Cboth ChanDir = Crecv | Csend
)

// Types stores pointers to predeclared named types.
//
// It also stores pointers to several special types:
//   - Types[TANY] is the placeholder "any" type recognized by SubstArgTypes.
//   - Types[TBLANK] represents the blank variable's type.
//   - Types[TINTER] is the canonical "interface{}" type.
//   - Types[TNIL] represents the predeclared "nil" value's type.