feat(rome_js_analyze): noParameterAssign

crates/rome_diagnostics_categories/src/categories.rs

@@ -97,6 +97,7 @@ define_categories! {
     "lint/nursery/noPrototypeBuiltins": "https://docs.rome.tools/lint/rules/noPrototypeBuiltins",
     "lint/nursery/noSvgWithoutTitle": "https://docs.rome.tools/lint/rules/noSvgWithoutTitle",
     "lint/nursery/noUselessCatch": "https://docs.rome.tools/lint/rules/noUselessCatch",
+"lint/nursery/noParameterAssign": "https://docs.rome.tools/lint/rules/noParameterAssign",
     // Insert new nursery rule here
     "lint/nursery/noRedeclaration": "https://docs.rome.tools/lint/rules/noRedeclaration",
 

crates/rome_js_analyze/src/semantic_analyzers/nursery/no_parameter_assign.rs

@@ -0,0 +1,115 @@
+use crate::semantic_services::Semantic;
+use rome_analyze::{context::RuleContext, declare_rule, Rule, RuleDiagnostic};
+use rome_console::markup;
+use rome_js_semantic::{AllBindingWriteReferencesIter, Reference, ReferencesExtensions};
+use rome_js_syntax::{AnyJsBindingPattern, AnyJsFormalParameter, AnyJsParameter};
+use rome_rowan::AstNode;
+
+declare_rule! {
+    /// Disallow reassigning `function` parameters.
+    ///
+    /// Assignment to a `function` parameters can be misleading and confusing,
+    /// as modifying parameters will also mutate the `arguments` object.
+    /// It is often unintended and indicative of a programmer error.
+    ///
+    /// Source: https://eslint.org/docs/latest/rules/no-param-reassign
+    ///
+    /// In contrast to the _ESLint_ rule, this rule cannot be configured to report
+    /// assignments to a property of a parameter.
+    ///
+    /// ## Examples
+    ///
+    /// ### Invalid
+    ///
+    /// ```js,expect_diagnostic
+    /// function f(param) {
+    ///     param = 13;
+    /// }
+    /// ```
+    ///
+    /// ```js,expect_diagnostic
+    /// function f(param) {
+    ///     param++;
+    /// }
+    /// ```
+    ///
+    /// ```js,expect_diagnostic
+    /// function f(param) {
+    ///     for (param of arr) {}
+    /// }
+    /// ```
+    ///
+    /// ```ts,expect_diagnostic
+    /// class C {
+    ///     constructor(readonly prop: number) {
+    ///         prop++
+    ///     }
+    /// }
+    /// ```
+    ///
+    /// ## Valid
+    ///
+    /// ```js
+    /// function f(param) {
+    ///     let local = param;
+    /// }
+    /// ```
+    ///
+    pub(crate) NoParameterAssign {
+        version: "next",
+        name: "noParameterAssign",
+        recommended: true,
+    }
+}
+
+impl Rule for NoParameterAssign {
+    type Query = Semantic<AnyJsParameter>;
+    type State = Reference;
+    type Signals = AllBindingWriteReferencesIter;
+    type Options = ();
+
+    fn run(ctx: &RuleContext<Self>) -> Self::Signals {
+        let param = ctx.query();
+        let model = ctx.model();
+        if let Some(binding) = binding_of(param) {
+            if let Some(binding) = binding.as_any_js_binding() {
+                return binding.all_writes(model);
+            }
+        }
+        // Empty iterator that conforms to `AllBindingWriteReferencesIter` type.
+        std::iter::successors(None, |_| None)
+    }
+
+    fn diagnostic(ctx: &RuleContext<Self>, reference: &Self::State) -> Option<RuleDiagnostic> {
+        let param = ctx.query();
+        Some(
+            RuleDiagnostic::new(
+                rule_category!(),
+                reference.syntax().text_trimmed_range(),
+                markup! {
+                    "Reassigning a "<Emphasis>"function parameter"</Emphasis>" is confusing."
+                },
+            )
+            .detail(
+                param.syntax().text_trimmed_range(),
+                markup! {
+                    "The "<Emphasis>"parameter"</Emphasis>" is declared here:"
+                },
+            )
+            .note(markup! {
+                "Use a local variable instead."
+            }),
+        )
+    }
+}
+
+fn binding_of(param: &AnyJsParameter) -> Option<AnyJsBindingPattern> {
+    match param {
+        AnyJsParameter::AnyJsFormalParameter(formal_param) => match &formal_param {
+            AnyJsFormalParameter::JsBogusParameter(_) => None,
+            AnyJsFormalParameter::JsFormalParameter(param) => param.binding().ok(),
+        },
+        AnyJsParameter::JsRestParameter(param) => param.binding().ok(),
+        AnyJsParameter::TsThisParameter(_) => None,
+    }
+}

crates/rome_js_analyze/tests/specs/nursery/noParameterAssign/invalid.jsonc

@@ -0,0 +1,21 @@
+[
+	"function foo(bar) { bar = 13; }",
+	"function foo(bar) { bar += 13; }",
+	"function foo(bar) { (function() { bar = 13; })(); }",
+	"function foo(bar) { ++bar; }",
+	"function foo(bar) { ++bar; }",
+	"function foo(bar) { --bar; }",
+	"function foo(bar) { bar--; }",
+	"function foo(bar) { bar--; }",
+	"function foo(bar) { bar--; }",
+	"function foo(bar) { ({bar} = {}); }",
+	"function foo(bar) { ({x: [, bar = 0]} = {}); }",
+	"function foo(bar) { for (bar in baz); }",
+	"function foo(bar) { for (bar of baz); }",
+	"function foo(a) { ({a} = obj); }",
+	"function foo(a) { ([...a] = obj); }",
+	"function foo(a) { ({...a} = obj); }",
+	"function foo(a) { a &&= b; }",
+	"function foo(a) { a ||= b; }",
+	"function foo(a) { a ??= b; }"
+]