Missing return statement for disabled directives

[maca88]

Example:
Supposing that TEST directive is not set

public void Test()
{
#if TEST
  SimpleFile.Read();
#else
  SimpleFile.Read();
#endif
}

Expected:

public Task TestAsync()
{
#if TEST
  SimpleFile.Read();
  return Task.Completed;
#else
  return SimpleFile.ReadAsync();
#endif
}

Actual:

public Task TestAsync()
{
#if TEST
  SimpleFile.Read();
#else
  return SimpleFile.ReadAsync();
#endif
}