CfgBasicBlockVertex: [Block, a: unknown[]] & [
    type: CfgVertexType,
    id: NodeId,
    elems: readonly Exclude<CfgVertex, CfgBasicBlockVertex>[],
]

A basic block vertex in the ControlFlowGraph. Contains the vertices that are part of this block, only connected by FDs, vertices should never occur in multiple bbs.