create table t1 (f1 integer primary key) engine innodb;
alter table t1 add constraint c1 foreign key (f1) references t1(f1);
ERROR HY000: Error on rename of '#sql-temporary' to './test/t1' (errno: 150 "Foreign key constraint is incorrectly formed")
InnoDB: has or is referenced in foreign key constraints
InnoDB: which are not compatible with the new table definition.
drop table t1;