This commit is contained in:
ajeffrey@roblox.com 2022-03-22 12:49:57 -05:00
parent 8aeba47463
commit c99c1aa486
9 changed files with 312 additions and 279 deletions

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@ -10,7 +10,7 @@ open import Agda.Builtin.String using (String)
open import FFI.Data.ByteString using (ByteString)
open import FFI.Data.HaskellString using (HaskellString; pack)
open import FFI.Data.Maybe using (Maybe; just; nothing)
open import FFI.Data.Either using (Either; mapLeft)
open import FFI.Data.Either using (Either; mapL)
open import FFI.Data.Scientific using (Scientific)
open import FFI.Data.Vector using (Vector)
@ -73,5 +73,5 @@ postulate
{-# COMPILE GHC eitherHDecode = Data.Aeson.eitherDecodeStrict #-}
eitherDecode : ByteString Either String Value
eitherDecode bytes = mapLeft pack (eitherHDecode bytes)
eitherDecode bytes = mapL pack (eitherHDecode bytes)

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@ -7,10 +7,22 @@ data Either (A B : Set) : Set where
Right : B Either A B
{-# COMPILE GHC Either = data Data.Either.Either (Data.Either.Left|Data.Either.Right) #-}
mapLeft : {A B C} (A B) (Either A C) (Either B C)
mapLeft f (Left x) = Left (f x)
mapLeft f (Right x) = Right x
swapLR : {A B} Either A B Either B A
swapLR (Left x) = Right x
swapLR (Right x) = Left x
mapRight : {A B C} (B C) (Either A B) (Either A C)
mapRight f (Left x) = Left x
mapRight f (Right x) = Right (f x)
mapL : {A B C} (A B) Either A C Either B C
mapL f (Left x) = Left (f x)
mapL f (Right x) = Right x
mapR : {A B C} (B C) Either A B Either A C
mapR f (Left x) = Left x
mapR f (Right x) = Right (f x)
mapLR : {A B C D} (A B) (C D) Either A C Either B D
mapLR f g (Left x) = Left (f x)
mapLR f g (Right x) = Right (g x)
cond : {A B C : Set} (A C) (B C) (Either A B) C
cond f g (Left x) = f x
cond f g (Right x) = g x

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@ -6,68 +6,17 @@ open import Agda.Builtin.Equality using (_≡_)
open import FFI.Data.Maybe using (just; nothing)
open import Luau.Syntax using (Expr; Stat; Block; BinaryOperator; yes; nil; addr; var; binexp; var_∈_; _⟨_⟩∈_; function_is_end; _$_; block_is_end; local_←_; _∙_; done; return; name; +; -; *; /; <; >; <=; >=; ··)
open import Luau.Type using (Type; strict; nil; number; string; boolean; none; any; _⇒_; __; _∩_; tgt)
open import Luau.Subtyping using (_≮:_)
open import Luau.Heap using (Heap; function_is_end) renaming (_[_] to _[_]ᴴ)
open import Luau.VarCtxt using (VarCtxt; ∅; _⋒_; _↦_; _⊕_↦_; _⊝_) renaming (_[_] to _[_]ⱽ)
open import Luau.TypeCheck(strict) using (_⊢ᴮ_∈_; _⊢ᴱ_∈_; ⊢ᴴ_; ⊢ᴼ_; _⊢ᴴᴱ_▷_∈_; _⊢ᴴᴮ_▷_∈_; var; addr; app; binexp; block; return; local; function; srcBinOp)
open import Properties.Contradiction using (¬)
open import Properties.Equality using (_≢_)
open import Properties.TypeCheck(strict) using (typeCheckᴮ)
open import Properties.Product using (_,_)
src : Type Type
src = Luau.Type.src strict
data Scalar : Type Set where
number : Scalar number
boolean : Scalar boolean
string : Scalar string
nil : Scalar nil
data Tree : Set where
scalar : {T} Scalar T Tree
function : Tree
function-ok : Tree Tree
function-err : Tree Tree
data Language : Type Tree Set
data ¬Language : Type Tree Set
data Language where
scalar : {T} (s : Scalar T) Language T (scalar s)
function : {T U} Language (T U) function
function-ok : {T U u} (Language U u) Language (T U) (function-ok u)
function-err : {T U t} (¬Language T t) Language (T U) (function-err t)
scalar-function-err : {S t} (Scalar S) Language S (function-err t)
left : {T U t} Language T t Language (T U) t
right : {T U u} Language U u Language (T U) u
_,_ : {T U t} Language T t Language U t Language (T U) t
any : {t} Language any t
data ¬Language where
scalar-scalar : {S T} (s : Scalar S) (Scalar T) (S T) ¬Language T (scalar s)
scalar-function : {S} (Scalar S) ¬Language S function
scalar-function-ok : {S u} (Scalar S) ¬Language S (function-ok u)
function-scalar : {S T U} (s : Scalar S) ¬Language (T U) (scalar s)
function-ok : {T U u} (¬Language U u) ¬Language (T U) (function-ok u)
function-err : {T U t} (Language T t) ¬Language (T U) (function-err t)
_,_ : {T U t} ¬Language T t ¬Language U t ¬Language (T U) t
left : {T U t} ¬Language T t ¬Language (T U) t
right : {T U u} ¬Language U u ¬Language (T U) u
none : {t} ¬Language none t
data _≮:_ (T U : Type) : Set where
witness : t
Language T t
¬Language U t
-----------------
T ≮: U
data Warningᴱ (H : Heap yes) {Γ} : {M T} (Γ ⊢ᴱ M T) Set
data Warningᴮ (H : Heap yes) {Γ} : {B T} (Γ ⊢ᴮ B T) Set

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@ -0,0 +1,62 @@
{-# OPTIONS --rewriting #-}
open import Luau.Type using (Type; Scalar; nil; number; string; boolean; none; any; _⇒_; __; _∩_)
open import Properties.Equality using (_≢_)
module Luau.Subtyping where
-- An implementation of semantic subtyping
-- We think of types as languages of trees
data Tree : Set where
scalar : {T} Scalar T Tree
function : Tree
function-ok : Tree Tree
function-err : Tree Tree
data Language : Type Tree Set
data ¬Language : Type Tree Set
data Language where
scalar : {T} (s : Scalar T) Language T (scalar s)
function : {T U} Language (T U) function
function-ok : {T U u} (Language U u) Language (T U) (function-ok u)
function-err : {T U t} (¬Language T t) Language (T U) (function-err t)
scalar-function-err : {S t} (Scalar S) Language S (function-err t)
left : {T U t} Language T t Language (T U) t
right : {T U u} Language U u Language (T U) u
_,_ : {T U t} Language T t Language U t Language (T U) t
any : {t} Language any t
data ¬Language where
scalar-scalar : {S T} (s : Scalar S) (Scalar T) (S T) ¬Language T (scalar s)
scalar-function : {S} (Scalar S) ¬Language S function
scalar-function-ok : {S u} (Scalar S) ¬Language S (function-ok u)
function-scalar : {S T U} (s : Scalar S) ¬Language (T U) (scalar s)
function-ok : {T U u} (¬Language U u) ¬Language (T U) (function-ok u)
function-err : {T U t} (Language T t) ¬Language (T U) (function-err t)
_,_ : {T U t} ¬Language T t ¬Language U t ¬Language (T U) t
left : {T U t} ¬Language T t ¬Language (T U) t
right : {T U u} ¬Language U u ¬Language (T U) u
none : {t} ¬Language none t
-- Subtyping as language inclusion
_<:_ : Type Type Set
(T <: U) = t (Language T t) (Language U t)
-- For warnings, we are interested in failures of subtyping,
-- which is whrn there is a tree in T's language that isn't in U's.
data _≮:_ (T U : Type) : Set where
witness : t
Language T t
¬Language U t
-----------------
T ≮: U

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@ -17,6 +17,13 @@ data Type : Set where
__ : Type Type Type
_∩_ : Type Type Type
data Scalar : Type Set where
number : Scalar number
boolean : Scalar boolean
string : Scalar string
nil : Scalar nil
lhs : Type Type
lhs (T _) = T
lhs (T _) = T

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@ -5,7 +5,9 @@ module Properties where
import Properties.Contradiction
import Properties.Dec
import Properties.Equality
import Properties.Functions
import Properties.Remember
import Properties.Step
import Properties.StrictMode
import Properties.Subtyping
import Properties.TypeCheck

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@ -0,0 +1,6 @@
module Properties.Functions where
infixr 5 _∘_
_∘_ : {A B C : Set} (B C) (A B) (A C)
(f g) x = f (g x)

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@ -4,11 +4,12 @@ module Properties.StrictMode where
import Agda.Builtin.Equality.Rewrite
open import Agda.Builtin.Equality using (_≡_; refl)
open import FFI.Data.Either using (Either; Left; Right)
open import FFI.Data.Either using (Either; Left; Right; mapL; mapR; mapLR; swapLR; cond)
open import FFI.Data.Maybe using (Maybe; just; nothing)
open import Luau.Heap using (Heap; Object; function_is_end; defn; alloc; ok; next; lookup-not-allocated) renaming (_≡_⊕_↦_ to _≡ᴴ_⊕_↦_; _[_] to _[_]ᴴ; to ∅ᴴ)
open import Luau.StrictMode using (Warningᴱ; Warningᴮ; Warningᴼ; Warningᴴ; UnallocatedAddress; UnboundVariable; FunctionCallMismatch; app₁; app₂; BinOpMismatch₁; BinOpMismatch₂; bin₁; bin₂; BlockMismatch; block₁; return; LocalVarMismatch; local₁; local₂; FunctionDefnMismatch; function₁; function₂; heap; expr; block; addr; _≮:_; witness; any; none; nil; number; string; boolean; scalar; function; scalar-function; scalar-function-ok; scalar-function-err; scalar-scalar; function-scalar; function-ok; function-err; left; right; _,_; Tree; Language; ¬Language; Scalar)
open import Luau.StrictMode using (Warningᴱ; Warningᴮ; Warningᴼ; Warningᴴ; UnallocatedAddress; UnboundVariable; FunctionCallMismatch; app₁; app₂; BinOpMismatch₁; BinOpMismatch₂; bin₁; bin₂; BlockMismatch; block₁; return; LocalVarMismatch; local₁; local₂; FunctionDefnMismatch; function₁; function₂; heap; expr; block; addr)
open import Luau.Substitution using (_[_/_]ᴮ; _[_/_]ᴱ; _[_/_]ᴮunless_; var_[_/_]ᴱwhenever_)
open import Luau.Subtyping using (_≮:_; witness; any; none; scalar; function; scalar-function; scalar-function-ok; scalar-function-err; scalar-scalar; function-scalar; function-ok; function-err; left; right; _,_; Tree; Language; ¬Language)
open import Luau.Syntax using (Expr; yes; var; val; var_∈_; _⟨_⟩∈_; _$_; addr; number; bool; string; binexp; nil; function_is_end; block_is_end; done; return; local_←_; _∙_; fun; arg; name; ==; ~=)
open import Luau.Type using (Type; strict; nil; number; boolean; string; _⇒_; none; any; _∩_; __; tgt; _≡ᵀ_; _≡ᴹᵀ_)
open import Luau.TypeCheck(strict) using (_⊢ᴮ_∈_; _⊢ᴱ_∈_; _⊢ᴴᴮ_▷_∈_; _⊢ᴴᴱ_▷_∈_; nil; var; addr; app; function; block; done; return; local; orAny; srcBinOp; tgtBinOp)
@ -20,37 +21,13 @@ open import Properties.Remember using (remember; _,_)
open import Properties.Equality using (_≢_; sym; cong; trans; subst₁)
open import Properties.Dec using (Dec; yes; no)
open import Properties.Contradiction using (CONTRADICTION; ¬)
open import Properties.Functions using (_∘_)
open import Properties.Subtyping using (any-≮:; ≡-trans-≮:; ≮:-trans-≡; none-tgt-≮:; tgt-none-≮:; src-any-≮:; any-src-≮:; ≮:-antitrans; ≮:-antirefl; scalar-≢-impl-≮:; function-≮:-scalar; scalar-≮:-function; function-≮:-none; any-≮:-scalar; scalar-≮:-none; any-≮:-none)
open import Properties.TypeCheck(strict) using (typeOfᴼ; typeOfᴹᴼ; typeOfⱽ; typeOfᴱ; typeOfᴮ; typeCheckᴱ; typeCheckᴮ; typeCheckᴼ; typeCheckᴴ)
open import Luau.OpSem using (_⟦_⟧_⟶_; _⊢_⟶*_⊣_; _⊢_⟶ᴮ_⊣_; _⊢_⟶ᴱ_⊣_; app₁; app₂; function; beta; return; block; done; local; subst; binOp₀; binOp₁; binOp₂; refl; step; +; -; *; /; <; >; ==; ~=; <=; >=; ··)
open import Luau.RuntimeError using (BinOpError; RuntimeErrorᴱ; RuntimeErrorᴮ; FunctionMismatch; BinOpMismatch₁; BinOpMismatch₂; UnboundVariable; SEGV; app₁; app₂; bin₁; bin₂; block; local; return; +; -; *; /; <; >; <=; >=; ··)
open import Luau.RuntimeType using (RuntimeType; valueType; number; string; boolean; nil; function)
-- Move these! --
swapLR : {A B} Either A B Either B A
swapLR (Left x) = Right x
swapLR (Right x) = Left x
mapL : {A B C} (A B) Either A C Either B C
mapL f (Left x) = Left (f x)
mapL f (Right x) = Right x
mapR : {A B C} (B C) Either A B Either A C
mapR f (Left x) = Left x
mapR f (Right x) = Right (f x)
mapLR : {A B C D} (A B) (C D) Either A C Either B D
mapLR f g (Left x) = Left (f x)
mapLR f g (Right x) = Right (g x)
cond : {A B C : Set} (A C) (B C) (Either A B) C
cond f g (Left x) = f x
cond f g (Right x) = g x
infixr 5 _∘_
_∘_ : {A B C : Set} (B C) (A B) (A C)
(f g) x = f (g x)
--
src = Luau.Type.src strict
data _⊑_ (H : Heap yes) : Heap yes Set where
@ -86,193 +63,6 @@ lookup-⊑-nothing {H} a (snoc defn) p with a ≡ᴬ next H
lookup-⊑-nothing {H} a (snoc defn) p | yes refl = refl
lookup-⊑-nothing {H} a (snoc o) p | no q = trans (lookup-not-allocated o q) p
dec-language : T t Either (¬Language T t) (Language T t)
dec-language nil (scalar number) = Left (scalar-scalar number nil (λ ()))
dec-language nil (scalar boolean) = Left (scalar-scalar boolean nil (λ ()))
dec-language nil (scalar string) = Left (scalar-scalar string nil (λ ()))
dec-language nil (scalar nil) = Right (scalar nil)
dec-language nil function = Left (scalar-function nil)
dec-language nil (function-ok t) = Left (scalar-function-ok nil)
dec-language nil (function-err t) = Right (scalar-function-err nil)
dec-language boolean (scalar number) = Left (scalar-scalar number boolean (λ ()))
dec-language boolean (scalar boolean) = Right (scalar boolean)
dec-language boolean (scalar string) = Left (scalar-scalar string boolean (λ ()))
dec-language boolean (scalar nil) = Left (scalar-scalar nil boolean (λ ()))
dec-language boolean function = Left (scalar-function boolean)
dec-language boolean (function-ok t) = Left (scalar-function-ok boolean)
dec-language boolean (function-err t) = Right (scalar-function-err boolean)
dec-language number (scalar number) = Right (scalar number)
dec-language number (scalar boolean) = Left (scalar-scalar boolean number (λ ()))
dec-language number (scalar string) = Left (scalar-scalar string number (λ ()))
dec-language number (scalar nil) = Left (scalar-scalar nil number (λ ()))
dec-language number function = Left (scalar-function number)
dec-language number (function-ok t) = Left (scalar-function-ok number)
dec-language number (function-err t) = Right (scalar-function-err number)
dec-language string (scalar number) = Left (scalar-scalar number string (λ ()))
dec-language string (scalar boolean) = Left (scalar-scalar boolean string (λ ()))
dec-language string (scalar string) = Right (scalar string)
dec-language string (scalar nil) = Left (scalar-scalar nil string (λ ()))
dec-language string function = Left (scalar-function string)
dec-language string (function-ok t) = Left (scalar-function-ok string)
dec-language string (function-err t) = Right (scalar-function-err string)
dec-language (T₁ T₂) (scalar s) = Left (function-scalar s)
dec-language (T₁ T₂) function = Right function
dec-language (T₁ T₂) (function-ok t) = mapLR function-ok function-ok (dec-language T₂ t)
dec-language (T₁ T₂) (function-err t) = mapLR function-err function-err (swapLR (dec-language T₁ t))
dec-language none t = Left none
dec-language any t = Right any
dec-language (T₁ T₂) t = cond (λ p cond (Left _,_ p) (Right right) (dec-language T₂ t)) (Right left) (dec-language T₁ t)
dec-language (T₁ T₂) t = cond (Left left) (λ p cond (Left right) (Right _,_ p) (dec-language T₂ t)) (dec-language T₁ t)
≮:-antirefl : {T} ¬(T ≮: T)
:-antirefl (witness (scalar s) (scalar s) (scalar-scalar s t p)) = CONTRADICTION (p refl)
:-antirefl (witness function function (scalar-function ()))
:-antirefl (witness (function-ok t) (function-ok p) (function-ok q)) = ≮:-antirefl (witness t p q)
:-antirefl (witness (function-err t) (function-err p) (function-err q)) = ≮:-antirefl (witness t q p)
:-antirefl (witness t (left p) (q₁ , q₂)) = ≮:-antirefl (witness t p q₁)
:-antirefl (witness t (right p) (q₁ , q₂)) = ≮:-antirefl (witness t p q₂)
:-antirefl (witness t (p₁ , p₂) (left q)) = ≮:-antirefl (witness t p₁ q)
:-antirefl (witness t (p₁ , p₂) (right q)) = ≮:-antirefl (witness t p₂ q)
:-antirefl (witness (scalar s) any (scalar-scalar s () t))
:-antirefl (witness (function-ok t) any (scalar-function-ok ()))
:-antirefl (witness (function-err t) (scalar-function-err number) ())
:-antirefl (witness (function-err t) (scalar-function-err boolean) ())
:-antirefl (witness (function-err t) (scalar-function-err string) ())
:-antirefl (witness (function-err t) (scalar-function-err nil) ())
≮:-antitrans : {S T U} (S ≮: U) Either (S ≮: T) (T ≮: U)
:-antitrans {T = T} (witness t p q) = mapLR (witness t p) (λ z witness t z q) (dec-language T t)
any-≮: : {T U} (T ≮: U) (any ≮: U)
any-≮: (witness t p q) = witness t any q
none-≮: : {T U} (T ≮: U) (T ≮: none)
none-≮: (witness t p q) = witness t p none
skalar = number (string (nil boolean))
tgt-function-ok : {T t} (Language (tgt T) t) Language T (function-ok t)
tgt-function-ok {T = nil} (scalar ())
tgt-function-ok {T = T₁ T₂} p = function-ok p
tgt-function-ok {T = none} (scalar ())
tgt-function-ok {T = any} p = any
tgt-function-ok {T = boolean} (scalar ())
tgt-function-ok {T = number} (scalar ())
tgt-function-ok {T = string} (scalar ())
tgt-function-ok {T = T₁ T₂} (left p) = left (tgt-function-ok p)
tgt-function-ok {T = T₁ T₂} (right p) = right (tgt-function-ok p)
tgt-function-ok {T = T₁ T₂} (p₁ , p₂) = (tgt-function-ok p₁ , tgt-function-ok p₂)
function-ok-tgt : {T t} Language T (function-ok t) (Language (tgt T) t)
function-ok-tgt (function-ok p) = p
function-ok-tgt (left p) = left (function-ok-tgt p)
function-ok-tgt (right p) = right (function-ok-tgt p)
function-ok-tgt (p₁ , p₂) = (function-ok-tgt p₁ , function-ok-tgt p₂)
function-ok-tgt any = any
skalar-function-ok : {t} (¬Language skalar (function-ok t))
skalar-function-ok = (scalar-function-ok number , (scalar-function-ok string , (scalar-function-ok nil , scalar-function-ok boolean)))
skalar-scalar : {T} (s : Scalar T) (Language skalar (scalar s))
skalar-scalar number = left (scalar number)
skalar-scalar boolean = right (right (right (scalar boolean)))
skalar-scalar string = right (left (scalar string))
skalar-scalar nil = right (right (left (scalar nil)))
tgt-src-≮: : {T U} (tgt T ≮: U) (T ≮: (skalar (none U)))
tgt-src-≮: (witness t p q) = witness (function-ok t) (tgt-function-ok p) (skalar-function-ok , function-ok q)
src-tgt-≮: : {T U} (T ≮: (skalar (none U))) (tgt T ≮: U)
src-tgt-≮: (witness (scalar s) p (q₁ , q₂)) = CONTRADICTION (≮:-antirefl (witness (scalar s) (skalar-scalar s) q₁))
src-tgt-≮: (witness function p (q₁ , scalar-function ()))
src-tgt-≮: (witness (function-ok t) p (q₁ , function-ok q₂)) = witness t (function-ok-tgt p) q₂
src-tgt-≮: (witness (function-err (scalar s)) p (q₁ , function-err (scalar ())))
function-err-src : {T t} (¬Language (src T) t) Language T (function-err t)
function-err-src {T = nil} none = scalar-function-err nil
function-err-src {T = T₁ T₂} p = function-err p
function-err-src {T = none} (scalar-scalar number () p)
function-err-src {T = none} (scalar-function-ok ())
function-err-src {T = any} none = any
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 = T₁ T₂} (left p) = left (function-err-src p)
function-err-src {T = T₁ T₂} (right p) = right (function-err-src p)
function-err-src {T = T₁ T₂} (p₁ , p₂) = function-err-src p₁ , function-err-src p₂
¬function-err-src : {T t} (Language (src T) t) ¬Language T (function-err t)
¬function-err-src {T = nil} (scalar ())
¬function-err-src {T = T₁ T₂} p = function-err p
¬function-err-src {T = none} any = none
¬function-err-src {T = any} (scalar ())
¬function-err-src {T = boolean} (scalar ())
¬function-err-src {T = number} (scalar ())
¬function-err-src {T = string} (scalar ())
¬function-err-src {T = T₁ T₂} (p₁ , p₂) = (¬function-err-src p₁ , ¬function-err-src p₂)
¬function-err-src {T = T₁ T₂} (left p) = left (¬function-err-src p)
¬function-err-src {T = T₁ T₂} (right p) = right (¬function-err-src p)
src-¬function-err : {T t} Language T (function-err t) (¬Language (src T) t)
src-¬function-err {T = nil} p = none
src-¬function-err {T = T₁ T₂} (function-err p) = p
src-¬function-err {T = none} (scalar-function-err ())
src-¬function-err {T = any} p = none
src-¬function-err {T = boolean} p = none
src-¬function-err {T = number} p = none
src-¬function-err {T = string} p = none
src-¬function-err {T = T₁ T₂} (left p) = left (src-¬function-err p)
src-¬function-err {T = T₁ T₂} (right p) = right (src-¬function-err p)
src-¬function-err {T = T₁ T₂} (p₁ , p₂) = (src-¬function-err p₁ , src-¬function-err p₂)
src-¬scalar : {S T t} (s : Scalar S) Language T (scalar s) (¬Language (src T) t)
src-¬scalar number (scalar number) = none
src-¬scalar boolean (scalar boolean) = none
src-¬scalar string (scalar string) = none
src-¬scalar nil (scalar nil) = none
src-¬scalar s (left p) = left (src-¬scalar s p)
src-¬scalar s (right p) = right (src-¬scalar s p)
src-¬scalar s (p₁ , p₂) = (src-¬scalar s p₁ , src-¬scalar s p₂)
src-¬scalar s any = none
src-any-≮: : {T U} (T ≮: src U) (U ≮: (T any))
src-any-≮: (witness t p q) = witness (function-err t) (function-err-src q) (¬function-err-src p)
any-src-≮: : {S T U} (U ≮: S) (T ≮: (U any)) (U ≮: src T)
any-src-≮: (witness t x x₁) (witness (scalar s) p (function-scalar s)) = witness t x (src-¬scalar s p)
any-src-≮: r (witness (function-ok (scalar s)) p (function-ok (scalar-scalar s () q)))
any-src-≮: r (witness (function-ok (function-ok _)) p (function-ok (scalar-function-ok ())))
any-src-≮: r (witness (function-err t) p (function-err q)) = witness t q (src-¬function-err p)
function-≮:-scalar : {S T U} (Scalar U) ((S T) ≮: U)
function-≮:-scalar s = witness function function (scalar-function s)
scalar-≮:-function : {S T U} (Scalar U) (U ≮: (S T))
scalar-≮:-function s = witness (scalar s) (scalar s) (function-scalar s)
any-≮:-scalar : {U} (Scalar U) (any ≮: U)
any-≮:-scalar s = witness (function-ok (scalar s)) any (scalar-function-ok s)
scalar-≮:-none : {U} (Scalar U) (U ≮: none)
scalar-≮:-none s = witness (scalar s) (scalar s) none
any-≮:-none : (any ≮: none)
any-≮:-none = witness (scalar nil) any none
function-≮:-none : {T U} ((T U) ≮: none)
function-≮:-none = witness function function none
scalar-≢-impl-≮: : {T U} (Scalar T) (Scalar U) (T U) (T ≮: U)
scalar-≢-impl-≮: s₁ s₂ p = witness (scalar s₁) (scalar s₁) (scalar-scalar s₁ s₂ p)
-- The rest of the proof just depends on those properties
≮:-trans-≡ : {S T U} (S ≮: T) (T U) (S ≮: U)
:-trans-≡ p refl = p
≡-trans-≮: : {S T U} (S T) (T ≮: U) (S ≮: U)
≡-trans-≮: refl p = p
heap-weakeningᴱ : Γ H M {H U} (H H) (typeOfᴱ H Γ M ≮: U) (typeOfᴱ H Γ M ≮: U)
heap-weakeningᴱ Γ H (var x) h p = p
heap-weakeningᴱ Γ H (val nil) h p = p
@ -283,7 +73,7 @@ heap-weakeningᴱ Γ H (val (addr a)) (snoc {a = b} q) p | no r = ≡-trans-≮:
heap-weakeningᴱ Γ H (val (number x)) h p = p
heap-weakeningᴱ Γ H (val (bool x)) h p = p
heap-weakeningᴱ Γ H (val (string x)) h p = p
heap-weakeningᴱ Γ H (M $ N) h p = src-tgt-≮: (heap-weakeningᴱ Γ H M h (tgt-src-≮: p))
heap-weakeningᴱ Γ H (M $ N) h p = none-tgt-≮: (heap-weakeningᴱ Γ H M h (tgt-none-≮: p))
heap-weakeningᴱ Γ H (function f var x T ⟩∈ U is B end) h p = p
heap-weakeningᴱ Γ H (block var b T is B end) h p = p
heap-weakeningᴱ Γ H (binexp M op N) h p = p
@ -304,7 +94,7 @@ substitutivityᴮ-unless-no : ∀ {Γ Γ′ T V} H B v x y (r : x ≢ y) → (Γ
substitutivityᴱ H (var y) v x p = substitutivityᴱ-whenever H v x y (x ≡ⱽ y) p
substitutivityᴱ H (val w) v x p = Left p
substitutivityᴱ H (binexp M op N) v x p = Left p
substitutivityᴱ H (M $ N) v x p = mapL src-tgt-≮: (substitutivityᴱ H M v x (tgt-src-≮: p))
substitutivityᴱ H (M $ N) v x p = mapL none-tgt-≮: (substitutivityᴱ H M v x (tgt-none-≮: p))
substitutivityᴱ H (function f var y T ⟩∈ U is B end) v x p = Left p
substitutivityᴱ H (block var b T is B end) v x p = Left p
substitutivityᴱ-whenever H v x x (yes refl) q = swapLR (≮:-antitrans q)
@ -335,8 +125,8 @@ binOpPreservation H (·· v w) = refl
reflect-subtypingᴱ : H M {H M T} (H M ⟶ᴱ M H) (typeOfᴱ H M ≮: T) Either (typeOfᴱ H M ≮: T) (Warningᴱ H (typeCheckᴱ H M))
reflect-subtypingᴮ : H B {H B T} (H B ⟶ᴮ B H) (typeOfᴮ H B ≮: T) Either (typeOfᴮ H B ≮: T) (Warningᴮ H (typeCheckᴮ H B))
reflect-subtypingᴱ H (M $ N) (app₁ s) p = mapLR src-tgt-≮: app₁ (reflect-subtypingᴱ H M s (tgt-src-≮: p))
reflect-subtypingᴱ H (M $ N) (app₂ v s) p = Left (src-tgt-≮: (heap-weakeningᴱ H M (rednᴱ⊑ s) (tgt-src-≮: p)))
reflect-subtypingᴱ H (M $ N) (app₁ s) p = mapLR none-tgt-≮: app₁ (reflect-subtypingᴱ H M s (tgt-none-≮: p))
reflect-subtypingᴱ H (M $ N) (app₂ v s) p = Left (none-tgt-≮: (heap-weakeningᴱ H M (rednᴱ⊑ s) (tgt-none-≮: p)))
reflect-subtypingᴱ H (M $ N) (beta (function f var y T ⟩∈ U is B end) v refl q) p = Left (≡-trans-≮: (cong tgt (cong orAny (cong typeOfᴹᴼ q))) p)
reflect-subtypingᴱ H (function f var x T ⟩∈ U is B end) (function a defn) p = Left p
reflect-subtypingᴱ H (block var b T is B end) (block s) p = Left p

View file

@ -0,0 +1,205 @@
{-# OPTIONS --rewriting #-}
module Properties.Subtyping where
open import Agda.Builtin.Equality using (_≡_; refl)
open import FFI.Data.Either using (Either; Left; Right; mapLR; swapLR; cond)
open import Luau.Subtyping using (_≮:_; Tree; Language; ¬Language; witness; any; none; scalar; function; scalar-function; scalar-function-ok; scalar-function-err; scalar-scalar; function-scalar; function-ok; function-err; left; right; _,_)
open import Luau.Type using (Type; Scalar; strict; nil; number; string; boolean; none; any; _⇒_; __; _∩_; tgt)
open import Properties.Contradiction using (CONTRADICTION; ¬)
open import Properties.Equality using (_≢_)
open import Properties.Functions using (_∘_)
src = Luau.Type.src strict
-- Language membership is decidable
dec-language : T t Either (¬Language T t) (Language T t)
dec-language nil (scalar number) = Left (scalar-scalar number nil (λ ()))
dec-language nil (scalar boolean) = Left (scalar-scalar boolean nil (λ ()))
dec-language nil (scalar string) = Left (scalar-scalar string nil (λ ()))
dec-language nil (scalar nil) = Right (scalar nil)
dec-language nil function = Left (scalar-function nil)
dec-language nil (function-ok t) = Left (scalar-function-ok nil)
dec-language nil (function-err t) = Right (scalar-function-err nil)
dec-language boolean (scalar number) = Left (scalar-scalar number boolean (λ ()))
dec-language boolean (scalar boolean) = Right (scalar boolean)
dec-language boolean (scalar string) = Left (scalar-scalar string boolean (λ ()))
dec-language boolean (scalar nil) = Left (scalar-scalar nil boolean (λ ()))
dec-language boolean function = Left (scalar-function boolean)
dec-language boolean (function-ok t) = Left (scalar-function-ok boolean)
dec-language boolean (function-err t) = Right (scalar-function-err boolean)
dec-language number (scalar number) = Right (scalar number)
dec-language number (scalar boolean) = Left (scalar-scalar boolean number (λ ()))
dec-language number (scalar string) = Left (scalar-scalar string number (λ ()))
dec-language number (scalar nil) = Left (scalar-scalar nil number (λ ()))
dec-language number function = Left (scalar-function number)
dec-language number (function-ok t) = Left (scalar-function-ok number)
dec-language number (function-err t) = Right (scalar-function-err number)
dec-language string (scalar number) = Left (scalar-scalar number string (λ ()))
dec-language string (scalar boolean) = Left (scalar-scalar boolean string (λ ()))
dec-language string (scalar string) = Right (scalar string)
dec-language string (scalar nil) = Left (scalar-scalar nil string (λ ()))
dec-language string function = Left (scalar-function string)
dec-language string (function-ok t) = Left (scalar-function-ok string)
dec-language string (function-err t) = Right (scalar-function-err string)
dec-language (T₁ T₂) (scalar s) = Left (function-scalar s)
dec-language (T₁ T₂) function = Right function
dec-language (T₁ T₂) (function-ok t) = mapLR function-ok function-ok (dec-language T₂ t)
dec-language (T₁ T₂) (function-err t) = mapLR function-err function-err (swapLR (dec-language T₁ t))
dec-language none t = Left none
dec-language any t = Right any
dec-language (T₁ T₂) t = cond (λ p cond (Left _,_ p) (Right right) (dec-language T₂ t)) (Right left) (dec-language T₁ t)
dec-language (T₁ T₂) t = cond (Left left) (λ p cond (Left right) (Right _,_ p) (dec-language T₂ t)) (dec-language T₁ t)
-- ≮: is anti-reflexive
≮:-antirefl : {T} ¬(T ≮: T)
:-antirefl (witness (scalar s) (scalar s) (scalar-scalar s t p)) = CONTRADICTION (p refl)
:-antirefl (witness function function (scalar-function ()))
:-antirefl (witness (function-ok t) (function-ok p) (function-ok q)) = ≮:-antirefl (witness t p q)
:-antirefl (witness (function-err t) (function-err p) (function-err q)) = ≮:-antirefl (witness t q p)
:-antirefl (witness t (left p) (q₁ , q₂)) = ≮:-antirefl (witness t p q₁)
:-antirefl (witness t (right p) (q₁ , q₂)) = ≮:-antirefl (witness t p q₂)
:-antirefl (witness t (p₁ , p₂) (left q)) = ≮:-antirefl (witness t p₁ q)
:-antirefl (witness t (p₁ , p₂) (right q)) = ≮:-antirefl (witness t p₂ q)
:-antirefl (witness (scalar s) any (scalar-scalar s () t))
:-antirefl (witness (function-ok t) any (scalar-function-ok ()))
:-antirefl (witness (function-err t) (scalar-function-err number) ())
:-antirefl (witness (function-err t) (scalar-function-err boolean) ())
:-antirefl (witness (function-err t) (scalar-function-err string) ())
:-antirefl (witness (function-err t) (scalar-function-err nil) ())
-- ≮: is anti-tramsitive
≮:-antitrans : {S T U} (S ≮: U) Either (S ≮: T) (T ≮: U)
:-antitrans {T = T} (witness t p q) = mapLR (witness t p) (λ z witness t z q) (dec-language T t)
≮:-trans-≡ : {S T U} (S ≮: T) (T U) (S ≮: U)
:-trans-≡ p refl = p
≡-trans-≮: : {S T U} (S T) (T ≮: U) (S ≮: U)
≡-trans-≮: refl p = p
any-≮: : {T U} (T ≮: U) (any ≮: U)
any-≮: (witness t p q) = witness t any q
none-≮: : {T U} (T ≮: U) (T ≮: none)
none-≮: (witness t p q) = witness t p none
skalar = number (string (nil boolean))
-- Properties of tgt
tgt-function-ok : {T t} (Language (tgt T) t) Language T (function-ok t)
tgt-function-ok {T = nil} (scalar ())
tgt-function-ok {T = T₁ T₂} p = function-ok p
tgt-function-ok {T = none} (scalar ())
tgt-function-ok {T = any} p = any
tgt-function-ok {T = boolean} (scalar ())
tgt-function-ok {T = number} (scalar ())
tgt-function-ok {T = string} (scalar ())
tgt-function-ok {T = T₁ T₂} (left p) = left (tgt-function-ok p)
tgt-function-ok {T = T₁ T₂} (right p) = right (tgt-function-ok p)
tgt-function-ok {T = T₁ T₂} (p₁ , p₂) = (tgt-function-ok p₁ , tgt-function-ok p₂)
function-ok-tgt : {T t} Language T (function-ok t) (Language (tgt T) t)
function-ok-tgt (function-ok p) = p
function-ok-tgt (left p) = left (function-ok-tgt p)
function-ok-tgt (right p) = right (function-ok-tgt p)
function-ok-tgt (p₁ , p₂) = (function-ok-tgt p₁ , function-ok-tgt p₂)
function-ok-tgt any = any
skalar-function-ok : {t} (¬Language skalar (function-ok t))
skalar-function-ok = (scalar-function-ok number , (scalar-function-ok string , (scalar-function-ok nil , scalar-function-ok boolean)))
skalar-scalar : {T} (s : Scalar T) (Language skalar (scalar s))
skalar-scalar number = left (scalar number)
skalar-scalar boolean = right (right (right (scalar boolean)))
skalar-scalar string = right (left (scalar string))
skalar-scalar nil = right (right (left (scalar nil)))
tgt-none-≮: : {T U} (tgt T ≮: U) (T ≮: (skalar (none U)))
tgt-none-≮: (witness t p q) = witness (function-ok t) (tgt-function-ok p) (skalar-function-ok , function-ok q)
none-tgt-≮: : {T U} (T ≮: (skalar (none U))) (tgt T ≮: U)
none-tgt-≮: (witness (scalar s) p (q₁ , q₂)) = CONTRADICTION (≮:-antirefl (witness (scalar s) (skalar-scalar s) q₁))
none-tgt-≮: (witness function p (q₁ , scalar-function ()))
none-tgt-≮: (witness (function-ok t) p (q₁ , function-ok q₂)) = witness t (function-ok-tgt p) q₂
none-tgt-≮: (witness (function-err (scalar s)) p (q₁ , function-err (scalar ())))
-- Properties of src
function-err-src : {T t} (¬Language (src T) t) Language T (function-err t)
function-err-src {T = nil} none = scalar-function-err nil
function-err-src {T = T₁ T₂} p = function-err p
function-err-src {T = none} (scalar-scalar number () p)
function-err-src {T = none} (scalar-function-ok ())
function-err-src {T = any} none = any
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 = T₁ T₂} (left p) = left (function-err-src p)
function-err-src {T = T₁ T₂} (right p) = right (function-err-src p)
function-err-src {T = T₁ T₂} (p₁ , p₂) = function-err-src p₁ , function-err-src p₂
¬function-err-src : {T t} (Language (src T) t) ¬Language T (function-err t)
¬function-err-src {T = nil} (scalar ())
¬function-err-src {T = T₁ T₂} p = function-err p
¬function-err-src {T = none} any = none
¬function-err-src {T = any} (scalar ())
¬function-err-src {T = boolean} (scalar ())
¬function-err-src {T = number} (scalar ())
¬function-err-src {T = string} (scalar ())
¬function-err-src {T = T₁ T₂} (p₁ , p₂) = (¬function-err-src p₁ , ¬function-err-src p₂)
¬function-err-src {T = T₁ T₂} (left p) = left (¬function-err-src p)
¬function-err-src {T = T₁ T₂} (right p) = right (¬function-err-src p)
src-¬function-err : {T t} Language T (function-err t) (¬Language (src T) t)
src-¬function-err {T = nil} p = none
src-¬function-err {T = T₁ T₂} (function-err p) = p
src-¬function-err {T = none} (scalar-function-err ())
src-¬function-err {T = any} p = none
src-¬function-err {T = boolean} p = none
src-¬function-err {T = number} p = none
src-¬function-err {T = string} p = none
src-¬function-err {T = T₁ T₂} (left p) = left (src-¬function-err p)
src-¬function-err {T = T₁ T₂} (right p) = right (src-¬function-err p)
src-¬function-err {T = T₁ T₂} (p₁ , p₂) = (src-¬function-err p₁ , src-¬function-err p₂)
src-¬scalar : {S T t} (s : Scalar S) Language T (scalar s) (¬Language (src T) t)
src-¬scalar number (scalar number) = none
src-¬scalar boolean (scalar boolean) = none
src-¬scalar string (scalar string) = none
src-¬scalar nil (scalar nil) = none
src-¬scalar s (left p) = left (src-¬scalar s p)
src-¬scalar s (right p) = right (src-¬scalar s p)
src-¬scalar s (p₁ , p₂) = (src-¬scalar s p₁ , src-¬scalar s p₂)
src-¬scalar s any = none
src-any-≮: : {T U} (T ≮: src U) (U ≮: (T any))
src-any-≮: (witness t p q) = witness (function-err t) (function-err-src q) (¬function-err-src p)
any-src-≮: : {S T U} (U ≮: S) (T ≮: (U any)) (U ≮: src T)
any-src-≮: (witness t x x₁) (witness (scalar s) p (function-scalar s)) = witness t x (src-¬scalar s p)
any-src-≮: r (witness (function-ok (scalar s)) p (function-ok (scalar-scalar s () q)))
any-src-≮: r (witness (function-ok (function-ok _)) p (function-ok (scalar-function-ok ())))
any-src-≮: r (witness (function-err t) p (function-err q)) = witness t q (src-¬function-err p)
-- Properties of scalars
function-≮:-scalar : {S T U} (Scalar U) ((S T) ≮: U)
function-≮:-scalar s = witness function function (scalar-function s)
scalar-≮:-function : {S T U} (Scalar U) (U ≮: (S T))
scalar-≮:-function s = witness (scalar s) (scalar s) (function-scalar s)
any-≮:-scalar : {U} (Scalar U) (any ≮: U)
any-≮:-scalar s = witness (function-ok (scalar s)) any (scalar-function-ok s)
scalar-≮:-none : {U} (Scalar U) (U ≮: none)
scalar-≮:-none s = witness (scalar s) (scalar s) none
scalar-≢-impl-≮: : {T U} (Scalar T) (Scalar U) (T U) (T ≮: U)
scalar-≢-impl-≮: s₁ s₂ p = witness (scalar s₁) (scalar s₁) (scalar-scalar s₁ s₂ p)
-- Properties of none
any-≮:-none : (any ≮: none)
any-≮:-none = witness (scalar nil) any none
function-≮:-none : {T U} ((T U) ≮: none)
function-≮:-none = witness function function none