rome · xunilrj · Dec 16, 2022 · Dec 10, 2022 · Dec 10, 2022 · Dec 12, 2022
diff --git a/crates/rome_diagnostics_categories/src/categories.rs b/crates/rome_diagnostics_categories/src/categories.rs
@@ -46,6 +46,7 @@ define_dategories! {
     "lint/nursery/noAssignInExpressions": "https://docs.rome.tools/lint/rules/noAssignInExpressions",
     "lint/nursery/noWith": "https://docs.rome.tools/lint/rules/noWith",
     "lint/nursery/noBannedTypes":"https://docs.rome.tools/lint/rules/noBannedTypes",
+    "lint/nursery/noClassAssign": "https://docs.rome.tools/lint/rules/noClassAssign",
     "lint/nursery/noCommaOperator": "https://docs.rome.tools/lint/rules/noCommaOperator",
     "lint/nursery/noConstEnum": "https://docs.rome.tools/lint/rules/noConstEnum",
     "lint/nursery/noConstructorReturn": "https://docs.rome.tools/lint/rules/noConstructorReturn",

diff --git a/crates/rome_js_analyze/src/semantic_analyzers/nursery.rs b/crates/rome_js_analyze/src/semantic_analyzers/nursery.rs
diff --git a/crates/rome_js_analyze/src/semantic_analyzers/nursery/no_class_assign.rs b/crates/rome_js_analyze/src/semantic_analyzers/nursery/no_class_assign.rs
@@ -0,0 +1,116 @@
+use rome_analyze::context::RuleContext;
+use rome_analyze::{declare_rule, Rule, RuleDiagnostic};
+use rome_console::markup;
+use rome_js_semantic::{Reference, ReferencesExtensions};
+use rome_js_syntax::AnyJsClass;
+
+use crate::semantic_services::Semantic;
+
+declare_rule! {
+    /// Disallow reassigning class members.
+    ///
+    /// A class declaration creates a variable that we can modify, however, the modification is a mistake in most cases.
+    ///
+    /// ## Examples
+    ///
+    /// ### Invalid
+    ///
+    /// ```js,expect_diagnostic
+    /// class A {}
+    /// A = 0;
+    /// ```
+    ///
+    /// ```js,expect_diagnostic
+    /// A = 0;
+    /// class A {}
+    /// ```
+    ///
+    /// ```js,expect_diagnostic
+    /// class A {
+    /// 	b() {
+    /// 		A = 0;
+    /// 	}
+    /// }
+    /// ```
+    ///
+    /// ```js,expect_diagnostic
+    /// let A = class A {
+    /// 	b() {
+    /// 		A = 0;
+    /// 		// `let A` is shadowed by the class name.
+    /// 	}
+    /// }
+    /// ```
+    ///
+    /// ### Valid
+    ///
+    /// ```js
+    /// let A = class A {}
+    /// A = 0; // A is a variable.
+    /// ```
+    ///
+    /// ```js
+    /// let A = class {
+    ///     b() {
+    ///         A = 0; // A is a variable.
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// ```js
+    /// class A {
+    /// 	b(A) {
+    /// 		A = 0; // A is a parameter.
+    /// 	}
+    /// }
+    /// ```
+    ///
+    pub(crate) NoClassAssign {
+        version: "12.0.0",
+        name: "noClassAssign",
+        recommended: true,
+    }
+}
+
+impl Rule for NoClassAssign {
+    type Query = Semantic<AnyJsClass>;
+    type State = Reference;
+    type Signals = Vec<Self::State>;
+    type Options = ();
+
+    fn run(ctx: &RuleContext<Self>) -> Self::Signals {
+        let node = ctx.query();
+        let model = ctx.model();
+
+        if let Ok(Some(id)) = node.id() {
+            if let Some(id_binding) = id.as_js_identifier_binding() {
+                return id_binding.all_writes(model).collect();
+            }
+        }
+
+        Vec::new()
+    }
+
+    fn diagnostic(ctx: &RuleContext<Self>, reference: &Self::State) -> Option<RuleDiagnostic> {
+        let binding = ctx
+            .query()
+            .id()
+            .ok()??
+            .as_js_identifier_binding()?
+            .name_token()
+            .ok()?;
+        let class_name = binding.text_trimmed();
+
+        Some(
+            RuleDiagnostic::new(
+                rule_category!(),
+                reference.syntax().text_trimmed_range(),
+                markup! {"'"{class_name}"' is a class."},
+            )
+            .detail(
+                binding.text_trimmed_range(),
+                markup! {"'"{class_name}"' is defined here."},
+            ),
+        )
+    }
+}
diff --git a/crates/rome_js_analyze/tests/specs/nursery/noClassAssign.js b/crates/rome_js_analyze/tests/specs/nursery/noClassAssign.js
@@ -0,0 +1,110 @@
+/* Valid  */
+function case1() {
+	class A { }
+	foo(A);
+}
+
+function case2() {
+	let A = class A { };
+	foo(A);
+}
+
+function case3() {
+	class A {
+		b(A) {
+			A = 0;
+		}
+	}
+}
+
+function case4() {
+	class A {
+		b() {
+			let A;
+			A = 0;
+		}
+	}
+}
+
+function case5() {
+	let A = class {
+		b() {
+			A = 0;
+		}
+	}
+}
+
+// /* Ignores non class. */
+function case6() {
+	var x = 0;
+	x = 1;
+}
+
+function case7() {
+	let x = 0;
+	x = 1;
+}
+
+function case8() {
+	const x = 0;
+	x = 1;
+}
+
+function case9() {
+	function x() {}
+	x = 1;
+}
+
+function case10(x) {
+	x = 1;
+}
+
+function case11() {
+	try {}
+	catch (x) {
+		x = 1;
+	}
+}
+
+// /* Invalid  */
+function case12() {
+	class A { }
+	A = 0;
+}
+
+function case13() {
+	class B { }
+	({B} = 0);
+}
+
+function case14() {
+	class C { }
+	({b: C = 0} = {});
+}
+
+function case15() {
+	D = 0;
+	class D { }
+}
+
+function case16() {
+	class E {
+		b() {
+			E = 0;
+		}
+	}
+}
+
+function case17() {
+	let F = class F {
+		b() {
+			F = 0;
+		}
+	}
+}
+
+function case18() {
+	class G { }
+	G = 0;
+	G = 1;
+}