This is from 2.0.6 and 2.0.4 of 3.0.4 Fpc generating a 64 bit windows target.
from the unit "strUtils"
If I copy and paste that code within a local call it will crash where I indicated...
Copy and pasted it, used the calling code from the bug report. Tested with FPC 3.3.1 64-bit (since I don't have 3.0.4 64-bit), everything fine.
As said, if it does, it is probably not related to the literal thingy, since ansilowercase does uniquestring() already.