fix: throw descriptive error if using `createRawSnippet` using custom renderer

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

@@ -197,6 +197,12 @@ Failed to hydrate the application
 Could not `{@render}` snippet due to the expression being `null` or `undefined`. Consider using optional chaining `{@render snippet?.()}`
 ```
 
+### invalid_snippet_in_custom_renderer
+
+```
+`createRawSnippet` cannot be used with a custom renderer
+```
+
 ### lifecycle_legacy_only
 
 ```

packages/svelte/messages/client-errors/errors.md

@@ -151,6 +151,10 @@ This can happen if you render a hydratable on the client that was not rendered o
 
 > Could not `{@render}` snippet due to the expression being `null` or `undefined`. Consider using optional chaining `{@render snippet?.()}`
 
+## invalid_snippet_in_custom_renderer
+
+> `createRawSnippet` cannot be used with a custom renderer
+
 ## lifecycle_legacy_only
 
 > `%name%(...)` cannot be used in runes mode

packages/svelte/src/internal/client/dom/blocks/snippet.js

@@ -16,6 +16,7 @@ import { DEV } from 'esm-env';
 import { get_first_child, get_next_sibling, insert_before, node_type } from '../operations.js';
 import { prevent_snippet_stringification } from '../../../shared/validate.js';
 import { BranchManager } from './branches.js';
+import { renderer } from '../../custom-renderer/state.js';
 
 /**
  * @template {(node: TemplateNode, ...args: any[]) => void} SnippetFn
@@ -71,9 +72,11 @@ export function wrap_snippet(component, fn) {
  * @returns {Snippet<Params>}
  */
 export function createRawSnippet(fn) {
-	// TODO RENDERER: throw an error for createRawSnippet in a non-browser environment, as it relies on DOM APIs
 	// @ts-expect-error the types are a lie
 	return (/** @type {TemplateNode} */ anchor, /** @type {Getters<Params>} */ ...params) => {
+		if (renderer != null) {
+			e.invalid_snippet_in_custom_renderer();
+		}
 		var snippet = fn(...params);
 
 		/** @type {Element} */

packages/svelte/src/internal/client/errors.js

@@ -361,6 +361,22 @@ export function invalid_snippet() {
 	}
 }
 
+/**
+ * `createRawSnippet` cannot be used with a custom renderer
+ * @returns {never}
+ */
+export function invalid_snippet_in_custom_renderer() {
+	if (DEV) {
+		const error = new Error(`invalid_snippet_in_custom_renderer\n\`createRawSnippet\` cannot be used with a custom renderer\nhttps://svelte.dev/e/invalid_snippet_in_custom_renderer`);
+
+		error.name = 'Svelte error';
+
+		throw error;
+	} else {
+		throw new Error(`https://svelte.dev/e/invalid_snippet_in_custom_renderer`);
+	}
+}
+
 /**
  * `%name%(...)` cannot be used in runes mode
  * @param {string} name

packages/svelte/tests/custom-renderers/samples/raw-snippet/_config.js

@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	error: '`createRawSnippet` cannot be used with a custom renderer'
+});

packages/svelte/tests/custom-renderers/samples/raw-snippet/main.svelte

@@ -0,0 +1,9 @@
+<script>
+	import { createRawSnippet } from 'svelte';
+
+	const snippet = createRawSnippet(() => ({
+		render: () => `<span>hello</span>`
+	}));
+</script>
+
+{@render snippet()}