syntax_data: {"ast_node_type":"other","tokens":[{"end":28,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// alternative layouts.
context_before:     /// Produces a `Tree` where each of the trees in `trees` are accepted as
context_after:     pub(crate) fn alt<const N: usize>(trees: [Tree<D, R, T>; N]) -> Self {