only output `null` as value for `append_styles` in `init` function if `dirty` is set

src/compiler/compile/render_dom/index.ts

@@ -529,6 +529,16 @@ export default function dom(
 			name: options.dev ? '@SvelteComponentDev' : '@SvelteComponent'
 		};
 
+		const optionalParameters = [];
+		if (should_add_css) {
+			optionalParameters.push(add_css);
+		} else if (dirty) {
+			optionalParameters.push(x`null`);
+		}
+		if (dirty) {
+			optionalParameters.push(dirty);
+		}
+
 		const declaration = b`
 			class ${name} extends ${superclass} {
 				constructor(options) {

src/runtime/internal/Component.ts

@@ -104,15 +104,7 @@ function make_dirty(component, i) {
 	component.$$.dirty[(i / 31) | 0] |= (1 << (i % 31));
 }
 
-let append_styles;
-export function set_append_styles(append_styles_fn) {
-	append_styles = function (root) {
-		append_styles_fn(root);
-		append_styles = null;
-	};
-}
-
-export function init(component, options, instance, create_fragment, not_equal, props, _append_styles_legacy, dirty = [-1]) {
+export function init(component, options, instance, create_fragment, not_equal, props, append_styles, dirty = [-1]) {
 	const parent_component = current_component;
 	set_current_component(component);