Error(s) in re-building vignettes:
  ...
--- re-building 'intro.Rnw' using Sweave
Loading required package: BiocGenerics
Loading required package: parallel

Attaching package: 'BiocGenerics'

The following objects are masked from 'package:parallel':

    clusterApply, clusterApplyLB, clusterCall, clusterEvalQ,
    clusterExport, clusterMap, parApply, parCapply, parLapply,
    parLapplyLB, parRapply, parSapply, parSapplyLB

The following objects are masked from 'package:stats':

    IQR, mad, sd, var, xtabs

The following objects are masked from 'package:base':

    Filter, Find, Map, Position, Reduce, anyDuplicated, append,
    as.data.frame, basename, cbind, colnames, dirname, do.call,
    duplicated, eval, evalq, get, grep, grepl, intersect, is.unsorted,
    lapply, mapply, match, mget, order, paste, pmax, pmax.int, pmin,
    pmin.int, rank, rbind, rownames, sapply, setdiff, sort, table,
    tapply, union, unique, unsplit, which, which.max, which.min


Attaching package: 'rsolr'

The following object is masked from 'package:stats':

    ftable

The following object is masked from 'package:base':

    grouping

Starting Solr...
Use options(verbose=TRUE) to diagnose any problems.
WARNING: An illegal reflective access operation has occurred
WARNING: Illegal reflective access by org.xnio.nio.NioXnio$2 (file:/home/hornik/.local/share/R/rsolr/solr-undertow-1.6.0-with-solr-5.5.0/lib/xnio-nio-3.3.4.Final.jar) to constructor sun.nio.ch.EPollSelectorProvider()
WARNING: Please consider reporting this to the maintainers of org.xnio.nio.NioXnio$2
WARNING: Use --illegal-access=warn to enable warnings of further illegal reflective access operations
WARNING: All illegal access operations will be denied in a future release
Solr started at: http://localhost:8983/solr/flights
Error: processing vignette 'intro.Rnw' failed with diagnostics:
'[' only accepts x[i] or x[] syntax
--- failed re-building 'intro.Rnw'

SUMMARY: processing the following file failed:
  'intro.Rnw'

Error: Vignette re-building failed.
Execution halted