I'd like to ask the developers to include some exact computation for
ties into wilcox.test(). Just try
wilcox.test(c(1,1,5),c(10,11))
wilcox.test(c(1,2,5),c(10,11))
The p-values differ significantly.
But if I try
library(exactRankTests)
wilcox.exact(c(1,1,5),c(10,11))
wilcox.exact(c(1,2,5),c(10,11))
then the p-values coincide as expected. (R is used by many
non-mathematicians/non-engineers who pay no attention at warnings.)