syntax_data: {"ast_node_type":"other","tokens":[{"end":56,"kind":"keyword","start":0,"text":"def::Res::Def(DefKind::AssocTy,"}]}
source_snippet:                 def::Res::Def(DefKind::AssocTy, _) => {}
context_before:             match child.res {
context_after:                 def::Res::Def(DefKind::TyAlias, _) => {}