lean4-htt/src/Lean/Meta/Tactic/Refl.lean
2022-07-24 21:36:33 -07:00

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/-
Copyright (c) 2022 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Leonardo de Moura
-/
import Lean.Meta.Reduce
import Lean.Meta.Tactic.Util
namespace Lean.Meta
private def useKernel (lhs rhs : Expr) : MetaM Bool := do
if lhs.hasFVar || lhs.hasMVar || rhs.hasFVar || rhs.hasMVar then
return false
else
return (← getTransparency) matches TransparencyMode.default | TransparencyMode.all
/--
Close given goal using `Eq.refl`.
-/
def _root_.Lean.MVarId.refl (mvarId : MVarId) : MetaM Unit := do
mvarId.withContext do
mvarId.checkNotAssigned `refl
let targetType ← mvarId.getType'
unless targetType.isAppOfArity ``Eq 3 do
throwTacticEx `rfl mvarId m!"equality expected{indentExpr targetType}"
let lhs ← instantiateMVars targetType.appFn!.appArg!
let rhs ← instantiateMVars targetType.appArg!
let success ← if (← useKernel lhs rhs) then
pure (Kernel.isDefEq (← getEnv) {} lhs rhs)
else
isDefEq lhs rhs
unless success do
throwTacticEx `rfl mvarId m!"equality lhs{indentExpr lhs}\nis not definitionally equal to rhs{indentExpr rhs}"
let us := targetType.getAppFn.constLevels!
let α := targetType.appFn!.appFn!.appArg!
mvarId.assign (mkApp2 (mkConst ``Eq.refl us) α lhs)
@[deprecated MVarId.refl]
def refl (mvarId : MVarId) : MetaM Unit := do
mvarId.refl
end Lean.Meta