Use this type to mark a Haskell function definition as an Asynchronous Rattus function:

{-# ANN myFunction AsyncRattus #-}

Or mark a whole module as consisting of Asynchronous Rattus functions only:

{-# ANN module AsyncRattus #-}

If you use the latter option, you can mark exceptions (i.e. functions that should be treated as ordinary Haskell function definitions) as follows:

{-# ANN myFunction NotAsyncRattus #-}

By default all Asynchronous Rattus functions are checked for use of lazy data types, since these may cause memory leaks. If any lazy data types are used, a warning is issued. These warnings can be disabled by annotating the module or the function with AllowLazyData

{-# ANN myFunction AllowLazyData #-}

{-# ANN module AllowLazyData #-}

Asynchronous Rattus only allows guarded recursion, i.e. recursive calls must occur in the scope of a tick. Structural recursion over strict data types is safe as well, but is currently not checked. To disable the guarded recursion check, annotate the module or function with AllowRecursion.