bayesian_as_frequentist() fails for brms 0 + Intercept formula

[DominiqueMakowski]

The 0 + Intercept syntax in brms is useful to facilitate prior specification for the intercept, but it leads to issues in check_model whereby it wrongly believes that Intercept is a variable and not a special term.

model <- brms::brm(qsec ~ mpg, data=mtcars, refresh=0)
#> Compiling Stan program...
#> Start sampling
performance::check_model(model)
#> Not enough model terms in the conditional part of the model to check for
#>   multicollinearity.

model <- brms::brm(qsec ~ 0 + Intercept + mpg, data=mtcars, refresh=0)
#> Compiling Stan program...
#> Start sampling
performance::check_model(model)
#> Error in eval(predvars, data, env): object 'Intercept' not found

^{Created on 2024-03-29 with reprex v2.0.2}

[strengejacke]

Error comes from bayestestR::bayesian_as_frequentist(model).

[DominiqueMakowski]

Should be fixed by making our own plot (see easystats/performance#477)

[strengejacke]

Not sure. Most of current checks don't work for Bayesian models, that's why we convert to frequentist