/-- error: Invalid projection: Type of x✝ is not known; cannot resolve projection `1` --- error: unsolved goals case refine'_1 ⊢ Sort ?u.8 case refine'_2 ⊢ Sort ?u.7 case refine'_3 ⊢ ?refine'_1 case refine'_4 ⊢ ?refine'_1 case refine'_5 ⊢ ¬(fun x => ?m.9) ?refine'_3 = (fun x => ?m.9) ?refine'_4 -/ #guard_msgs in example : False := by refine' absurd (congrArg (·.1) sorry) _