Found two bugs that I should report here:

Bug 1

This code doesn't compile - looks like lua's const feature breaks picotron's shorthands (are shorthands still using a preprocessor in picotron?)

local test <const> = 1
a = {3}
a[1] += 4

(same happens with close instead of const)

Bug 2

This code takes takes a ton of real time to execute.
This only happens due to the "<<32" and doesn't reproduce on the latest lua 5.4

t={}; for i=0,0x10000 do t[i<<32] = i end

I was curious so I checked what was happening and it looks like the older lua version picotron is using is computing hash for integers based on the low bits, meaning large powers of two get really bad hashing. Some later lua version (still in the 5.4 line) fixed this to use modulo with a non-power-of-2 instead