Hello Dominic, Monday, January 02, 2006, 11:59:53 AM, you wrote: *Codec.ASN1.BER>> :t choiceAux DS> choiceAux :: forall (m :: * -> *) e e1. DS> (MonadState [Maybe Encoding] m, DS> MonadState [Maybe Encoding] (StateT [Maybe Encoding] m), DS> MonadError e (StateT [Maybe Encoding] m), DS> MonadError e1 m) => DS> (TagPlicity, NamedType) -> Encoding -> m Defaulted DS> But if I try to give it a type annotation of DS> choiceAux :: (MonadState [Maybe Encoding] m, DS> MonadState [Maybe Encoding] (StateT [Maybe Encoding] m), DS> MonadError e (StateT [Maybe Encoding] m), DS> MonadError e1 m) => DS> (TagPlicity, NamedType) -> Encoding -> m Defaulted you omited `forall` specifier, which, i think, makes the difference -- Best regards, Bulat mailto:bulatz@HotPOP.com