Function clearAllFunctionLookups

src/ast/ast_parse.cpp:667–673

`Function::lookup` keys cache entries by `intptr_t(structType)` via `getLookupHash(types)`. After gc sweep, freed Structure addresses can be reused by later allocations — a stale cached `false` then poisons the lookup for the new Structure at the same address, surfacing as a flaky "no matching functions or generics" on legitimate calls. Clear every function/generic cache before gc_guard sweeps.

    // "no matching functions or generics" on legitimate calls. Clear every
    // function/generic cache before gc_guard sweeps.
    static void clearAllFunctionLookups() {
        Module::foreach([](Module * m) -> bool {
            m->functions.foreach([](auto & fn) { fn->lookup.clear(); });
            m->generics.foreach([](auto & fn) { fn->lookup.clear(); });
            return true;
        });
    }

    // compileDaScript runs its top-level post-parse steps (deriveAliases/allocateStack/...)
    // on a transient gc_guard root; on exit this merges that scratch into the program's