[Haskell-cafe] better error message for "undefined"

the haskell prelude introduces the type undefined and contains a remark to the effect that compilers are expected to intrudocue a meaningful error message. GHC just prints 'Prelude undefined' which is not very informativ. is there a way to have different kinds of undefined? such that i get a message which one was hit. something like writing in the code 'unefined 'my error 123' which prints 'undefined - my error 123' when it is accidentally hit. i searched the web, but found nothing. any suggestions? thanks a lot! andrew