ppProofs.lean:8:47-8:48: error: don't know how to synthesize placeholder context: α β : Sort u_1 b : β a : α h : α = β ⊢ h ▸ a = b ppProofs.lean:9:50-9:51: error: don't know how to synthesize placeholder context: α β : Sort u_1 b : β a : α h : α = β ⊢ ⋯ ▸ a = b ppProofs.lean:10:50-10:98: error: unsolved goals α β : Sort u_1 b : β a : α h : α = β ⊢ ⋯ ▸ a = b ppProofs.lean:12:50-12:51: error: don't know how to synthesize placeholder context: α β : Sort u_1 b : β a : α h : α = β ⊢ ⋯ ▸ a = b ppProofs.lean:14:50-14:51: error: don't know how to synthesize placeholder context: α β : Sort u_1 b : β a : α h : α = β ⊢ id h ▸ a = b let x := ⋯; 0 : Nat let x := Nat.le_succ 1; 0 : Nat