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fix(linter/no-unused-private-class-members): correctly detect value context for private members in assignment expressions #15553

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

fix(linter/no-unused-private-class-members): correctly detect value context for private members in assignment expressions #15553

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36 changes: 22 additions & 14 deletions crates/oxc_linter/src/rules/eslint/no_unused_private_class_members.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -146,7 +146,7 @@ fn is_read(current_node_id: NodeId, semantic: &Semantic) -> bool {
| AstKind::IdentifierReference(_),
) => {}
// All these are read contexts for private fields
(AstKind::PrivateFieldExpression(_), _) if is_value_context(parent, semantic) => {
(AstKind::PrivateFieldExpression(_), _) if is_value_context(parent, curr, semantic) => {
return true;
}
// AssignmentExpression: right-hand side is a read, compound assignment result in value context is a read
Expand Down Expand Up @@ -191,7 +191,7 @@ fn is_read(current_node_id: NodeId, semantic: &Semantic) -> bool {
if conditional_expr.test.span() == curr.span() {
return true;
}
if is_value_context(parent, semantic) {
if is_value_context(parent, curr, semantic) {
return true;
}
}
Expand All @@ -204,8 +204,9 @@ fn is_read(current_node_id: NodeId, semantic: &Semantic) -> bool {
}

/// Check if the given AST kind represents a context where a value is being read/used
fn is_value_context(kind: &AstNode, semantic: &Semantic<'_>) -> bool {
match kind.kind() {
/// `parent` is the parent node, `child` is the child node we're checking
fn is_value_context(parent: &AstNode, child: &AstNode, semantic: &Semantic<'_>) -> bool {
match parent.kind() {
AstKind::ReturnStatement(_)
| AstKind::CallExpression(_)
| AstKind::BinaryExpression(_)
Expand All @@ -227,11 +228,15 @@ fn is_value_context(kind: &AstNode, semantic: &Semantic<'_>) -> bool {
| AstKind::ThrowStatement(_)
| AstKind::WhileStatement(_)
| AstKind::DoWhileStatement(_) => true,
AstKind::AssignmentExpression(assign_expr) => {
// The right-hand side of an assignment is always in a value context (being read for assignment)
assign_expr.right.span().contains_inclusive(child.span())
}
AstKind::ExpressionStatement(_) => {
let parent_node = semantic.nodes().parent_node(kind.id());
if let AstKind::FunctionBody(_) = parent_node.kind()
let grandparent = semantic.nodes().parent_node(parent.id());
if let AstKind::FunctionBody(_) = grandparent.kind()
&& let AstKind::ArrowFunctionExpression(arrow) =
semantic.nodes().parent_kind(parent_node.id())
semantic.nodes().parent_kind(grandparent.id())
&& arrow.expression
{
return true;
Expand All @@ -248,7 +253,8 @@ fn is_value_context(kind: &AstNode, semantic: &Semantic<'_>) -> bool {
| AstKind::AwaitExpression(_)
| AstKind::ConditionalExpression(_)
| AstKind::LogicalExpression(_) => {
is_value_context(semantic.nodes().parent_node(kind.id()), semantic)
let grandparent = semantic.nodes().parent_node(parent.id());
is_value_context(grandparent, parent, semantic)
}

_ => false,
Expand All @@ -257,12 +263,10 @@ fn is_value_context(kind: &AstNode, semantic: &Semantic<'_>) -> bool {

/// Check if a compound assignment result is being used in a value context
fn is_compound_assignment_read(parent_id: NodeId, semantic: &Semantic) -> bool {
semantic
.nodes()
.ancestors(parent_id)
.tuple_windows::<(&AstNode<'_>, &AstNode<'_>)>()
.next()
.is_some_and(|(grandparent, _)| is_value_context(grandparent, semantic))
let assignment_expr = semantic.nodes().get_node(parent_id);
semantic.nodes().ancestors(parent_id).next().is_some_and(|assignment_parent| {
is_value_context(assignment_parent, assignment_expr, semantic)
})
}

#[test]
Expand Down Expand Up @@ -486,6 +490,10 @@ fn test() {
r"class Foo { #x; method() { throw a ? this.#x : new Error(); } }",
r"class Foo { #x; method() { while (a ? this.#x : b) {} } }",
r"class Foo { #a; #b; #c; method() { return this.#a ? this.#b : this.#c; } }",
// Issue #15548: Private member used in logical expression on RHS of assignment
r"class ExampleFoo { #foo = 0; foo(foo) { foo = foo ?? this.#foo; return foo; } }",
// Issue #15548: Private member used in update expression on RHS of assignment
r"class ExampleBar { #bar = 0; bar(bar) { bar = ++this.#bar; return bar; } }",
];

let fail = vec![
Expand Down
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