syntax_data: {"ast_node_type":"import","tokens":[{"end":99,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// However, for boxes we can use a built-in deref instead, which doesn't borrow the scrutinee;
context_before:     /// pattern's scrutinee by calling `DerefMut::deref_mut`, and otherwise we call `Deref::deref`.
context_after:     /// in this case, we return `ByRef::No`.