Skip to content

fix(ecmascript): fix may_have_side_effects for binary expressions #8991

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
graphite-app merged 1 commit into from
Feb 10, 2025
Merged

fix(ecmascript): fix may_have_side_effects for binary expressions #8991

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
5 changes: 5 additions & 0 deletions crates/oxc_ast/src/ast_impl/literal.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,11 @@ impl BigIntLiteral<'_> {
pub fn is_zero(&self) -> bool {
self.raw == "0n"
}

/// Is this BigInt literal negative? (e.g. `-1n`).
pub fn is_negative(&self) -> bool {
self.raw.starts_with('-')
}
}

impl fmt::Display for BigIntLiteral<'_> {
Expand Down
194 changes: 149 additions & 45 deletions crates/oxc_ecmascript/src/side_effects/may_have_side_effects.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,11 +4,12 @@ use oxc_ast::ast::*;
///
/// This trait assumes the following:
/// - `.toString()`, `.valueOf()`, and `[Symbol.toPrimitive]()` are side-effect free.
/// - This is mainly to assume `ToPrimitive` is side-effect free.
/// - Errors thrown when creating a String or an Array that exceeds the maximum length does not happen.
/// - TDZ errors does not happen.
///
/// Ported from [closure-compiler](https://github.com/google/closure-compiler/blob/f3ce5ed8b630428e311fe9aa2e20d36560d975e2/src/com/google/javascript/jscomp/AstAnalyzer.java#L94)
pub trait MayHaveSideEffects {
pub trait MayHaveSideEffects: Sized {
fn is_global_reference(&self, ident: &IdentifierReference<'_>) -> bool;

fn expression_may_have_side_effects(&self, e: &Expression<'_>) -> bool {
Expand Down Expand Up @@ -73,58 +74,99 @@ pub trait MayHaveSideEffects {
}
}
UnaryOperator::UnaryPlus => {
match &e.argument {
Expression::NumericLiteral(_)
| Expression::NullLiteral(_)
| Expression::BooleanLiteral(_)
| Expression::StringLiteral(_) => false,
Expression::Identifier(ident) => {
!(matches!(ident.name.as_str(), "Infinity" | "NaN" | "undefined")
&& self.is_global_reference(ident))
}
Expression::ArrayExpression(arr) => {
self.array_expression_may_have_side_effects(arr)
}
// unless `Symbol.toPrimitive`, `valueOf`, `toString` is overridden,
// ToPrimitive for an object returns `"[object Object]"`
Expression::ObjectExpression(obj) => !obj.properties.is_empty(),
// ToNumber throws an error when the argument is Symbol / BigInt / an object that
// returns Symbol or BigInt from ToPrimitive
_ => true,
}
// ToNumber throws an error when the argument is Symbol / BigInt / an object that
// returns Symbol or BigInt from ToPrimitive
maybe_symbol_or_bigint_or_to_primitive_may_return_symbol_or_bigint(
self,
&e.argument,
) || self.expression_may_have_side_effects(&e.argument)
}
UnaryOperator::UnaryNegation | UnaryOperator::BitwiseNot => {
match &e.argument {
Expression::BigIntLiteral(_)
| Expression::NumericLiteral(_)
| Expression::NullLiteral(_)
| Expression::BooleanLiteral(_)
| Expression::StringLiteral(_) => false,
Expression::Identifier(ident) => {
!(matches!(ident.name.as_str(), "Infinity" | "NaN" | "undefined")
&& self.is_global_reference(ident))
}
Expression::ArrayExpression(arr) => {
self.array_expression_may_have_side_effects(arr)
}
// unless `Symbol.toPrimitive`, `valueOf`, `toString` is overridden,
// ToPrimitive for an object returns `"[object Object]"`
Expression::ObjectExpression(obj) => !obj.properties.is_empty(),
// ToNumber throws an error when the argument is Symbol an object that
// returns Symbol from ToPrimitive
_ => true,
}
// ToNumeric throws an error when the argument is Symbol / an object that
// returns Symbol from ToPrimitive
maybe_symbol_or_to_primitive_may_return_symbol(self, &e.argument)
|| self.expression_may_have_side_effects(&e.argument)
}
}
}

fn binary_expression_may_have_side_effects(&self, e: &BinaryExpression<'_>) -> bool {
// `instanceof` and `in` can throw `TypeError`
if matches!(e.operator, BinaryOperator::In | BinaryOperator::Instanceof) {
return true;
match e.operator {
BinaryOperator::Equality
| BinaryOperator::Inequality
| BinaryOperator::StrictEquality
| BinaryOperator::StrictInequality
| BinaryOperator::LessThan
| BinaryOperator::LessEqualThan
| BinaryOperator::GreaterThan
| BinaryOperator::GreaterEqualThan => {
self.expression_may_have_side_effects(&e.left)
|| self.expression_may_have_side_effects(&e.right)
}
BinaryOperator::In | BinaryOperator::Instanceof => {
// instanceof and in can throw `TypeError`
true
}
BinaryOperator::Addition => {
if is_string_or_to_primitive_returns_string(&e.left)
|| is_string_or_to_primitive_returns_string(&e.right)
{
let other_side = if is_string_or_to_primitive_returns_string(&e.left) {
&e.right
} else {
&e.left
};
maybe_symbol_or_to_primitive_may_return_symbol(self, other_side)
|| self.expression_may_have_side_effects(&e.left)
|| self.expression_may_have_side_effects(&e.right)
} else if e.left.is_number() || e.right.is_number() {
let other_side = if e.left.is_number() { &e.right } else { &e.left };
!matches!(
other_side,
Expression::NullLiteral(_)
| Expression::NumericLiteral(_)
| Expression::BooleanLiteral(_)
)
} else {
!(e.left.is_big_int_literal() && e.right.is_big_int_literal())
}
}
BinaryOperator::Subtraction
| BinaryOperator::Multiplication
| BinaryOperator::Division
| BinaryOperator::Remainder
| BinaryOperator::ShiftLeft
| BinaryOperator::BitwiseOR
| BinaryOperator::ShiftRight
| BinaryOperator::BitwiseXOR
| BinaryOperator::BitwiseAnd
| BinaryOperator::Exponential
| BinaryOperator::ShiftRightZeroFill => {
if e.left.is_big_int_literal() || e.right.is_big_int_literal() {
if let (Expression::BigIntLiteral(_), Expression::BigIntLiteral(right)) =
(&e.left, &e.right)
{
match e.operator {
BinaryOperator::Exponential => right.is_negative(),
BinaryOperator::Division | BinaryOperator::Remainder => right.is_zero(),
BinaryOperator::ShiftRightZeroFill => true,
_ => false,
}
} else {
true
}
} else if !(maybe_symbol_or_bigint_or_to_primitive_may_return_symbol_or_bigint(
self, &e.left,
) || maybe_symbol_or_bigint_or_to_primitive_may_return_symbol_or_bigint(
self, &e.right,
)) {
self.expression_may_have_side_effects(&e.left)
|| self.expression_may_have_side_effects(&e.right)
} else {
true
}
}
}
self.expression_may_have_side_effects(&e.left)
|| self.expression_may_have_side_effects(&e.right)
}

fn logical_expression_may_have_side_effects(&self, e: &LogicalExpression<'_>) -> bool {
Expand Down Expand Up @@ -215,3 +257,65 @@ pub trait MayHaveSideEffects {
}
}
}

fn is_string_or_to_primitive_returns_string(expr: &Expression<'_>) -> bool {
match expr {
Expression::StringLiteral(_)
| Expression::TemplateLiteral(_)
| Expression::RegExpLiteral(_)
| Expression::ArrayExpression(_) => true,
// unless `Symbol.toPrimitive`, `valueOf`, `toString` is overridden,
// ToPrimitive for an object returns `"[object Object]"`
Expression::ObjectExpression(obj) => obj.properties.is_empty(),
_ => false,
}
}

/// Whether the given expression may be a `Symbol` or converted to a `Symbol` when passed to `toPrimitive`.
fn maybe_symbol_or_to_primitive_may_return_symbol(
m: &impl MayHaveSideEffects,
expr: &Expression<'_>,
) -> bool {
match expr {
Expression::Identifier(ident) => {
!(matches!(ident.name.as_str(), "Infinity" | "NaN" | "undefined")
&& m.is_global_reference(ident))
}
Expression::StringLiteral(_)
| Expression::TemplateLiteral(_)
| Expression::NullLiteral(_)
| Expression::NumericLiteral(_)
| Expression::BigIntLiteral(_)
| Expression::BooleanLiteral(_)
| Expression::RegExpLiteral(_)
| Expression::ArrayExpression(_) => false,
// unless `Symbol.toPrimitive`, `valueOf`, `toString` is overridden,
// ToPrimitive for an object returns `"[object Object]"`
Expression::ObjectExpression(obj) => !obj.properties.is_empty(),
_ => true,
}
}

/// Whether the given expression may be a `Symbol`/`BigInt` or converted to a `Symbol`/`BigInt` when passed to `toPrimitive`.
fn maybe_symbol_or_bigint_or_to_primitive_may_return_symbol_or_bigint(
m: &impl MayHaveSideEffects,
expr: &Expression<'_>,
) -> bool {
match expr {
Expression::Identifier(ident) => {
!(matches!(ident.name.as_str(), "Infinity" | "NaN" | "undefined")
&& m.is_global_reference(ident))
}
Expression::StringLiteral(_)
| Expression::TemplateLiteral(_)
| Expression::NullLiteral(_)
| Expression::NumericLiteral(_)
| Expression::BooleanLiteral(_)
| Expression::RegExpLiteral(_)
| Expression::ArrayExpression(_) => false,
// unless `Symbol.toPrimitive`, `valueOf`, `toString` is overridden,
// ToPrimitive for an object returns `"[object Object]"`
Expression::ObjectExpression(obj) => !obj.properties.is_empty(),
_ => true,
}
}
Loading
Loading