// Copyright (c) Microsoft Corporation.  All Rights Reserved.  See License.txt in the project root for license information.

// Reflection on F# values. Analyze an object to see if it the representation
// of an F# value.

namespace Microsoft.FSharp.Reflection

open System
open System.Collections.Generic
open System.Reflection
open Microsoft.FSharp.Core
open Microsoft.FSharp.Core.Operators
open Microsoft.FSharp.Core.LanguagePrimitives.IntrinsicOperators
open Microsoft.FSharp.Collections
open Microsoft.FSharp.Primitives.Basics
open System.Linq.Expressions

module internal ReflectionUtils =

    type BindingFlags = System.Reflection.BindingFlags

    let toBindingFlags allowAccessToNonPublicMembers =
        if allowAccessToNonPublicMembers then
            BindingFlags.NonPublic ||| BindingFlags.Public
        else
            BindingFlags.Public

[<AutoOpen>]
module internal Impl =

    let getBindingFlags allowAccess =
        ReflectionUtils.toBindingFlags (defaultArg allowAccess false)

    let inline checkNonNull argName (v: 'T) =
        match box v with
        | null -> nullArg argName
        | _ -> ()

    let isNamedType (typ: Type) =
        not (typ.IsArray || typ.IsByRef || typ.IsPointer)

    let equivHeadTypes (ty1: Type) (ty2: Type) =
        isNamedType ty1
        && if ty1.IsGenericType then
               ty2.IsGenericType
               && Type.op_Equality (ty1.GetGenericTypeDefinition(), ty2.GetGenericTypeDefinition())
           else
               Type.op_Equality (ty1, ty2)

    let func = typedefof<(obj -> obj)>

    let isOptionType typ =
        equivHeadTypes typ (typeof<int option>)

    let isFunctionType typ =
        equivHeadTypes typ (typeof<(int -> int)>)

    let isListType typ =
        equivHeadTypes typ (typeof<int list>)

    //-----------------------------------------------------------------
    // GENERAL UTILITIES
    let instanceFieldFlags = BindingFlags.GetField ||| BindingFlags.Instance
    let instancePropertyFlags = BindingFlags.GetProperty ||| BindingFlags.Instance
    let staticPropertyFlags = BindingFlags.GetProperty ||| BindingFlags.Static
    let staticFieldFlags = BindingFlags.GetField ||| BindingFlags.Static
    let staticMethodFlags = BindingFlags.Static

    let getInstancePropertyInfo (typ: Type, propName, bindingFlags) =
        typ.GetProperty(propName, instancePropertyFlags ||| bindingFlags)

    let getInstancePropertyInfos (typ, names, bindingFlags) =
        names |> Array.map (fun nm -> getInstancePropertyInfo (typ, nm, bindingFlags))

    let getInstancePropertyReader (typ: Type, propName, bindingFlags) =
        match getInstancePropertyInfo (typ, propName, bindingFlags) with
        | null -> None
        | prop -> Some(fun (obj: obj) -> prop.GetValue(obj, instancePropertyFlags ||| bindingFlags, null, null, null))

    //-----------------------------------------------------------------
    // EXPRESSION TREE COMPILATION

    let compilePropGetterFunc (prop: PropertyInfo) =
        let param = Expression.Parameter(typeof<obj>, "param")

        let propExpr =
            Expression.Property(Expression.Convert(param, prop.DeclaringType), prop)

        let expr =
            Expression.Lambda<Func<obj, obj>>(Expression.Convert(propExpr, typeof<obj>), param)

        expr.Compile()

    let compileRecordOrUnionCaseReaderFunc (typ, props: PropertyInfo[]) =
        let param = Expression.Parameter(typeof<obj>, "param")
        let typedParam = Expression.Variable typ

        let expr =
            Expression.Lambda<Func<obj, obj[]>>(
                Expression.Block(
                    [ typedParam ],
                    Expression.Assign(typedParam, Expression.Convert(param, typ)),
                    Expression.NewArrayInit(
                        typeof<obj>,
                        [
                            for prop in props ->
                                Expression.Convert(Expression.Property(typedParam, prop), typeof<obj>) :> Expression
                        ]
                    )
                ),
                param
            )

        expr.Compile()

    let compileRecordConstructorFunc (ctorInfo: ConstructorInfo) =
        let ctorParams = ctorInfo.GetParameters()
        let paramArray = Expression.Parameter(typeof<obj[]>, "paramArray")

        let expr =
            Expression.Lambda<Func<obj[], obj>>(
                Expression.Convert(
                    Expression.New(
                        ctorInfo,
                        [
                            for paramIndex in 0 .. ctorParams.Length - 1 do
                                let p = ctorParams.[paramIndex]

                                let accessExpr = Expression.ArrayAccess(paramArray, Expression.Constant paramIndex)
                                Expression.Convert(accessExpr, p.ParameterType) :> Expression
                        ]
                    ),
                    typeof<obj>
                ),
                paramArray
            )

        expr.Compile()

    let compileUnionCaseConstructorFunc (methodInfo: MethodInfo) =
        let methodParams = methodInfo.GetParameters()
        let paramArray = Expression.Parameter(typeof<obj[]>, "param")

        let expr =
            Expression.Lambda<Func<obj[], obj>>(
                Expression.Convert(
                    Expression.Call(
                        methodInfo,
                        [
                            for paramIndex in 0 .. methodParams.Length - 1 do
                                let p = methodParams.[paramIndex]

                                let accessExpr = Expression.ArrayAccess(paramArray, Expression.Constant paramIndex)
                                Expression.Convert(accessExpr, p.ParameterType) :> Expression
                        ]
                    ),
                    typeof<obj>
                ),
                paramArray
            )

        expr.Compile()

    let compileUnionTagReaderFunc (info: Choice<MethodInfo, PropertyInfo>) =
        let param = Expression.Parameter(typeof<obj>, "param")

        let tag =
            match info with
            | Choice1Of2 info -> Expression.Call(info, Expression.Convert(param, info.DeclaringType)) :> Expression
            | Choice2Of2 info -> Expression.Property(Expression.Convert(param, info.DeclaringType), info) :> _

        let expr = Expression.Lambda<Func<obj, int>>(tag, param)
        expr.Compile()

    let compileTupleConstructor tupleEncField getTupleConstructorMethod typ =
        let rec constituentTuple (typ: Type) elements startIndex =
            Expression.New(
                getTupleConstructorMethod typ,
                [
                    let genericArgs = typ.GetGenericArguments()

                    for paramIndex in 0 .. genericArgs.Length - 1 do
                        let genericArg = genericArgs.[paramIndex]

                        if paramIndex = tupleEncField then
                            constituentTuple genericArg elements (startIndex + paramIndex) :> Expression
                        else
                            Expression.Convert(
                                Expression.ArrayAccess(elements, Expression.Constant(startIndex + paramIndex)),
                                genericArg
                            )
                ]
            )

        let elements = Expression.Parameter(typeof<obj[]>, "elements")

        let expr =
            Expression.Lambda<Func<obj[], obj>>(
                Expression.Convert(constituentTuple typ elements 0, typeof<obj>),
                elements
            )

        expr.Compile()

    let compileTupleReader tupleEncField getTupleElementAccessors typ =
        let rec writeTupleIntoArray (typ: Type) (tuple: Expression) outputArray startIndex =
            seq {
                let elements =
                    match getTupleElementAccessors typ with
                    // typ is a struct tuple and its elements are accessed via fields
                    | Choice1Of2 (fi: FieldInfo[]) ->
                        fi |> Array.map (fun fi -> Expression.Field(tuple, fi), fi.FieldType)
                    // typ is a class tuple and its elements are accessed via properties
                    | Choice2Of2 (pi: PropertyInfo[]) ->
                        pi |> Array.map (fun pi -> Expression.Property(tuple, pi), pi.PropertyType)

                for index, (element, elementType) in elements |> Array.indexed do
                    if index = tupleEncField then
                        let innerTupleParam = Expression.Parameter(elementType, "innerTuple")

                        Expression.Block(
                            [ innerTupleParam ],
                            [
                                yield Expression.Assign(innerTupleParam, element) :> Expression
                                yield! writeTupleIntoArray elementType innerTupleParam outputArray (startIndex + index)
                            ]
                        )
                        :> Expression
                    else
                        Expression.Assign(
                            Expression.ArrayAccess(outputArray, Expression.Constant(index + startIndex)),
                            Expression.Convert(element, typeof<obj>)
                        )
                        :> Expression
            }

        let param = Expression.Parameter(typeof<obj>, "outerTuple")
        let outputArray = Expression.Variable(typeof<obj[]>, "output")

        let rec outputLength tupleEncField (typ: Type) =
            let genericArgs = typ.GetGenericArguments()

            if genericArgs.Length > tupleEncField then
                tupleEncField + outputLength tupleEncField genericArgs.[genericArgs.Length - 1]
            else
                genericArgs.Length

        let expr =
            Expression.Lambda<Func<obj, obj[]>>(
                Expression.Block(
                    [ outputArray ],
                    [
                        let arrayBounds =
                            Expression.NewArrayBounds(typeof<obj>, Expression.Constant(outputLength tupleEncField typ))

                        Expression.Assign(outputArray, arrayBounds) :> Expression
                        yield! writeTupleIntoArray typ (Expression.Convert(param, typ)) outputArray 0
                        outputArray :> Expression
                    ]
                ),
                param
            )

        expr.Compile()

    //-----------------------------------------------------------------
    // ATTRIBUTE DECOMPILATION

    let tryFindCompilationMappingAttribute (attrs: obj[]) =
        match attrs with
        | null
        | [||] -> None
        | [| res |] ->
            let a = (res :?> CompilationMappingAttribute)
            Some(a.SourceConstructFlags, a.SequenceNumber, a.VariantNumber)
        | _ -> invalidOp (SR.GetString(SR.multipleCompilationMappings))

    let findCompilationMappingAttribute (attrs: obj[]) =
        match tryFindCompilationMappingAttribute attrs with
        | None -> failwith "no compilation mapping attribute"
        | Some a -> a

    let cmaName = typeof<CompilationMappingAttribute>.FullName
    let assemblyName = typeof<CompilationMappingAttribute>.Assembly.GetName().Name
    let _ = assert (assemblyName = "FSharp.Core")

    let tryFindCompilationMappingAttributeFromData (attrs: IList<CustomAttributeData>) =
        match attrs with
        | null -> None
        | _ ->
            let mutable res = None

            for a in attrs do
                if a.Constructor.DeclaringType.FullName = cmaName then
                    let args = a.ConstructorArguments

                    let flags =
                        match args.Count with
                        | 1 ->
                            let arg0 = args.[0]
                            let v0 = arg0.Value :?> SourceConstructFlags
                            (v0, 0, 0)
                        | 2 ->
                            let arg0 = args.[0]
                            let v0 = arg0.Value :?> SourceConstructFlags
                            let arg1 = args.[1]
                            let v1 = arg1.Value :?> int
                            (v0, v1, 0)
                        | 3 ->
                            let arg0 = args.[0]
                            let v0 = arg0.Value :?> SourceConstructFlags
                            let arg1 = args.[1]
                            let v1 = arg1.Value :?> int
                            let arg2 = args.[2]
                            let v2 = arg2.Value :?> int
                            (v0, v1, v2)
                        | _ -> (enum 0, 0, 0)

                    res <- Some flags

            res

    let findCompilationMappingAttributeFromData attrs =
        match tryFindCompilationMappingAttributeFromData attrs with
        | None -> failwith "no compilation mapping attribute"
        | Some a -> a

    let tryFindCompilationMappingAttributeFromType (typ: Type) =
        let assem = typ.Assembly

        if (not (isNull assem)) && assem.ReflectionOnly then
            tryFindCompilationMappingAttributeFromData (typ.GetCustomAttributesData())
        else
            tryFindCompilationMappingAttribute (typ.GetCustomAttributes(typeof<CompilationMappingAttribute>, false))

    let tryFindCompilationMappingAttributeFromMemberInfo (info: MemberInfo) =
        let assem = info.DeclaringType.Assembly

        if (not (isNull assem)) && assem.ReflectionOnly then
            tryFindCompilationMappingAttributeFromData (info.GetCustomAttributesData())
        else
            tryFindCompilationMappingAttribute (info.GetCustomAttributes(typeof<CompilationMappingAttribute>, false))

    let findCompilationMappingAttributeFromMemberInfo (info: MemberInfo) =
        let assem = info.DeclaringType.Assembly

        if (not (isNull assem)) && assem.ReflectionOnly then
            findCompilationMappingAttributeFromData (info.GetCustomAttributesData())
        else
            findCompilationMappingAttribute (info.GetCustomAttributes(typeof<CompilationMappingAttribute>, false))

    let sequenceNumberOfMember (x: MemberInfo) =
        let (_, n, _) = findCompilationMappingAttributeFromMemberInfo x in n

    let variantNumberOfMember (x: MemberInfo) =
        let (_, _, vn) = findCompilationMappingAttributeFromMemberInfo x in vn

    let sortFreshArray f arr =
        Array.sortInPlaceWith f arr
        arr

    let isFieldProperty (prop: PropertyInfo) =
        match tryFindCompilationMappingAttributeFromMemberInfo prop with
        | None -> false
        | Some (flags, _n, _vn) -> (flags &&& SourceConstructFlags.KindMask) = SourceConstructFlags.Field

    let tryFindSourceConstructFlagsOfType (typ: Type) =
        match tryFindCompilationMappingAttributeFromType typ with
        | None -> None
        | Some (flags, _n, _vn) -> Some flags

    //-----------------------------------------------------------------
    // UNION DECOMPILATION

    // Get the type where the type definitions are stored
    let getUnionCasesTyp (typ: Type, _bindingFlags) =
#if CASES_IN_NESTED_CLASS
        let casesTyp = typ.GetNestedType("Cases", bindingFlags)

        if casesTyp.IsGenericTypeDefinition then
            casesTyp.MakeGenericType(typ.GetGenericArguments())
        else
            casesTyp
#else
        typ
#endif

    let getUnionTypeTagNameMap (typ: Type, bindingFlags) =
        let enumTyp = typ.GetNestedType("Tags", bindingFlags)
        // Unions with a singleton case do not get a Tags type (since there is only one tag), hence enumTyp may be null in this case
        match enumTyp with
        | null ->
            typ.GetMethods(staticMethodFlags ||| bindingFlags)
            |> Array.choose (fun minfo ->
                match tryFindCompilationMappingAttributeFromMemberInfo minfo with
                | None -> None
                | Some (flags, n, _vn) ->
                    if (flags &&& SourceConstructFlags.KindMask) = SourceConstructFlags.UnionCase then
                        let nm = minfo.Name
                        // chop "get_" or  "New" off the front
                        let nm =
                            if not (isListType typ) && not (isOptionType typ) && nm.Length > 3 then
                                if nm.StartsWith("get_", StringComparison.Ordinal) then
                                    nm.[4..]
                                elif nm.StartsWith("New", StringComparison.Ordinal) then
                                    nm.[3..]
                                else
                                    nm
                            else
                                nm

                        Some(n, nm)
                    else
                        None)
        | _ ->
            enumTyp.GetFields(staticFieldFlags ||| bindingFlags)
            |> Array.filter (fun (f: FieldInfo) -> f.IsStatic && f.IsLiteral)
            |> sortFreshArray (fun f1 f2 -> compare (f1.GetValue null :?> int) (f2.GetValue null :?> int))
            |> Array.map (fun tagfield -> (tagfield.GetValue null :?> int), tagfield.Name)

    let getUnionCaseTyp (typ: Type, tag: int, bindingFlags) =
        let tagFields = getUnionTypeTagNameMap (typ, bindingFlags)

        let tagField =
            tagFields |> Array.pick (fun (i, f) -> if i = tag then Some f else None)

        if tagFields.Length = 1 then
            typ
        else
            // special case: two-cased DU annotated with CompilationRepresentation(UseNullAsTrueValue)
            // in this case it will be compiled as one class: return self type for non-nullary case and null for nullary
            let isTwoCasedDU =
                if tagFields.Length = 2 then
                    match typ.GetCustomAttributes(typeof<CompilationRepresentationAttribute>, false) with
                    | [| :? CompilationRepresentationAttribute as attr |] ->
                        (attr.Flags &&& CompilationRepresentationFlags.UseNullAsTrueValue) = CompilationRepresentationFlags.UseNullAsTrueValue
                    | _ -> false
                else
                    false

            if isTwoCasedDU then
                typ
            else
                let casesTyp = getUnionCasesTyp (typ, bindingFlags)
                let caseTyp = casesTyp.GetNestedType(tagField, bindingFlags) // if this is null then the union is nullary

                match caseTyp with
                | null -> null
                | _ when caseTyp.IsGenericTypeDefinition -> caseTyp.MakeGenericType(casesTyp.GetGenericArguments())
                | _ -> caseTyp

    let getUnionTagConverter (typ: Type, bindingFlags) =
        if isOptionType typ then
            (fun tag ->
                match tag with
                | 0 -> "None"
                | 1 -> "Some"
                | _ -> invalidArg "tag" (SR.GetString(SR.outOfRange)))
        elif isListType typ then
            (fun tag ->
                match tag with
                | 0 -> "Empty"
                | 1 -> "Cons"
                | _ -> invalidArg "tag" (SR.GetString(SR.outOfRange)))
        else
            let tagfieldmap = getUnionTypeTagNameMap (typ, bindingFlags) |> Map.ofSeq
            (fun tag -> tagfieldmap.[tag])

    let isUnionType (typ: Type, bindingFlags: BindingFlags) =
        isOptionType typ
        || isListType typ
        || match tryFindSourceConstructFlagsOfType typ with
           | None -> false
           | Some flags ->
               (flags &&& SourceConstructFlags.KindMask) = SourceConstructFlags.SumType
               &&
               // We see private representations only if BindingFlags.NonPublic is set
               (if (flags &&& SourceConstructFlags.NonPublicRepresentation) <> enum 0 then
                    (bindingFlags &&& BindingFlags.NonPublic) <> enum 0
                else
                    true)

    // Check the base type - if it is also an F# type then
    // for the moment we know it is a Discriminated Union
    let isConstructorRepr (typ, bindingFlags) =
        let rec get typ =
            isUnionType (typ, bindingFlags)
            || match typ.BaseType with
               | null -> false
               | b -> get b

        get typ

    let unionTypeOfUnionCaseType (typ, bindingFlags) =
        let rec get typ =
            if isUnionType (typ, bindingFlags) then
                typ
            else
                match typ.BaseType with
                | null -> typ
                | b -> get b

        get typ

    let fieldsPropsOfUnionCase (typ, tag, bindingFlags) =
        if isOptionType typ then
            match tag with
            | 0 (* None *)  -> getInstancePropertyInfos (typ, [||], bindingFlags)
            | 1 (* Some *)  -> getInstancePropertyInfos (typ, [| "Value" |], bindingFlags)
            | _ -> failwith "fieldsPropsOfUnionCase"
        elif isListType typ then
            match tag with
            | 0 (* Nil *)  -> getInstancePropertyInfos (typ, [||], bindingFlags)
            | 1 (* Cons *)  -> getInstancePropertyInfos (typ, [| "Head"; "Tail" |], bindingFlags)
            | _ -> failwith "fieldsPropsOfUnionCase"
        else
            // Lookup the type holding the fields for the union case
            let caseTyp = getUnionCaseTyp (typ, tag, bindingFlags)

            let caseTyp =
                match caseTyp with
                | null -> typ
                | _ -> caseTyp

            caseTyp.GetProperties(instancePropertyFlags ||| bindingFlags)
            |> Array.filter isFieldProperty
            |> Array.filter (fun prop -> variantNumberOfMember prop = tag)
            |> sortFreshArray (fun p1 p2 -> compare (sequenceNumberOfMember p1) (sequenceNumberOfMember p2))

    let getUnionCaseRecordReader (typ: Type, tag: int, bindingFlags) =
        let props = fieldsPropsOfUnionCase (typ, tag, bindingFlags)

        (fun (obj: obj) ->
            props
            |> Array.map (fun prop -> prop.GetValue(obj, bindingFlags, null, null, null)))

    let getUnionCaseRecordReaderCompiled (typ: Type, tag: int, bindingFlags) =
        let props = fieldsPropsOfUnionCase (typ, tag, bindingFlags)
        let caseTyp = getUnionCaseTyp (typ, tag, bindingFlags)
        let caseTyp = if isNull caseTyp then typ else caseTyp
        compileRecordOrUnionCaseReaderFunc(caseTyp, props).Invoke

    let getUnionTagReader (typ: Type, bindingFlags) : (obj -> int) =
        if isOptionType typ then
            (fun (obj: obj) ->
                match obj with
                | null -> 0
                | _ -> 1)
        else
            let tagMap = getUnionTypeTagNameMap (typ, bindingFlags)

            if tagMap.Length <= 1 then
                (fun (_obj: obj) -> 0)
            else
                match getInstancePropertyReader (typ, "Tag", bindingFlags) with
                | Some reader -> (fun (obj: obj) -> reader obj :?> int)
                | None ->
                    let m2b =
                        typ.GetMethod("GetTag", BindingFlags.Static ||| bindingFlags, null, [| typ |], null)

                    (fun (obj: obj) -> m2b.Invoke(null, [| obj |]) :?> int)

    let getUnionTagReaderCompiled (typ: Type, bindingFlags) : (obj -> int) =
        if isOptionType typ then
            (fun (obj: obj) ->
                match obj with
                | null -> 0
                | _ -> 1)
        else
            let tagMap = getUnionTypeTagNameMap (typ, bindingFlags)

            if tagMap.Length <= 1 then
                (fun (_obj: obj) -> 0)
            else
                match getInstancePropertyInfo (typ, "Tag", bindingFlags) with
                | null ->
                    let m2b =
                        typ.GetMethod("GetTag", BindingFlags.Static ||| bindingFlags, null, [| typ |], null)

                    compileUnionTagReaderFunc(Choice1Of2 m2b).Invoke
                | info -> compileUnionTagReaderFunc(Choice2Of2 info).Invoke

    let getUnionTagMemberInfo (typ: Type, bindingFlags) =
        match getInstancePropertyInfo (typ, "Tag", bindingFlags) with
        | null -> (typ.GetMethod("GetTag", BindingFlags.Static ||| bindingFlags) :> MemberInfo)
        | info -> (info :> MemberInfo)

    let isUnionCaseNullary (typ: Type, tag: int, bindingFlags) =
        fieldsPropsOfUnionCase(typ, tag, bindingFlags).Length = 0

    let getUnionCaseConstructorMethod (typ: Type, tag: int, bindingFlags) =
        let constrname = getUnionTagConverter (typ, bindingFlags) tag

        let methname =
            if isUnionCaseNullary (typ, tag, bindingFlags) then
                "get_" + constrname
            elif isListType typ || isOptionType typ then
                constrname
            else
                "New" + constrname

        match typ.GetMethod(methname, BindingFlags.Static ||| bindingFlags) with
        | null ->
            let msg = String.Format(SR.GetString(SR.constructorForUnionCaseNotFound), methname)
            invalidOp msg
        | meth -> meth

    let getUnionCaseConstructor (typ: Type, tag: int, bindingFlags) =
        let meth = getUnionCaseConstructorMethod (typ, tag, bindingFlags)

        (fun args ->
            meth.Invoke(null, BindingFlags.Static ||| BindingFlags.InvokeMethod ||| bindingFlags, null, args, null))

    let getUnionCaseConstructorCompiled (typ: Type, tag: int, bindingFlags) =
        let meth = getUnionCaseConstructorMethod (typ, tag, bindingFlags)
        compileUnionCaseConstructorFunc(meth).Invoke

    let checkUnionType (unionType, bindingFlags) =
        checkNonNull "unionType" unionType

        if not (isUnionType (unionType, bindingFlags)) then
            if isUnionType (unionType, bindingFlags ||| BindingFlags.NonPublic) then
                let msg = String.Format(SR.GetString(SR.privateUnionType), unionType.FullName)
                invalidArg "unionType" msg
            else
                let msg = String.Format(SR.GetString(SR.notAUnionType), unionType.FullName)
                invalidArg "unionType" msg

    //-----------------------------------------------------------------
    // TUPLE DECOMPILATION

    let simpleTupleNames =
        [|
            "Tuple`1"
            "Tuple`2"
            "Tuple`3"
            "Tuple`4"
            "Tuple`5"
            "Tuple`6"
            "Tuple`7"
            "Tuple`8"
            "ValueTuple`1"
            "ValueTuple`2"
            "ValueTuple`3"
            "ValueTuple`4"
            "ValueTuple`5"
            "ValueTuple`6"
            "ValueTuple`7"
            "ValueTuple`8"
        |]

    let isTupleType (typ: Type) =
        // We need to be careful that we only rely typ.IsGenericType, typ.Namespace and typ.Name here.
        //
        // Historically the FSharp.Core reflection utilities get used on implementations of
        // System.Type that don't have functionality such as .IsEnum and .FullName fully implemented.
        // This happens particularly over TypeBuilderInstantiation types in the ProvideTypes implementation of System.Type
        // used in F# type providers.
        typ.IsGenericType
        && typ.Namespace = "System"
        && simpleTupleNames |> Array.exists typ.Name.StartsWith

    let maxTuple = 8
    // Which field holds the nested tuple?
    let tupleEncField = maxTuple - 1

    module internal TupleFromSpecifiedAssembly =
        let private tupleNames =
            [|
                "System.Tuple`1"
                "System.Tuple`2"
                "System.Tuple`3"
                "System.Tuple`4"
                "System.Tuple`5"
                "System.Tuple`6"
                "System.Tuple`7"
                "System.Tuple`8"
                "System.Tuple"
                "System.ValueTuple`1"
                "System.ValueTuple`2"
                "System.ValueTuple`3"
                "System.ValueTuple`4"
                "System.ValueTuple`5"
                "System.ValueTuple`6"
                "System.ValueTuple`7"
                "System.ValueTuple`8"
                "System.ValueTuple"
            |]

        let private dictionaryLock = obj ()
        let private refTupleTypes = Dictionary<Assembly, Type[]>()
        let private valueTupleTypes = Dictionary<Assembly, Type[]>()

        let rec mkTupleType isStruct (asm: Assembly) (tys: Type[]) =
            let table =
                let makeIt n =
                    let tupleFullName n =
                        let structOffset = if isStruct then 9 else 0
                        let index = n - 1 + structOffset
                        tupleNames.[index]

                    match n with
                    | 1 -> asm.GetType(tupleFullName 1)
                    | 2 -> asm.GetType(tupleFullName 2)
                    | 3 -> asm.GetType(tupleFullName 3)
                    | 4 -> asm.GetType(tupleFullName 4)
                    | 5 -> asm.GetType(tupleFullName 5)
                    | 6 -> asm.GetType(tupleFullName 6)
                    | 7 -> asm.GetType(tupleFullName 7)
                    | 8 -> asm.GetType(tupleFullName 8)
                    | _ -> invalidArg "tys" (SR.GetString(SR.invalidTupleTypes))

                let tables =
                    if isStruct then
                        valueTupleTypes
                    else
                        refTupleTypes

                match lock dictionaryLock (fun () -> tables.TryGetValue asm) with
                | false, _ ->
                    // the Dictionary<>s here could be ConcurrentDictionary<>'s, but then
                    // that would lock while initializing the Type array (maybe not an issue)
                    let mutable a = Array.init<Type> 8 (fun i -> makeIt (i + 1))

                    lock dictionaryLock (fun () ->
                        match tables.TryGetValue asm with
                        | true, t -> a <- t
                        | false, _ -> tables.Add(asm, a))

                    a
                | true, t -> t

            match tys.Length with
            | 1 -> table.[0].MakeGenericType tys
            | 2 -> table.[1].MakeGenericType tys
            | 3 -> table.[2].MakeGenericType tys
            | 4 -> table.[3].MakeGenericType tys
            | 5 -> table.[4].MakeGenericType tys
            | 6 -> table.[5].MakeGenericType tys
            | 7 -> table.[6].MakeGenericType tys
            | n when n >= maxTuple ->
                let tysA = tys.[0 .. tupleEncField - 1]
                let tysB = tys.[maxTuple - 1 ..]
                let tyB = mkTupleType isStruct asm tysB
                table.[7].MakeGenericType(Array.append tysA [| tyB |])
            | _ -> invalidArg "tys" (SR.GetString(SR.invalidTupleTypes))

    let refTupleTypesNetStandard =
        [|
            typedefof<System.Tuple<_>>
            typedefof<System.Tuple<_, _>>
            typedefof<System.Tuple<_, _, _>>
            typedefof<System.Tuple<_, _, _, _>>
            typedefof<System.Tuple<_, _, _, _, _>>
            typedefof<System.Tuple<_, _, _, _, _, _>>
            typedefof<System.Tuple<_, _, _, _, _, _, _>>
            typedefof<System.Tuple<_, _, _, _, _, _, _, _>>
        |]

    let structTupleTypesNetStandard =
        [|
            typedefof<System.ValueTuple<_>>
            typedefof<System.ValueTuple<_, _>>
            typedefof<System.ValueTuple<_, _, _>>
            typedefof<System.ValueTuple<_, _, _, _>>
            typedefof<System.ValueTuple<_, _, _, _, _>>
            typedefof<System.ValueTuple<_, _, _, _, _, _>>
            typedefof<System.ValueTuple<_, _, _, _, _, _, _>>
            typedefof<System.ValueTuple<_, _, _, _, _, _, _, _>>
        |]

    /// Index of the recursively-nested Tuple type within the table of types
    [<Literal>]
    let nestedTupIndex = 7

    /// Index of the last regular (non-nested) tuple type within the table of types
    [<Literal>]
    let lastRegularTupIndex = 6 //nestedTupIndex - 1 (wait for arithmetic in constants)

    let rec mkTupleTypeNetStandard (tupTyTbl: Type[]) (tys: Type[]) =
        let tblIdx = tys.Length - 1
        assert (tblIdx >= 0)
        assert (nestedTupIndex = tupTyTbl.Length - 1)

        match tblIdx with
        | idx when idx < nestedTupIndex -> tupTyTbl[ idx ].MakeGenericType tys
        | _ ->
            let tysA = tys.[0..lastRegularTupIndex]
            let tysB = tys.[nestedTupIndex..]
            let tyB = mkTupleTypeNetStandard tupTyTbl tysB
            tupTyTbl.[nestedTupIndex].MakeGenericType([| yield! tysA; yield tyB |])

    let rec getTupleTypeInfo (typ: Type) =
        if not (isTupleType typ) then
            let msg = String.Format(SR.GetString(SR.notATupleType), typ.FullName)
            invalidArg "typ" msg

        let tyargs = typ.GetGenericArguments()

        if tyargs.Length = maxTuple then
            let tysA = tyargs.[0 .. tupleEncField - 1]
            let tyB = tyargs.[tupleEncField]
            Array.append tysA (getTupleTypeInfo tyB)
        else
            tyargs

    let orderTupleProperties (props: PropertyInfo[]) =
        // The PropertyInfo[] may not come back in order, so ensure ordering here.
        props |> Array.sortBy (fun p -> p.Name) // alphabetic works because there is max. 8 of them

    let orderTupleFields (fields: FieldInfo[]) =
        // The FieldInfo[] may not come back in order, so ensure ordering here.
        fields |> Array.sortBy (fun fi -> fi.Name) // alphabetic works because there is max. 8 of them

    let getTupleConstructorMethod (typ: Type) =
        let ctor =
            if typ.IsValueType then
                let fields =
                    typ.GetFields(instanceFieldFlags ||| BindingFlags.Public) |> orderTupleFields

                typ.GetConstructor(
                    BindingFlags.Public ||| BindingFlags.Instance,
                    null,
                    fields |> Array.map (fun fi -> fi.FieldType),
                    null
                )
            else
                let props = typ.GetProperties() |> orderTupleProperties

                typ.GetConstructor(
                    BindingFlags.Public ||| BindingFlags.Instance,
                    null,
                    props |> Array.map (fun p -> p.PropertyType),
                    null
                )

        match ctor with
        | null ->
            let msg = String.Format(SR.GetString(SR.invalidTupleTypeConstructorNotDefined))
            raise (ArgumentException(msg, typ.FullName))
        | _ -> ()

        ctor

    let getTupleCtor (typ: Type) =
        let ctor = getTupleConstructorMethod typ

        (fun (args: obj[]) ->
            ctor.Invoke(BindingFlags.InvokeMethod ||| BindingFlags.Instance ||| BindingFlags.Public, null, args, null))

    let getTupleElementAccessors (typ: Type) =
        if typ.IsValueType then
            Choice1Of2(typ.GetFields(instanceFieldFlags ||| BindingFlags.Public) |> orderTupleFields)
        else
            Choice2Of2(
                typ.GetProperties(instancePropertyFlags ||| BindingFlags.Public)
                |> orderTupleProperties
            )

    let rec getTupleReader (typ: Type) =
        let etys = typ.GetGenericArguments()
        // Get the reader for the outer tuple record
        let reader =
            match getTupleElementAccessors typ with
            | Choice1Of2 fi -> fun obj -> fi |> Array.map (fun f -> f.GetValue obj)
            | Choice2Of2 pi -> fun obj -> pi |> Array.map (fun p -> p.GetValue(obj, null))

        if etys.Length < maxTuple then
            reader
        else
            let tyBenc = etys.[tupleEncField]
            let reader2 = getTupleReader tyBenc

            (fun obj ->
                let directVals = reader obj
                let encVals = reader2 directVals.[tupleEncField]
                Array.append directVals.[0 .. tupleEncField - 1] encVals)

    let rec getTupleConstructor (typ: Type) =
        let etys = typ.GetGenericArguments()
        let maker1 = getTupleCtor typ

        if etys.Length < maxTuple then
            maker1
        else
            let tyBenc = etys.[tupleEncField]
            let maker2 = getTupleConstructor tyBenc

            (fun (args: obj[]) ->
                let encVal = maker2 args.[tupleEncField..]
                maker1 (Array.append args.[0 .. tupleEncField - 1] [| encVal |]))

    let getTupleConstructorInfo (typ: Type) =
        let etys = typ.GetGenericArguments()
        let maker1 = getTupleConstructorMethod typ

        if etys.Length < maxTuple then
            maker1, None
        else
            maker1, Some(etys.[tupleEncField])

    let getTupleReaderInfo (typ: Type, index: int) =
        if index < 0 then
            let msg =
                String.Format(SR.GetString(SR.tupleIndexOutOfRange), typ.FullName, index.ToString())

            invalidArg "index" msg

        let get index =
            if typ.IsValueType then
                let props =
                    typ.GetProperties(instancePropertyFlags ||| BindingFlags.Public)
                    |> orderTupleProperties

                if index >= props.Length then
                    let msg =
                        String.Format(SR.GetString(SR.tupleIndexOutOfRange), typ.FullName, index.ToString())

                    invalidArg "index" msg

                props.[index]
            else
                let props =
                    typ.GetProperties(instancePropertyFlags ||| BindingFlags.Public)
                    |> orderTupleProperties

                if index >= props.Length then
                    let msg =
                        String.Format(SR.GetString(SR.tupleIndexOutOfRange), typ.FullName, index.ToString())

                    invalidArg "index" msg

                props.[index]

        if index < tupleEncField then
            get index, None
        else
            let etys = typ.GetGenericArguments()
            get tupleEncField, Some(etys.[tupleEncField], index - (maxTuple - 1))

    let getFunctionTypeInfo (typ: Type) =
        if not (isFunctionType typ) then
            invalidArg "typ" (String.Format(SR.GetString(SR.notAFunctionType), typ.FullName))

        let tyargs = typ.GetGenericArguments()
        tyargs.[0], tyargs.[1]

    let isModuleType (typ: Type) =
        match tryFindSourceConstructFlagsOfType typ with
        | None -> false
        | Some flags -> (flags &&& SourceConstructFlags.KindMask) = SourceConstructFlags.Module

    let rec isClosureRepr typ =
        isFunctionType typ
        || (match typ.BaseType with
            | null -> false
            | bty -> isClosureRepr bty)

    let isRecordType (typ: Type, bindingFlags: BindingFlags) =
        match tryFindSourceConstructFlagsOfType typ with
        | None -> false
        | Some flags ->
            (flags &&& SourceConstructFlags.KindMask) = SourceConstructFlags.RecordType
            &&
            // We see private representations only if BindingFlags.NonPublic is set
            (if (flags &&& SourceConstructFlags.NonPublicRepresentation) <> enum 0 then
                 (bindingFlags &&& BindingFlags.NonPublic) <> enum 0
             else
                 true)

    let fieldPropsOfRecordType (typ: Type, bindingFlags) =
        typ.GetProperties(instancePropertyFlags ||| bindingFlags)
        |> Array.filter isFieldProperty
        |> sortFreshArray (fun p1 p2 -> compare (sequenceNumberOfMember p1) (sequenceNumberOfMember p2))

    let getRecordReader (typ: Type, bindingFlags) =
        let props = fieldPropsOfRecordType (typ, bindingFlags)
        (fun (obj: obj) -> props |> Array.map (fun prop -> prop.GetValue(obj, null)))

    let getRecordReaderCompiled (typ: Type, bindingFlags) =
        let props = fieldPropsOfRecordType (typ, bindingFlags)
        compileRecordOrUnionCaseReaderFunc(typ, props).Invoke

    let getRecordConstructorMethod (typ: Type, bindingFlags) =
        let props = fieldPropsOfRecordType (typ, bindingFlags)

        let ctor =
            typ.GetConstructor(
                BindingFlags.Instance ||| bindingFlags,
                null,
                props |> Array.map (fun p -> p.PropertyType),
                null
            )

        match ctor with
        | null ->
            let msg =
                String.Format(SR.GetString(SR.invalidRecordTypeConstructorNotDefined), typ.FullName)

            raise (ArgumentException(msg))
        | _ -> ()

        ctor

    let getRecordConstructor (typ: Type, bindingFlags) =
        let ctor = getRecordConstructorMethod (typ, bindingFlags)

        (fun (args: obj[]) ->
            ctor.Invoke(BindingFlags.InvokeMethod ||| BindingFlags.Instance ||| bindingFlags, null, args, null))

    let getRecordConstructorCompiled (typ: Type, bindingFlags) =
        let ctor = getRecordConstructorMethod (typ, bindingFlags)
        compileRecordConstructorFunc(ctor).Invoke

    /// EXCEPTION DECOMPILATION
    // Check the base type - if it is also an F# type then
    // for the moment we know it is a Discriminated Union
    let isExceptionRepr (typ: Type, bindingFlags) =
        match tryFindSourceConstructFlagsOfType typ with
        | None -> false
        | Some flags ->
            ((flags &&& SourceConstructFlags.KindMask) = SourceConstructFlags.Exception)
            &&
            // We see private representations only if BindingFlags.NonPublic is set
            (if (flags &&& SourceConstructFlags.NonPublicRepresentation) <> enum 0 then
                 (bindingFlags &&& BindingFlags.NonPublic) <> enum 0
             else
                 true)

    let getTypeOfReprType (typ: Type, bindingFlags) =
        if isExceptionRepr (typ, bindingFlags) then
            typ.BaseType
        elif isConstructorRepr (typ, bindingFlags) then
            unionTypeOfUnionCaseType (typ, bindingFlags)
        elif isClosureRepr typ then
            let rec get (typ: Type) =
                if isFunctionType typ then
                    typ
                else
                    match typ.BaseType with
                    | null -> typ
                    | b -> get b

            get typ
        else
            typ

    //-----------------------------------------------------------------
    // CHECKING ROUTINES

    let checkExnType (exceptionType, bindingFlags) =
        if not (isExceptionRepr (exceptionType, bindingFlags)) then
            if isExceptionRepr (exceptionType, bindingFlags ||| BindingFlags.NonPublic) then
                let msg =
                    String.Format(SR.GetString(SR.privateExceptionType), exceptionType.FullName)

                invalidArg "exceptionType" msg
            else
                let msg = String.Format(SR.GetString(SR.notAnExceptionType), exceptionType.FullName)
                invalidArg "exceptionType" msg

    let checkRecordType (argName, recordType, bindingFlags) =
        checkNonNull argName recordType

        if not (isRecordType (recordType, bindingFlags)) then
            if isRecordType (recordType, bindingFlags ||| BindingFlags.NonPublic) then
                let msg = String.Format(SR.GetString(SR.privateRecordType), recordType.FullName)
                invalidArg argName msg
            else
                let msg = String.Format(SR.GetString(SR.notARecordType), recordType.FullName)
                invalidArg argName msg

    let checkTupleType (argName, (tupleType: Type)) =
        checkNonNull argName tupleType

        if not (isTupleType tupleType) then
            let msg = String.Format(SR.GetString(SR.notATupleType), tupleType.FullName)
            invalidArg argName msg

[<Sealed>]
type UnionCaseInfo(typ: System.Type, tag: int) =

    // Cache the tag -> name map
    let mutable names = None

    let getMethInfo () =
        getUnionCaseConstructorMethod (typ, tag, BindingFlags.Public ||| BindingFlags.NonPublic)

    member _.Name =
        match names with
        | None ->
            let conv =
                getUnionTagConverter (typ, BindingFlags.Public ||| BindingFlags.NonPublic)

            names <- Some conv
            conv tag
        | Some conv -> conv tag

    member _.DeclaringType = typ

    member _.GetFields() =
        fieldsPropsOfUnionCase (typ, tag, BindingFlags.Public ||| BindingFlags.NonPublic)

    member _.GetCustomAttributes() =
        getMethInfo().GetCustomAttributes false

    member _.GetCustomAttributes attributeType =
        getMethInfo().GetCustomAttributes(attributeType, false)

    member _.GetCustomAttributesData() =
        getMethInfo().CustomAttributes |> Seq.toArray :> IList<_>

    member _.Tag = tag

    override x.ToString() =
        typ.Name + "." + x.Name

    override x.GetHashCode() =
        typ.GetHashCode() + tag

    override _.Equals(obj: obj) =
        match obj with
        | :? UnionCaseInfo as uci -> uci.DeclaringType = typ && uci.Tag = tag
        | _ -> false

[<AbstractClass; Sealed>]
type FSharpType =

    static member IsTuple(typ: Type) =
        checkNonNull "typ" typ
        isTupleType typ

    static member IsRecord(typ: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "typ" typ
        isRecordType (typ, bindingFlags)

    static member IsUnion(typ: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "typ" typ
        let typ = getTypeOfReprType (typ, BindingFlags.Public ||| BindingFlags.NonPublic)
        isUnionType (typ, bindingFlags)

    static member IsFunction(typ: Type) =
        checkNonNull "typ" typ
        let typ = getTypeOfReprType (typ, BindingFlags.Public ||| BindingFlags.NonPublic)
        isFunctionType typ

    static member IsModule(typ: Type) =
        checkNonNull "typ" typ
        isModuleType typ

    static member MakeFunctionType(domain: Type, range: Type) =
        checkNonNull "domain" domain
        checkNonNull "range" range
        func.MakeGenericType [| domain; range |]

    static member MakeTupleType(types: Type[]) =
        checkNonNull "types" types

        if types.Length = 0 then
            invalidArg "types" (SR.GetString(SR.invalidTupleTypes))

        if types |> Array.exists isNull then
            invalidArg "types" (SR.GetString(SR.nullsNotAllowedInArray))

        mkTupleTypeNetStandard refTupleTypesNetStandard types

    static member MakeTupleType(asm: Assembly, types: Type[]) =
        checkNonNull "types" types

        if
            types
            |> Array.exists (function
                | null -> true
                | _ -> false)
        then
            invalidArg "types" (SR.GetString(SR.nullsNotAllowedInArray))

        TupleFromSpecifiedAssembly.mkTupleType false asm types

    static member MakeStructTupleType(asm: Assembly, types: Type[]) =
        checkNonNull "types" types

        if
            types
            |> Array.exists (function
                | null -> true
                | _ -> false)
        then
            invalidArg "types" (SR.GetString(SR.nullsNotAllowedInArray))

        TupleFromSpecifiedAssembly.mkTupleType true asm types

    static member MakeStructTupleType(types: Type[]) =
        checkNonNull "types" types

        if types.Length = 0 then
            invalidArg "types" (SR.GetString(SR.invalidTupleTypes))

        if types |> Array.exists isNull then
            invalidArg "types" (SR.GetString(SR.nullsNotAllowedInArray))

        mkTupleTypeNetStandard structTupleTypesNetStandard types

    static member GetTupleElements(tupleType: Type) =
        checkTupleType ("tupleType", tupleType)
        getTupleTypeInfo tupleType

    static member GetFunctionElements(functionType: Type) =
        checkNonNull "functionType" functionType

        let functionType =
            getTypeOfReprType (functionType, BindingFlags.Public ||| BindingFlags.NonPublic)

        getFunctionTypeInfo functionType

    static member GetRecordFields(recordType: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkRecordType ("recordType", recordType, bindingFlags)
        fieldPropsOfRecordType (recordType, bindingFlags)

    static member GetUnionCases(unionType: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "unionType" unionType
        let unionType = getTypeOfReprType (unionType, bindingFlags)
        checkUnionType (unionType, bindingFlags)

        getUnionTypeTagNameMap (unionType, bindingFlags)
        |> Array.mapi (fun i _ -> UnionCaseInfo(unionType, i))

    static member IsExceptionRepresentation(exceptionType: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "exceptionType" exceptionType
        isExceptionRepr (exceptionType, bindingFlags)

    static member GetExceptionFields(exceptionType: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "exceptionType" exceptionType
        checkExnType (exceptionType, bindingFlags)
        fieldPropsOfRecordType (exceptionType, bindingFlags)

type DynamicFunction<'T1, 'T2>() =
    inherit FSharpFunc<obj -> obj, obj>()

    override _.Invoke(impl: obj -> obj) : obj =
        box<('T1 -> 'T2)> (fun inp -> unbox<'T2> (impl (box<'T1> (inp))))

[<AbstractClass; Sealed>]
type FSharpValue =

    static member MakeRecord(recordType: Type, values, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkRecordType ("recordType", recordType, bindingFlags)
        getRecordConstructor (recordType, bindingFlags) values

    static member GetRecordField(record: obj, info: PropertyInfo) =
        checkNonNull "info" info
        checkNonNull "record" record
        let reprty = record.GetType()

        if not (isRecordType (reprty, BindingFlags.Public ||| BindingFlags.NonPublic)) then
            invalidArg "record" (SR.GetString(SR.objIsNotARecord))

        info.GetValue(record, null)

    static member GetRecordFields(record: obj, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "record" record
        let typ = record.GetType()

        if not (isRecordType (typ, bindingFlags)) then
            invalidArg "record" (SR.GetString(SR.objIsNotARecord))

        getRecordReader (typ, bindingFlags) record

    static member PreComputeRecordFieldReader(info: PropertyInfo) : obj -> obj =
        checkNonNull "info" info
        compilePropGetterFunc(info).Invoke

    static member PreComputeRecordReader(recordType: Type, ?bindingFlags) : (obj -> obj[]) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkRecordType ("recordType", recordType, bindingFlags)
        getRecordReaderCompiled (recordType, bindingFlags)

    static member PreComputeRecordConstructor(recordType: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkRecordType ("recordType", recordType, bindingFlags)
        getRecordConstructorCompiled (recordType, bindingFlags)

    static member PreComputeRecordConstructorInfo(recordType: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkRecordType ("recordType", recordType, bindingFlags)
        getRecordConstructorMethod (recordType, bindingFlags)

    static member MakeFunction(functionType: Type, implementation: (obj -> obj)) =
        checkNonNull "functionType" functionType

        if not (isFunctionType functionType) then
            let msg = String.Format(SR.GetString(SR.notAFunctionType), functionType.FullName)
            invalidArg "functionType" msg

        checkNonNull "implementation" implementation
        let domain, range = getFunctionTypeInfo functionType
        let dynCloMakerTy = typedefof<DynamicFunction<obj, obj>>
        let saverTy = dynCloMakerTy.MakeGenericType [| domain; range |]
        let o = Activator.CreateInstance saverTy
        let (f: (obj -> obj) -> obj) = downcast o
        f implementation

    static member MakeTuple(tupleElements: obj[], tupleType: Type) =
        checkNonNull "tupleElements" tupleElements
        checkTupleType ("tupleType", tupleType)
        getTupleConstructor tupleType tupleElements

    static member GetTupleFields(tuple: obj) = // argument name(s) used in error message
        checkNonNull "tuple" tuple
        let typ = tuple.GetType()

        if not (isTupleType typ) then
            let msg = String.Format(SR.GetString(SR.notATupleType), tuple.GetType().FullName)
            invalidArg "tuple" msg

        getTupleReader typ tuple

    static member GetTupleField(tuple: obj, index: int) = // argument name(s) used in error message
        checkNonNull "tuple" tuple
        let typ = tuple.GetType()

        if not (isTupleType typ) then
            let msg = String.Format(SR.GetString(SR.notATupleType), tuple.GetType().FullName)
            invalidArg "tuple" msg

        let fields = getTupleReader typ tuple

        if index < 0 || index >= fields.Length then
            let msg =
                String.Format(SR.GetString(SR.tupleIndexOutOfRange), tuple.GetType().FullName, index.ToString())

            invalidArg "index" msg

        fields.[index]

    static member PreComputeTupleReader(tupleType: Type) : (obj -> obj[]) =
        checkTupleType ("tupleType", tupleType)
        (compileTupleReader tupleEncField getTupleElementAccessors tupleType).Invoke

    static member PreComputeTuplePropertyInfo(tupleType: Type, index: int) =
        checkTupleType ("tupleType", tupleType)
        getTupleReaderInfo (tupleType, index)

    static member PreComputeTupleConstructor(tupleType: Type) =
        checkTupleType ("tupleType", tupleType)

        (compileTupleConstructor tupleEncField getTupleConstructorMethod tupleType)
            .Invoke

    static member PreComputeTupleConstructorInfo(tupleType: Type) =
        checkTupleType ("tupleType", tupleType)
        getTupleConstructorInfo tupleType

    static member MakeUnion(unionCase: UnionCaseInfo, args: obj[], ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "unionCase" unionCase
        getUnionCaseConstructor (unionCase.DeclaringType, unionCase.Tag, bindingFlags) args

    static member PreComputeUnionConstructor(unionCase: UnionCaseInfo, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "unionCase" unionCase
        getUnionCaseConstructorCompiled (unionCase.DeclaringType, unionCase.Tag, bindingFlags)

    static member PreComputeUnionConstructorInfo(unionCase: UnionCaseInfo, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "unionCase" unionCase
        getUnionCaseConstructorMethod (unionCase.DeclaringType, unionCase.Tag, bindingFlags)

    static member GetUnionFields(value: obj, unionType: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public

        let ensureType (typ: Type, obj: obj) =
            match typ with
            | null ->
                match obj with
                | null -> invalidArg "obj" (SR.GetString(SR.objIsNullAndNoType))
                | _ -> obj.GetType()
            | _ -> typ

        let unionType = ensureType (unionType, value)

        checkNonNull "unionType" unionType
        let unionType = getTypeOfReprType (unionType, bindingFlags)

        checkUnionType (unionType, bindingFlags)
        let tag = getUnionTagReader (unionType, bindingFlags) value
        let flds = getUnionCaseRecordReader (unionType, tag, bindingFlags) value
        UnionCaseInfo(unionType, tag), flds

    static member PreComputeUnionTagReader(unionType: Type, ?bindingFlags) : (obj -> int) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "unionType" unionType
        let unionType = getTypeOfReprType (unionType, bindingFlags)
        checkUnionType (unionType, bindingFlags)
        getUnionTagReaderCompiled (unionType, bindingFlags)

    static member PreComputeUnionTagMemberInfo(unionType: Type, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "unionType" unionType
        let unionType = getTypeOfReprType (unionType, bindingFlags)
        checkUnionType (unionType, bindingFlags)
        getUnionTagMemberInfo (unionType, bindingFlags)

    static member PreComputeUnionReader(unionCase: UnionCaseInfo, ?bindingFlags) : (obj -> obj[]) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "unionCase" unionCase
        let typ = unionCase.DeclaringType
        getUnionCaseRecordReaderCompiled (typ, unionCase.Tag, bindingFlags)

    static member GetExceptionFields(exn: obj, ?bindingFlags) =
        let bindingFlags = defaultArg bindingFlags BindingFlags.Public
        checkNonNull "exn" exn
        let typ = exn.GetType()
        checkExnType (typ, bindingFlags)
        getRecordReader (typ, bindingFlags) exn

module FSharpReflectionExtensions =

    type FSharpType with

        static member GetExceptionFields(exceptionType: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpType.GetExceptionFields(exceptionType, bindingFlags)

        static member IsExceptionRepresentation(exceptionType: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpType.IsExceptionRepresentation(exceptionType, bindingFlags)

        static member GetUnionCases(unionType: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpType.GetUnionCases(unionType, bindingFlags)

        static member GetRecordFields(recordType: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpType.GetRecordFields(recordType, bindingFlags)

        static member IsUnion(typ: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpType.IsUnion(typ, bindingFlags)

        static member IsRecord(typ: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpType.IsRecord(typ, bindingFlags)

    type FSharpValue with

        static member MakeRecord(recordType: Type, values, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.MakeRecord(recordType, values, bindingFlags)

        static member GetRecordFields(record: obj, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.GetRecordFields(record, bindingFlags)

        static member PreComputeRecordReader(recordType: Type, ?allowAccessToPrivateRepresentation) : (obj -> obj[]) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.PreComputeRecordReader(recordType, bindingFlags)

        static member PreComputeRecordConstructor(recordType: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.PreComputeRecordConstructor(recordType, bindingFlags)

        static member PreComputeRecordConstructorInfo(recordType: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.PreComputeRecordConstructorInfo(recordType, bindingFlags)

        static member MakeUnion(unionCase: UnionCaseInfo, args: obj[], ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.MakeUnion(unionCase, args, bindingFlags)

        static member PreComputeUnionConstructor(unionCase: UnionCaseInfo, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.PreComputeUnionConstructor(unionCase, bindingFlags)

        static member PreComputeUnionConstructorInfo(unionCase: UnionCaseInfo, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.PreComputeUnionConstructorInfo(unionCase, bindingFlags)

        static member PreComputeUnionTagMemberInfo(unionType: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.PreComputeUnionTagMemberInfo(unionType, bindingFlags)

        static member GetUnionFields(value: obj, unionType: Type, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.GetUnionFields(value, unionType, bindingFlags)

        static member PreComputeUnionTagReader(unionType: Type, ?allowAccessToPrivateRepresentation) : (obj -> int) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.PreComputeUnionTagReader(unionType, bindingFlags)

        static member PreComputeUnionReader
            (
                unionCase: UnionCaseInfo,
                ?allowAccessToPrivateRepresentation
            ) : (obj -> obj[]) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.PreComputeUnionReader(unionCase, bindingFlags)

        static member GetExceptionFields(exn: obj, ?allowAccessToPrivateRepresentation) =
            let bindingFlags = getBindingFlags allowAccessToPrivateRepresentation
            FSharpValue.GetExceptionFields(exn, bindingFlags)
