id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
7593,Unable to print exceptions of unicode identifiers,dagit,,"I suspect this is windows specific but I'm not certain (I couldn't reproduce it with an older ghc on osx).

Here is an example of the problem:
{{{
$ ghcii.sh
GHCi, version 7.6.1: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Prelude λ> ⇒

<interactive>:2:1: parse error on input `*** Exception: <stderr>: hPutChar: invalid argument (invalid character)
}}}

On other platforms the message looks more like: parse error on input `=>'

(not the automatic translation from ⇒ to =>, I think that's a separate bug related to the unicode symbols extension)

On windows my ghc is version 7.6.1. On OSX (where I could NOT reproduce the exception), my ghc is 7.4.1. I don't know if the GHC version matters. I strongly suspect this is a windows unicode issue.

GHC gives similar behavior to ghci, for example on this input:
{{{
⇒ = 1
}}}

ghc tries to give an error message but throws an exception printing ⇒.",bug,new,normal,7.8.1,Compiler,7.6.1,,,,Windows,Unknown/Multiple,Incorrect warning at compile-time,Unknown,,,,