syntax_data: {"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let ty = Ty::relate(relation, ty_a, ty_b)?;
context_before:             (ty::ImplSubject::Inherent(ty_a), ty::ImplSubject::Inherent(ty_b)) => {
context_after:                 Ok(ty::ImplSubject::Inherent(ty))