syntax_data: {"ast_node_type":"other","tokens":[{"end":67,"kind":"keyword","start":0,"text":"(ty::Alias(a_kind,"}]}
source_snippet:         (ty::Alias(a_kind, a_data), ty::Alias(b_kind, b_data)) => {
context_before:         // Alias tend to mostly already be handled downstream due to normalization.
context_after:             let alias_ty = relation.relate(a_data, b_data)?;