fix

Author: Rich-Harris

packages/svelte/src/compiler/phases/2-analyze/visitors/Attribute.js

@@ -64,6 +64,7 @@ export function Attribute(node, context) {
 
 			node.metadata.expression.has_state ||= chunk.metadata.expression.has_state;
 			node.metadata.expression.has_call ||= chunk.metadata.expression.has_call;
+			node.metadata.expression.is_async ||= chunk.metadata.expression.is_async;
 		}
 
 		if (is_event_attribute(node)) {

packages/svelte/src/compiler/phases/2-analyze/visitors/StyleDirective.js

@@ -32,6 +32,7 @@ export function StyleDirective(node, context) {
 
 			node.metadata.expression.has_state ||= chunk.metadata.expression.has_state;
 			node.metadata.expression.has_call ||= chunk.metadata.expression.has_call;
+			node.metadata.expression.is_async ||= chunk.metadata.expression.is_async;
 		}
 	}
 }

packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/component.js

@@ -94,6 +94,10 @@ export function build_component(node, component_name, context, anchor = context.
 	}
 
 	for (const attribute of node.attributes) {
+		if (attribute.type === 'Attribute' || attribute.type === 'SpreadAttribute') {
+			context.state.metadata.init_is_async ||= attribute.metadata.expression.is_async;
+		}
+
 		if (attribute.type === 'LetDirective') {
 			if (!slot_scope_applies_to_itself) {
 				lets.push(/** @type {ExpressionStatement} */ (context.visit(attribute, states.default)));