[Haskell-cafe] Prelude.head: empty list

Han Joosten han.joosten.han at gmail.com
Fri Mar 11 15:56:57 UTC 2016


In a rather large program I made some changes, and now I get the runtime
error:

ampersand.exe: Prelude.head: empty list

Of course I know that head is partial, and should be used with care. It is
used many times (we have 100+ modules in the program). Is there an elegant
way to get some information about where the specific call to head is being
made?

Thanks!
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