lib.misc.closePropagationFast

The following is the current implementation of this function.

closePropagationFast =
    list:
    builtins.map (x: x.val) (
      builtins.genericClosure {
        startSet = builtins.map (x: {
          key = x.outPath;
          val = x;
        }) (builtins.filter (x: x != null) list);
        operator =
          item:
          if !builtins.isAttrs item.val then
            [ ]
          else
            builtins.concatMap (
              x:
              if x != null then
                [
                  {
                    key = x.outPath;
                    val = x;
                  }
                ]
              else
                [ ]
            ) ((item.val.propagatedBuildInputs or [ ]) ++ (item.val.propagatedNativeBuildInputs or [ ]));
      }
    );