feat(linter): add rule no-undefined

related to #479

Author: jordan-boyer

crates/oxc_linter/src/rules.rs

@@ -96,6 +96,7 @@ mod eslint {
     pub mod no_ternary;
     pub mod no_this_before_super;
     pub mod no_undef;
+    pub mod no_undefined;
     pub mod no_unreachable;
     pub mod no_unsafe_finally;
     pub mod no_unsafe_negation;
@@ -494,6 +495,7 @@ oxc_macros::declare_all_lint_rules! {
     eslint::no_shadow_restricted_names,
     eslint::no_sparse_arrays,
     eslint::no_undef,
+    eslint::no_undefined,
     eslint::no_unreachable,
     eslint::no_unsafe_finally,
     eslint::no_unsafe_negation,

crates/oxc_linter/src/rules/eslint/no_undefined.rs

@@ -0,0 +1,146 @@
+use oxc_ast::AstKind;
+use oxc_diagnostics::OxcDiagnostic;
+use oxc_macros::declare_oxc_lint;
+use oxc_span::Span;
+
+use crate::{context::LintContext, rule::Rule, AstNode};
+
+#[derive(Debug, Default, Clone)]
+pub struct NoUndefined;
+
+fn no_undefined_diagnostic(span0: Span) -> OxcDiagnostic {
+    OxcDiagnostic::warn("eslint(no-undefined): Disallow the use of `undefined` as an identifier")
+        .with_help("Unexpected use of undefined.")
+        .with_label(span0)
+}
+
+declare_oxc_lint!(
+    /// ### What it does
+    /// Disallow the use of `undefined` as an identifier
+    ///
+    /// ### Why is this bad?
+    ///
+    ///
+    /// ### Example of bad code
+    /// ```javascript
+    ///
+    /// var foo = undefined;
+    ///
+    /// var undefined = "foo";
+    ///
+    /// if (foo === undefined) {
+    /// ...
+    /// }
+    ///
+    /// function baz(undefined) {
+    /// ...
+    /// }
+    ///
+    /// bar(undefined, "lorem");
+    ///
+    /// ```
+    ///
+    /// ### Example of good code
+    /// ```javascript
+    /// var foo = void 0;
+    ///
+    /// var Undefined = "foo";
+    ///
+    /// if (typeof foo === "undefined") {
+    /// ...
+    /// }
+    ///
+    /// global.undefined = "foo";
+    ///
+    /// bar(void 0, "lorem");
+    /// ```
+    ///
+    NoUndefined,
+    restriction,
+);
+
+fn diagnostic_undefined_keyword(name: String, span0: Span, ctx: &LintContext) {
+    if name == "undefined" {
+        ctx.diagnostic(no_undefined_diagnostic(span0));
+    }
+}
+
+impl Rule for NoUndefined {
+    fn run<'a>(&self, node: &AstNode<'a>, ctx: &LintContext<'a>) {
+        match node.kind() {
+            AstKind::IdentifierReference(ident) => {
+                diagnostic_undefined_keyword(ident.name.to_string(), ident.span, ctx);
+            }
+            AstKind::BindingIdentifier(ident) => {
+                diagnostic_undefined_keyword(ident.name.to_string(), ident.span, ctx);
+            }
+            _ => {}
+        }
+    }
+}
+
+#[test]
+fn test() {
+    use crate::tester::Tester;
+
+    let pass = vec![
+        "void 0",
+        "void!0",
+        "void-0",
+        "void+0",
+        "null",
+        "undefine",
+        "ndefined",
+        "a.undefined",
+        "this.undefined",
+        "global['undefined']",
+        "({ undefined: bar })",
+        "({ undefined: bar } = foo)",
+        "({ undefined() {} })",
+        "class Foo { undefined() {} }",
+        "(class { undefined() {} })",
+        "import { undefined as a } from 'foo'", // ES6_MODULE,
+        "export { undefined } from 'foo'",      // ES6_MODULE,
+        "export { undefined as a } from 'foo'", // ES6_MODULE,
+        "export { a as undefined } from 'foo'", // ES6_MODULE
+    ];
+
+    let fail = vec![
+        "undefined",
+        "undefined.a",
+        "a[undefined]",
+        "undefined[0]",
+        "f(undefined)",
+        "function f(undefined) {}",
+        "function f() { var undefined; }",
+        "function f() { undefined = true; }",
+        "var undefined;",
+        "try {} catch(undefined) {}",
+        "function undefined() {}",
+        "(function undefined(){}())",
+        "var foo = function undefined() {}",
+        "foo = function undefined() {}",
+        "undefined = true",
+        "var undefined = true",
+        "({ undefined })",
+        "({ [undefined]: foo })",
+        "({ bar: undefined })",
+        "({ bar: undefined } = foo)",
+        "var { undefined } = foo",
+        "var { bar: undefined } = foo",
+        "({ undefined: function undefined() {} })",
+        "({ foo: function undefined() {} })",
+        "class Foo { [undefined]() {} }",
+        "(class { [undefined]() {} })",
+        "var undefined = true; undefined = false;",
+        "import undefined from 'foo'",          // ES6_MODULE,
+        "import * as undefined from 'foo'",     // ES6_MODULE,
+        "import { undefined } from 'foo'",      // ES6_MODULE,
+        "import { a as undefined } from 'foo'", // ES6_MODULE,
+        "let a = [b, ...undefined]",
+        "[a, ...undefined] = b",
+        "[a = undefined] = b",
+    ];
+
+    Tester::new(NoUndefined::NAME, pass, fail).test_and_snapshot();
+}