title: RStudio - Markdown Crash: Error in (function (srcref) : unimplemented type (29) in 'eval'
body: <p>My RStudio crashed a number of times with the following error: </p>
  
  <p><code>Error in (function (srcref) : unimplemented type (29) in 'eval'</code></p>
  
  <p>The similarities where this has happened were: </p>
  
  <ul>
  <li>I was working in a Markdown Notebook</li>
  <li>I believe it was always when I selected the "Run all chunks above" command</li>
  <li>I had run some code chunks in the current session before (so it wasn't upon starting work)</li>
  </ul>
  
  <p>The error was always displayed just before the RStudio session aborted. I lose all my data and variables in the environment, but most of the code seems to be recoverable.</p>
  
  <p>Anyone with an idea of what might cause this or how to deal with it? </p>
  
  <p>Here my <code>SessionInfo</code></p>
  
  <pre><code>R version 4.0.0 (2020-04-24)
  Platform: x86_64-w64-mingw32/x64 (64-bit)
  Running under: Windows 10 x64 (build 18363)
  
  Matrix products: default
  
  locale:
  [1] LC_COLLATE=English_United Kingdom.1252  LC_CTYPE=English_United Kingdom.1252    LC_MONETARY=English_United Kingdom.1252
  [4] LC_NUMERIC=C                            LC_TIME=English_United Kingdom.1252    
  
  attached base packages:
  [1] stats     graphics  grDevices utils     datasets  methods   base     
  
  other attached packages:
   [1] data.table_1.12.8 forcats_0.5.0     stringr_1.4.0     dplyr_0.8.5       purrr_0.3.4       readr_1.3.1      
   [7] tidyr_1.0.2       tibble_3.0.0      ggplot2_3.3.0     tidyverse_1.3.0  
  
  loaded via a namespace (and not attached):
   [1] Rcpp_1.0.4.6     cellranger_1.1.0 pillar_1.4.3     compiler_4.0.0   dbplyr_1.4.3     tools_4.0.0      packrat_0.5.0   
   [8] lubridate_1.7.8  jsonlite_1.6.1   lifecycle_0.2.0  nlme_3.1-147     gtable_0.3.0     lattice_0.20-41  pkgconfig_2.0.3 
  [15] rlang_0.4.5      reprex_0.3.0     cli_2.0.2        DBI_1.1.0        rstudioapi_0.11  haven_2.2.0      xfun_0.13       
  [22] withr_2.2.0      xml2_1.3.1       httr_1.4.1       knitr_1.28       fs_1.4.1         hms_0.5.3        generics_0.0.2  
  [29] vctrs_0.2.4      grid_4.0.0       tidyselect_1.0.0 glue_1.4.0       R6_2.4.1         fansi_0.4.1      readxl_1.3.1    
  [36] modelr_0.1.6     magrittr_1.5     backports_1.1.6  scales_1.1.0     ellipsis_0.3.0   rvest_0.3.5      assertthat_0.2.1
  [43] colorspace_1.4-1 stringi_1.4.6    munsell_0.5.0    broom_0.5.6      crayon_1.3.4    
  </code></pre>
  
  <p>I sadly can't give you a reproducible example, but this is a screenshot of the last time it happened: 
  <a href="https://i.stack.imgur.com/RGf2C.png" rel="noreferrer"><img src="https://i.stack.imgur.com/RGf2C.png" alt="enter image description here"></a></p>
  
  <p>And the next time following a fairly simple ggplot command: 
  <a href="https://i.stack.imgur.com/R0WSc.png" rel="noreferrer"><img src="https://i.stack.imgur.com/R0WSc.png" alt="enter image description here"></a></p>