glm.cmp would give an error if the model matrix doesn't have full rank

[thomas-fung]

library(tidyverse)
library(mpcmp)
dat <- tribble(~count, ~ code1, ~code2,
               3, "Code 1", "Code 1",
               4, "Code 2", "Code 1",
               2, "Code 2", "Code 1",
               5, "Code 2", "Code 2",
               1, "Code 2", "Code 2")
M1 <- glm(formula=count ~ code1 * code2, data = dat, family = poisson)
coef(M1)
#>             (Intercept)             code1Code 2             code2Code 2 
#>            1.098612e+00           -2.167798e-16            5.768888e-16 
#> code1Code 2:code2Code 2 
#>                      NA
M2 <- glm.cmp(formula=count ~ code1 * code2, data = dat)
#> Error in if (update_info_matrix < 0) {: missing value where TRUE/FALSE needed

^{Created on 2020-10-30 by the reprex package (v0.3.0)}

Need to update the main fitting function to make it behave more like the glm function.