Better exception for non-exhaustive patterns in case

Posted by toofarsideways on Stack Overflow See other posts from Stack Overflow or by toofarsideways
Published on 2010-04-29T13:25:42Z Indexed on 2010/04/29 15:47 UTC
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haskell

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exception

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exception-handling

Is there a way to get GHCi to produce better exception messages when it finds at runtime that a call has produced value that does not match the function's pattern matching?

It currently gives the line numbers of the function which produced the non-exhaustive pattern match which though helpful at times does require a round of debugging which at times I feel is doing the same set of things over and over. So before I tried to put together a solution I wanted to see if something else exists.

An exception message that in addition to giving the line numbers shows what kind of call it attempted to make?

Is this even possible?

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