Issue380.err

Issue380.agda:19,16-27
Sigma (_a_29 y z == _a_29 y z) (_B_27 y z) !=<
fst (fst z , _25 y z) == fst y → snd (fst z , _25 y z) == snd z
when checking that the expression refl , refl has type
fst (fst z , _25 y z) == fst y → snd (fst z , _25 y z) == snd z