disallow non-expression directive values

src/parse/state/tag.ts

@@ -390,6 +390,15 @@ function readAttribute(parser: Parser, uniqueNames: Set<string>) {
 	if (type) {
 		const [directive_name, ...modifiers] = name.slice(colon_index + 1).split('|');
 
+		if (value[0]) {
+			if (value.length > 1 || value[0].type === 'Text') {
+				parser.error({
+					code: `invalid-directive-value`,
+					message: `Directive value must be a JavaScript expression enclosed in curly braces`
+				}, value[0].start);
+			}
+		}
+
 		const directive = {
 			start,
 			end,

test/runtime/samples/class-boolean/main.html

@@ -1 +1 @@
-<div class:one="true"></div>
+<div class:one={true}></div>

test/validator/samples/directive-non-expression/errors.json

@@ -0,0 +1,15 @@
+[{
+	"code": "invalid-directive-value",
+	"message": "Directive value must be a JavaScript expression enclosed in curly braces",
+	"pos": 15,
+	"start": {
+		"line": 1,
+		"column": 15,
+		"character": 15
+	},
+	"end": {
+		"line": 1,
+		"column": 15,
+		"character": 15
+	}
+}]

test/validator/samples/directive-non-expression/input.html

@@ -0,0 +1 @@
+<div on:click="invalid"></div>

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

@@ -8,8 +8,8 @@
 	},
 	"end": {
 		"line": 1,
-		"column": 52,
+		"column": 50,
-		"character": 52
+		"character": 50
 	},
 	"pos": 5
 }]

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

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

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

@@ -8,8 +8,8 @@
 	},
 	"end": {
 		"line": 1,
-		"column": 36,
+		"column": 34,
-		"character": 36
+		"character": 34
 	},
 	"pos": 8
 }]

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

@@ -1 +1 @@
-<button on:click|stop|bad="doThat()"></button>
+<button on:click|stop|bad={doThat}></button>