proc getSystemConfigPath(conf: ConfigRef; filename: RelativeFile): AbsoluteFile {.
    ...raises: [OSError], tags: [ReadIOEffect].}

proc getUserConfigPath(filename: RelativeFile): AbsoluteFile {.
    ...raises: [OSError], tags: [ReadEnvEffect, ReadIOEffect].}

proc loadConfigs(cfg: RelativeFile; cache: IdentCache; conf: ConfigRef;
                 idgen: IdGenerator) {....raises: [OSError, IOError, Exception,
    KeyError, ValueError, ERecoverableError, EOFError], tags: [ReadIOEffect,
    ReadDirEffect, ReadEnvEffect, RootEffect, WriteIOEffect, WriteEnvEffect,
    WriteDirEffect].}

proc readConfigFile(filename: AbsoluteFile; cache: IdentCache; config: ConfigRef): bool {....raises: [
    IOError, Exception, KeyError, ValueError, OSError, ERecoverableError,
    EOFError], tags: [ReadIOEffect, RootEffect, ReadDirEffect, WriteIOEffect,
                      ReadEnvEffect, WriteEnvEffect, WriteDirEffect].}