fix: disallow bind:group to snippet parameters

.changeset/hip-oranges-hang.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: disallow `bind:group` to snippet parameters

documentation/docs/98-reference/.generated/compile-errors.md

@@ -84,6 +84,12 @@ Attribute values containing `{...}` must be enclosed in quote marks, unless the
 `bind:group` can only bind to an Identifier or MemberExpression
 ```
 
+### bind_group_invalid_snippet_parameter
+
+```
+Cannot `bind:group` to a snippet parameter
+```
+
 ### bind_invalid_expression
 
 ```

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

@@ -54,6 +54,10 @@
 
 > `bind:group` can only bind to an Identifier or MemberExpression
 
+## bind_group_invalid_snippet_parameter
+
+> Cannot `bind:group` to a snippet parameter
+
 ## bind_invalid_expression
 
 > Can only bind to an Identifier or MemberExpression or a `{get, set}` pair

packages/svelte/src/compiler/errors.js

@@ -752,6 +752,15 @@ export function bind_group_invalid_expression(node) {
 	e(node, 'bind_group_invalid_expression', `\`bind:group\` can only bind to an Identifier or MemberExpression\nhttps://svelte.dev/e/bind_group_invalid_expression`);
 }
 
+/**
+ * Cannot `bind:group` to a snippet parameter
+ * @param {null | number | NodeLike} node
+ * @returns {never}
+ */
+export function bind_group_invalid_snippet_parameter(node) {
+	e(node, 'bind_group_invalid_snippet_parameter', `Cannot \`bind:group\` to a snippet parameter\nhttps://svelte.dev/e/bind_group_invalid_snippet_parameter`);
+}
+
 /**
  * Can only bind to an Identifier or MemberExpression or a `{get, set}` pair
  * @param {null | number | NodeLike} node

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

@@ -191,6 +191,10 @@ export function BindDirective(node, context) {
 			throw new Error('Cannot find declaration for bind:group');
 		}
 
+		if (binding.kind === 'snippet') {
+			e.bind_group_invalid_snippet_parameter(node);
+		}
+
 		// Traverse the path upwards and find all EachBlocks who are (indirectly) contributing to bind:group,
 		// i.e. one of their declarations is referenced in the binding. This allows group bindings to work
 		// correctly when referencing a variable declared in an EachBlock by using the index of the each block

packages/svelte/tests/validator/samples/bind-group-snippet-parameter/errors.json

@@ -0,0 +1,14 @@
+[
+	{
+		"code": "bind_group_invalid_snippet_parameter",
+		"end": {
+			"column": 44,
+			"line": 2
+		},
+		"message": "Cannot `bind:group` to a snippet parameter",
+		"start": {
+			"column": 21,
+			"line": 2
+		}
+	}
+]

packages/svelte/tests/validator/samples/bind-group-snippet-parameter/input.svelte

@@ -0,0 +1,3 @@
+{#snippet test(group)}
+	<input type="radio" bind:group={group.name} />
+{/snippet}