disallow passive|preventDefault combo

src/compile/nodes/Element.ts

@@ -585,6 +585,13 @@ export default class Element extends Node {
 		]);
 
 		this.handlers.forEach(handler => {
+			if (handler.modifiers.has('passive') && handler.modifiers.has('preventDefault')) {
+				component.error(handler, {
+					code: 'invalid-event-modifier',
+					message: `The 'passive' and 'preventDefault' modifiers cannot be used together`
+				});
+			}
+
 			handler.modifiers.forEach(modifier => {
 				if (!validModifiers.has(modifier)) {
 					component.error(handler, {
@@ -619,7 +626,7 @@ export default class Element extends Node {
 				}
 			});
 
-			if (passiveEvents.has(handler.name) && !handler.usesEventObject) {
+			if (passiveEvents.has(handler.name) && !handler.usesEventObject && !handler.modifiers.has('preventDefault')) {
 				// touch/wheel events should be passive by default
 				handler.modifiers.add('passive');
 			}

test/validator/samples/event-modifiers-invalid-passive/errors.json

@@ -0,0 +1,15 @@
+[{
+	"message": "The 'passive' and 'preventDefault' modifiers cannot be used together",
+	"code": "invalid-event-modifier",
+	"start": {
+		"line": 1,
+		"column": 5,
+		"character": 5
+	},
+	"end": {
+		"line": 1,
+		"column": 52,
+		"character": 52
+	},
+	"pos": 5
+}]

test/validator/samples/event-modifiers-invalid-passive/input.html

@@ -0,0 +1,3 @@
+<div on:wheel|passive|preventDefault="handleWheel()">
+	oops
+</div>