idris-1.3.0: test/regression001/reg064.idr
sigmaEq2 : {A : Type} ->
{P : A -> Type} ->
{s1: DPair A P} ->
{s2: DPair A P} ->
fst s1 = fst s2 ->
snd s1 = snd s2 ->
s1 = s2
sigmaEq2 {A=a} {P=p} {s1 = (x ** prf)} {s2 = (x ** prf)} Refl Refl = Refl