"X sets SpacemanDMM_should_be_pure but calls a Y that does impure operations" happens when changing proc argument variables

[mc-oofert]

https://github.com/tgstation/tgstation/actions/runs/7408501187/job/20156828882 this is where the linter marks an issue here is marked the impurity, where gravity_turf (proc arg) is changed

potato says the issue is failing to treat proc arguments as local to the proc i do not know what else to add to this

[Ghommie]

PR where this happened: https://github.com/tgstation/tgstation/pull/80790

[SpaceManiac]

Hmm, it seems to have originally been intentional:

https://github.com/SpaceManiac/SpacemanDMM/blob/59cfdbf826acb4f72adc2cbd4ffe2147baa7c0ad/crates/dreamchecker/src/lib.rs#L1158

It'll take some investigation to be sure that changing this doesn't have side-effects.