role vs user@localhost acl_cache key confusion

create database db;

create table db.t1(a varchar(40));

insert into db.t1 values ('role-cache-collision-row');

create role r1;

create user r1@localhost identified by 'r1pass';

create user u1@'127.0.0.1' identified by 'u1pass';

grant select on db.* to r1@localhost;

grant r1 to u1@'127.0.0.1';

#flush privileges;

connect r1,localhost,r1,r1pass;

select a from db.t1;

connect u1,127.0.0.1,u1,u1pass;

set role r1;

show grants;

select a from db.t1;