diff --git a/R/conditional_effects.R b/R/conditional_effects.R
index 0954aae8..c7737467 100644
--- a/R/conditional_effects.R
+++ b/R/conditional_effects.R
@@ -934,7 +934,7 @@ make_point_frame <- function(bterms, mf, effects, conditions,
     model.frame(bterms$respform, mf, na.action = na.pass)
   )
   req_vars <- names(mf)
-  groups <- get_re_groups(bterms)
+  groups <- get_re_group_vars(bterms)
   if (length(groups)) {
     c(req_vars) <- unlist(strsplit(groups, ":"))
   }
diff --git a/R/exclude_pars.R b/R/exclude_pars.R
index 9172c46f..fb3aa017 100644
--- a/R/exclude_pars.R
+++ b/R/exclude_pars.R
@@ -111,7 +111,7 @@ exclude_pars_re <- function(bframe, save_pars, ...) {
       c(out) <- paste0("r_", sub_reframe$id, sub_p, "_", sub_reframe$cn)
     }
   }
-  reframe_t <- get_dist_groups(reframe, "student")
+  reframe_t <- subset_reframe_dist(reframe, "student")
   if (!save_pars$all && has_rows(reframe_t)) {
     c(out) <- paste0(c("udf_", "dfm_"), reframe_t$ggn)
   }
diff --git a/R/formula-ac.R b/R/formula-ac.R
index 29b1a38d..8b76cc0b 100644
--- a/R/formula-ac.R
+++ b/R/formula-ac.R
@@ -607,8 +607,8 @@ get_ac_vars <- function(x, var, ...) {
   setdiff(na.omit(out), "NA")
 }
 
-# get names of autocor grouping variables
-get_ac_groups <- function(x, ...) {
+# get names of grouping variables from ac terms
+get_ac_group_vars <- function(x, ...) {
   get_ac_vars(x, "gr", ...)
 }
 
diff --git a/R/formula-re.R b/R/formula-re.R
index 2987310f..fb7cfe87 100644
--- a/R/formula-re.R
+++ b/R/formula-re.R
@@ -781,7 +781,7 @@ get_group_vars.mvbrmsterms <- function(x, ...) {
 }
 
 .get_group_vars <- function(x, ...) {
-  out <- c(get_re_groups(x), get_me_groups(x), get_ac_groups(x))
+  out <- c(get_re_group_vars(x), get_me_group_vars(x), get_ac_group_vars(x))
   out <- out[nzchar(out)]
   if (length(out)) {
     c(out) <- unlist(strsplit(out, ":"))
@@ -790,13 +790,14 @@ get_group_vars.mvbrmsterms <- function(x, ...) {
   out
 }
 
-# get names of grouping variables of re terms
-get_re_groups <- function(x, ...) {
+# get names of grouping variables from re terms
+get_re_group_vars <- function(x, ...) {
   ufrom_list(get_re(x)$gcall, "groups")
 }
 
-# extract information about groups with a certain distribution
-get_dist_groups <- function(reframe, dist) {
+# extract information about groups with a certain distribution from an reframe
+subset_reframe_dist <- function(reframe, dist) {
+  stopifnot(is.reframe(reframe))
   out <- subset2(reframe, dist = dist)
   out[!duplicated(out$group), c("group", "ggn", "id")]
 }
diff --git a/R/formula-sp.R b/R/formula-sp.R
index 1fa22ff9..da5d1a1e 100644
--- a/R/formula-sp.R
+++ b/R/formula-sp.R
@@ -496,8 +496,8 @@ get_sdy <- function(x, data = NULL) {
   sdy
 }
 
-# names of grouping variables used in measurement error terms
-get_me_groups <- function(x) {
+# get names of grouping variables from me terms
+get_me_group_vars <- function(x) {
   uni_me <- get_uni_me(x)
   out <- lapply(uni_me, eval2)
   out <- ufrom_list(out, "gr")
diff --git a/R/priors.R b/R/priors.R
index a161ee56..d3342aa6 100644
--- a/R/priors.R
+++ b/R/priors.R
@@ -965,7 +965,7 @@ prior_re <- function(bframe, internal = FALSE, ...) {
       }
     }
   }
-  reframe_t <- get_dist_groups(reframe, "student")
+  reframe_t <- subset_reframe_dist(reframe, "student")
   if (isTRUE(nrow(reframe_t) > 0L)) {
     prior <- prior +
       brmsprior("gamma(2, 0.1)", class = "df", group = reframe_t$group, lb = "1")
diff --git a/R/rename_pars.R b/R/rename_pars.R
index 98c7dfff..299f5c4c 100644
--- a/R/rename_pars.R
+++ b/R/rename_pars.R
@@ -440,7 +440,7 @@ rename_re <- function(bframe, pars, ...) {
   if (any(grepl("^r_", pars))) {
     c(out) <- rename_re_levels(bframe, pars = pars)
   }
-  reframe_t <- get_dist_groups(reframe, "student")
+  reframe_t <- subset_reframe_dist(reframe, "student")
   for (i in seq_rows(reframe_t)) {
     df_pos <- grepl(paste0("^df_", reframe_t$ggn[i], "$"), pars)
     df_name <- paste0("df_", reframe_t$group[i])
diff --git a/R/stan-predictor.R b/R/stan-predictor.R
index 180217e0..2384ea1c 100644
--- a/R/stan-predictor.R
+++ b/R/stan-predictor.R
@@ -471,7 +471,7 @@ stan_re <- function(bframe, prior, normalize, ...) {
   out <- list()
   # special handling of student-t group effects as their 'df' parameters
   # are defined on a per-group basis instead of a per-ID basis
-  reframe_t <- get_dist_groups(reframe, "student")
+  reframe_t <- subset_reframe_dist(reframe, "student")
   if (has_rows(reframe_t)) {
     str_add(out$par) <-
       "  // parameters for student-t distributed group-level effects\n"
@@ -619,7 +619,7 @@ stan_re <- function(bframe, prior, normalize, ...) {
 
   # define group-level coefficients
   dfm <- ""
-  tr <- get_dist_groups(r, "student")
+  tr <- subset_reframe_dist(r, "student")
   if (nrow(r) > 1L && r$cor[1]) {
     # multiple correlated group-level effects
     str_add(out$data) <- glue(