rename() Changes Variable Type

[billdenney]

When I rename a variable, its type changes from whatever it was before to na:

library(xpose)
#> Loading required package: ggplot2
#> 
#> Attaching package: 'xpose'
#> The following object is masked from 'package:stats':
#> 
#>     filter
list_vars(xpdb_ex_pk)
#> 
#> List of available variables for problem no. 1 
#>  - Subject identifier (id)               : ID
#>  - Dependent variable (dv)               : DV
#>  - Independent variable (idv)            : TIME
#>  - Dose amount (amt)                     : AMT
#>  - Event identifier (evid)               : EVID
#>  - Model typical predictions (pred)      : PRED
#>  - Model individual predictions (ipred)  : IPRED
#>  - Model parameter (param)               : KA, CL, V, ALAG1
#>  - Eta (eta)                             : ETA1, ETA2, ETA3
#>  - Residuals (res)                       : CWRES, IWRES, RES, WRES
#>  - Categorical covariates (catcov)       : SEX, MED1, MED2
#>  - Continuous covariates (contcov)       : CLCR, AGE, WT
#>  - Compartment amounts (a)               : A1, A2
#>  - Not attributed (na)                   : DOSE, SS, II, TAD, CPRED
#> 
#> List of available variables for problem no. 2 
#>  - Subject identifier (id)               : ID
#>  - Dependent variable (dv)               : DV
#>  - Independent variable (idv)            : TIME
#>  - Dose amount (amt)                     : AMT
#>  - Event identifier (evid)               : EVID
#>  - Model individual predictions (ipred)  : IPRED
#>  - Not attributed (na)                   : DOSE, TAD, SEX, CLCR, AGE, WT
xpdb_new <- rename(xpdb_ex_pk, AMT2=AMT)
list_vars(xpdb_new)
#> 
#> List of available variables for problem no. 1 
#>  - Subject identifier (id)               : ID
#>  - Dependent variable (dv)               : DV
#>  - Independent variable (idv)            : TIME
#>  - Event identifier (evid)               : EVID
#>  - Model typical predictions (pred)      : PRED
#>  - Model individual predictions (ipred)  : IPRED
#>  - Model parameter (param)               : KA, CL, V, ALAG1
#>  - Eta (eta)                             : ETA1, ETA2, ETA3
#>  - Residuals (res)                       : CWRES, IWRES, RES, WRES
#>  - Categorical covariates (catcov)       : SEX, MED1, MED2
#>  - Continuous covariates (contcov)       : CLCR, AGE, WT
#>  - Compartment amounts (a)               : A1, A2
#>  - Not attributed (na)                   : DOSE, SS, II, TAD, CPRED, AMT2
#> 
#> List of available variables for problem no. 2 
#>  - Subject identifier (id)               : ID
#>  - Dependent variable (dv)               : DV
#>  - Independent variable (idv)            : TIME
#>  - Event identifier (evid)               : EVID
#>  - Model individual predictions (ipred)  : IPRED
#>  - Not attributed (na)                   : DOSE, TAD, SEX, CLCR, AGE, WT, AMT2

^{Created on 2019-10-14 by the reprex package (v0.3.0)}