Error(s) in re-building vignettes:
  ...
--- re-building 'Crossover.Rnw' using knitr
Loading required package: mvtnorm
Loading required package: survival
Loading required package: TH.data

Attaching package: 'TH.data'

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

    geyser

 ----------- FAILURE REPORT -------------- 
 --- failure: the condition has length > 1 ---
 --- srcref --- 
: 
 --- package (from environment) --- 
Crossover
 --- call from context --- 
general.carryover(design, model = 1)
 --- call from argument --- 
if (class(design) == "CrossoverSearchResult") {
    if (missing(model)) {
        model <- design@model
    }
    else {
        if (model != design@model) 
            warning("Model from object does not equal specified model")
    }
    design <- design@design
}
 --- R stacktrace ---
where 1: general.carryover(design, model = 1)
where 2: eval(expr, envir, enclos)
where 3: eval(expr, envir, enclos)
where 4: withVisible(eval(expr, envir, enclos))
where 5: withCallingHandlers(withVisible(eval(expr, envir, enclos)), warning = wHandler, 
    error = eHandler, message = mHandler)
where 6: handle(ev <- withCallingHandlers(withVisible(eval(expr, envir, 
    enclos)), warning = wHandler, error = eHandler, message = mHandler))
where 7: timing_fn(handle(ev <- withCallingHandlers(withVisible(eval(expr, 
    envir, enclos)), warning = wHandler, error = eHandler, message = mHandler)))
where 8: evaluate_call(expr, parsed$src[[i]], envir = envir, enclos = enclos, 
    debug = debug, last = i == length(out), use_try = stop_on_error != 
        2L, keep_warning = keep_warning, keep_message = keep_message, 
    output_handler = output_handler, include_timing = include_timing)
where 9: evaluate::evaluate(...)
where 10: evaluate(code, envir = env, new_device = FALSE, keep_warning = !isFALSE(options$warning), 
    keep_message = !isFALSE(options$message), stop_on_error = if (options$error && 
        options$include) 0L else 2L, output_handler = knit_handlers(options$render, 
        options))
where 11: in_dir(input_dir(), evaluate(code, envir = env, new_device = FALSE, 
    keep_warning = !isFALSE(options$warning), keep_message = !isFALSE(options$message), 
    stop_on_error = if (options$error && options$include) 0L else 2L, 
    output_handler = knit_handlers(options$render, options)))
where 12: block_exec(params)
where 13: call_block(x)
where 14: process_group.block(group)
where 15: process_group(group)
where 16: withCallingHandlers(if (tangle) process_tangle(group) else process_group(group), 
    error = function(e) {
        setwd(wd)
        cat(res, sep = "\n", file = output %n% "")
        message("Quitting from lines ", paste(current_lines(i), 
            collapse = "-"), " (", knit_concord$get("infile"), 
            ") ")
    })
where 17: process_file(text, output)
where 18: (if (grepl("\\.[Rr]md$", file)) knit2html_v1 else if (grepl("\\.[Rr]rst$", 
    file)) knit2pandoc else knit)(file, encoding = encoding, 
    quiet = quiet, envir = globalenv(), ...)
where 19: engine$weave(file, quiet = quiet, encoding = enc)
where 20: doTryCatch(return(expr), name, parentenv, handler)
where 21: tryCatchOne(expr, names, parentenv, handlers[[1L]])
where 22: tryCatchList(expr, classes, parentenv, handlers)
where 23: tryCatch({
    engine$weave(file, quiet = quiet, encoding = enc)
    setwd(startdir)
    output <- find_vignette_product(name, by = "weave", engine = engine)
    if (!have.makefile && vignette_is_tex(output)) {
        texi2pdf(file = output, clean = FALSE, quiet = quiet)
        output <- find_vignette_product(name, by = "texi2pdf", 
            engine = engine)
    }
    outputs <- c(outputs, output)
}, error = function(e) {
    thisOK <<- FALSE
    fails <<- c(fails, file)
    message(gettextf("Error: processing vignette '%s' failed with diagnostics:\n%s", 
        file, conditionMessage(e)))
})
where 24: tools:::buildVignettes(dir = "/home/hornik/tmp/R.check/r-devel-clang/Work/PKGS/Crossover.Rcheck/vign_test/Crossover", 
    ser_elibs = "/tmp/RtmpRiZD7m/file37bb6b634a3b.rds")

 --- value of length: 2 type: logical ---
[1] FALSE FALSE
 --- function from context --- 
function (design, v = length(table(design)), model, ppp = 0.5, 
    placebos = 1, contrasts) 
{
    if (class(design) == "CrossoverSearchResult") {
        if (missing(model)) {
            model <- design@model
        }
        else {
            if (model != design@model) 
                warning("Model from object does not equal specified model")
        }
        design <- design@design
    }
    if (class(design) == "CrossoverDesign") {
        if (missing(model)) {
            model <- design@model
        }
        else {
            if (model != design@model) 
                warning("Model from object does not equal specified model")
        }
        design <- design@design
    }
    model <- getModelNr(model)
    if (missing(contrasts)) {
        contrasts <- getPairwiseContrasts(model, v)
    }
    if (is.matrix(contrasts)) {
        contrasts <- list(contrasts)
    }
    H <- linkMatrix(model, v, ppp, placebos)
    p <- dim(design)[1]
    s <- dim(design)[2]
    rcDesign <- rcd(design, v = v, model = model)
    Xr <- rcdMatrix(rcDesign, v = v, model = model)
    Ar <- t(Xr) %*% (diag(s * p) - getPZ(s, p)) %*% Xr
    A <- t(H) %*% Ar %*% H
    result <- list()
    for (C in contrasts) {
        n <- sum(colSums(C == 0) < dim(C)[1])
        m <- matrix(0, n, n)
        if (!estimable(design, v, model, C)) {
            m[row(m) != col(m)] <- NA
        }
        else {
            m[lower.tri(m)] <- diag(C %*% ginv(A) %*% t(C))
            m[upper.tri(m)] <- t(m)[upper.tri(m)]
        }
        result <- c(result, list(m))
    }
    names(result)[1] <- "Var.trt.pair"
    if (length(result) == 2) {
        names(result)[2] <- "Var.car.pair"
    }
    if (length(result) == 3) {
        names(result)[2:3] <- c("Var.car.pair.1", "Var.car.pair.2")
    }
    result$model <- model
    return(result)
}
<bytecode: 0x126b2460>
<environment: namespace:Crossover>
 --- function search by body ---
Function general.carryover in namespace Crossover has this body.
 ----------- END OF FAILURE REPORT -------------- 
Quitting from lines 243-247 (Crossover.Rnw) 
Error: processing vignette 'Crossover.Rnw' failed with diagnostics:
the condition has length > 1
--- failed re-building 'Crossover.Rnw'

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

Error: Vignette re-building failed.
Execution halted