{"ast_node_type":"variable","tokens":[{"end":92,"kind":"keyword","start":0,"text":"let"}]}
    let (adjustments, ty) = table.coerce(&ty1_with_vars, &ty2_with_vars, CoerceNever::Yes)?;
    let ty2_with_vars = vars.apply(tys.value.1.clone(), Interner);
    // default any type vars that weren't unified back to their original bound vars