Handling decrementing for...next loop indices

[sparxfly]

Converting my project across from BasicX to ZBasic, I am getting warnings where I use for...next loops with decrementing loop indices.
They worked fine for BasicX, seem also work fine for ZBasic.
Looks like the error checker doesn't correctly handle decrementing indices.

eg
public const windqsize as byte = 60
dim loopctr as byte

for loopctr = windqsize to 1 step -1
...
...
next

Gives...Warning: For loop will never be executed

[dkinzer]