fix: disallow TODO errors (#10326)

* disallow TODO errors

* replace TODO errors

* changeset

---------

Co-authored-by: Rich Harris <[email protected]>

Author: Rich-Harris

.changeset/lemon-geese-call.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: replace TODO errors

packages/svelte/src/compiler/errors.js

@@ -88,7 +88,9 @@ const parse = {
 	'illegal-subscription': () => `Cannot reference store value inside <script context="module">`,
 	'duplicate-style-element': () => `A component can have a single top-level <style> element`,
 	'duplicate-script-element': () =>
-		`A component can have a single top-level <script> element and/or a single top-level <script context="module"> element`
+		`A component can have a single top-level <script> element and/or a single top-level <script context="module"> element`,
+	'invalid-render-expression': () => 'expected an identifier followed by (...)',
+	'invalid-render-arguments': () => 'expected at most one argument'
 };
 
 /** @satisfies {Errors} */
@@ -508,7 +510,7 @@ export class CompileError extends Error {
 }
 
 /**
- * @template {keyof typeof errors} T
+ * @template {Exclude<keyof typeof errors, 'TODO'>} T
  * @param {NodeLike | number | null} node
  * @param {T} code
  * @param  {Parameters<typeof errors[T]>} args

packages/svelte/src/compiler/phases/1-parse/state/tag.js

@@ -586,11 +586,11 @@ function special(parser) {
 		const expression = read_expression(parser);
 
 		if (expression.type !== 'CallExpression' || expression.callee.type !== 'Identifier') {
-			error(expression, 'TODO', 'expected an identifier followed by (...)');
+			error(expression, 'invalid-render-expression');
 		}
 
 		if (expression.arguments.length > 1) {
-			error(expression.arguments[1], 'TODO', 'expected at most one argument');
+			error(expression.arguments[1], 'invalid-render-arguments');
 		}
 
 		parser.allow_whitespace();