Throw an error if an attribute name contains a bracket

Fixes #4648

src/compiler/compile/nodes/Element.ts

@@ -378,6 +378,14 @@ export default class Element extends Node {
 				}
 			}
 
+
+			if (/[{}]/.test(name)) {
+				component.error(attribute, {
+					code: `illegal-attribute`,
+					message: `'${name}' is not a valid attribute name`,
+				});
+			}
+
 			if (name === 'slot') {
 				if (!attribute.is_static) {
 					component.error(attribute, {

test/validator/samples/attribute-invalid-name-2/errors.json

@@ -0,0 +1,15 @@
+[{
+	"code": "illegal-attribute",
+	"message": "'a}a' is not a valid attribute name",
+	"start": {
+		"line": 1,
+		"column": 3,
+		"character": 3
+	},
+	"end": {
+		"line": 1,
+		"column": 6,
+		"character": 6
+	},
+	"pos": 3
+}]

test/validator/samples/attribute-invalid-name-2/input.svelte

@@ -0,0 +1 @@
+<p a}a>Test</p>

test/validator/samples/attribute-invalid-name-3/errors.json

@@ -0,0 +1,16 @@
+[
+{
+	"code": "illegal-attribute",
+	"message": "'a{a' is not a valid attribute name",
+	"start": {
+		"line": 1,
+		"column": 3,
+		"character": 3
+	},
+	"end": {
+		"line": 1,
+		"column": 6,
+		"character": 6
+	},
+	"pos": 3
+}]

test/validator/samples/attribute-invalid-name-3/input.svelte

@@ -0,0 +1 @@
+<p a{a>Test</p>

test/validator/samples/attribute-invalid-name-4/errors.json

@@ -0,0 +1,15 @@
+[{
+	"code": "illegal-attribute",
+	"message": "'}a' is not a valid attribute name",
+	"start": {
+		"line": 1,
+		"column": 3,
+		"character": 3
+	},
+	"end": {
+		"line": 1,
+		"column": 5,
+		"character": 5
+	},
+	"pos": 3
+}]

test/validator/samples/attribute-invalid-name-4/input.svelte

@@ -0,0 +1 @@
+<p }a>Test</p>

test/validator/samples/attribute-invalid-name-5/errors.json

@@ -0,0 +1,15 @@
+[{
+	"code": "illegal-attribute",
+	"message": "'a}' is not a valid attribute name",
+	"start": {
+		"line": 1,
+		"column": 3,
+		"character": 3
+	},
+	"end": {
+		"line": 1,
+		"column": 5,
+		"character": 5
+	},
+	"pos": 3
+}]

test/validator/samples/attribute-invalid-name-5/input.svelte

@@ -0,0 +1 @@
+<p a}>Test</p>

test/validator/samples/attribute-invalid-name/errors.json

@@ -0,0 +1,15 @@
+[{
+	"code": "illegal-attribute",
+	"message": "'}' is not a valid attribute name",
+	"start": {
+		"line": 1,
+		"column": 3,
+		"character": 3
+	},
+	"end": {
+		"line": 1,
+		"column": 4,
+		"character": 4
+	},
+	"pos": 3
+}]

test/validator/samples/attribute-invalid-name/input.svelte

@@ -0,0 +1 @@
+<p }>Test</p>