conf.int values for random effects do not depend on scales argument in tidy()

[joelgautschi]

if I use scales = "vcov" to set scales for random effects terms to variances and covariances instead of the default "sd-cor" in broom.mixed::tidy(), the random effects' confidence interval reported remain on the scale "sd-cor" and not the scale of my random effects "vcov"`. Is this a bug or by design?

library(lme4)
library(broom.mixed)
fm1 <- lmer(Reaction ~ Days + (Days | Subject), sleepstudy)

tidy(fm1,
     effects = "ran_pars",
     conf.int = TRUE,
     conf.method = "profile")
#> Computing profile confidence intervals ...
#> # A tibble: 4 x 6
#>   effect   group    term                  estimate conf.low conf.high
#>   <chr>    <chr>    <chr>                    <dbl>    <dbl>     <dbl>
#> 1 ran_pars Subject  sd__(Intercept)        24.7      14.4      37.7  
#> 2 ran_pars Subject  cor__(Intercept).Days   0.0656   -0.482     0.685
#> 3 ran_pars Subject  sd__Days                5.92      3.80      8.75 
#> 4 ran_pars Residual sd__Observation        25.6      22.9      28.9

# set scales for random effects terms to variances and covariances
tidy(fm1,
     effects = "ran_pars",
     scales = "vcov",
     conf.int = TRUE,
     conf.method = "profile")
#> Computing profile confidence intervals ...
#> # A tibble: 4 x 6
#>   effect   group    term                  estimate conf.low conf.high
#>   <chr>    <chr>    <chr>                    <dbl>    <dbl>     <dbl>
#> 1 ran_pars Subject  var__(Intercept)        612.     14.4      37.7  
#> 2 ran_pars Subject  cov__(Intercept).Days     9.60   -0.482     0.685
#> 3 ran_pars Subject  var__Days                35.1     3.80      8.75 
#> 4 ran_pars Residual var__Observation        655.     22.9      28.9

^{Created on 2020-04-28 by the reprex package (v0.3.0)}

Session info

devtools::session_info()
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