I should’ve clarified it more: Before Maintain expanded attrs/lists/attr params/inherits by infinisil · Pull Request #224 · NixOS/nixfmt · GitHub, if lists with 3 elements were allowed to be on a single line, this code:
buildInputs = [
a
b
c
]
Would’ve been formatted as
buildInputs = [ a b c ];
Which is why it would’ve been a really bad choice. But now that expanded attribute sets are preserved, the above wouldn’t get reformatted, while also allowing the second style