mirror of
https://github.com/danbulant/oxc
synced 2026-05-19 12:19:15 +00:00
feat(linter): implement eslint/no-multi-assign (#8158)
Implements [eslint/no-multi-assign](https://eslint.org/docs/latest/rules/no-multi-assign) rule.
This commit is contained in:
Anson Heung
GitHub
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384858b9ed
commit
ef76e288ca
3 changed files with 388 additions and 0 deletions
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@ -92,6 +92,7 @@ mod eslint {
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pub mod no_labels;
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pub mod no_loss_of_precision;
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pub mod no_magic_numbers;
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pub mod no_multi_assign;
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pub mod no_multi_str;
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pub mod no_negated_condition;
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pub mod no_nested_ternary;
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@ -539,6 +540,7 @@ oxc_macros::declare_all_lint_rules! {
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eslint::max_classes_per_file,
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eslint::max_lines,
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eslint::max_params,
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eslint::no_multi_assign,
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eslint::no_nested_ternary,
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eslint::no_labels,
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eslint::no_restricted_imports,
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226
crates/oxc_linter/src/rules/eslint/no_multi_assign.rs
Normal file
226
crates/oxc_linter/src/rules/eslint/no_multi_assign.rs
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@ -0,0 +1,226 @@
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use oxc_ast::{ast::Expression, AstKind};
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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 crate::{context::LintContext, rule::Rule, AstNode};
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fn no_multi_assign_diagnostic(span: Span) -> OxcDiagnostic {
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OxcDiagnostic::warn("Do not use chained assignment")
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.with_help("Separate each assignment into its own statement")
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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 NoMultiAssign {
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ignore_non_declaration: 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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/// Disallow use of chained assignment expressions.
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///
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/// ### Why is this bad?
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///
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/// Chaining the assignment of variables can lead to unexpected results and be difficult to read.
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/// ```js
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/// (function() {
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/// const foo = bar = 0; // Did you mean `foo = bar == 0`?
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/// bar = 1; // This will not fail since `bar` is not constant.
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/// })();
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/// console.log(bar); // This will output 1 since `bar` is not scoped.
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/// ```
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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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/// ```js
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/// var a = b = c = 5;
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///
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/// const foo = bar = "baz";
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///
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/// let d =
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/// e =
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/// f;
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///
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/// class Foo {
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/// a = b = 10;
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/// }
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///
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/// a = b = "quux";
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/// ```
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///
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/// Examples of **correct** code for this rule:
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/// ```js
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/// var a = 5;
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/// var b = 5;
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/// var c = 5;
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///
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/// const foo = "baz";
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/// const bar = "baz";
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///
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/// let d = c;
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/// let e = c;
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///
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/// class Foo {
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/// a = 10;
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/// b = 10;
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/// }
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///
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/// a = "quux";
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/// b = "quux";
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/// ```
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///
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/// ### Options
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///
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/// This rule has an object option:
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/// * `"ignoreNonDeclaration"`: When set to `true`, the rule allows chains that don't include initializing a variable in a declaration or initializing a class field. Default is `false`.
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///
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/// #### ignoreNonDeclaration
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///
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/// Examples of **correct** code for the `{ "ignoreNonDeclaration": true }` option:
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/// ```js
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/// let a;
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/// let b;
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/// a = b = "baz";
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///
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/// const x = {};
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/// const y = {};
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/// x.one = y.one = 1;
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/// ```
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///
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/// Examples of **incorrect** code for the `{ "ignoreNonDeclaration": true }` option:
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/// ```js
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/// let a = b = "baz";
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///
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/// const foo = bar = 1;
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///
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/// class Foo {
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/// a = b = 10;
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/// }
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/// ```
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NoMultiAssign,
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style,
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);
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impl Rule for NoMultiAssign {
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fn from_configuration(value: serde_json::Value) -> Self {
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let ignore_non_declaration = value
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.get(0)
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.and_then(|config| config.get("ignoreNonDeclaration"))
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.and_then(serde_json::Value::as_bool)
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.unwrap_or(false);
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Self { ignore_non_declaration }
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}
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fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
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// e.g. `var a = b = c;`
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if let AstKind::VariableDeclarator(declarator) = node.kind() {
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let Some(Expression::AssignmentExpression(assign_expr)) = &declarator.init else {
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return;
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};
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ctx.diagnostic(no_multi_assign_diagnostic(assign_expr.span));
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}
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// e.g. `class A { a = b = 1; }`
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if let AstKind::PropertyDefinition(prop_def) = node.kind() {
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let Some(Expression::AssignmentExpression(assign_expr)) = &prop_def.value else {
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return;
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};
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ctx.diagnostic(no_multi_assign_diagnostic(assign_expr.span));
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}
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// e.g. `let a; let b; a = b = 1;`
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if !self.ignore_non_declaration {
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if let AstKind::AssignmentExpression(parent_expr) = node.kind() {
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let Expression::AssignmentExpression(expr) = &parent_expr.right else {
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return;
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};
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ctx.diagnostic(no_multi_assign_diagnostic(expr.span));
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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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"var a, b, c,
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d = 0;",
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None,
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),
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(
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"var a = 1; var b = 2; var c = 3;
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var d = 0;",
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None,
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),
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("var a = 1 + (b === 10 ? 5 : 4);", None),
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("const a = 1, b = 2, c = 3;", None), // { "ecmaVersion": 6 },
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(
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"const a = 1;
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const b = 2;
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const c = 3;",
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None,
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), // { "ecmaVersion": 6 },
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("for(var a = 0, b = 0;;){}", None),
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("for(let a = 0, b = 0;;){}", None), // { "ecmaVersion": 6 },
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("for(const a = 0, b = 0;;){}", None), // { "ecmaVersion": 6 },
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("export let a, b;", None), // { "ecmaVersion": 6, "sourceType": "module" },
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(
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"export let a,
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b = 0;",
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None,
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), // { "ecmaVersion": 6, "sourceType": "module" },
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(
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"const x = {};const y = {};x.one = y.one = 1;",
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Some(serde_json::json!([{ "ignoreNonDeclaration": true }])),
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), // { "ecmaVersion": 6 },
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("let a, b;a = b = 1", Some(serde_json::json!([{ "ignoreNonDeclaration": true }]))), // { "ecmaVersion": 6 },
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("class C { [foo = 0] = 0 }", None), // { "ecmaVersion": 2022 }
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];
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let fail = vec![
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("var a = b = c;", None),
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("var a = b = c = d;", None),
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("let foo = bar = cee = 100;", None), // { "ecmaVersion": 6 },
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("a=b=c=d=e", None),
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("a=b=c", None),
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(
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"a
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=b
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=c",
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None,
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),
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("var a = (b) = (((c)))", None),
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("var a = ((b)) = (c)", None),
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("var a = b = ( (c * 12) + 2)", None),
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(
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"var a =
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((b))
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= (c)",
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None,
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),
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("a = b = '=' + c + 'foo';", None),
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("a = b = 7 * 12 + 5;", None),
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(
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"const x = {};
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const y = x.one = 1;",
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Some(serde_json::json!([{ "ignoreNonDeclaration": true }])),
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), // { "ecmaVersion": 6 },
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("let a, b;a = b = 1", Some(serde_json::json!([{}]))), // { "ecmaVersion": 6 },
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("let x, y;x = y = 'baz'", Some(serde_json::json!([{ "ignoreNonDeclaration": false }]))), // { "ecmaVersion": 6 },
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("const a = b = 1", Some(serde_json::json!([{ "ignoreNonDeclaration": true }]))), // { "ecmaVersion": 6 },
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("class C { field = foo = 0 }", None), // { "ecmaVersion": 2022 },
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(
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"class C { field = foo = 0 }",
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Some(serde_json::json!([{ "ignoreNonDeclaration": true }])),
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), // { "ecmaVersion": 2022 }
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];
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Tester::new(NoMultiAssign::NAME, NoMultiAssign::CATEGORY, pass, fail).test_and_snapshot();
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}
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160
crates/oxc_linter/src/snapshots/eslint_no_multi_assign.snap
Normal file
160
crates/oxc_linter/src/snapshots/eslint_no_multi_assign.snap
Normal file
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@ -0,0 +1,160 @@
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---
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source: crates/oxc_linter/src/tester.rs
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snapshot_kind: text
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---
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:9]
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1 │ var a = b = c;
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· ─────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:9]
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1 │ var a = b = c = d;
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· ─────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:13]
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1 │ var a = b = c = d;
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· ─────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:11]
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1 │ let foo = bar = cee = 100;
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· ───────────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:17]
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1 │ let foo = bar = cee = 100;
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· ─────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:3]
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1 │ a=b=c=d=e
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· ───────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:5]
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1 │ a=b=c=d=e
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· ─────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:7]
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1 │ a=b=c=d=e
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· ───
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:3]
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1 │ a=b=c
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· ───
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:2:5]
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1 │ a
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2 │ ╭─▶ =b
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3 │ ╰─▶ =c
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:9]
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1 │ var a = (b) = (((c)))
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· ─────────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:9]
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1 │ var a = ((b)) = (c)
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· ───────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:9]
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1 │ var a = b = ( (c * 12) + 2)
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· ───────────────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:2:4]
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1 │ var a =
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2 │ ╭─▶ ((b))
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3 │ ╰─▶ = (c)
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:5]
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1 │ a = b = '=' + c + 'foo';
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· ───────────────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:5]
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1 │ a = b = 7 * 12 + 5;
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· ──────────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:2:14]
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1 │ const x = {};
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2 │ const y = x.one = 1;
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· ─────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:14]
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1 │ let a, b;a = b = 1
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· ─────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:14]
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1 │ let x, y;x = y = 'baz'
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· ─────────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:11]
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1 │ const a = b = 1
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· ─────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:19]
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1 │ class C { field = foo = 0 }
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· ───────
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╰────
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help: Separate each assignment into its own statement
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⚠ eslint(no-multi-assign): Do not use chained assignment
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╭─[no_multi_assign.tsx:1:19]
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1 │ class C { field = foo = 0 }
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· ───────
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╰────
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help: Separate each assignment into its own statement
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