pstate.lean:4:26: error: unsolved placeholder, don't know how to synthesize it
A : Type,
a : A,
b : A,
c : A,
h₁ : a = b,
h₂ : b = c
⊢ b = c
pstate.lean:4:7: error: failed to add declaration 'foo' to environment, value has metavariables
  λ (A : Type) (a b c : A) (h₁ : a = b) (h₂ : b = c),
    eq.trans h₁ ?M_1