ConsiderFlag = enum
  CoProc, CoType, CoOwnerSig, CoIgnoreRange, CoConsiderOwned, CoDistinct,
  CoHashTypeInsideNode

proc hashNonProc(s: PSym): SigHash {....raises: [], tags: [].}

proc hashOwner(s: PSym): SigHash {....raises: [], tags: [].}

proc hashProc(s: PSym; conf: ConfigRef): SigHash {....raises: [OSError, Exception],
    tags: [RootEffect].}

proc hashType(t: PType; conf: ConfigRef; flags: set[ConsiderFlag] = {CoType}): SigHash {.
    ...raises: [OSError, Exception], tags: [RootEffect].}

proc idOrSig(s: PSym; currentModule: string;
             sigCollisions: var CountTable[SigHash]; conf: ConfigRef): Rope {.
    ...raises: [OSError, Exception], tags: [RootEffect].}

proc sigHash(s: PSym; conf: ConfigRef): SigHash {....raises: [OSError, Exception],
    tags: [RootEffect].}

proc symBodyDigest(graph: ModuleGraph; sym: PSym): SigHash {.
    ...raises: [OSError, Exception, KeyError], tags: [RootEffect, ReadDirEffect].}