bail out of CSS optimisations on encountering spread - fixes #1300

src/css/Selector.ts

@@ -223,6 +223,9 @@ const operators = {
 };
 
 function attributeMatches(node: Node, name: string, expectedValue: string, operator: string, caseInsensitive: boolean) {
+	const spread = node.attributes.find(attr => attr.type === 'Spread');
+	if (spread) return true;
+
 	const attr = node.attributes.find((attr: Node) => attr.name === name);
 	if (!attr) return false;
 	if (attr.value === true) return operator === null;

test/css/samples/spread/_config.js

@@ -0,0 +1,3 @@
+export default {
+	cascade: false
+};

test/css/samples/spread/expected.css

@@ -0,0 +1 @@
+.foo.svelte-xyz{color:red;font-size:2em;font-family:'Comic Sans MS'}

test/css/samples/spread/input.html

@@ -0,0 +1,11 @@
+<div {{...props}} >
+	Big red Comic Sans
+</div>
+
+<style>
+	.foo {
+		color: red;
+		font-size: 2em;
+		font-family: 'Comic Sans MS';
+	}
+</style>