fix: add empty stack to CompileDiagnostic to show error on build

Author: paoloricciuti

.changeset/brave-fans-sneeze.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: add empty stack to `CompileDiagnostic` to show error on build

packages/svelte/src/compiler/utils/compile_diagnostic.js

@@ -39,6 +39,7 @@ function get_code_frame(source, line, column) {
  * @typedef {{
  * 	code: string;
  * 	message: string;
+ *  stack: string;
  * 	filename?: string;
  * 	start?: Location;
  * 	end?: Location;
@@ -50,6 +51,7 @@ function get_code_frame(source, line, column) {
 /** @implements {ICompileDiagnostic} */
 export class CompileDiagnostic {
 	name = 'CompileDiagnostic';
+	stack = '';
 
 	/**
 	 * @param {string} code

packages/svelte/tests/migrate/samples/impossible-migrate-with-errors/_config.js

@@ -20,6 +20,7 @@ export default test({
                         ^`,
 			message: 'Unexpected end of input',
 			name: 'CompileError',
+			stack: '',
 			position: [30, 30],
 			start: {
 				character: 30,