fix: error on incorrect attributes for svelte:body (#13084)

* fix: error on spreading attributes for svelte:body

* tweak

Author: trueadm

.changeset/eleven-icons-sniff.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: error on incorrect attributes for svelte:body

packages/svelte/messages/compile-errors/template.md

@@ -274,6 +274,10 @@ HTML restricts where certain elements can appear. In case of a violation the bro
 
 > A component can have a single top-level `<style>` element
 
+## svelte_body_illegal_attribute
+
+> `<svelte:body>` does not support non-event attributes or spread attributes
+
 ## svelte_component_invalid_this
 
 > Invalid component definition — must be an `{expression}`

packages/svelte/src/compiler/errors.js

@@ -1183,6 +1183,15 @@ export function style_duplicate(node) {
 	e(node, "style_duplicate", "A component can have a single top-level `<style>` element");
 }
 
+/**
+ * `<svelte:body>` does not support non-event attributes or spread attributes
+ * @param {null | number | NodeLike} node
+ * @returns {never}
+ */
+export function svelte_body_illegal_attribute(node) {
+	e(node, "svelte_body_illegal_attribute", "`<svelte:body>` does not support non-event attributes or spread attributes");
+}
+
 /**
  * Invalid component definition — must be an `{expression}`
  * @param {null | number | NodeLike} node

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

@@ -1,5 +1,7 @@
 /** @import { SvelteBody } from '#compiler' */
 /** @import { Context } from '../types' */
+import * as e from '../../../errors.js';
+import { is_event_attribute } from '../../../utils/ast.js';
 import { disallow_children } from './shared/special-element.js';
 
 /**
@@ -8,5 +10,13 @@ import { disallow_children } from './shared/special-element.js';
  */
 export function SvelteBody(node, context) {
 	disallow_children(node);
+	for (const attribute of node.attributes) {
+		if (
+			attribute.type === 'SpreadAttribute' ||
+			(attribute.type === 'Attribute' && !is_event_attribute(attribute))
+		) {
+			e.svelte_body_illegal_attribute(attribute);
+		}
+	}
 	context.next();
 }

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

@@ -1,7 +1,6 @@
 /** @import { Expression } from 'estree' */
 /** @import { SvelteBody, SvelteDocument, SvelteWindow } from '#compiler' */
 /** @import { ComponentContext } from '../../types' */
-import { is_event_attribute } from '../../../../../utils/ast.js';
 import * as b from '../../../../../utils/builders.js';
 
 /**