Csaba Hruska
Hi Ben,
I thought that it is possible to rely on unique values *in case of non exported Ids* because they are local to a specific module and can not appear in expressions in other modules because they are not exported. Do I miss something?
Uniques should be treated as being non-reproducible across compiler sessions. To make this more concrete: if GHC compiles the same module twice it will not necessarily assign the same uniques to the module's Names. Uniques are derived from local UniqSupplies conjured up at a variety of points in the compilation pipeline (search from mkSplitUniqSupply). These supplies are themselves derived from an impure global counter (see compiler/cbits/genSym.c). The state of this counter (and consequently the uniques derived from it) should be treated as being entirely unpredictable. Cheers, - Ben