Error(s) in re-building vignettes:
  ...
--- re-building ‘user-guide.Rmd’ using rmarkdown
** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/spqdep.Rcheck/vign_test/spqdep/vignettes/user-guide_files/figure-html/unnamed-chunk-5-1.png
288x288 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 29342 bytes
Input file size = 29456 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 21548
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 21548

Output IDAT size = 21548 bytes (7794 bytes decrease)
Output file size = 21626 bytes (7830 bytes = 26.58% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/spqdep.Rcheck/vign_test/spqdep/vignettes/user-guide_files/figure-html/plot mh-1.png
288x288 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 29819 bytes
Input file size = 29933 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 27237
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 27237

Output IDAT size = 27237 bytes (2582 bytes decrease)
Output file size = 27315 bytes (2618 bytes = 8.75% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/spqdep.Rcheck/vign_test/spqdep/vignettes/user-guide_files/figure-html/plot mh prune-1.png
288x288 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 28643 bytes
Input file size = 28757 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 25872
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 25872

Output IDAT size = 25872 bytes (2771 bytes decrease)
Output file size = 25950 bytes (2807 bytes = 9.76% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/spqdep.Rcheck/vign_test/spqdep/vignettes/user-guide_files/figure-html/unnamed-chunk-10-1.png
288x288 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 28077 bytes
Input file size = 28191 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 20523
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 20523

Output IDAT size = 20523 bytes (7554 bytes decrease)
Output file size = 20601 bytes (7590 bytes = 26.92% decrease)

** Processing: /home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/spqdep.Rcheck/vign_test/spqdep/vignettes/user-guide_files/figure-html/unnamed-chunk-10-2.png
288x288 pixels, 3x8 bits/pixel, RGB
Input IDAT size = 21617 bytes
Input file size = 21719 bytes

Trying:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 16170
  zc = 9  zm = 8  zs = 1  f = 0
  zc = 1  zm = 8  zs = 2  f = 0
  zc = 9  zm = 8  zs = 3  f = 0
  zc = 9  zm = 8  zs = 0  f = 5
  zc = 9  zm = 8  zs = 1  f = 5
  zc = 1  zm = 8  zs = 2  f = 5
  zc = 9  zm = 8  zs = 3  f = 5
                               
Selecting parameters:
  zc = 9  zm = 8  zs = 0  f = 0		IDAT size = 16170

Output IDAT size = 16170 bytes (5447 bytes decrease)
Output file size = 16248 bytes (5471 bytes = 25.19% decrease)


Quitting from lines 273-279 [unnamed-chunk-11] (user-guide.Rmd)
Error: processing vignette 'user-guide.Rmd' failed with diagnostics:
no applicable method for 'units' applied to an object of class "NULL"
--- failed re-building ‘user-guide.Rmd’

SUMMARY: processing the following file failed:
  ‘user-guide.Rmd’

Error: Vignette re-building failed.
Execution halted