Function fold_stmts 

pub fn fold_stmts<'new, 'src, F: Fold<'src> + ?Sized>(
    folder: &mut F,
    arena: &'new Bump,
    stmts: &[Stmt<'_, 'src>],
) -> ArenaVec<'new, Stmt<'new, 'src>>

Folds each statement of a list in order.