {
-                x.inner.as_ref().clone().shl(n as usize)
-            } else {
-                x.inner.as_ref().clone().shr(n.unsigned_abs())
-            };
-
-            Ok(Self::new(inner))
-        } else {
-            Err(JsNativeError::range()
+        match y.inner.to_i32() {
+            Some(n) if n > 0 => Ok(Self::new(x.inner.as_ref().clone().shl(n as usize))),
+            Some(n) => Ok(Self::new(x.inner.as_ref().clone().shr(n.unsigned_abs()))),
+            None => Err(JsNativeError::range()
                 .with_message("Maximum BigInt size exceeded")
-                .into())
+                .into()),
         }
     }
 
@@ -211,56 +214,77 @@ impl JsBigInt {
     /// assert_eq!((8).mod_floor(&-3), -1);
     /// ```
     #[inline]
+    #[must_use]
     pub fn mod_floor(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.mod_floor(&y.inner))
     }
 
+    /// Performs the `+` operation.
     #[inline]
+    #[must_use]
     pub fn add(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.as_ref().clone().add(y.inner.as_ref()))
     }
 
+    /// Performs the `-` operation.
     #[inline]
+    #[must_use]
     pub fn sub(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.as_ref().clone().sub(y.inner.as_ref()))
     }
 
+    /// Performs the `*` operation.
     #[inline]
+    #[must_use]
     pub fn mul(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.as_ref().clone().mul(y.inner.as_ref()))
     }
 
+    /// Performs the `/` operation.
     #[inline]
+    #[must_use]
     pub fn div(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.as_ref().clone().div(y.inner.as_ref()))
     }
 
+    /// Performs the `%` operation.
     #[inline]
+    #[must_use]
     pub fn rem(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.as_ref().clone().rem(y.inner.as_ref()))
     }
 
+    /// Performs the `&` operation.
     #[inline]
+    #[must_use]
     pub fn bitand(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.as_ref().clone().bitand(y.inner.as_ref()))
     }
 
+    /// Performs the `|` operation.
     #[inline]
+    #[must_use]
     pub fn bitor(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.as_ref().clone().bitor(y.inner.as_ref()))
     }
 
+    /// Performs the `^` operation.
     #[inline]
+    #[must_use]
     pub fn bitxor(x: &Self, y: &Self) -> Self {
         Self::new(x.inner.as_ref().clone().bitxor(y.inner.as_ref()))
     }
 
+    /// Performs the unary `-` operation.
     #[inline]
+    #[must_use]
     pub fn neg(x: &Self) -> Self {
         Self::new(x.as_inner().neg())
     }
 
+    /// Performs the unary `!` operation.
     #[inline]
+    #[must_use]
     pub fn not(x: &Self) -> Self {
         Self::new(!x.as_inner())
     }
@@ -386,6 +410,7 @@ impl From<usize> for JsBigInt {
     }
 }
 
+/// The error indicates that the conversion from [`f64`] to [`JsBigInt`] failed.
 #[derive(Debug, Clone, Copy, Hash, PartialEq, Eq, PartialOrd, Ord)]
 pub struct TryFromF64Error;
 
@@ -407,10 +432,7 @@ impl TryFrom<f64> for JsBigInt {
         if !Number::equal(n.trunc(), n) {
             return Err(TryFromF64Error);
         }
-        match RawBigInt::from_f64(n) {
-            Some(bigint) => Ok(Self::new(bigint)),
-            None => Err(TryFromF64Error),
-        }
+        RawBigInt::from_f64(n).map_or(Err(TryFromF64Error), |bigint| Ok(Self::new(bigint)))
     }
 }
 

boa_engine/src/builtins/array/array_iterator.rs

@@ -1,3 +1,10 @@
+//! This module implements the `ArrayIterator` object.
+//!
+//! More information:
+//!  - [ECMAScript reference][spec]
+//!
+//! [spec]: https://tc39.es/ecma262/#sec-array-iterator-objects
+
 use crate::{
     builtins::{function::make_builtin_fn, iterable::create_iter_result_object, Array, JsValue},
     error::JsNativeError,

boa_engine/src/builtins/array/mod.rs

@@ -236,10 +236,8 @@ impl Array {
         // 3. Let A be ! MakeBasicObject(« [[Prototype]], [[Extensible]] »).
         // 4. Set A.[[Prototype]] to proto.
         // 5. Set A.[[DefineOwnProperty]] as specified in 10.4.2.1.
-        let prototype = match prototype {
-            Some(prototype) => prototype,
-            None => context.intrinsics().constructors().array().prototype(),
-        };
+        let prototype =
+            prototype.unwrap_or_else(|| context.intrinsics().constructors().array().prototype());
         let array = JsObject::from_proto_and_data(prototype, ObjectData::array());
 
         // 6. Perform ! OrdinaryDefineOwnProperty(A, "length", PropertyDescriptor { [[Value]]: 𝔽(length), [[Writable]]: true, [[Enumerable]]: false, [[Configurable]]: false }).
@@ -380,15 +378,15 @@ impl Array {
             return Self::array_create(length, None, context);
         }
 
-        // 7. If IsConstructor(C) is false, throw a TypeError exception.
         if let Some(c) = c.as_constructor() {
             // 8. Return ? Construct(C, « 𝔽(length) »).
-            c.construct(&[JsValue::new(length)], Some(c), context)
-        } else {
-            Err(JsNativeError::typ()
-                .with_message("Symbol.species must be a constructor")
-                .into())
+            return c.construct(&[JsValue::new(length)], Some(c), context);
         }
+
+        // 7. If IsConstructor(C) is false, throw a TypeError exception.
+        Err(JsNativeError::typ()
+            .with_message("Symbol.species must be a constructor")
+            .into())
     }
 
     /// `Array.from(arrayLike)`
@@ -670,7 +668,7 @@ impl Array {
         let mut n = 0;
         // 4. Prepend O to items.
         // 5. For each element E of items, do
-        for item in [JsValue::new(obj)].iter().chain(args.iter()) {
+        for item in std::iter::once(&JsValue::new(obj)).chain(args.iter()) {
             // a. Let spreadable be ? IsConcatSpreadable(E).
             let spreadable = Self::is_concat_spreadable(item, context)?;
             // b. If spreadable is true, then
@@ -1776,13 +1774,13 @@ impl Array {
                 }
 
                 // iii. Let shouldFlatten be false
-                let mut should_flatten = false;
-
                 // iv. If depth > 0, then
-                if depth > 0 {
+                let should_flatten = if depth > 0 {
                     // 1. Set shouldFlatten to ? IsArray(element).
-                    should_flatten = element.is_array()?;
-                }
+                    element.is_array()?
+                } else {
+                    false
+                };
 
                 // v. If shouldFlatten is true
                 if should_flatten {