Loading required package: shiny
Loading required package: methods

Listening on http://127.0.0.1:8765
Warning: Error in badfunc: boom
Stack trace (innermost first):
    113: badfunc [${PWD}/stacktrace1/app.R#4]
    112: reactive A [${PWD}/stacktrace1/app.R#8]
    101: A [${SHINY}/R/reactives.R#376]
    100: reactive B [${PWD}/stacktrace1/app.R#12]
     89: B [${SHINY}/R/reactives.R#376]
     88: reactive C [${PWD}/stacktrace1/app.R#16]
     77: C [${SHINY}/R/reactives.R#376]
     76: renderPlot [${PWD}/stacktrace1/app.R#27]
     68: output$foo [${SHINY}/R/render-plot.R#111]
      1: shiny::runApp [${SHINY}/R/server.R#685]
NULL