ctx.lean:3:0: error: don't know how to synthesize placeholder
A B : Type,
a1 a2 a3 a4 a5 a6 a7 a8 a9 a10 : nat,
b1 b2 b3 : bool,
h : A = B,
p1 p2 : A × B
⊢ nat
ctx.lean:3:0: error: failed to add declaration 'foo' to environment, value has metavariables
  λ (A B : Type) (a1 a2 a3 a4 a5 a6 a7 a8 a9 a10 : nat) (b1 b2 b3 : bool) (h : A = B) (p1 p2 : A × B),
    ?M_1