fix(compiler-sfc): fix <script> and <script setup> co-usage ordering edge case (#4419)

Fix: #4395
Fix: #4376

packages/compiler-sfc/__tests__/compileScript.spec.ts

@@ -202,6 +202,24 @@ defineExpose({ foo: 123 })
       `)
       assertCode(content)
     })
+
+    // #4395
+    test('script setup first, lang="ts", script block content export default', () => {
+      const { content } = compile(`
+      <script setup lang="ts">
+      import { x } from './x'
+      x()
+      </script>
+      <script lang="ts">
+      export default {
+        name: "test"
+      }
+      </script>
+      `)
+      // ensure __default__ is declared before used
+      expect(content).toMatch(/const __default__[\S\s]*\.\.\.__default__/m)
+      assertCode(content)
+    })
   })
 
   describe('imports', () => {