luau/prototyping/Properties/ResolveOverloads.agda

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{-# OPTIONS --rewriting #-}
module Properties.ResolveOverloads where
open import FFI.Data.Either using (Left; Right)
open import Luau.ResolveOverloads using (Resolved; src; srcⁿ; resolve; resolveⁿ; resolveᶠ; resolveˢ; target; yes; no)
open import Luau.Subtyping using (_<:_; _≮:_; Language; ¬Language; witness; scalar; unknown; never; function; function-ok; function-err; function-tgt; function-scalar; function-ok₁; function-ok₂; scalar-scalar; scalar-function; scalar-function-ok; scalar-function-err; scalar-function-tgt; _,_; left; right)
open import Luau.Type using (Type ; Scalar; _⇒_; _∩_; __; nil; boolean; number; string; unknown; never)
open import Luau.TypeSaturation using (saturate)
open import Luau.TypeNormalization using (normalize)
open import Properties.Contradiction using (CONTRADICTION)
open import Properties.DecSubtyping using (dec-subtyping; dec-subtypingⁿ; <:-impl-<:ᵒ)
open import Properties.Functions using (_∘_)
open import Properties.Subtyping using (<:-refl; <:-trans; <:-trans-≮:; ≮:-trans-<:; <:-∩-left; <:-∩-right; <:-∩-glb; <:-impl-¬≮:; <:-unknown; <:-function; function-≮:-never; <:-never; unknown-≮:-function; scalar-≮:-function; ≮:--right; scalar-≮:-never; <:--left; <:--right; <:-impl-⊇; language-comp)
open import Properties.TypeNormalization using (Normal; FunType; normal; _⇒_; _∩_; __; never; unknown; <:-normalize; normalize-<:; fun-≮:-never; unknown-≮:-fun; scalar-≮:-fun)
open import Properties.TypeSaturation using (Overloads; Saturated; _⊆ᵒ_; _<:ᵒ_; normal-saturate; saturated; <:-saturate; saturate-<:; defn; here; left; right)
-- Properties of src
function-err-srcⁿ : {T t} (FunType T) (¬Language (srcⁿ T) t) Language T (function-err t)
function-err-srcⁿ (S T) p = function-err p
function-err-srcⁿ (S T) (p₁ , p₂) = (function-err-srcⁿ S p₁ , function-err-srcⁿ T p₂)
¬function-err-srcᶠ : {T t} (FunType T) (Language (srcⁿ T) t) ¬Language T (function-err t)
¬function-err-srcᶠ (S T) p = function-err p
¬function-err-srcᶠ (S T) (left p) = left (¬function-err-srcᶠ S p)
¬function-err-srcᶠ (S T) (right p) = right (¬function-err-srcᶠ T p)
¬function-err-srcⁿ : {T t} (Normal T) (Language (srcⁿ T) t) ¬Language T (function-err t)
¬function-err-srcⁿ never p = never
¬function-err-srcⁿ unknown (scalar ())
¬function-err-srcⁿ (S T) p = function-err p
¬function-err-srcⁿ (S T) (left p) = left (¬function-err-srcᶠ S p)
¬function-err-srcⁿ (S T) (right p) = right (¬function-err-srcᶠ T p)
¬function-err-srcⁿ (S T) (scalar ())
¬function-err-src : {T t} (Language (src T) t) ¬Language T (function-err t)
¬function-err-src {T = S T} p = function-err p
¬function-err-src {T = nil} p = scalar-function-err nil
¬function-err-src {T = never} p = never
¬function-err-src {T = unknown} (scalar ())
¬function-err-src {T = boolean} p = scalar-function-err boolean
¬function-err-src {T = number} p = scalar-function-err number
¬function-err-src {T = string} p = scalar-function-err string
¬function-err-src {T = S T} p = <:-impl-⊇ (<:-normalize (S T)) _ (¬function-err-srcⁿ (normal (S T)) p)
¬function-err-src {T = S T} p = <:-impl-⊇ (<:-normalize (S T)) _ (¬function-err-srcⁿ (normal (S T)) p)
src-¬function-errᶠ : {T t} (FunType T) Language T (function-err t) (¬Language (srcⁿ T) t)
src-¬function-errᶠ (S T) (function-err p) = p
src-¬function-errᶠ (S T) (p₁ , p₂) = (src-¬function-errᶠ S p₁ , src-¬function-errᶠ T p₂)
src-¬function-errⁿ : {T t} (Normal T) Language T (function-err t) (¬Language (srcⁿ T) t)
src-¬function-errⁿ unknown p = never
src-¬function-errⁿ (S T) (function-err p) = p
src-¬function-errⁿ (S T) (p₁ , p₂) = (src-¬function-errᶠ S p₁ , src-¬function-errᶠ T p₂)
src-¬function-errⁿ (S T) p = never
src-¬function-err : {T t} Language T (function-err t) (¬Language (src T) t)
src-¬function-err {T = S T} (function-err p) = p
src-¬function-err {T = unknown} p = never
src-¬function-err {T = S T} p = src-¬function-errⁿ (normal (S T)) (<:-normalize (S T) _ p)
src-¬function-err {T = S T} p = src-¬function-errⁿ (normal (S T)) (<:-normalize (S T) _ p)
fun-¬scalar : {S T} (s : Scalar S) FunType T ¬Language T (scalar s)
fun-¬scalar s (S T) = function-scalar s
fun-¬scalar s (S T) = left (fun-¬scalar s S)
¬fun-scalar : {S T t} (s : Scalar S) FunType T Language T t ¬Language S t
¬fun-scalar s (S T) function = scalar-function s
¬fun-scalar s (S T) (function-ok₁ p) = scalar-function-ok s
¬fun-scalar s (S T) (function-ok₂ p) = scalar-function-ok s
¬fun-scalar s (S T) (function-err p) = scalar-function-err s
¬fun-scalar s (S T) (function-tgt p) = scalar-function-tgt s
¬fun-scalar s (S T) (p₁ , p₂) = ¬fun-scalar s T p₂
fun-function : {T} FunType T Language T function
fun-function (S T) = function
fun-function (S T) = (fun-function S , fun-function T)
srcⁿ-¬scalar : {S T t} (s : Scalar S) Normal T Language T (scalar s) (¬Language (srcⁿ T) t)
srcⁿ-¬scalar s never (scalar ())
srcⁿ-¬scalar s unknown p = never
srcⁿ-¬scalar s (S T) (scalar ())
srcⁿ-¬scalar s (S T) (p₁ , p₂) = CONTRADICTION (language-comp (scalar s) (fun-¬scalar s S) p₁)
srcⁿ-¬scalar s (S T) p = never
src-¬scalar : {S T t} (s : Scalar S) Language T (scalar s) (¬Language (src T) t)
src-¬scalar {T = nil} s p = never
src-¬scalar {T = T U} s (scalar ())
src-¬scalar {T = never} s (scalar ())
src-¬scalar {T = unknown} s p = never
src-¬scalar {T = boolean} s p = never
src-¬scalar {T = number} s p = never
src-¬scalar {T = string} s p = never
src-¬scalar {T = T U} s p = srcⁿ-¬scalar s (normal (T U)) (<:-normalize (T U) (scalar s) p)
src-¬scalar {T = T U} s p = srcⁿ-¬scalar s (normal (T U)) (<:-normalize (T U) (scalar s) p)
srcⁿ-unknown-≮: : {T U} (Normal U) (T ≮: srcⁿ U) (U ≮: (T unknown))
srcⁿ-unknown-≮: never (witness t p q) = CONTRADICTION (language-comp t q unknown)
srcⁿ-unknown-≮: unknown (witness t p q) = witness (function-err t) unknown (function-err p)
srcⁿ-unknown-≮: (U V) (witness t p q) = witness (function-err t) (function-err q) (function-err p)
srcⁿ-unknown-≮: (U V) (witness t p q) = witness (function-err t) (function-err-srcⁿ (U V) q) (function-err p)
srcⁿ-unknown-≮: (U V) (witness t p q) = witness (scalar V) (right (scalar V)) (function-scalar V)
src-unknown-≮: : {T U} (T ≮: src U) (U ≮: (T unknown))
src-unknown-≮: {U = nil} (witness t p q) = witness (scalar nil) (scalar nil) (function-scalar nil)
src-unknown-≮: {U = T U} (witness t p q) = witness (function-err t) (function-err q) (function-err p)
src-unknown-≮: {U = never} (witness t p q) = CONTRADICTION (language-comp t q unknown)
src-unknown-≮: {U = unknown} (witness t p q) = witness (function-err t) unknown (function-err p)
src-unknown-≮: {U = boolean} (witness t p q) = witness (scalar boolean) (scalar boolean) (function-scalar boolean)
src-unknown-≮: {U = number} (witness t p q) = witness (scalar number) (scalar number) (function-scalar number)
src-unknown-≮: {U = string} (witness t p q) = witness (scalar string) (scalar string) (function-scalar string)
src-unknown-≮: {U = T U} p = <:-trans-≮: (normalize-<: (T U)) (srcⁿ-unknown-≮: (normal (T U)) p)
src-unknown-≮: {U = T U} p = <:-trans-≮: (normalize-<: (T U)) (srcⁿ-unknown-≮: (normal (T U)) p)
unknown-src-≮: : {S T U} (U ≮: S) (T ≮: (U unknown)) (U ≮: src T)
unknown-src-≮: (witness t x x₁) (witness (scalar s) p (function-scalar s)) = witness t x (src-¬scalar s p)
unknown-src-≮: r (witness (function-ok s .(scalar s₁)) p (function-ok x (scalar-scalar s₁ () x₂)))
unknown-src-≮: r (witness (function-ok s .function) p (function-ok x (scalar-function ())))
unknown-src-≮: r (witness (function-ok s .(function-ok _ _)) p (function-ok x (scalar-function-ok ())))
unknown-src-≮: r (witness (function-ok s .(function-err _)) p (function-ok x (scalar-function-err ())))
unknown-src-≮: r (witness (function-err t) p (function-err q)) = witness t q (src-¬function-err p)
unknown-src-≮: r (witness (function-tgt t) p (function-tgt (scalar-function-tgt ())))
-- Properties of resolve
resolveˢ-<:-⇒ : {F V U} (FunType F) (Saturated F) (FunType (V U)) (r : Resolved F V) (F <: (V U)) (target r <: U)
resolveˢ-<:-⇒ Fᶠ V⇒Uᶠ r F<:V⇒U with <:-impl-<:ᵒ Fᶠ V⇒Uᶠ F<:V⇒U here
resolveˢ-<:-⇒ Fᶠ V⇒Uᶠ (yes V<:Sʳ tgtʳ) F<:V⇒U | defn o o₁ o₂ = <:-trans (tgtʳ o o₁) o₂
resolveˢ-<:-⇒ Fᶠ V⇒Uᶠ (no tgtʳ) F<:V⇒U | defn o o₁ o₂ = CONTRADICTION (<:-impl-¬≮: o₁ (tgtʳ o))
resolveⁿ-<:-⇒ : {F V U} (Fⁿ : Normal F) (Vⁿ : Normal V) (Uⁿ : Normal U) (F <: (V U)) (resolveⁿ Fⁿ Vⁿ <: U)
resolveⁿ-<:-⇒ (Sⁿ Tⁿ) Vⁿ Uⁿ F<:V⇒U = resolveˢ-<:-⇒ (normal-saturate (Sⁿ Tⁿ)) (saturated (Sⁿ Tⁿ)) (Vⁿ Uⁿ) (resolveˢ (normal-saturate (Sⁿ Tⁿ)) (saturated (Sⁿ Tⁿ)) Vⁿ (λ o o)) F<:V⇒U
resolveⁿ-<:-⇒ (Fⁿ Gⁿ) Vⁿ Uⁿ F<:V⇒U = resolveˢ-<:-⇒ (normal-saturate (Fⁿ Gⁿ)) (saturated (Fⁿ Gⁿ)) (Vⁿ Uⁿ) (resolveˢ (normal-saturate (Fⁿ Gⁿ)) (saturated (Fⁿ Gⁿ)) Vⁿ (λ o o)) (<:-trans (saturate-<: (Fⁿ Gⁿ)) F<:V⇒U)
resolveⁿ-<:-⇒ (Sⁿ ) Vⁿ Uⁿ F<:V⇒U = CONTRADICTION (<:-impl-¬≮: F<:V⇒U (<:-trans-≮: <:--right (scalar-≮:-function )))
resolveⁿ-<:-⇒ never Vⁿ Uⁿ F<:V⇒U = <:-never
resolveⁿ-<:-⇒ unknown Vⁿ Uⁿ F<:V⇒U = CONTRADICTION (<:-impl-¬≮: F<:V⇒U unknown-≮:-function)
resolve-<:-⇒ : {F V U} (F <: (V U)) (resolve F V <: U)
resolve-<:-⇒ {F} {V} {U} F<:V⇒U = <:-trans (resolveⁿ-<:-⇒ (normal F) (normal V) (normal U) (<:-trans (normalize-<: F) (<:-trans F<:V⇒U (<:-normalize (V U))))) (normalize-<: U)
resolve-≮:-⇒ : {F V U} (resolve F V ≮: U) (F ≮: (V U))
resolve-≮:-⇒ {F} {V} {U} FV≮:U with dec-subtyping F (V U)
resolve-≮:-⇒ {F} {V} {U} FV≮:U | Left F≮:V⇒U = F≮:V⇒U
resolve-≮:-⇒ {F} {V} {U} FV≮:U | Right F<:V⇒U = CONTRADICTION (<:-impl-¬≮: (resolve-<:-⇒ F<:V⇒U) FV≮:U)
<:-resolveˢ-⇒ : {S T V} (r : Resolved (S T) V) (V <: S) T <: target r
<:-resolveˢ-⇒ (yes S T here _ _) V<:S = <:-refl
<:-resolveˢ-⇒ (no _) V<:S = <:-unknown
<:-resolveⁿ-⇒ : {S T V} (Sⁿ : Normal S) (Tⁿ : Normal T) (Vⁿ : Normal V) (V <: S) T <: resolveⁿ (Sⁿ Tⁿ) Vⁿ
<:-resolveⁿ-⇒ Sⁿ Tⁿ Vⁿ V<:S = <:-resolveˢ-⇒ (resolveˢ (Sⁿ Tⁿ) (saturated (Sⁿ Tⁿ)) Vⁿ (λ o o)) V<:S
<:-resolve-⇒ : {S T V} (V <: S) T <: resolve (S T) V
<:-resolve-⇒ {S} {T} {V} V<:S = <:-trans (<:-normalize T) (<:-resolveⁿ-⇒ (normal S) (normal T) (normal V) (<:-trans (normalize-<: V) (<:-trans V<:S (<:-normalize S))))
<:-resolveˢ : {F G V W} (r : Resolved F V) (s : Resolved G W) (F <:ᵒ G) (V <: W) target r <: target s
<:-resolveˢ (yes V<:Sʳ tgtʳ) (yes W<:Sˢ tgtˢ) F<:G V<:W with F<:G
<:-resolveˢ (yes V<:Sʳ tgtʳ) (yes W<:Sˢ tgtˢ) F<:G V<:W | defn o o₁ o₂ = <:-trans (tgtʳ o (<:-trans (<:-trans V<:W W<:Sˢ) o₁)) o₂
<:-resolveˢ (no r) (yes W<:Sˢ tgtˢ) F<:G V<:W with F<:G
<:-resolveˢ (no r) (yes W<:Sˢ tgtˢ) F<:G V<:W | defn o o₁ o₂ = CONTRADICTION (<:-impl-¬≮: (<:-trans V<:W (<:-trans W<:Sˢ o₁)) (r o))
<:-resolveˢ r (no s) F<:G V<:W = <:-unknown
<:-resolveᶠ : {F G V W} (Fᶠ : FunType F) (Gᶠ : FunType G) (Vⁿ : Normal V) (Wⁿ : Normal W) (F <: G) (V <: W) resolveᶠ Fᶠ Vⁿ <: resolveᶠ Gᶠ Wⁿ
<:-resolveᶠ Fᶠ Gᶠ Vⁿ Wⁿ F<:G V<:W = <:-resolveˢ
(resolveˢ (normal-saturate Fᶠ) (saturated Fᶠ) Vⁿ (λ o o))
(resolveˢ (normal-saturate Gᶠ) (saturated Gᶠ) Wⁿ (λ o o))
(<:-impl-<:ᵒ (normal-saturate Fᶠ) (saturated Fᶠ) (normal-saturate Gᶠ) (<:-trans (saturate-<: Fᶠ) (<:-trans F<:G (<:-saturate Gᶠ))))
V<:W
<:-resolveⁿ : {F G V W} (Fⁿ : Normal F) (Gⁿ : Normal G) (Vⁿ : Normal V) (Wⁿ : Normal W) (F <: G) (V <: W) resolveⁿ Fⁿ Vⁿ <: resolveⁿ Gⁿ Wⁿ
<:-resolveⁿ (Rⁿ Sⁿ) (Tⁿ Uⁿ) Vⁿ Wⁿ F<:G V<:W = <:-resolveᶠ (Rⁿ Sⁿ) (Tⁿ Uⁿ) Vⁿ Wⁿ F<:G V<:W
<:-resolveⁿ (Rⁿ Sⁿ) (Gⁿ Hⁿ) Vⁿ Wⁿ F<:G V<:W = <:-resolveᶠ (Rⁿ Sⁿ) (Gⁿ Hⁿ) Vⁿ Wⁿ F<:G V<:W
<:-resolveⁿ (Eⁿ Fⁿ) (Tⁿ Uⁿ) Vⁿ Wⁿ F<:G V<:W = <:-resolveᶠ (Eⁿ Fⁿ) (Tⁿ Uⁿ) Vⁿ Wⁿ F<:G V<:W
<:-resolveⁿ (Eⁿ Fⁿ) (Gⁿ Hⁿ) Vⁿ Wⁿ F<:G V<:W = <:-resolveᶠ (Eⁿ Fⁿ) (Gⁿ Hⁿ) Vⁿ Wⁿ F<:G V<:W
<:-resolveⁿ (Fⁿ ) (Tⁿ Uⁿ) Vⁿ Wⁿ F<:G V<:W = CONTRADICTION (<:-impl-¬≮: F<:G (≮:--right (scalar-≮:-function )))
<:-resolveⁿ unknown (Tⁿ Uⁿ) Vⁿ Wⁿ F<:G V<:W = CONTRADICTION (<:-impl-¬≮: F<:G unknown-≮:-function)
<:-resolveⁿ (Fⁿ ) (Gⁿ Hⁿ) Vⁿ Wⁿ F<:G V<:W = CONTRADICTION (<:-impl-¬≮: F<:G (≮:--right (scalar-≮:-fun (Gⁿ Hⁿ) )))
<:-resolveⁿ unknown (Gⁿ Hⁿ) Vⁿ Wⁿ F<:G V<:W = CONTRADICTION (<:-impl-¬≮: F<:G (unknown-≮:-fun (Gⁿ Hⁿ)))
<:-resolveⁿ (Rⁿ Sⁿ) never Vⁿ Wⁿ F<:G V<:W = CONTRADICTION (<:-impl-¬≮: F<:G (fun-≮:-never (Rⁿ Sⁿ)))
<:-resolveⁿ (Eⁿ Fⁿ) never Vⁿ Wⁿ F<:G V<:W = CONTRADICTION (<:-impl-¬≮: F<:G (fun-≮:-never (Eⁿ Fⁿ)))
<:-resolveⁿ (Fⁿ ) never Vⁿ Wⁿ F<:G V<:W = CONTRADICTION (<:-impl-¬≮: F<:G (≮:--right (scalar-≮:-never )))
<:-resolveⁿ unknown never Vⁿ Wⁿ F<:G V<:W = F<:G
<:-resolveⁿ never Gⁿ Vⁿ Wⁿ F<:G V<:W = <:-never
<:-resolveⁿ Fⁿ (Gⁿ ) Vⁿ Wⁿ F<:G V<:W = <:-unknown
<:-resolveⁿ Fⁿ unknown Vⁿ Wⁿ F<:G V<:W = <:-unknown
<:-resolve : {F G V W} (F <: G) (V <: W) resolve F V <: resolve G W
<:-resolve {F} {G} {V} {W} F<:G V<:W = <:-resolveⁿ (normal F) (normal G) (normal V) (normal W)
(<:-trans (normalize-<: F) (<:-trans F<:G (<:-normalize G)))
(<:-trans (normalize-<: V) (<:-trans V<:W (<:-normalize W)))