consistent-function-scoping: Check use of this and arguments (#590)

Author: fisker

rules/consistent-function-scoping.js

@@ -95,9 +95,16 @@ const isReactHook = scope =>
 	scope.block.parent.callee.type === 'Identifier' &&
 	reactHooks.has(scope.block.parent.callee.name);
 
+const isArrowFunctionWithThis = scope =>
+	scope.type === 'function' &&
+	scope.block &&
+	scope.block.type === 'ArrowFunctionExpression' &&
+	(scope.thisFound || scope.childScopes.some(scope => isArrowFunctionWithThis(scope)));
+
 function checkNode(node, scopeManager) {
 	const scope = scopeManager.acquire(node);
-	if (!scope) {
+
+	if (!scope || isArrowFunctionWithThis(scope)) {
 		return true;
 	}
 

test/consistent-function-scoping.js

@@ -194,6 +194,32 @@ ruleTester.run('consistent-function-scoping', rule, {
 				return Bar;
 			};
 		`,
+		// `this`
+		outdent`
+			function doFoo(Foo) {
+				const doBar = () => this;
+				return doBar();
+			};
+		`,
+		outdent`
+			function doFoo(Foo) {
+				const doBar = () => () => this;
+				return doBar();
+			};
+		`,
+		outdent`
+			function doFoo(Foo) {
+				const doBar = () => () => () => this;
+				return doBar();
+			};
+		`,
+		// `arguments`
+		outdent`
+			function doFoo(Foo) {
+				const doBar = () => arguments;
+				return doBar();
+			};
+		`,
 		// React Hooks
 		outdent`
 			useEffect(() => {
@@ -317,6 +343,57 @@ ruleTester.run('consistent-function-scoping', rule, {
 			`,
 			errors: [createError({arrow: true})]
 		},
+		// `this`
+		{
+			code: outdent`
+				function doFoo(Foo) {
+					function doBar() {
+						return this;
+					}
+					return doBar();
+				};
+			`,
+			errors: [createError({name: 'doBar'})]
+		},
+		{
+			code: outdent`
+				function doFoo(Foo) {
+					const doBar = () => (function() {return this})();
+					return doBar();
+				};
+			`,
+			errors: [createError({name: 'doBar', arrow: true})]
+		},
+		{
+			code: outdent`
+				function doFoo(Foo) {
+					const doBar = () => (function() {return () => this})();
+					return doBar();
+				};
+			`,
+			errors: [createError({name: 'doBar', arrow: true})]
+		},
+		// `arguments`
+		{
+			code: outdent`
+				function doFoo(Foo) {
+					function doBar() {
+						return arguments;
+					}
+					return doBar();
+				};
+			`,
+			errors: [createError({name: 'doBar'})]
+		},
+		{
+			code: outdent`
+				function doFoo(Foo) {
+					const doBar = () => (function() {return arguments})();
+					return doBar();
+				};
+			`,
+			errors: [createError({name: 'doBar', arrow: true})]
+		},
 		{
 			code: outdent`
 				function doFoo(foo) {