proc hashTree(n: PNode): Hash {....raises: [], tags: [], forbids: [].}

proc nodeTableGet(t: TNodeTable; key: PNode): int {....raises: [Exception],
    tags: [RootEffect], forbids: [].}

proc nodeTablePut(t: var TNodeTable; key: PNode; val: int) {.
    ...raises: [Exception], tags: [RootEffect], forbids: [].}

proc nodeTableTestOrSet(t: var TNodeTable; key: PNode; val: int): int {.
    ...raises: [Exception], tags: [RootEffect], forbids: [].}