import Lean open Lean open Lean.Elab open Lean.Elab.Term def tst1 : TermElabM Unit := do let opt ← getOptions; let stx ← `(forall (a b : Nat), Nat); IO.println "message 1"; -- This message goes direct to stdio. It will be displayed before trace messages. let e ← elabTermAndSynthesize stx none; logDbgTrace m!">>> {e}"; -- display message when `trace.Elab.debug` is true IO.println "message 2" #eval tst1 def tst2 : TermElabM Unit := do let opt ← getOptions; let a := mkIdent `a; let b := mkIdent `b; let stx ← `((fun ($a : Type) (x : $a) => @id $a x) _ 1); let e ← elabTermAndSynthesize stx none; logDbgTrace m!">>> {e}"; throwErrorIfErrors #eval tst2