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feat: improve isDefEq for projections

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When solving `a.i =?= b.i`, we first reduce `a` and `b` without using
delta reduction. If at least one become a structure, we reduce the
projection. Otherwise, we try to solve `a =?= b`, only reduce `a.i`
and `b.i` if it fails.
This commit is contained in:
Leonardo de Moura 2022-06-30 17:00:43 -07:00
parent f3bb0be045
commit dba1f79170
1 changed files with 22 additions and 16 deletions
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38
src/Lean/Meta/ExprDefEq.lean
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@ -1588,22 +1588,27 @@ private def isDefEqUnitLike (t : Expr) (s : Expr) : MetaM Bool := do
return false
private def isExprDefEqExpensive (t : Expr) (s : Expr) : MetaM Bool := do
if (← (isDefEqEta t s <||> isDefEqEta s t)) then pure true else
if (← (isDefEqEta t s <||> isDefEqEta s t)) then return true
-- TODO: investigate whether this is the place for putting this check
if (← (isDefEqEtaStruct t s <||> isDefEqEtaStruct s t)) then pure true else
if (← isDefEqProj t s) then pure true else
whenUndefDo (isDefEqNative t s) do
whenUndefDo (isDefEqNat t s) do
whenUndefDo (isDefEqOffset t s) do
whenUndefDo (isDefEqDelta t s) do
if t.isConst && s.isConst then
if t.constName! == s.constName! then isListLevelDefEqAux t.constLevels! s.constLevels! else return false
else if (← pure t.isApp <&&> pure s.isApp <&&> isDefEqApp t s) then
return true
if (← (isDefEqEtaStruct t s <||> isDefEqEtaStruct s t)) then return true
if (← isDefEqProj t s) then return true
let t' ← whnfCore t
let s' ← whnfCore s
if t != t' || s != s' then
Meta.isExprDefEqAux t' s'
else
whenUndefDo (isDefEqStringLit t s) do
if (← isDefEqUnitLike t s) then return true else
isDefEqOnFailure t s
whenUndefDo (isDefEqNative t s) do
whenUndefDo (isDefEqNat t s) do
whenUndefDo (isDefEqOffset t s) do
whenUndefDo (isDefEqDelta t s) do
if t.isConst && s.isConst then
if t.constName! == s.constName! then isListLevelDefEqAux t.constLevels! s.constLevels! else return false
else if (← pure t.isApp <&&> pure s.isApp <&&> isDefEqApp t s) then
return true
else
whenUndefDo (isDefEqStringLit t s) do
if (← isDefEqUnitLike t s) then return true else
isDefEqOnFailure t s
-- We only check DefEq cache for default and all transparency modes
private def skipDefEqCache : MetaM Bool := do
@ -1635,8 +1640,9 @@ partial def isExprDefEqAuxImpl (t : Expr) (s : Expr) : MetaM Bool := withIncRecD
withNestedTraces do
whenUndefDo (isDefEqQuick t s) do
whenUndefDo (isDefEqProofIrrel t s) do
let t' ← whnfCore t
let s' ← whnfCore s
-- We perform `whnfCore` again with `deltaAtProj := true` at `isExprDefEqExpensive` after `isDefEqProj`
let t' ← whnfCore t (deltaAtProj := false)
let s' ← whnfCore s (deltaAtProj := false)
if t != t' || s != s' then
isExprDefEqAuxImpl t' s'
else if (← skipDefEqCache) then