```
#include <coroutine>
#include <string>

template<typename T>
struct Awaiter final {
    bool await_ready() const { return false; }    
    void await_suspend(std::coroutine_handle<>) const {}    
    T await_resume() const { return T{}; }
};

struct ReturnObject {
  struct promise_type {
    ReturnObject get_return_object() { return {}; }
    std::suspend_never initial_suspend() 
        noexcept { return {}; }
    std::suspend_never final_suspend() 
        noexcept { return {}; }
    void return_void() {}
    void unhandled_exception() {}
  };
};

ReturnObject f()
{
    auto a1 = Awaiter<int>{};
    [[maybe_unused]] auto v1 = co_await a1; // ok    
    auto a2 = Awaiter<std::string>{};
    [[maybe_unused]] auto v2 = co_await a2; // error
}

int main() { f(); }

```

See: [online demo](https://godbolt.org/z/85K46zEG1)

The error message:

```
error: no suspend point info for ''co_await' not supported 
       by dump_decl<declaration error>'
   37 |     [[maybe_unused]] auto v2 = co_await a2; // error
      |                                ^~~~~~~~

```

**Why can't co\_await return a string?**