One thing that seems to be a problem is if there is no inactive set.
X = matrix(rnorm(500), 50, 10)
Y = rnorm(50)
library(selectiveInference)
randomizedLassoInf(X, Y, 1.e-5)
Error in [<-(*tmp*, inactive_set[i], i, value = 1) :
subscript out of bounds