Using insig and p.mat causes an error.

[Sumidu]

When I use insig and p.mat at the same time, I get an error. The created plot works fine though.

I have added a draft pull request, that has a test-case demonstrating the problem.

The following code produces an error, but the desired plot.

pvalues <- corrplot::cor.mtest(mtcars, conf.level = 0.95)
res <- stats::cor(mtcars, use = "pairwise.complete.obs")

# This throws an error in cbind(corrpos, pNew)
corrplot::corrplot(res,  method = "color", insig = "n", addCoef.col = "black", p.mat = pvalues$p)