438.lean:10:41: error: don't know how to synthesize placeholder
P₀ : Type,
P : group P₀
⊢ Type
438.lean:10:39: error: don't know how to synthesize placeholder
P₀ : Type,
P : group P₀
⊢ ?M_1
438.lean:10:43: error: don't know how to synthesize placeholder
P₀ : Type,
P : group P₀
⊢ ?M_1
438.lean:10:2: error: failed to add declaration 'lambda_morphism.mk' to environment, type has metavariables
remark: set 'formatter.hide_full_terms' to false to see the complete term
  Π {P₀} {P},
    ?M_2 = ?M_3 → …