CAS memory corruption (6975)

[parisse]

Sorry, I have resolved the bug a few days ago, but I forgot to post about it. The fix is in giac 1.1.4 source (and will be soon in the unstable version of Xcas).
The problem arises when purge is called on an implicitly created global variable in a local context (you are in a local context each time you call a user function), the implicit global variable was given the value 'symbolic assumed' instead of being removed (like if it was a local variable: if you purge any local variable, it remains with the value 'symbolic assumed', that way you can have a symbolic local variable). At the end, the global variables map was messed up (not alphabetically sorted anymore) because the string name of the global implicit variable had been deleted, but the variable was still in the map (since it was not purged, but had the value 'symbolic assumed').
In other words, you may have this kind of problem if your function calls a CAS function that creates implicit variables like sum and integrate.