Add repro

Author: RobbinBaauw

src/main.ts

@@ -2,3 +2,6 @@ import { createApp } from 'vue'
 import App from './App.vue'
 
 createApp(App).mount('#app')
+
+let x = 1;
+x = "INVALID TYPE2!";

vue.config.js

@@ -0,0 +1,16 @@
+module.exports = {
+    parallel: true,
+    chainWebpack: config => {
+        const tsLoader = config.module.rule('ts')
+        tsLoader
+            .use('ts-loader')
+            .loader('ts-loader')
+            .tap(options => {
+                return {
+                    errorFormatter: (message, colors) => {
+                        return "CUSTOM ERROR!";
+                    }
+                }
+            })
+    }
+}