---
source: crates/oxc_isolated_declarations/tests/mod.rs
input_file: crates/oxc_isolated_declarations/tests/fixtures/async-function.ts
---
```
==================== .D.TS ====================

declare function asyncFunctionGood(): Promise<number>;
declare const asyncFunctionGoo2: () => Promise<number>;
declare class AsyncClassGood {
	method(): number;
}
declare function asyncFunction();
declare const asyncFunction2: unknown;
declare class AsyncClassBad {
	method();
}


==================== Errors ====================

  x TS9007: Function must have an explicit return type annotation with
  | --isolatedDeclarations.
    ,-[16:16]
 15 | // Incorrect
 16 | async function asyncFunction() {
    :                ^^^^^^^^^^^^^
 17 |   return 42;
    `----

  x TS9007: Function must have an explicit return type annotation with
  | --isolatedDeclarations.
    ,-[20:30]
 19 | 
 20 | const asyncFunction2 = async () => {
    :                              ^^^^^^^
 21 |   return "Hello, World!";
    `----

  x TS9008: Method must have an explicit return type annotation with
  | --isolatedDeclarations.
    ,-[25:9]
 24 | class AsyncClassBad {
 25 |   async method() {
    :         ^^^^^^
 26 |     return 42;
    `----


```