4947215325
This PR improves the support for `funext` in `grind`. We will push another PR to minimize the number of case-splits later.
41 lines
1.9 KiB
Text
41 lines
1.9 KiB
Text
/-
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Copyright (c) 2025 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Leonardo de Moura
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-/
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prelude
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import Lean.Meta.Tactic.Grind.Types
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namespace Lean.Meta.Grind
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/-! Extensionality theorems support. -/
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def instantiateExtTheorem (thm : Ext.ExtTheorem) (e : Expr) : GoalM Unit := withNewMCtxDepth do
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unless (← getGeneration e) < (← getMaxGeneration) do return ()
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let c ← mkConstWithFreshMVarLevels thm.declName
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let (mvars, bis, type) ← withDefault <| forallMetaTelescopeReducing (← inferType c)
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unless (← isDefEq e type) do
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reportIssue! "failed to apply extensionality theorem `{thm.declName}` for {indentExpr e}\nis not definitionally equal to{indentExpr type}"
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return ()
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-- Instantiate type class instances
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for mvar in mvars, bi in bis do
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if bi.isInstImplicit && !(← mvar.mvarId!.isAssigned) then
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let type ← inferType mvar
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unless (← synthesizeInstanceAndAssign mvar type) do
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reportIssue! "failed to synthesize instance when instantiating extensionality theorem `{thm.declName}` for {indentExpr e}"
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return ()
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-- Remark: `proof c mvars` has type `e`
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let proof ← instantiateMVars (mkAppN c mvars)
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-- `e` is equal to `False`
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let eEqFalse ← mkEqFalseProof e
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-- So, we use `Eq.mp` to build a `proof` of `False`
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let proof := mkApp4 (mkConst ``Eq.mp [levelZero]) e (← getFalseExpr) eEqFalse proof
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let mvars ← mvars.filterM fun mvar => return !(← mvar.mvarId!.isAssigned)
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let proof' ← instantiateMVars (← mkLambdaFVars mvars proof)
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let prop' ← inferType proof'
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if proof'.hasMVar || prop'.hasMVar then
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reportIssue! "failed to apply extensionality theorem `{thm.declName}` for {indentExpr e}\nresulting terms contain metavariables"
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return ()
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trace[grind.ext] "{prop'}"
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addNewRawFact proof' prop' ((← getGeneration e) + 1)
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end Lean.Meta.Grind
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