Bug in rcompare with multiple random effects

[pitakakariki]

Original model e.g. [fe] + (1 | g1) + (x || g2).

Test e.g. rcompare(~ (x || g2)).

re part ends up as c([a], [b]).

then str_c gives c("[fe] + [a]", "[fe] + [b]").

meaning as.formula gives a warning and the incorrect formula y ~ [fe] + [a].

[pitakakariki]

Simpler reprex:

fm <- lmer(y ~ (1|x) + (1|z) + (1|g), data=simdata)
doTest(fm, rcompare(~ (1|x) + (1|g)))