62 lines
1.5 KiB
Text
62 lines
1.5 KiB
Text
import Lean.Meta
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open Lean
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open Lean.Meta
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class HasCoerce (a : semiOutParam Type) (b : Type) :=
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(coerce : a → b)
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def coerce {a b : Type} [HasCoerce a b] : a → b :=
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@HasCoerce.coerce a b _
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instance coerceTrans {a b c : Type} [HasCoerce b c] [HasCoerce a b] : HasCoerce a c :=
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⟨fun x => coerce (coerce x : b)⟩
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instance coerceBoolToProp : HasCoerce Bool Prop :=
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⟨fun y => y = true⟩
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instance coerceDecidableEq (x : Bool) : Decidable (coerce x) :=
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inferInstanceAs (Decidable (x = true))
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instance coerceNatToBool : HasCoerce Nat Bool :=
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⟨fun x => x == 0⟩
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instance coerceNatToInt : HasCoerce Nat Int :=
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⟨fun x => Int.ofNat x⟩
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def print {α} [ToString α] (a : α) : MetaM Unit := do
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trace[Meta.synthInstance] (toString a)
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def tst1 : MetaM Unit := do
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let inst ← mkAppM `HasCoerce #[mkConst `Nat, mkSort levelZero]
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let r ← synthInstance inst
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print r
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set_option trace.Meta.synthInstance true in
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set_option trace.Meta.synthInstance.tryResolve false in
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#eval tst1
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def tst2 : MetaM Unit := do
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let inst ← mkAppM `Bind #[mkConst `IO]
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-- globalInstances ← getGlobalInstances
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-- print (format globalInstances)
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-- result ← globalInstances.getUnify inst
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-- print result
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let r ← synthInstance inst
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print r
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pure ()
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set_option trace.Meta.synthInstance true in
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set_option trace.Meta.synthInstance.tryResolve false in
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#eval tst2
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def tst3 : MetaM Unit := do
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let inst ← mkAppM `BEq #[mkConst `Nat]
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let r ← synthInstance inst
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print r
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pure ()
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set_option trace.Meta.synthInstance true in
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set_option trace.Meta.synthInstance.tryResolve false in
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#eval tst3
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