mirror of
https://github.com/danbulant/oxc
synced 2026-05-19 12:19:15 +00:00
feat(linter): implement typescript/no-unused-expressions (#7498)
This commit is contained in:
camc314
parent
7da9a39b5d
commit
053bc081fb
3 changed files with 622 additions and 0 deletions
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@ -180,6 +180,7 @@ mod typescript {
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pub mod no_unnecessary_type_constraint;
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pub mod no_unsafe_declaration_merging;
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pub mod no_unsafe_function_type;
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pub mod no_unused_expressions;
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pub mod no_useless_empty_export;
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pub mod no_var_requires;
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pub mod no_wrapper_object_types;
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@ -854,6 +855,7 @@ oxc_macros::declare_all_lint_rules! {
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typescript::consistent_type_definitions,
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typescript::consistent_type_imports,
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typescript::explicit_function_return_type,
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typescript::no_unused_expressions,
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typescript::no_inferrable_types,
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typescript::no_confusing_non_null_assertion,
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typescript::no_duplicate_enum_values,
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418
crates/oxc_linter/src/rules/typescript/no_unused_expressions.rs
Normal file
418
crates/oxc_linter/src/rules/typescript/no_unused_expressions.rs
Normal file
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@ -0,0 +1,418 @@
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use oxc_ast::{
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ast::{ChainElement, Expression, UnaryOperator},
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AstKind,
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};
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use oxc_diagnostics::OxcDiagnostic;
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use oxc_macros::declare_oxc_lint;
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use oxc_span::Span;
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use serde_json::Value;
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use crate::{context::LintContext, rule::Rule, AstNode};
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fn no_unused_expressions_diagnostic(span: Span) -> OxcDiagnostic {
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OxcDiagnostic::warn("Disallow unused expressions")
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.with_help("Consider removing this expression")
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.with_label(span)
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}
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#[derive(Debug, Default, Clone)]
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pub struct NoUnusedExpressions(Box<NoUnusedExpressionsConfig>);
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#[derive(Debug, Default, Clone)]
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pub struct NoUnusedExpressionsConfig {
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allow_short_circuit: bool,
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allow_ternary: bool,
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allow_tagged_templates: bool,
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enforce_for_jsx: bool,
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}
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declare_oxc_lint!(
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/// ### What it does
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///
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/// This rule disallows unused expressions.
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///
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/// ### Why is this bad?
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///
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/// Unused expressions are usually a mistake. They can be a symptom of a bug or a misunderstanding of the code.
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///
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/// ### Examples
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///
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/// Examples of **incorrect** code for this rule:
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/// ```ts
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/// Set<number>;
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/// 1 as number;
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/// window!;
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/// ```
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///
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/// Examples of **correct** code for this rule:
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/// ```ts
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/// const foo = new Set<number>();
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/// ```
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NoUnusedExpressions,
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restriction
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);
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impl Rule for NoUnusedExpressions {
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fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
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let AstKind::ExpressionStatement(expression_stmt) = node.kind() else {
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return;
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};
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if self.is_disallowed(&expression_stmt.expression) {
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ctx.diagnostic(no_unused_expressions_diagnostic(expression_stmt.span));
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}
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}
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fn from_configuration(value: serde_json::Value) -> Self {
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Self(Box::new(NoUnusedExpressionsConfig {
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allow_short_circuit: value
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.get(0)
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.and_then(|x| x.get("allowShortCircuit"))
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.and_then(Value::as_bool)
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.unwrap_or_default(),
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allow_ternary: value
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.get(0)
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.and_then(|x| x.get("allowTernary"))
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.and_then(Value::as_bool)
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.unwrap_or_default(),
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allow_tagged_templates: value
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.get(0)
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.and_then(|x| x.get("allowTaggedTemplates"))
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.and_then(Value::as_bool)
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.unwrap_or_default(),
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enforce_for_jsx: value
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.get(0)
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.and_then(|x| x.get("enforceForJSX"))
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.and_then(Value::as_bool)
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.unwrap_or_default(),
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}))
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}
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}
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impl NoUnusedExpressions {
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fn is_disallowed(&self, expr: &Expression) -> bool {
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match expr {
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Expression::BooleanLiteral(_)
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| Expression::NullLiteral(_)
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| Expression::NumericLiteral(_)
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| Expression::BigIntLiteral(_)
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| Expression::RegExpLiteral(_)
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| Expression::StringLiteral(_)
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| Expression::SequenceExpression(_)
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| Expression::FunctionExpression(_)
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| Expression::ArrayExpression(_)
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| Expression::ComputedMemberExpression(_)
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| Expression::MetaProperty(_)
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| Expression::ObjectExpression(_)
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| Expression::PrivateFieldExpression(_)
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| Expression::StaticMemberExpression(_)
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| Expression::TemplateLiteral(_)
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| Expression::ArrowFunctionExpression(_)
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| Expression::ClassExpression(_)
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| Expression::BinaryExpression(_)
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| Expression::PrivateInExpression(_)
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| Expression::ThisExpression(_)
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| Expression::Identifier(_) => true,
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Expression::ChainExpression(chain_expression) => match &chain_expression.expression {
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ChainElement::CallExpression(_) => false,
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ChainElement::TSNonNullExpression(ts_non_null_expression) => {
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self.is_disallowed(&ts_non_null_expression.expression)
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}
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ChainElement::ComputedMemberExpression(_)
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| ChainElement::StaticMemberExpression(_)
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| ChainElement::PrivateFieldExpression(_) => true,
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},
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Expression::AssignmentExpression(_)
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| Expression::AwaitExpression(_)
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| Expression::NewExpression(_)
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| Expression::ImportExpression(_)
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| Expression::Super(_)
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| Expression::CallExpression(_)
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| Expression::UpdateExpression(_)
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| Expression::YieldExpression(_) => false,
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Expression::ConditionalExpression(conditional_expression) => {
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if self.0.allow_ternary {
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return self.is_disallowed(&conditional_expression.alternate)
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|| self.is_disallowed(&conditional_expression.consequent);
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}
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true
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}
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Expression::LogicalExpression(logical_expression) => {
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if self.0.allow_short_circuit {
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return self.is_disallowed(&logical_expression.right);
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}
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true
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}
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Expression::ParenthesizedExpression(parenthesized_expression) => {
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self.is_disallowed(&parenthesized_expression.expression)
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}
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Expression::TaggedTemplateExpression(_) => !self.0.allow_tagged_templates,
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Expression::UnaryExpression(unary_expression) => {
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!matches!(unary_expression.operator, UnaryOperator::Delete | UnaryOperator::Void)
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}
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Expression::JSXElement(_) | Expression::JSXFragment(_) => self.0.enforce_for_jsx,
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Expression::TSAsExpression(ts_as_expression) => {
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self.is_disallowed(&ts_as_expression.expression)
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}
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Expression::TSSatisfiesExpression(ts_satisfies_expression) => {
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self.is_disallowed(&ts_satisfies_expression.expression)
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}
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Expression::TSTypeAssertion(ts_type_assertion) => {
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self.is_disallowed(&ts_type_assertion.expression)
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}
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Expression::TSNonNullExpression(ts_non_null_expression) => {
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self.is_disallowed(&ts_non_null_expression.expression)
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}
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Expression::TSInstantiationExpression(ts_instantiation_expression) => {
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self.is_disallowed(&ts_instantiation_expression.expression)
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}
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}
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}
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}
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#[test]
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fn test() {
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use crate::tester::Tester;
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let pass = vec![
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(
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"
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test.age?.toLocaleString();
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",
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None,
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),
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(
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"
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let a = (a?.b).c;
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",
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None,
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),
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(
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"
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let b = a?.['b'];
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",
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None,
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),
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(
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"
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let c = one[2]?.[3][4];
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",
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None,
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),
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(
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"
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one[2]?.[3][4]?.();
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",
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None,
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),
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(
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"
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a?.['b']?.c();
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",
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None,
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),
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(
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"
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module Foo {
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'use strict';
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}
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",
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None,
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),
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(
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"
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namespace Foo {
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'use strict';
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export class Foo {}
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export class Bar {}
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}
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",
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None,
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),
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(
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"
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function foo() {
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'use strict';
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return null;
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}
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",
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None,
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),
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(
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"
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import('./foo');
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",
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None,
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),
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(
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"
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import('./foo').then(() => {});
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",
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None,
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),
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(
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"
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class Foo<T> {}
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new Foo<string>();
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",
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None,
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),
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("foo && foo?.();", Some(serde_json::json!([{ "allowShortCircuit": true }]))),
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("foo && import('./foo');", Some(serde_json::json!([{ "allowShortCircuit": true }]))),
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(
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"foo ? import('./foo') : import('./bar');",
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Some(serde_json::json!([{ "allowTernary": true }])),
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),
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];
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let fail = vec![
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(
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"
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if (0) 0;
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",
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None,
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),
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(
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"
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f(0), {};
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",
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None,
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),
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(
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"
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a, b();
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",
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None,
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),
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(
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"
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a() &&
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function namedFunctionInExpressionContext() {
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f();
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};
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",
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None,
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),
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(
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"
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a?.b;
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",
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None,
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),
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(
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"
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(a?.b).c;
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",
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None,
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),
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(
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"
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a?.['b'];
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",
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None,
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),
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(
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"
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(a?.['b']).c;
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",
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None,
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),
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(
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"
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a?.b()?.c;
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",
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None,
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),
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(
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"
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(a?.b()).c;
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",
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None,
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),
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(
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"
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one[2]?.[3][4];
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",
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None,
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),
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(
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"
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one.two?.three.four;
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",
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None,
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),
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(
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"
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module Foo {
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const foo = true;
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'use strict';
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}
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",
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None,
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),
|
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(
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"
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namespace Foo {
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export class Foo {}
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export class Bar {}
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'use strict';
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}
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",
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None,
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),
|
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(
|
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"
|
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function foo() {
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const foo = true;
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|
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'use strict';
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}
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",
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None,
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),
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("foo && foo?.bar;", Some(serde_json::json!([{ "allowShortCircuit": true }]))),
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("foo ? foo?.bar : bar.baz;", Some(serde_json::json!([{ "allowTernary": true }]))),
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(
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"
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class Foo<T> {}
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Foo<string>;
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",
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None,
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),
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("Map<string, string>;", None),
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(
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"
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declare const foo: number | undefined;
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foo;
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",
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None,
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),
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(
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"
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declare const foo: number | undefined;
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foo as any;
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",
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None,
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),
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(
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"
|
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declare const foo: number | undefined;
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<any>foo;
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",
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None,
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),
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(
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"
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declare const foo: number | undefined;
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foo!;
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",
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None,
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),
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];
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|
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Tester::new(NoUnusedExpressions::NAME, NoUnusedExpressions::CATEGORY, pass, fail)
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.test_and_snapshot();
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}
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@ -0,0 +1,202 @@
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---
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source: crates/oxc_linter/src/tester.rs
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---
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⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
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╭─[no_unused_expressions.tsx:2:11]
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1 │
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2 │ if (0) 0;
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· ──
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3 │
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╰────
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help: Consider removing this expression
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⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
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╭─[no_unused_expressions.tsx:2:4]
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1 │
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2 │ f(0), {};
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· ─────────
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3 │
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╰────
|
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help: Consider removing this expression
|
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|
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⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
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╭─[no_unused_expressions.tsx:2:4]
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1 │
|
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2 │ a, b();
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· ───────
|
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3 │
|
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╰────
|
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help: Consider removing this expression
|
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|
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⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
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╭─[no_unused_expressions.tsx:2:4]
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1 │
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2 │ ╭─▶ a() &&
|
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3 │ │ function namedFunctionInExpressionContext() {
|
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4 │ │ f();
|
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5 │ ╰─▶ };
|
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6 │
|
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╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
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╭─[no_unused_expressions.tsx:2:4]
|
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1 │
|
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2 │ a?.b;
|
||||
· ─────
|
||||
3 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:2:4]
|
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1 │
|
||||
2 │ (a?.b).c;
|
||||
· ─────────
|
||||
3 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:2:4]
|
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1 │
|
||||
2 │ a?.['b'];
|
||||
· ─────────
|
||||
3 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:2:4]
|
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1 │
|
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2 │ (a?.['b']).c;
|
||||
· ─────────────
|
||||
3 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:2:4]
|
||||
1 │
|
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2 │ a?.b()?.c;
|
||||
· ──────────
|
||||
3 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:2:4]
|
||||
1 │
|
||||
2 │ (a?.b()).c;
|
||||
· ───────────
|
||||
3 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:2:4]
|
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1 │
|
||||
2 │ one[2]?.[3][4];
|
||||
· ───────────────
|
||||
3 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:2:4]
|
||||
1 │
|
||||
2 │ one.two?.three.four;
|
||||
· ────────────────────
|
||||
3 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:4:6]
|
||||
3 │ const foo = true;
|
||||
4 │ 'use strict';
|
||||
· ─────────────
|
||||
5 │ }
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:6:6]
|
||||
5 │
|
||||
6 │ 'use strict';
|
||||
· ─────────────
|
||||
7 │ }
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:5:6]
|
||||
4 │
|
||||
5 │ 'use strict';
|
||||
· ─────────────
|
||||
6 │ }
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:1:1]
|
||||
1 │ foo && foo?.bar;
|
||||
· ────────────────
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:1:1]
|
||||
1 │ foo ? foo?.bar : bar.baz;
|
||||
· ─────────────────────────
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:3:4]
|
||||
2 │ class Foo<T> {}
|
||||
3 │ Foo<string>;
|
||||
· ────────────
|
||||
4 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:1:1]
|
||||
1 │ Map<string, string>;
|
||||
· ────────────────────
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:3:4]
|
||||
2 │ declare const foo: number | undefined;
|
||||
3 │ foo;
|
||||
· ────
|
||||
4 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:3:4]
|
||||
2 │ declare const foo: number | undefined;
|
||||
3 │ foo as any;
|
||||
· ───────────
|
||||
4 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
|
||||
× Expected `<` but found `EOF`
|
||||
╭─[no_unused_expressions.tsx:4:10]
|
||||
3 │ <any>foo;
|
||||
4 │
|
||||
╰────
|
||||
|
||||
⚠ typescript-eslint(no-unused-expressions): Disallow unused expressions
|
||||
╭─[no_unused_expressions.tsx:3:4]
|
||||
2 │ declare const foo: number | undefined;
|
||||
3 │ foo!;
|
||||
· ─────
|
||||
4 │
|
||||
╰────
|
||||
help: Consider removing this expression
|
||||
Loading…
Reference in a new issue