3 focused goals
(shelved: 1)
  
  ============================
  ?Goal 0

goal 2 is:
 forall n : nat, ?Goal n -> ?Goal (S n)
goal 3 is:
 nat
unification constraint:
 ?Goal ?Goal2 <=
   True /\ True /\ True \/
   veeryyyyyyyyyyyyloooooooooooooonggidentifier =
   veeryyyyyyyyyyyyloooooooooooooonggidentifier
3 focused goals
(shelved: 1)
  
  n, m : nat
  ============================
  ?Goal@{n:=n; m:=m} 0

goal 2 is:
 forall n0 : nat, ?Goal@{n:=n; m:=m} n0 -> ?Goal@{n:=n; m:=m} (S n0)
goal 3 is:
 nat
unification constraint:
 ?Goal@{n:=n; m:=m} ?Goal2@{n:=n; m:=m} <=
   True /\ True /\ True \/
   veeryyyyyyyyyyyyloooooooooooooonggidentifier =
   veeryyyyyyyyyyyyloooooooooooooonggidentifier
3 focused goals
(shelved: 1)
  
  m : nat
  ============================
  ?Goal1@{m:=m} 0

goal 2 is:
 forall n0 : nat, ?Goal1@{m:=m} n0 -> ?Goal1@{m:=m} (S n0)
goal 3 is:
 nat
unification constraint:
 
 n, m : nat |- ?Goal1@{m:=m} ?Goal0@{n:=n; m:=m} <=
   True /\ True /\ True \/
   veeryyyyyyyyyyyyloooooooooooooonggidentifier =
   veeryyyyyyyyyyyyloooooooooooooonggidentifier
3 focused goals
(shelved: 1)
  
  m : nat
  ============================
  ?Goal0@{m:=m} 0

goal 2 is:
 forall n0 : nat, ?Goal0@{m:=m} n0 -> ?Goal0@{m:=m} (S n0)
goal 3 is:
 nat
unification constraint:
 
 n, m : nat |- ?Goal0@{m:=m} ?Goal2@{n:=n} <=
   True /\ True /\ True \/
   veeryyyyyyyyyyyyloooooooooooooonggidentifier =
   veeryyyyyyyyyyyyloooooooooooooonggidentifier
The command has indeed failed with message:
In environment
P : nat -> Type
x : nat
h : P x
Unable to unify "P x" with "?P x"
(unable to find a well-typed instantiation for "?P": cannot ensure that
"nat -> Type" is a subtype of "nat -> Prop").