if (symbol_table.lookup<func::FuncOp>(func.getName())) continue;

    // Find any SymbolRefAttr in func that maps to a FuncOp. We need to clone
    // all found FuncOps to new_module to make sure new_module is
    // self-contained.
    std::optional<SymbolTable::UseRange> uses =
        SymbolTable::getSymbolUses(func);
    assert(uses && "expected to be able to collect symbol uses");