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fix(ecmascript): fix may_have_side_effects for unary expressions #8989

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

fix(ecmascript): fix may_have_side_effects for unary expressions #8989

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53 changes: 43 additions & 10 deletions crates/oxc_ecmascript/src/side_effects/may_have_side_effects.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -60,17 +60,50 @@ pub trait MayHaveSideEffects {
}

fn unary_expression_may_have_side_effects(&self, e: &UnaryExpression<'_>) -> bool {
/// A "simple" operator is one whose children are expressions, has no direct side-effects.
fn is_simple_unary_operator(operator: UnaryOperator) -> bool {
operator != UnaryOperator::Delete
}
if e.operator == UnaryOperator::Typeof && matches!(&e.argument, Expression::Identifier(_)) {
return false;
}
if is_simple_unary_operator(e.operator) {
return self.expression_may_have_side_effects(&e.argument);
match e.operator {
UnaryOperator::Delete => true,
UnaryOperator::Void | UnaryOperator::LogicalNot => {
self.expression_may_have_side_effects(&e.argument)
}
UnaryOperator::Typeof => {
if matches!(&e.argument, Expression::Identifier(_)) {
false
} else {
self.expression_may_have_side_effects(&e.argument)
}
}
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))
}
// ToNumber throws an error when the argument is Symbol / BigInt / an object that
// returns Symbol or BigInt from ToPrimitive
_ => true,
}
}
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))
}
// ToNumber throws an error when the argument is Symbol an object that
// returns Symbol from ToPrimitive
_ => true,
}
}
}
true
}

fn binary_expression_may_have_side_effects(&self, e: &BinaryExpression<'_>) -> bool {
Expand Down
59 changes: 40 additions & 19 deletions crates/oxc_minifier/tests/ecmascript/may_have_side_effects.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -120,9 +120,9 @@ fn closure_compiler_tests() {
test("undefined", false);
test("void 0", false);
test("void foo()", true);
test("-Infinity", false);
test("Infinity", false);
test("NaN", false);
test_with_global_variables("-Infinity", vec!["Infinity".to_string()], false);
test_with_global_variables("Infinity", vec!["Infinity".to_string()], false);
test_with_global_variables("NaN", vec!["NaN".to_string()], false);
// test("({}||[]).foo = 2;", false);
// test("(true ? {} : []).foo = 2;", false);
// test("({},[]).foo = 2;", false);
Expand Down Expand Up @@ -344,21 +344,48 @@ fn test_simple_expressions() {

#[test]
fn test_unary_expressions() {
test("+'foo'", false);
test("+foo()", true);
test("-'foo'", false);
test("-foo()", true);
test("delete 'foo'", true);
test("delete foo()", true);

test("void 'foo'", false);
test("void foo()", true);
test("!'foo'", false);
test("!foo()", true);
test("~'foo'", false);
test("~foo()", true);

test("typeof 'foo'", false);
test_with_global_variables("typeof a", vec!["a".to_string()], false);
test("typeof foo()", true);
test("void 'foo'", false);
test("void foo()", true);
test("delete 'foo'", true);
test("delete foo()", true);

test("+0", false);
test("+0n", true);
test("+null", false); // 0
test("+true", false); // 1
test("+'foo'", false); // NaN
test_with_global_variables("+Infinity", vec!["Infinity".to_string()], false);
test_with_global_variables("+NaN", vec!["NaN".to_string()], false);
test_with_global_variables("+undefined", vec!["undefined".to_string()], false); // NaN
test("+foo()", true);
test("+foo", true); // foo can be Symbol or BigInt
test("+Symbol()", true);
test("+{ valueOf() { return Symbol() } }", true);

test("-0", false);
test("-0n", false);
test("-null", false); // -0
test("-true", false); // -1
test("-'foo'", false); // -NaN
test_with_global_variables("-Infinity", vec!["Infinity".to_string()], false);
test_with_global_variables("-NaN", vec!["NaN".to_string()], false);
test_with_global_variables("-undefined", vec!["undefined".to_string()], false); // NaN
test("-foo()", true);
test("-foo", true); // foo can be Symbol
test("-Symbol()", true);
test("-{ valueOf() { return Symbol() } }", true);

test("~0", false);
test("~'foo'", false);
test("~foo()", true);
test("~foo", true);
}

#[test]
Expand Down Expand Up @@ -477,12 +504,6 @@ fn tests() {
test("'' + { valueOf() { console.log('sideeffect') } }", false);
test("'' + { [s]() { console.log('sideeffect') } }", false); // assuming s is Symbol.toPrimitive

// FIXME: actually these have a side effect, but it's ignored now
test("+s", false); // assuming s is a Symbol
test("+b", false); // assuming b is a BitInt
test("+{ valueOf() { return Symbol() } }", false);
test("~s", false); // assuming s is a Symbol

// FIXME: actually these have a side effect, but it's ignored now
// same for -, *, /, %, **, <<, >>
test("'' + s", false); // assuming s is Symbol
Expand Down
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