syntax_data: {"ast_node_type":"other","tokens":[{"end":30,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// and `false` otherwise.
context_before:     /// Returns `true` if `def_id` refers to a trait alias (i.e., `trait Foo = ...;`),
context_after:     pub fn is_trait_alias(self, def_id: DefId) -> bool {