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

namespace Microsoft.FSharp.Quotations

open System
open System.IO
open System.Reflection
open System.Collections.Generic
open Microsoft.FSharp
open Microsoft.FSharp.Core
open Microsoft.FSharp.Core.LanguagePrimitives.IntrinsicOperators
open Microsoft.FSharp.Core.Operators
open Microsoft.FSharp.Primitives.Basics
open Microsoft.FSharp.Collections
open Microsoft.FSharp.Reflection
open Microsoft.FSharp.Core.Printf
open Microsoft.FSharp.Text.StructuredPrintfImpl
open Microsoft.FSharp.Text.StructuredPrintfImpl.Layout
open Microsoft.FSharp.Text.StructuredPrintfImpl.TaggedText

#nowarn "52" // The value has been copied to ensure the original is not mutated by this operation
//--------------------------------------------------------------------------
// RAW quotations - basic data types
//--------------------------------------------------------------------------

module Helpers =
    let qOneOrMoreRLinear q inp =
        let rec queryAcc rvs e =
            match q e with
            | Some (v, body) -> queryAcc (v :: rvs) body
            | None ->
                match rvs with
                | [] -> None
                | _ -> Some(List.rev rvs, e)

        queryAcc [] inp

    let qOneOrMoreLLinear q inp =
        let rec queryAcc e rvs =
            match q e with
            | Some (body, v) -> queryAcc body (v :: rvs)
            | None ->
                match rvs with
                | [] -> None
                | _ -> Some(e, rvs)

        queryAcc inp []

    let mkRLinear mk (vs, body) =
        List.foldBack (fun v acc -> mk (v, acc)) vs body

    let mkLLinear mk (body, vs) =
        List.fold (fun acc v -> mk (acc, v)) body vs

    let staticBindingFlags =
        BindingFlags.Static
        ||| BindingFlags.Public
        ||| BindingFlags.NonPublic
        ||| BindingFlags.DeclaredOnly

    let staticOrInstanceBindingFlags =
        BindingFlags.Instance
        ||| BindingFlags.Static
        ||| BindingFlags.Public
        ||| BindingFlags.NonPublic
        ||| BindingFlags.DeclaredOnly

    let instanceBindingFlags =
        BindingFlags.Instance
        ||| BindingFlags.Public
        ||| BindingFlags.NonPublic
        ||| BindingFlags.DeclaredOnly

    let publicOrPrivateBindingFlags = BindingFlags.Public ||| BindingFlags.NonPublic

    let isDelegateType (typ: Type) =
        if typ.IsSubclassOf(typeof<Delegate>) then
            match typ.GetMethod("Invoke", instanceBindingFlags) with
            | null -> false
            | _ -> true
        else
            false

    let getDelegateInvoke ty =
        if not (isDelegateType ty) then
            invalidArg "ty" (SR.GetString(SR.delegateExpected))

        ty.GetMethod("Invoke", instanceBindingFlags)

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

    let getTypesFromParamInfos (infos: ParameterInfo[]) =
        infos |> Array.map (fun pi -> pi.ParameterType)

open Helpers

[<Sealed>]
[<CompiledName("FSharpVar")>]
type Var(name: string, typ: Type, ?isMutable: bool) =
    inherit obj()

    static let getStamp =
        let mutable lastStamp = -1L // first value retrieved will be 0
        fun () -> System.Threading.Interlocked.Increment &lastStamp

    static let globals = new Dictionary<(string * Type), Var>(11)

    let stamp = getStamp ()
    let isMutable = defaultArg isMutable false

    member _.Name = name

    member _.IsMutable = isMutable

    member _.Type = typ

    member _.Stamp = stamp

    static member Global(name, typ: Type) =
        checkNonNull "name" name
        checkNonNull "typ" typ

        lock globals (fun () ->
            let mutable res = Unchecked.defaultof<Var>
            let ok = globals.TryGetValue((name, typ), &res)

            if ok then
                res
            else
                let res = new Var(name, typ)
                globals.[(name, typ)] <- res
                res)

    override _.ToString() =
        name

    override _.GetHashCode() =
        base.GetHashCode()

    override v.Equals(obj: obj) =
        match obj with
        | :? Var as v2 -> System.Object.ReferenceEquals(v, v2)
        | _ -> false

    interface System.IComparable with
        member v.CompareTo(obj: obj) =
            match obj with
            | :? Var as v2 ->
                if System.Object.ReferenceEquals(v, v2) then
                    0
                else
                    let c = compare v.Name v2.Name

                    if c <> 0 then
                        c
                    else
                        let c = compare v.Type.MetadataToken v2.Type.MetadataToken

                        if c <> 0 then
                            c
                        else
                            let c = compare v.Type.Module.MetadataToken v2.Type.Module.MetadataToken

                            if c <> 0 then
                                c
                            else
                                let c = compare v.Type.Assembly.FullName v2.Type.Assembly.FullName

                                if c <> 0 then
                                    c
                                else
                                    compare v.Stamp v2.Stamp
            | _ -> 0

/// Represents specifications of a subset of F# expressions
[<StructuralEquality; NoComparison>]
type Tree =
    | CombTerm of ExprConstInfo * Expr list
    | VarTerm of Var
    | LambdaTerm of Var * Expr
    | HoleTerm of Type * int

and [<StructuralEquality; NoComparison>] ExprConstInfo =
    | AppOp
    | IfThenElseOp
    | LetRecOp
    | LetRecCombOp
    | LetOp
    | NewRecordOp of Type
    | NewUnionCaseOp of UnionCaseInfo
    | UnionCaseTestOp of UnionCaseInfo
    | NewTupleOp of Type
    | TupleGetOp of Type * int
    | InstancePropGetOp of PropertyInfo
    | StaticPropGetOp of PropertyInfo
    | InstancePropSetOp of PropertyInfo
    | StaticPropSetOp of PropertyInfo
    | InstanceFieldGetOp of FieldInfo
    | StaticFieldGetOp of FieldInfo
    | InstanceFieldSetOp of FieldInfo
    | StaticFieldSetOp of FieldInfo
    | NewObjectOp of ConstructorInfo
    | InstanceMethodCallOp of MethodInfo
    | StaticMethodCallOp of MethodInfo
    /// A new Call node type in F# 5.0, storing extra information about witnesses
    | InstanceMethodCallWOp of MethodInfo * MethodInfo * int
    /// A new Call node type in F# 5.0, storing extra information about witnesses
    | StaticMethodCallWOp of MethodInfo * MethodInfo * int
    | CoerceOp of Type
    | NewArrayOp of Type
    | NewDelegateOp of Type
    | QuoteOp of bool
    | SequentialOp
    | AddressOfOp
    | VarSetOp
    | AddressSetOp
    | TypeTestOp of Type
    | TryWithOp
    | TryFinallyOp
    | ForIntegerRangeLoopOp
    | WhileLoopOp
    // Arbitrary spliced values - not serialized
    | ValueOp of obj * Type * string option
    | WithValueOp of obj * Type
    | DefaultValueOp of Type

and [<CompiledName("FSharpExpr"); StructuredFormatDisplay("{DebugText}")>] Expr(term: Tree, attribs: Expr list) =
    member x.Tree = term
    member x.CustomAttributes = attribs

    override x.Equals obj =
        match obj with
        | :? Expr as y ->
            let rec eq t1 t2 =
                match t1, t2 with
                // We special-case ValueOp to ensure that ValueWithName = Value
                | CombTerm (ValueOp (v1, ty1, _), []), CombTerm (ValueOp (v2, ty2, _), []) -> (v1 = v2) && (ty1 = ty2)

                // We strip off InstanceMethodCallWOp to ensure that CallWithWitness = Call
                | CombTerm (InstanceMethodCallWOp (minfo1, _minfoW1, nWitnesses1), obj1 :: args1WithoutObj), _ ->
                    if nWitnesses1 <= args1WithoutObj.Length then
                        let args1WithoutWitnesses = List.skip nWitnesses1 args1WithoutObj
                        eq (CombTerm(InstanceMethodCallOp(minfo1), obj1 :: args1WithoutWitnesses)) t2
                    else
                        false

                // We strip off InstanceMethodCallWOp to ensure that CallWithWitness = Call
                | _, CombTerm (InstanceMethodCallWOp (minfo2, _minfoW2, nWitnesses2), obj2 :: args2WithoutObj) when
                    nWitnesses2 <= args2WithoutObj.Length
                    ->
                    let args2WithoutWitnesses = List.skip nWitnesses2 args2WithoutObj
                    eq t1 (CombTerm(InstanceMethodCallOp(minfo2), obj2 :: args2WithoutWitnesses))

                // We strip off StaticMethodCallWOp to ensure that CallWithWitness = Call
                | CombTerm (StaticMethodCallWOp (minfo1, _minfoW1, nWitnesses1), args1), _ when
                    nWitnesses1 <= args1.Length
                    ->
                    let argsWithoutWitnesses1 = List.skip nWitnesses1 args1
                    eq (CombTerm(StaticMethodCallOp(minfo1), argsWithoutWitnesses1)) t2

                // We strip off StaticMethodCallWOp to ensure that CallWithWitness = Call
                | _, CombTerm (StaticMethodCallWOp (minfo2, _minfoW2, nWitnesses2), args2) when
                    nWitnesses2 <= args2.Length
                    ->
                    let argsWithoutWitnesses2 = List.skip nWitnesses2 args2
                    eq t1 (CombTerm(StaticMethodCallOp(minfo2), argsWithoutWitnesses2))

                | CombTerm (c1, es1), CombTerm (c2, es2) -> c1 = c2 && es1.Length = es2.Length && (es1 = es2)
                | VarTerm v1, VarTerm v2 -> (v1 = v2)
                | LambdaTerm (v1, e1), LambdaTerm (v2, e2) -> (v1 = v2) && (e1 = e2)
                | HoleTerm (ty1, n1), HoleTerm (ty2, n2) -> (ty1 = ty2) && (n1 = n2)
                | _ -> false

            eq x.Tree y.Tree
        | _ -> false

    override x.GetHashCode() =
        x.Tree.GetHashCode()

    override x.ToString() =
        x.ToString false

    member x.ToString full =
        Display.layout_to_string FormatOptions.Default (x.GetLayout(full))

    member x.DebugText = x.ToString(false)

    member x.GetLayout long =
        let expr (e: Expr) =
            e.GetLayout long

        let exprs (es: Expr list) =
            es |> List.map expr

        let parens ls =
            bracketL (commaListL ls)

        let pairL l1 l2 =
            bracketL (l1 ^^ sepL comma ^^ l2)

        let listL ls =
            squareBracketL (commaListL ls)

        let combTaggedL nm ls =
            wordL nm ^^ parens ls

        let combL nm ls =
            combTaggedL (tagKeyword nm) ls

        let noneL = wordL (tagProperty "None")

        let someL e =
            combTaggedL (tagMethod "Some") [ expr e ]

        let typeL (o: Type) =
            wordL (tagClass (if long then o.FullName else o.Name))

        let objL (o: 'T) =
            wordL (tagText (sprintf "%A" o))

        let varL (v: Var) =
            wordL (tagLocal v.Name)

        let (|E|) (e: Expr) =
            e.Tree

        let (|Lambda|_|) (E x) =
            match x with
            | LambdaTerm (a, b) -> Some(a, b)
            | _ -> None

        let (|IteratedLambda|_|) (e: Expr) =
            qOneOrMoreRLinear (|Lambda|_|) e

        let ucaseL (unionCase: UnionCaseInfo) =
            (if long then
                 objL unionCase
             else
                 wordL (tagUnionCase unionCase.Name))

        let minfoL (minfo: MethodInfo) =
            if long then
                objL minfo
            else
                wordL (tagMethod minfo.Name)

        let cinfoL (cinfo: ConstructorInfo) =
            if long then
                objL cinfo
            else
                wordL (tagMethod cinfo.DeclaringType.Name)

        let pinfoL (pinfo: PropertyInfo) =
            if long then
                objL pinfo
            else
                wordL (tagProperty pinfo.Name)

        let finfoL (finfo: FieldInfo) =
            if long then
                objL finfo
            else
                wordL (tagField finfo.Name)

        let rec (|NLambdas|_|) n (e: Expr) =
            match e with
            | _ when n <= 0 -> Some([], e)
            | Lambda (v, NLambdas ((-) n 1) (vs, b)) -> Some(v :: vs, b)
            | _ -> None

        match x.Tree with
        | CombTerm (AppOp, args) -> combL "Application" (exprs args)
        | CombTerm (IfThenElseOp, args) -> combL "IfThenElse" (exprs args)
        | CombTerm (LetRecOp, [ IteratedLambda (vs, E (CombTerm (LetRecCombOp, b2 :: bs))) ]) ->
            combL "LetRecursive" [ listL (List.map2 pairL (List.map varL vs) (exprs bs)); b2.GetLayout long ]
        | CombTerm (LetOp, [ e; E (LambdaTerm (v, b)) ]) -> combL "Let" [ varL v; e.GetLayout long; b.GetLayout long ]
        | CombTerm (NewRecordOp ty, args) -> combL "NewRecord" (typeL ty :: exprs args)
        | CombTerm (NewUnionCaseOp unionCase, args) -> combL "NewUnionCase" (ucaseL unionCase :: exprs args)
        | CombTerm (UnionCaseTestOp unionCase, args) -> combL "UnionCaseTest" (exprs args @ [ ucaseL unionCase ])
        | CombTerm (NewTupleOp _, args) -> combL "NewTuple" (exprs args)
        | CombTerm (TupleGetOp (_, i), [ arg ]) -> combL "TupleGet" ([ expr arg ] @ [ objL i ])
        | CombTerm (ValueOp (v, _, Some nm), []) -> combL "ValueWithName" [ objL v; wordL (tagLocal nm) ]
        | CombTerm (ValueOp (v, _, None), []) -> combL "Value" [ objL v ]
        | CombTerm (WithValueOp (v, _), [ defn ]) -> combL "WithValue" [ objL v; expr defn ]

        | CombTerm (InstanceMethodCallOp (minfo), obj :: args) ->
            combL "Call" [ someL obj; minfoL minfo; listL (exprs args) ]

        | CombTerm (StaticMethodCallOp (minfo), args) -> combL "Call" [ noneL; minfoL minfo; listL (exprs args) ]

        | CombTerm (InstanceMethodCallWOp (minfo, _minfoW, nWitnesses), obj :: argsWithoutObj) when
            nWitnesses <= argsWithoutObj.Length
            ->
            let argsWithoutWitnesses = List.skip nWitnesses argsWithoutObj
            combL "Call" [ someL obj; minfoL minfo; listL (exprs argsWithoutWitnesses) ]

        | CombTerm (StaticMethodCallWOp (minfo, _minfoW, nWitnesses), args) when nWitnesses <= args.Length ->
            let argsWithoutWitnesses = List.skip nWitnesses args
            combL "Call" [ noneL; minfoL minfo; listL (exprs argsWithoutWitnesses) ]

        | CombTerm (InstancePropGetOp (pinfo), (obj :: args)) ->
            combL "PropertyGet" [ someL obj; pinfoL pinfo; listL (exprs args) ]
        | CombTerm (StaticPropGetOp (pinfo), args) -> combL "PropertyGet" [ noneL; pinfoL pinfo; listL (exprs args) ]
        | CombTerm (InstancePropSetOp (pinfo), (obj :: args)) ->
            combL "PropertySet" [ someL obj; pinfoL pinfo; listL (exprs args) ]
        | CombTerm (StaticPropSetOp (pinfo), args) -> combL "PropertySet" [ noneL; pinfoL pinfo; listL (exprs args) ]
        | CombTerm (InstanceFieldGetOp (finfo), [ obj ]) -> combL "FieldGet" [ someL obj; finfoL finfo ]
        | CombTerm (StaticFieldGetOp (finfo), []) -> combL "FieldGet" [ noneL; finfoL finfo ]
        | CombTerm (InstanceFieldSetOp (finfo), [ obj; v ]) -> combL "FieldSet" [ someL obj; finfoL finfo; expr v ]
        | CombTerm (StaticFieldSetOp (finfo), [ v ]) -> combL "FieldSet" [ noneL; finfoL finfo; expr v ]
        | CombTerm (CoerceOp (ty), [ arg ]) -> combL "Coerce" [ expr arg; typeL ty ]
        | CombTerm (NewObjectOp cinfo, args) -> combL "NewObject" ([ cinfoL cinfo ] @ exprs args)
        | CombTerm (DefaultValueOp ty, args) -> combL "DefaultValue" ([ typeL ty ] @ exprs args)
        | CombTerm (NewArrayOp ty, args) -> combL "NewArray" ([ typeL ty ] @ exprs args)
        | CombTerm (TypeTestOp ty, args) -> combL "TypeTest" ([ typeL ty ] @ exprs args)
        | CombTerm (AddressOfOp, args) -> combL "AddressOf" (exprs args)
        | CombTerm (VarSetOp, [ E (VarTerm v); e ]) -> combL "VarSet" [ varL v; expr e ]
        | CombTerm (AddressSetOp, args) -> combL "AddressSet" (exprs args)
        | CombTerm (ForIntegerRangeLoopOp, [ e1; e2; E (LambdaTerm (v, e3)) ]) ->
            combL "ForIntegerRangeLoop" [ varL v; expr e1; expr e2; expr e3 ]
        | CombTerm (WhileLoopOp, args) -> combL "WhileLoop" (exprs args)
        | CombTerm (TryFinallyOp, args) -> combL "TryFinally" (exprs args)
        | CombTerm (TryWithOp, [ e1; Lambda (v1, e2); Lambda (v2, e3) ]) ->
            combL "TryWith" [ expr e1; varL v1; expr e2; varL v2; expr e3 ]
        | CombTerm (SequentialOp, args) -> combL "Sequential" (exprs args)

        | CombTerm (NewDelegateOp ty, [ e ]) ->
            let nargs = (getDelegateInvoke ty).GetParameters().Length

            if nargs = 0 then
                match e with
                | NLambdas 1 ([ _ ], e) -> combL "NewDelegate" ([ typeL ty ] @ [ expr e ])
                | NLambdas 0 ([], e) -> combL "NewDelegate" ([ typeL ty ] @ [ expr e ])
                | _ -> combL "NewDelegate" [ typeL ty; expr e ]
            else
                match e with
                | NLambdas nargs (vs, e) -> combL "NewDelegate" ([ typeL ty ] @ (vs |> List.map varL) @ [ expr e ])
                | _ -> combL "NewDelegate" [ typeL ty; expr e ]
        | VarTerm v -> wordL (tagLocal v.Name)
        | LambdaTerm (v, b) -> combL "Lambda" [ varL v; expr b ]
        | HoleTerm _ -> wordL (tagLocal "_")
        | CombTerm (QuoteOp _, args) -> combL "Quote" (exprs args)
        | _ -> failwithf "Unexpected term"

and [<CompiledName("FSharpExpr`1")>] Expr<'T>(term: Tree, attribs) =
    inherit Expr(term, attribs)
    member x.Raw = (x :> Expr)

[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
module Patterns =

    /// Internal type representing a deserialized object that is yet to be instantiated. Representation is
    /// as a computation.
    type Instantiable<'T> = (int -> Type) -> 'T

    type ByteStream(bytes: byte[], initial: int, len: int) =

        let mutable pos = initial
        let lim = initial + len

        member b.ReadByte() =
            if pos >= lim then
                failwith "end of stream"

            let res = int32 bytes.[pos]
            pos <- pos + 1
            res

        member b.ReadBytes n =
            if pos + n > lim then
                failwith "ByteStream.ReadBytes: end of stream"

            let res = bytes.[pos .. pos + n - 1]
            pos <- pos + n
            res

        member b.ReadUtf8BytesAsString n =
            let res = System.Text.Encoding.UTF8.GetString(bytes, pos, n)
            pos <- pos + n
            res

    let E t =
        new Expr(t, [])

    let EA (t, attribs) =
        new Expr(t, attribs)

    let (|E|) (e: Expr) =
        e.Tree

    let (|FrontAndBack|_|) es =
        let rec loop acc xs =
            match xs with
            | [] -> None
            | [ h ] -> Some(List.rev acc, h)
            | h :: t -> loop (h :: acc) t

        loop [] es

    let funTyC = typeof<(obj -> obj)>.GetGenericTypeDefinition ()
    let exprTyC = typedefof<Expr<int>>
    let voidTy = typeof<System.Void>
    let unitTy = typeof<unit>

    let removeVoid a =
        if a = voidTy then unitTy else a

    let mkFunTy a b =
        let (a, b) = removeVoid a, removeVoid b
        funTyC.MakeGenericType([| a; b |])

    let mkArrayTy (t: Type) =
        t.MakeArrayType()

    let mkExprTy (t: Type) =
        exprTyC.MakeGenericType([| t |])

    let rawExprTy = typeof<Expr>

    //--------------------------------------------------------------------------
    // Active patterns for decomposing quotations
    //--------------------------------------------------------------------------

    let (|Comb0|_|) (E x) =
        match x with
        | CombTerm (k, []) -> Some k
        | _ -> None

    let (|Comb1|_|) (E x) =
        match x with
        | CombTerm (k, [ x ]) -> Some(k, x)
        | _ -> None

    let (|Comb2|_|) (E x) =
        match x with
        | CombTerm (k, [ x1; x2 ]) -> Some(k, x1, x2)
        | _ -> None

    let (|Comb3|_|) (E x) =
        match x with
        | CombTerm (k, [ x1; x2; x3 ]) -> Some(k, x1, x2, x3)
        | _ -> None

    [<CompiledName("VarPattern")>]
    let (|Var|_|) (E x) =
        match x with
        | VarTerm v -> Some v
        | _ -> None

    [<CompiledName("ApplicationPattern")>]
    let (|Application|_|) input =
        match input with
        | Comb2 (AppOp, a, b) -> Some(a, b)
        | _ -> None

    [<CompiledName("LambdaPattern")>]
    let (|Lambda|_|) (E x) =
        match x with
        | LambdaTerm (a, b) -> Some(a, b)
        | _ -> None

    [<CompiledName("QuotePattern")>]
    let (|Quote|_|) (E x) =
        match x with
        | CombTerm (QuoteOp _, [ a ]) -> Some(a)
        | _ -> None

    [<CompiledName("QuoteRawPattern")>]
    let (|QuoteRaw|_|) (E x) =
        match x with
        | CombTerm (QuoteOp false, [ a ]) -> Some(a)
        | _ -> None

    [<CompiledName("QuoteTypedPattern")>]
    let (|QuoteTyped|_|) (E x) =
        match x with
        | CombTerm (QuoteOp true, [ a ]) -> Some(a)
        | _ -> None

    [<CompiledName("IfThenElsePattern")>]
    let (|IfThenElse|_|) input =
        match input with
        | Comb3 (IfThenElseOp, e1, e2, e3) -> Some(e1, e2, e3)
        | _ -> None

    [<CompiledName("NewTuplePattern")>]
    let (|NewTuple|_|) input =
        match input with
        | E (CombTerm (NewTupleOp (_), es)) -> Some es
        | _ -> None

    [<CompiledName("NewStructTuplePattern")>]
    let (|NewStructTuple|_|) input =
        match input with
        | E (CombTerm (NewTupleOp (ty), es)) when ty.IsValueType -> Some es
        | _ -> None

    [<CompiledName("DefaultValuePattern")>]
    let (|DefaultValue|_|) input =
        match input with
        | E (CombTerm (DefaultValueOp ty, [])) -> Some ty
        | _ -> None

    [<CompiledName("NewRecordPattern")>]
    let (|NewRecord|_|) input =
        match input with
        | E (CombTerm (NewRecordOp x, es)) -> Some(x, es)
        | _ -> None

    [<CompiledName("NewUnionCasePattern")>]
    let (|NewUnionCase|_|) input =
        match input with
        | E (CombTerm (NewUnionCaseOp unionCase, es)) -> Some(unionCase, es)
        | _ -> None

    [<CompiledName("UnionCaseTestPattern")>]
    let (|UnionCaseTest|_|) input =
        match input with
        | Comb1 (UnionCaseTestOp unionCase, e) -> Some(e, unionCase)
        | _ -> None

    [<CompiledName("TupleGetPattern")>]
    let (|TupleGet|_|) input =
        match input with
        | Comb1 (TupleGetOp (_, n), e) -> Some(e, n)
        | _ -> None

    [<CompiledName("CoercePattern")>]
    let (|Coerce|_|) input =
        match input with
        | Comb1 (CoerceOp ty, e1) -> Some(e1, ty)
        | _ -> None

    [<CompiledName("TypeTestPattern")>]
    let (|TypeTest|_|) input =
        match input with
        | Comb1 (TypeTestOp ty, e1) -> Some(e1, ty)
        | _ -> None

    [<CompiledName("NewArrayPattern")>]
    let (|NewArray|_|) input =
        match input with
        | E (CombTerm (NewArrayOp ty, es)) -> Some(ty, es)
        | _ -> None

    [<CompiledName("AddressSetPattern")>]
    let (|AddressSet|_|) input =
        match input with
        | E (CombTerm (AddressSetOp, [ e; v ])) -> Some(e, v)
        | _ -> None

    [<CompiledName("TryFinallyPattern")>]
    let (|TryFinally|_|) input =
        match input with
        | E (CombTerm (TryFinallyOp, [ e1; e2 ])) -> Some(e1, e2)
        | _ -> None

    [<CompiledName("TryWithPattern")>]
    let (|TryWith|_|) input =
        match input with
        | E (CombTerm (TryWithOp, [ e1; Lambda (v1, e2); Lambda (v2, e3) ])) -> Some(e1, v1, e2, v2, e3)
        | _ -> None

    [<CompiledName("VarSetPattern")>]
    let (|VarSet|_|) input =
        match input with
        | E (CombTerm (VarSetOp, [ E (VarTerm v); e ])) -> Some(v, e)
        | _ -> None

    [<CompiledName("ValuePattern")>]
    let (|Value|_|) input =
        match input with
        | E (CombTerm (ValueOp (v, ty, _), _)) -> Some(v, ty)
        | _ -> None

    [<CompiledName("ValueObjPattern")>]
    let (|ValueObj|_|) input =
        match input with
        | E (CombTerm (ValueOp (v, _, _), _)) -> Some v
        | _ -> None

    [<CompiledName("ValueWithNamePattern")>]
    let (|ValueWithName|_|) input =
        match input with
        | E (CombTerm (ValueOp (v, ty, Some nm), _)) -> Some(v, ty, nm)
        | _ -> None

    [<CompiledName("WithValuePattern")>]
    let (|WithValue|_|) input =
        match input with
        | E (CombTerm (WithValueOp (v, ty), [ e ])) -> Some(v, ty, e)
        | _ -> None

    [<CompiledName("AddressOfPattern")>]
    let (|AddressOf|_|) input =
        match input with
        | Comb1 (AddressOfOp, e) -> Some e
        | _ -> None

    [<CompiledName("SequentialPattern")>]
    let (|Sequential|_|) input =
        match input with
        | Comb2 (SequentialOp, e1, e2) -> Some(e1, e2)
        | _ -> None

    [<CompiledName("ForIntegerRangeLoopPattern")>]
    let (|ForIntegerRangeLoop|_|) input =
        match input with
        | Comb3 (ForIntegerRangeLoopOp, e1, e2, Lambda (v, e3)) -> Some(v, e1, e2, e3)
        | _ -> None

    [<CompiledName("WhileLoopPattern")>]
    let (|WhileLoop|_|) input =
        match input with
        | Comb2 (WhileLoopOp, e1, e2) -> Some(e1, e2)
        | _ -> None

    [<CompiledName("PropertyGetPattern")>]
    let (|PropertyGet|_|) input =
        match input with
        | E (CombTerm (StaticPropGetOp pinfo, args)) -> Some(None, pinfo, args)
        | E (CombTerm (InstancePropGetOp pinfo, obj :: args)) -> Some(Some obj, pinfo, args)
        | _ -> None

    [<CompiledName("PropertySetPattern")>]
    let (|PropertySet|_|) input =
        match input with
        | E (CombTerm (StaticPropSetOp pinfo, FrontAndBack (args, v))) -> Some(None, pinfo, args, v)
        | E (CombTerm (InstancePropSetOp pinfo, obj :: FrontAndBack (args, v))) -> Some(Some obj, pinfo, args, v)
        | _ -> None

    [<CompiledName("FieldGetPattern")>]
    let (|FieldGet|_|) input =
        match input with
        | E (CombTerm (StaticFieldGetOp finfo, [])) -> Some(None, finfo)
        | E (CombTerm (InstanceFieldGetOp finfo, [ obj ])) -> Some(Some obj, finfo)
        | _ -> None

    [<CompiledName("FieldSetPattern")>]
    let (|FieldSet|_|) input =
        match input with
        | E (CombTerm (StaticFieldSetOp finfo, [ v ])) -> Some(None, finfo, v)
        | E (CombTerm (InstanceFieldSetOp finfo, [ obj; v ])) -> Some(Some obj, finfo, v)
        | _ -> None

    [<CompiledName("NewObjectPattern")>]
    let (|NewObject|_|) input =
        match input with
        | E (CombTerm (NewObjectOp ty, e)) -> Some(ty, e)
        | _ -> None

    [<CompiledName("CallPattern")>]
    let (|Call|_|) input =
        match input with
        | E (CombTerm (StaticMethodCallOp minfo, args)) -> Some(None, minfo, args)

        | E (CombTerm (InstanceMethodCallOp minfo, (obj :: args))) -> Some(Some(obj), minfo, args)

        // A StaticMethodCallWOp matches as if it were a StaticMethodCallOp
        | E (CombTerm (StaticMethodCallWOp (minfo, _minfoW, nWitnesses), args)) when nWitnesses <= args.Length ->
            Some(None, minfo, List.skip nWitnesses args)

        // A InstanceMethodCallWOp matches as if it were a InstanceMethodCallOp
        | E (CombTerm (InstanceMethodCallWOp (minfo, _minfoW, nWitnesses), obj :: argsWithoutObj)) when
            nWitnesses <= argsWithoutObj.Length
            ->
            let argsWithoutWitnesses = List.skip nWitnesses argsWithoutObj
            Some(Some obj, minfo, argsWithoutWitnesses)

        | _ -> None

    [<CompiledName("CallWithWitnessesPattern")>]
    let (|CallWithWitnesses|_|) input =
        match input with
        | E (CombTerm (StaticMethodCallWOp (minfo, minfoW, nWitnesses), args)) ->
            if args.Length >= nWitnesses then
                let witnessArgs, argsWithoutWitnesses = List.splitAt nWitnesses args
                Some(None, minfo, minfoW, witnessArgs, argsWithoutWitnesses)
            else
                None

        | E (CombTerm (InstanceMethodCallWOp (minfo, minfoW, nWitnesses), obj :: argsWithoutObj)) ->
            if argsWithoutObj.Length >= nWitnesses then
                let witnessArgs, argsWithoutWitnesses = List.splitAt nWitnesses argsWithoutObj
                Some(Some obj, minfo, minfoW, witnessArgs, argsWithoutWitnesses)
            else
                None

        | _ -> None

    let (|LetRaw|_|) input =
        match input with
        | Comb2 (LetOp, e1, e2) -> Some(e1, e2)
        | _ -> None

    let (|LetRecRaw|_|) input =
        match input with
        | Comb1 (LetRecOp, e1) -> Some e1
        | _ -> None

    [<CompiledName("LetPattern")>]
    let (|Let|_|) input =
        match input with
        | LetRaw (e, Lambda (v, body)) -> Some(v, e, body)
        | _ -> None

    let (|IteratedLambda|_|) (e: Expr) =
        qOneOrMoreRLinear (|Lambda|_|) e

    let rec (|NLambdas|_|) n (e: Expr) =
        match e with
        | _ when n <= 0 -> Some([], e)
        | Lambda (v, NLambdas ((-) n 1) (vs, b)) -> Some(v :: vs, b)
        | _ -> None

    [<CompiledName("NewDelegatePattern")>]
    let (|NewDelegate|_|) input =
        match input with
        | Comb1 (NewDelegateOp ty, e) ->
            let nargs = (getDelegateInvoke ty).GetParameters().Length

            if nargs = 0 then
                match e with
                | NLambdas 1 ([ _ ], e) -> Some(ty, [], e) // try to strip the unit parameter if there is one
                | NLambdas 0 ([], e) -> Some(ty, [], e)
                | _ -> None
            else
                match e with
                | NLambdas nargs (vs, e) -> Some(ty, vs, e)
                | _ -> None
        | _ -> None

    [<CompiledName("LetRecursivePattern")>]
    let (|LetRecursive|_|) input =
        match input with
        | LetRecRaw (IteratedLambda (vs1, E (CombTerm (LetRecCombOp, body :: es)))) -> Some(List.zip vs1 es, body)
        | _ -> None

    //--------------------------------------------------------------------------
    // Getting the type of Raw quotations
    //--------------------------------------------------------------------------

    // Returns record member specified by name
    let getRecordProperty (ty, fieldName) =
        let mems = FSharpType.GetRecordFields(ty, publicOrPrivateBindingFlags)

        match mems |> Array.tryFind (fun minfo -> minfo.Name = fieldName) with
        | Some (m) -> m
        | _ -> invalidArg "fieldName" (String.Format(SR.GetString(SR.QmissingRecordField), ty.FullName, fieldName))

    let getUnionCaseInfo (ty, unionCaseName) =
        let cases = FSharpType.GetUnionCases(ty, publicOrPrivateBindingFlags)

        match cases |> Array.tryFind (fun ucase -> ucase.Name = unionCaseName) with
        | Some case -> case
        | _ ->
            invalidArg "unionCaseName" (String.Format(SR.GetString(SR.QmissingUnionCase), ty.FullName, unionCaseName))

    let getUnionCaseInfoField (unionCase: UnionCaseInfo, index) =
        let fields = unionCase.GetFields()

        if index < 0 || index >= fields.Length then
            invalidArg "index" (SR.GetString(SR.QinvalidCaseIndex))

        fields.[index]

    /// Returns type of lambda application - something like "(fun a -> ..) b"
    let rec typeOfAppliedLambda f =
        let fty = ((typeOf f): Type)

        match fty.GetGenericArguments() with
        | [| _; b |] -> b
        | _ -> invalidOp (SR.GetString(SR.QillFormedAppOrLet))

    /// Returns type of the Raw quotation or fails if the quotation is ill formed
    /// if 'verify' is true, verifies all branches, otherwise ignores some of them when not needed
    and typeOf<'T when 'T :> Expr> (e: 'T) : Type =
        let (E t) = e

        match t with
        | VarTerm v -> v.Type
        | LambdaTerm (v, b) -> mkFunTy v.Type (typeOf b)
        | HoleTerm (ty, _) -> ty
        | CombTerm (c, args) ->
            match c, args with
            | AppOp, [ f; _ ] -> typeOfAppliedLambda f
            | LetOp, _ ->
                match e with
                | Let (_, _, b) -> typeOf b
                | _ -> failwith "unreachable"
            | IfThenElseOp, [ _; t; _ ] -> typeOf t
            | LetRecOp, _ ->
                match e with
                | LetRecursive (_, b) -> typeOf b
                | _ -> failwith "unreachable"
            | LetRecCombOp, _ -> failwith "typeOfConst: LetRecCombOp"
            | NewRecordOp ty, _ -> ty
            | NewUnionCaseOp unionCase, _ -> unionCase.DeclaringType
            | UnionCaseTestOp _, _ -> typeof<Boolean>
            | ValueOp (_, ty, _), _ -> ty
            | WithValueOp (_, ty), _ -> ty
            | TupleGetOp (ty, i), _ -> FSharpType.GetTupleElements(ty).[i]
            | NewTupleOp ty, _ -> ty
            | StaticPropGetOp prop, _ -> prop.PropertyType
            | InstancePropGetOp prop, _ -> prop.PropertyType
            | StaticPropSetOp _, _ -> typeof<Unit>
            | InstancePropSetOp _, _ -> typeof<Unit>
            | InstanceFieldGetOp fld, _ -> fld.FieldType
            | StaticFieldGetOp fld, _ -> fld.FieldType
            | InstanceFieldSetOp _, _ -> typeof<Unit>
            | StaticFieldSetOp _, _ -> typeof<Unit>
            | NewObjectOp ctor, _ -> ctor.DeclaringType
            | InstanceMethodCallOp minfo, _ -> minfo.ReturnType |> removeVoid
            | StaticMethodCallOp minfo, _ -> minfo.ReturnType |> removeVoid
            | InstanceMethodCallWOp (_, minfoW, _), _ -> minfoW.ReturnType |> removeVoid
            | StaticMethodCallWOp (_, minfoW, _), _ -> minfoW.ReturnType |> removeVoid
            | CoerceOp ty, _ -> ty
            | SequentialOp, [ _; b ] -> typeOf b
            | ForIntegerRangeLoopOp, _ -> typeof<Unit>
            | NewArrayOp ty, _ -> mkArrayTy ty
            | NewDelegateOp ty, _ -> ty
            | DefaultValueOp ty, _ -> ty
            | TypeTestOp _, _ -> typeof<bool>
            | QuoteOp true, [ expr ] -> mkExprTy (typeOf expr)
            | QuoteOp false, [ _ ] -> rawExprTy
            | TryFinallyOp, [ e1; _ ] -> typeOf e1
            | TryWithOp, [ e1; _; _ ] -> typeOf e1
            | WhileLoopOp, _
            | VarSetOp, _
            | AddressSetOp, _ -> typeof<Unit>
            | AddressOfOp, [ expr ] -> (typeOf expr).MakeByRefType()
            | (AddressOfOp | QuoteOp _ | SequentialOp | TryWithOp | TryFinallyOp | IfThenElseOp | AppOp), _ ->
                failwith "unreachable"

    //--------------------------------------------------------------------------
    // Constructors for building Raw quotations
    //--------------------------------------------------------------------------

    let mkFEN op l =
        E(CombTerm(op, l))

    let mkFE0 op =
        E(CombTerm(op, []))

    let mkFE1 op x =
        E(CombTerm(op, [ (x :> Expr) ]))

    let mkFE2 op (x, y) =
        E(CombTerm(op, [ (x :> Expr); (y :> Expr) ]))

    let mkFE3 op (x, y, z) =
        E(CombTerm(op, [ (x :> Expr); (y :> Expr); (z :> Expr) ]))

    //--------------------------------------------------------------------------
    // Type-checked constructors for building Raw quotations
    //--------------------------------------------------------------------------

    // t2 is inherited from t1 / t2 implements interface t1 or t2 == t1
    let assignableFrom (t1: Type) (t2: Type) =
        t1.IsAssignableFrom t2

    let checkTypesSR (expectedType: Type) (receivedType: Type) name (threeHoleSR: string) =
        if (expectedType <> receivedType) then
            invalidArg "receivedType" (String.Format(threeHoleSR, name, expectedType, receivedType))

    let checkTypesWeakSR (expectedType: Type) (receivedType: Type) name (threeHoleSR: string) =
        if (not (assignableFrom expectedType receivedType)) then
            invalidArg "receivedType" (String.Format(threeHoleSR, name, expectedType, receivedType))

    let checkArgs (paramInfos: ParameterInfo[]) (args: Expr list) =
        if (paramInfos.Length <> args.Length) then
            invalidArg "args" (SR.GetString(SR.QincorrectNumArgs))

        List.iter2
            (fun (p: ParameterInfo) a ->
                checkTypesWeakSR p.ParameterType (typeOf a) "args" (SR.GetString(SR.QtmmInvalidParam)))
            (paramInfos |> Array.toList)
            args
    // todo: shouldn't this be "strong" type check? sometimes?

    let checkObj (membInfo: MemberInfo) (obj: Expr) =
        // The MemberInfo may be a property associated with a union
        // find the actual related union type
        let rec loop (ty: Type) =
            if FSharpType.IsUnion ty && FSharpType.IsUnion ty.BaseType then
                loop ty.BaseType
            else
                ty

        let declType = loop membInfo.DeclaringType

        if not (assignableFrom declType (typeOf obj)) then
            invalidArg "obj" (SR.GetString(SR.QincorrectInstanceType))

    // Checks lambda application for correctness
    let checkAppliedLambda (f, v) =
        let fty = typeOf f

        let ftyG =
            (if fty.IsGenericType then
                 fty.GetGenericTypeDefinition()
             else
                 fty)

        checkTypesSR funTyC ftyG "f" (SR.GetString(SR.QtmmExpectedFunction))
        let vty = (typeOf v)

        match fty.GetGenericArguments() with
        | [| a; _ |] -> checkTypesSR vty a "f" (SR.GetString(SR.QtmmFunctionArgTypeMismatch))
        | _ -> invalidArg "f" (SR.GetString(SR.QinvalidFuncType))

    let checkBind (v: Var, e) =
        let ety = typeOf e
        checkTypesSR v.Type ety "let" (SR.GetString(SR.QtmmVarTypeNotMatchRHS))

    // [Correct by definition]
    let mkVar v =
        E(VarTerm v)

    let mkQuote (a, isTyped) =
        E(CombTerm(QuoteOp isTyped, [ (a :> Expr) ]))

    let mkValue (v, ty) =
        mkFE0 (ValueOp(v, ty, None))

    let mkValueWithName (v, ty, nm) =
        mkFE0 (ValueOp(v, ty, Some nm))

    let mkValueWithDefn (v, ty, defn) =
        mkFE1 (WithValueOp(v, ty)) defn

    let mkLiftedValueOpG (v, ty: System.Type) =
        let obj =
            if ty.IsEnum then
                System.Enum.ToObject(ty, box v)
            else
                box v

        ValueOp(obj, ty, None)

    let mkUnit () =
        mkValue (null, typeof<unit>)

    let mkAddressOf v =
        mkFE1 AddressOfOp v

    let mkSequential (e1, e2) =
        mkFE2 SequentialOp (e1, e2)

    let mkTypeTest (e, ty) =
        mkFE1 (TypeTestOp ty) e

    let mkVarSet (v, e) =
        mkFE2 VarSetOp (mkVar v, e)

    let mkAddressSet (e1, e2) =
        mkFE2 AddressSetOp (e1, e2)

    let mkLambda (var, body) =
        E(LambdaTerm(var, (body :> Expr)))

    let mkTryWith (e1, v1, e2, v2, e3) =
        mkFE3 TryWithOp (e1, mkLambda (v1, e2), mkLambda (v2, e3))

    let mkTryFinally (e1, e2) =
        mkFE2 TryFinallyOp (e1, e2)

    let mkCoerce (ty, x) =
        mkFE1 (CoerceOp ty) x

    let mkApplication v =
        checkAppliedLambda v
        mkFE2 AppOp v

    let mkLetRaw v =
        mkFE2 LetOp v

    let mkLetRawWithCheck ((e1, e2) as v) =
        checkAppliedLambda (e2, e1)
        mkLetRaw v

    // Tuples
    let mkNewTupleWithType (ty, args: Expr list) =
        let mems = FSharpType.GetTupleElements ty |> Array.toList

        if (args.Length <> mems.Length) then
            invalidArg "args" (SR.GetString(SR.QtupleLengthsDiffer))

        List.iter2 (fun mt a -> checkTypesSR mt (typeOf a) "args" (SR.GetString(SR.QtmmTuple))) mems args
        mkFEN (NewTupleOp ty) args

    let mkNewTuple (args) =
        let ty = FSharpType.MakeTupleType(Array.map typeOf (Array.ofList args))
        mkFEN (NewTupleOp ty) args

    let mkNewStructTuple (asm, args) =
        let ty = FSharpType.MakeStructTupleType(asm, Array.map typeOf (Array.ofList args))
        mkFEN (NewTupleOp ty) args

    let mkNewStructTupleNetStandard args =
        let ty = FSharpType.MakeStructTupleType(Array.map typeOf (Array.ofList args))
        mkFEN (NewTupleOp ty) args

    let mkTupleGet (ty, n, x) =
        checkTypesSR ty (typeOf x) "tupleGet" (SR.GetString(SR.QtmmExprNotMatchTuple))
        let mems = FSharpType.GetTupleElements ty

        if (n < 0 || mems.Length <= n) then
            invalidArg "n" (SR.GetString(SR.QtupleAccessOutOfRange))

        mkFE1 (TupleGetOp(ty, n)) x

    // Records
    let mkNewRecord (ty, args: Expr list) =
        let mems = FSharpType.GetRecordFields(ty, publicOrPrivateBindingFlags)

        if (args.Length <> mems.Length) then
            invalidArg "args" (SR.GetString(SR.QincompatibleRecordLength))

        List.iter2
            (fun (minfo: PropertyInfo) a ->
                checkTypesSR minfo.PropertyType (typeOf a) "recd" (SR.GetString(SR.QtmmIncorrectArgForRecord)))
            (Array.toList mems)
            args

        mkFEN (NewRecordOp ty) args

    // Discriminated unions
    let mkNewUnionCase (unionCase: UnionCaseInfo, args: Expr list) =
        if Unchecked.defaultof<UnionCaseInfo> = unionCase then
            raise (new ArgumentNullException())

        let sargs = unionCase.GetFields()

        if (args.Length <> sargs.Length) then
            invalidArg "args" (SR.GetString(SR.QunionNeedsDiffNumArgs))

        List.iter2
            (fun (minfo: PropertyInfo) a ->
                checkTypesSR minfo.PropertyType (typeOf a) "sum" (SR.GetString(SR.QtmmIncorrectArgForUnion)))
            (Array.toList sargs)
            args

        mkFEN (NewUnionCaseOp unionCase) args

    let mkUnionCaseTest (unionCase: UnionCaseInfo, expr) =
        if Unchecked.defaultof<UnionCaseInfo> = unionCase then
            raise (new ArgumentNullException())

        checkTypesSR unionCase.DeclaringType (typeOf expr) "UnionCaseTagTest" (SR.GetString(SR.QtmmExprTypeMismatch))
        mkFE1 (UnionCaseTestOp unionCase) expr

    // Conditional etc..
    let mkIfThenElse (e, t, f) =
        checkTypesSR (typeOf t) (typeOf f) "cond" (SR.GetString(SR.QtmmTrueAndFalseMustMatch))
        checkTypesSR (typeof<Boolean>) (typeOf e) "cond" (SR.GetString(SR.QtmmCondMustBeBool))
        mkFE3 IfThenElseOp (e, t, f)

    let mkNewArray (ty, args) =
        List.iter (fun a -> checkTypesSR ty (typeOf a) "newArray" (SR.GetString(SR.QtmmInitArray))) args
        mkFEN (NewArrayOp ty) args

    let mkInstanceFieldGet (obj, finfo: FieldInfo) =
        if Unchecked.defaultof<FieldInfo> = finfo then
            raise (new ArgumentNullException())

        match finfo.IsStatic with
        | false ->
            checkObj finfo obj
            mkFE1 (InstanceFieldGetOp finfo) obj
        | true -> invalidArg "finfo" (SR.GetString(SR.QstaticWithReceiverObject))

    let mkStaticFieldGet (finfo: FieldInfo) =
        if Unchecked.defaultof<FieldInfo> = finfo then
            raise (new ArgumentNullException())

        match finfo.IsStatic with
        | true -> mkFE0 (StaticFieldGetOp finfo)
        | false -> invalidArg "finfo" (SR.GetString(SR.QnonStaticNoReceiverObject))

    let mkStaticFieldSet (finfo: FieldInfo, value: Expr) =
        if Unchecked.defaultof<FieldInfo> = finfo then
            raise (new ArgumentNullException())

        checkTypesSR (typeOf value) finfo.FieldType "value" (SR.GetString(SR.QtmmBadFieldType))

        match finfo.IsStatic with
        | true -> mkFE1 (StaticFieldSetOp finfo) value
        | false -> invalidArg "finfo" (SR.GetString(SR.QnonStaticNoReceiverObject))

    let mkInstanceFieldSet (obj, finfo: FieldInfo, value: Expr) =
        if Unchecked.defaultof<FieldInfo> = finfo then
            raise (new ArgumentNullException())

        checkTypesSR (typeOf value) finfo.FieldType "value" (SR.GetString(SR.QtmmBadFieldType))

        match finfo.IsStatic with
        | false ->
            checkObj finfo obj
            mkFE2 (InstanceFieldSetOp finfo) (obj, value)
        | true -> invalidArg "finfo" (SR.GetString(SR.QstaticWithReceiverObject))

    let mkCtorCall (ci: ConstructorInfo, args: Expr list) =
        if Unchecked.defaultof<ConstructorInfo> = ci then
            raise (new ArgumentNullException())

        checkArgs (ci.GetParameters()) args
        mkFEN (NewObjectOp ci) args

    let mkDefaultValue (ty: Type) =
        mkFE0 (DefaultValueOp ty)

    let mkStaticPropGet (pinfo: PropertyInfo, args: Expr list) =
        if Unchecked.defaultof<PropertyInfo> = pinfo then
            raise (new ArgumentNullException())

        if (not pinfo.CanRead) then
            invalidArg "pinfo" (SR.GetString(SR.QreadingSetOnly))

        checkArgs (pinfo.GetIndexParameters()) args

        match pinfo.GetGetMethod(true).IsStatic with
        | true -> mkFEN (StaticPropGetOp pinfo) args
        | false -> invalidArg "pinfo" (SR.GetString(SR.QnonStaticNoReceiverObject))

    let mkInstancePropGet (obj, pinfo: PropertyInfo, args: Expr list) =
        if Unchecked.defaultof<PropertyInfo> = pinfo then
            raise (new ArgumentNullException())

        if (not pinfo.CanRead) then
            invalidArg "pinfo" (SR.GetString(SR.QreadingSetOnly))

        checkArgs (pinfo.GetIndexParameters()) args

        match pinfo.GetGetMethod(true).IsStatic with
        | false ->
            checkObj pinfo obj
            mkFEN (InstancePropGetOp pinfo) (obj :: args)
        | true -> invalidArg "pinfo" (SR.GetString(SR.QstaticWithReceiverObject))

    let mkStaticPropSet (pinfo: PropertyInfo, args: Expr list, value: Expr) =
        if Unchecked.defaultof<PropertyInfo> = pinfo then
            raise (new ArgumentNullException())

        if (not pinfo.CanWrite) then
            invalidArg "pinfo" (SR.GetString(SR.QwritingGetOnly))

        checkArgs (pinfo.GetIndexParameters()) args

        match pinfo.GetSetMethod(true).IsStatic with
        | true -> mkFEN (StaticPropSetOp pinfo) (args @ [ value ])
        | false -> invalidArg "pinfo" (SR.GetString(SR.QnonStaticNoReceiverObject))

    let mkInstancePropSet (obj, pinfo: PropertyInfo, args: Expr list, value: Expr) =
        if Unchecked.defaultof<PropertyInfo> = pinfo then
            raise (new ArgumentNullException())

        if (not pinfo.CanWrite) then
            invalidArg "pinfo" (SR.GetString(SR.QwritingGetOnly))

        checkArgs (pinfo.GetIndexParameters()) args

        match pinfo.GetSetMethod(true).IsStatic with
        | false ->
            checkObj pinfo obj
            mkFEN (InstancePropSetOp pinfo) (obj :: (args @ [ value ]))
        | true -> invalidArg "pinfo" (SR.GetString(SR.QstaticWithReceiverObject))

    let mkInstanceMethodCall (obj, minfo: MethodInfo, args: Expr list) =
        if Unchecked.defaultof<MethodInfo> = minfo then
            raise (new ArgumentNullException())

        checkArgs (minfo.GetParameters()) args

        match minfo.IsStatic with
        | false ->
            checkObj minfo obj
            mkFEN (InstanceMethodCallOp minfo) (obj :: args)
        | true -> invalidArg "minfo" (SR.GetString(SR.QstaticWithReceiverObject))

    let mkInstanceMethodCallW (obj, minfo: MethodInfo, minfoW: MethodInfo, nWitnesses: int, args: Expr list) =
        if Unchecked.defaultof<MethodInfo> = minfo then
            raise (new ArgumentNullException())

        checkArgs (minfoW.GetParameters()) args

        match minfoW.IsStatic with
        | false ->
            checkObj minfo obj
            mkFEN (InstanceMethodCallWOp(minfo, minfoW, nWitnesses)) (obj :: args)
        | true -> invalidArg "minfo" (SR.GetString(SR.QstaticWithReceiverObject))

    let mkStaticMethodCall (minfo: MethodInfo, args: Expr list) =
        if Unchecked.defaultof<MethodInfo> = minfo then
            raise (new ArgumentNullException())

        checkArgs (minfo.GetParameters()) args

        match minfo.IsStatic with
        | true -> mkFEN (StaticMethodCallOp minfo) args
        | false -> invalidArg "minfo" (SR.GetString(SR.QnonStaticNoReceiverObject))

    let mkStaticMethodCallW (minfo: MethodInfo, minfoW: MethodInfo, nWitnesses: int, args: Expr list) =
        if Unchecked.defaultof<MethodInfo> = minfo then
            raise (new ArgumentNullException())

        checkArgs (minfoW.GetParameters()) args

        match minfo.IsStatic with
        | true -> mkFEN (StaticMethodCallWOp(minfo, minfoW, nWitnesses)) args
        | false -> invalidArg "minfo" (SR.GetString(SR.QnonStaticNoReceiverObject))

    let mkForLoop (v: Var, lowerBound, upperBound, body) =
        checkTypesSR (typeof<int>) (typeOf lowerBound) "lowerBound" (SR.GetString(SR.QtmmLowerUpperBoundMustBeInt))
        checkTypesSR (typeof<int>) (typeOf upperBound) "upperBound" (SR.GetString(SR.QtmmLowerUpperBoundMustBeInt))
        checkTypesSR (typeof<int>) (v.Type) "for" (SR.GetString(SR.QtmmLoopBodyMustBeLambdaTakingInteger))
        mkFE3 ForIntegerRangeLoopOp (lowerBound, upperBound, mkLambda (v, body))

    let mkWhileLoop (guard, body) =
        checkTypesSR (typeof<bool>) (typeOf guard) "guard" (SR.GetString(SR.QtmmGuardMustBeBool))
        checkTypesSR (typeof<Unit>) (typeOf body) "body" (SR.GetString(SR.QtmmBodyMustBeUnit))
        mkFE2 (WhileLoopOp) (guard, body)

    let mkNewDelegate (ty, e) =
        let mi = getDelegateInvoke ty
        let ps = mi.GetParameters()

        let dlfun =
            Array.foldBack (fun (p: ParameterInfo) retTy -> mkFunTy p.ParameterType retTy) ps mi.ReturnType

        checkTypesSR dlfun (typeOf e) "ty" (SR.GetString(SR.QtmmFunTypeNotMatchDelegate))
        mkFE1 (NewDelegateOp ty) e

    let mkLet (v, e, b) =
        checkBind (v, e)
        mkLetRaw (e, mkLambda (v, b))

    //let mkLambdas(vs, b) = mkRLinear mkLambdaRaw (vs, (b:>Expr))
    let mkTupledApplication (f, args) =
        match args with
        | [] -> mkApplication (f, mkUnit ())
        | [ x ] -> mkApplication (f, x)
        | _ -> mkApplication (f, mkNewTuple args)

    let mkApplications (f: Expr, es: Expr list list) =
        mkLLinear mkTupledApplication (f, es)

    let mkIteratedLambdas (vs, b) =
        mkRLinear mkLambda (vs, b)

    let mkLetRecRaw v =
        mkFE1 LetRecOp v

    let mkLetRecCombRaw v =
        mkFEN LetRecCombOp v

    let mkLetRec (ves: (Var * Expr) list, body) =
        List.iter checkBind ves
        let vs, es = List.unzip ves
        mkLetRecRaw (mkIteratedLambdas (vs, mkLetRecCombRaw (body :: es)))

    let ReflectedDefinitionsResourceNameBase = "ReflectedDefinitions"

    //-------------------------------------------------------------------------
    // General Method Binder

    /// Usually functions in modules are not overloadable so having name is enough to recover the function.
    /// However type extensions break this assumption - it is possible to have multiple extension methods in module that will have the same name.
    /// This type is used to denote different binding results so we can distinguish the latter case and retry binding later when more information is available.
    [<NoEquality; NoComparison>]
    type ModuleDefinitionBindingResult<'T, 'R> =
        | Unique of 'T
        | Ambiguous of 'R

    let typeEquals (ty1: Type) (ty2: Type) =
        Type.op_Equality (ty1, ty2)

    let typesEqual (tys1: Type list) (tys2: Type list) =
        (tys1.Length = tys2.Length) && List.forall2 typeEquals tys1 tys2

    let instFormal (typarEnv: Type[]) (ty: Instantiable<'T>) =
        ty (fun i -> typarEnv.[i])

    let getGenericArguments (genericType: Type) =
        if genericType.IsGenericType then
            genericType.GetGenericArguments()
        else
            [||]

    let getNumGenericArguments (genericType: Type) =
        if genericType.IsGenericType then
            genericType.GetGenericArguments().Length
        else
            0

    let bindMethodBySearch (knownArgCount: int voption, parentT: Type, nm, marity, argTys, retTy) =
        let methInfos = parentT.GetMethods staticOrInstanceBindingFlags |> Array.toList
        // First, filter on name, if unique, then binding "done"
        let tyargTs = getGenericArguments parentT
        let methInfos = methInfos |> List.filter (fun methInfo -> methInfo.Name = nm)

        match methInfos with
        | [ methInfo ] -> methInfo
        | _ ->
            // Second, type match.
            let select (methInfo: MethodInfo) =
                // mref implied Types
                let mtyargTIs =
                    if methInfo.IsGenericMethod then
                        methInfo.GetGenericArguments()
                    else
                        [||]

                if mtyargTIs.Length <> marity then
                    false (* method generic arity mismatch *)
                else
                    let typarEnv = (Array.append tyargTs mtyargTIs)
                    let argTs = argTys |> List.map (instFormal typarEnv)
                    let resT = instFormal typarEnv retTy

                    // methInfo implied Types
                    let haveArgTs =
                        let parameters = Array.toList (methInfo.GetParameters())
                        parameters |> List.map (fun param -> param.ParameterType)

                    let haveResT = methInfo.ReturnType

                    let nargTs = argTs.Length

                    // check for match
                    if nargTs <> haveArgTs.Length then
                        false (* method argument length mismatch *)
                    else

                    // If a known-number-of-arguments-including-object-argument has been given then check that
                    if
                        (match knownArgCount with
                         | ValueNone -> false
                         | ValueSome n -> n <> (if methInfo.IsStatic then 0 else 1) + nargTs)
                    then
                        false
                    else

                        let res = typesEqual (resT :: argTs) (haveResT :: haveArgTs)
                        res
            // return MethodInfo for (generic) type's (generic) method
            match List.tryFind select methInfos with
            | None -> invalidOp (SR.GetString SR.QcannotBindToMethod)
            | Some methInfo -> methInfo

    let bindMethodHelper (knownArgCount, (parentT: Type, nm, marity, argTys, retTy)) =
        if isNull parentT then
            invalidArg "parentT" (SR.GetString(SR.QparentCannotBeNull))

        if marity = 0 then
            let tyargTs =
                if parentT.IsGenericType then
                    parentT.GetGenericArguments()
                else
                    [||]

            let argTs = Array.ofList (List.map (instFormal tyargTs) argTys)
            let resT = instFormal tyargTs retTy

            let methInfo =
                try
                    match parentT.GetMethod(nm, staticOrInstanceBindingFlags, null, argTs, null) with
                    | null -> None
                    | res -> Some res
                with :? AmbiguousMatchException ->
                    None

            match methInfo with
            | Some methInfo when (typeEquals resT methInfo.ReturnType) -> methInfo
            | _ -> bindMethodBySearch (knownArgCount, parentT, nm, marity, argTys, retTy)
        else
            bindMethodBySearch (knownArgCount, parentT, nm, marity, argTys, retTy)

    let bindModuleProperty (ty: Type, nm) =
        match ty.GetProperty(nm, staticBindingFlags) with
        | null -> invalidOp (String.Format(SR.GetString(SR.QcannotBindProperty), nm, ty.ToString()))
        | res -> res

    let bindModuleFunctionWithCallSiteArgs (ty: Type, nm, argTypes: Type list, tyArgs: Type list) =
        let argTypes = List.toArray argTypes
        let tyArgs = List.toArray tyArgs

        let methInfo =
            try
                match ty.GetMethod(nm, staticOrInstanceBindingFlags, null, argTypes, null) with
                | null -> None
                | res -> Some res
            with :? AmbiguousMatchException ->
                None

        match methInfo with
        | Some methInfo -> methInfo
        | _ ->
            // narrow down set of candidates by removing methods with a different name\number of arguments\number of type parameters
            let candidates =
                ty.GetMethods staticBindingFlags
                |> Array.filter (fun mi ->
                    mi.Name = nm
                    && mi.GetParameters().Length = argTypes.Length
                    && let methodTyArgCount =
                        if mi.IsGenericMethod then
                            mi.GetGenericArguments().Length
                        else
                            0 in
                       methodTyArgCount = tyArgs.Length)

            let fail () =
                invalidOp (String.Format(SR.GetString(SR.QcannotBindFunction), nm, ty.ToString()))

            match candidates with
            | [||] -> fail ()
            | [| solution |] -> solution
            | candidates ->
                let solution =
                    // no type arguments - just perform pairwise comparison of type in methods signature and argument type from the callsite
                    if tyArgs.Length = 0 then
                        candidates
                        |> Array.tryFind (fun mi ->
                            let paramTys = mi.GetParameters() |> Array.map (fun pi -> pi.ParameterType)
                            Array.forall2 (=) argTypes paramTys)
                    else
                        let FAIL = -1
                        let MATCH = 2
                        let GENERIC_MATCH = 1
                        // if signature has type arguments then it is possible to have several candidates like
                        // - Foo(_ : 'a)
                        // - Foo(_ : int)
                        // and callsite
                        // - Foo<int>(_ : int)
                        // here instantiation of first method we'll have two similar signatures
                        // however compiler will pick second one and we must do the same.

                        // here we compute weights for every signature
                        // for every parameter type:
                        // - non-matching with actual argument type stops computation and return FAIL as the final result
                        // - exact match with actual argument type adds MATCH value to the final result
                        // - parameter type is generic that after instantiation matches actual argument type adds GENERIC_MATCH to the final result
                        // - parameter type is generic that after instantiation doesn't actual argument type stops computation and return FAIL as the final result
                        let weight (mi: MethodInfo) =
                            let parameters = mi.GetParameters()

                            let rec iter i acc =
                                if i >= argTypes.Length then
                                    acc
                                else
                                    let param = parameters.[i]

                                    if param.ParameterType.IsGenericParameter then
                                        let actualTy = tyArgs.[param.ParameterType.GenericParameterPosition]

                                        if actualTy = argTypes.[i] then
                                            iter (i + 1) (acc + GENERIC_MATCH)
                                        else
                                            FAIL
                                    else if param.ParameterType = argTypes.[i] then
                                        iter (i + 1) (acc + MATCH)
                                    else
                                        FAIL

                            iter 0 0

                        let solution, weight =
                            candidates |> Array.map (fun mi -> mi, weight mi) |> Array.maxBy snd

                        if weight = FAIL then
                            None
                        else
                            Some solution

                match solution with
                | Some mi -> mi
                | None -> fail ()

    let mkNamedType (genericType: Type, tyargs) =
        match tyargs with
        | [] -> genericType
        | _ -> genericType.MakeGenericType(Array.ofList tyargs)

    let inline checkNonNullResult (arg: string, err: string) y =
        match box y with
        | null -> raise (new ArgumentNullException(arg, err))
        | _ -> y

    let inst (tyargs: Type list) (i: Instantiable<'T>) =
        i (fun idx -> tyargs.[idx]) // Note, O n looks, but #tyargs is always small

    let bindProp (genericType, propName, retType, argTypes, tyargs) =
        // We search in the instantiated type, rather than searching the generic type.
        let typ = mkNamedType (genericType, tyargs)
        let argTypes: Type list = argTypes |> inst tyargs
        let retType: Type = retType |> inst tyargs |> removeVoid
        // fxcop may not see "propName" as an arg
        typ.GetProperty(propName, staticOrInstanceBindingFlags, null, retType, Array.ofList argTypes, null)
        |> checkNonNullResult ("propName", String.Format(SR.GetString(SR.QfailedToBindProperty), propName))

    let bindField (genericType, fldName, tyargs) =
        let typ = mkNamedType (genericType, tyargs)

        typ.GetField(fldName, staticOrInstanceBindingFlags)
        |> checkNonNullResult ("fldName", String.Format(SR.GetString(SR.QfailedToBindField), fldName)) // fxcop may not see "fldName" as an arg

    let bindGenericCctor (genericType: Type) =
        genericType.GetConstructor(staticBindingFlags, null, [||], null)
        |> checkNonNullResult ("genericType", SR.GetString(SR.QfailedToBindConstructor))

    let bindGenericCtor (genericType: Type, argTypes: Instantiable<Type list>) =
        let argTypes = instFormal (getGenericArguments genericType) argTypes

        genericType.GetConstructor(instanceBindingFlags, null, Array.ofList argTypes, null)
        |> checkNonNullResult ("genericType", SR.GetString(SR.QfailedToBindConstructor))

    let bindCtor (genericType, argTypes: Instantiable<Type list>, tyargs) =
        let typ = mkNamedType (genericType, tyargs)
        let argTypes = argTypes |> inst tyargs

        typ.GetConstructor(instanceBindingFlags, null, Array.ofList argTypes, null)
        |> checkNonNullResult ("genericType", SR.GetString(SR.QfailedToBindConstructor))

    let chop n xs =
        if n < 0 then
            invalidArg "n" (SR.GetString(SR.inputMustBeNonNegative))

        let rec split l =
            match l with
            | 0, xs -> [], xs
            | n, x :: xs ->
                let front, back = split (n - 1, xs)
                x :: front, back
            | _, [] -> failwith "List.chop: not enough elts list"

        split (n, xs)

    let instMeth (ngmeth: MethodInfo, methTypeArgs) =
        if ngmeth.GetGenericArguments().Length = 0 then
            ngmeth (* non generic *)
        else
            ngmeth.MakeGenericMethod(Array.ofList methTypeArgs)

    let bindGenericMeth (knownArgCount, (genericType: Type, argTypes, retType, methName, numMethTyargs)) =
        bindMethodHelper (knownArgCount, (genericType, methName, numMethTyargs, argTypes, retType))

    let bindMeth (knownArgCount, (genericType: Type, argTypes, retType, methName, numMethTyargs), tyargs) =
        let numEnclTypeArgs = genericType.GetGenericArguments().Length
        let enclTypeArgs, methTypeArgs = chop numEnclTypeArgs tyargs
        let ty = mkNamedType (genericType, enclTypeArgs)

        let ngmeth =
            bindMethodHelper (knownArgCount, (ty, methName, numMethTyargs, argTypes, retType))

        instMeth (ngmeth, methTypeArgs)

    let pinfoIsStatic (pinfo: PropertyInfo) =
        if pinfo.CanRead then
            pinfo.GetGetMethod(true).IsStatic
        elif pinfo.CanWrite then
            pinfo.GetSetMethod(true).IsStatic
        else
            false

    /// Unpickling
    module SimpleUnpickle =

        [<NoEquality; NoComparison>]
        type InputState =
            {
                is: ByteStream
                istrings: string[]
                localAssembly: System.Reflection.Assembly
                referencedTypeDefs: Type[]
            }

        let u_byte_as_int st =
            st.is.ReadByte()

        let u_bool st =
            let b = u_byte_as_int st
            (b = 1)

        let u_void (_: InputState) =
            ()

        let prim_u_int32 st =
            let b0 = (u_byte_as_int st)
            let b1 = (u_byte_as_int st)
            let b2 = (u_byte_as_int st)
            let b3 = (u_byte_as_int st)
            b0 ||| (b1 <<< 8) ||| (b2 <<< 16) ||| (b3 <<< 24)

        let u_int32 st =
            let b0 = u_byte_as_int st

            if b0 <= 0x7F then
                b0
            elif b0 <= 0xbf then
                let b0 = b0 &&& 0x7f
                let b1 = (u_byte_as_int st)
                (b0 <<< 8) ||| b1
            else
                prim_u_int32 st

        let u_bytes st =
            let len = u_int32 st
            st.is.ReadBytes len

        let prim_u_string st =
            let len = u_int32 st
            st.is.ReadUtf8BytesAsString len

        let u_int st =
            u_int32 st

        let u_sbyte st =
            sbyte (u_int32 st)

        let u_byte st =
            byte (u_byte_as_int st)

        let u_int16 st =
            int16 (u_int32 st)

        let u_uint16 st =
            uint16 (u_int32 st)

        let u_uint32 st =
            uint32 (u_int32 st)

        let u_int64 st =
            let b1 = int64 (u_int32 st) &&& 0xFFFFFFFFL
            let b2 = int64 (u_int32 st)
            b1 ||| (b2 <<< 32)

        let u_uint64 st =
            uint64 (u_int64 st)

        let u_double st =
            System.BitConverter.ToDouble(System.BitConverter.GetBytes(u_int64 st), 0)

        let u_float32 st =
            System.BitConverter.ToSingle(System.BitConverter.GetBytes(u_int32 st), 0)

        let u_char st =
            char (int32 (u_uint16 st))

        let inline u_tup2 p1 p2 st =
            let a = p1 st in
            let b = p2 st in
            (a, b)

        let inline u_tup3 p1 p2 p3 st =
            let a = p1 st in
            let b = p2 st in
            let c = p3 st in
            (a, b, c)

        let inline u_tup4 p1 p2 p3 p4 st =
            let a = p1 st in
            let b = p2 st in
            let c = p3 st in
            let d = p4 st in
            (a, b, c, d)

        let inline u_tup5 p1 p2 p3 p4 p5 st =
            let a = p1 st in
            let b = p2 st in
            let c = p3 st in
            let d = p4 st in
            let e = p5 st in
            (a, b, c, d, e)

        let u_uniq (tbl: _ array) st =
            let n = u_int st

            if n < 0 || n >= tbl.Length then
                failwith ("u_uniq: out of range, n = " + string n + ", sizeof tab = " + string tbl.Length)

            tbl.[n]

        let u_string st =
            u_uniq st.istrings st

        let rec u_list_aux f acc st =
            let tag = u_byte_as_int st

            match tag with
            | 0 -> List.rev acc
            | 1 -> let a = f st in u_list_aux f (a :: acc) st
            | n -> failwith ("u_list: found number " + string n)

        let u_list f st =
            u_list_aux f [] st

        let unpickleObj localAssembly referencedTypeDefs u phase2bytes =
            let phase2data =
                let st2 =
                    {
                        is = new ByteStream(phase2bytes, 0, phase2bytes.Length)
                        istrings = [||]
                        localAssembly = localAssembly
                        referencedTypeDefs = referencedTypeDefs
                    }

                u_tup2 (u_list prim_u_string) u_bytes st2

            let stringTab, phase1bytes = phase2data

            let st1 =
                {
                    is = new ByteStream(phase1bytes, 0, phase1bytes.Length)
                    istrings = Array.ofList stringTab
                    localAssembly = localAssembly
                    referencedTypeDefs = referencedTypeDefs
                }

            let res = u st1
            res

    open SimpleUnpickle

    let decodeFunTy args =
        match args with
        | [ d; r ] -> funTyC.MakeGenericType([| d; r |])
        | _ -> invalidArg "args" (SR.GetString(SR.QexpectedTwoTypes))

    let decodeArrayTy n (tys: Type list) =
        match tys with
        | [ ty ] ->
            if (n = 1) then
                ty.MakeArrayType()
            else
                ty.MakeArrayType n
        // typeof<int>.MakeArrayType 1 returns "Int[*]" but we need "Int[]"
        | _ -> invalidArg "tys" (SR.GetString(SR.QexpectedOneType))

    let mkNamedTycon (tcName, assembly: Assembly) =
        match assembly.GetType tcName with
        | null ->
            // For some reason we can get 'null' returned here even when a type with the right name exists... Hence search the slow way...
            match (assembly.GetTypes() |> Array.tryFind (fun a -> a.FullName = tcName)) with
            | Some ty -> ty
            | None ->
                invalidArg
                    "tcName"
                    (String.Format(SR.GetString(SR.QfailedToBindTypeInAssembly), tcName, assembly.FullName))
        | ty -> ty

    let decodeNamedTy genericType tsR =
        mkNamedType (genericType, tsR)

    let mscorlib = typeof<System.Int32>.Assembly

    let u_assemblyRef st =
        u_string st

    let decodeAssemblyRef st a =
        if a = "" then
            mscorlib
        elif a = "." then
            st.localAssembly
        else
            match System.Reflection.Assembly.Load a with
            | null -> invalidOp (String.Format(SR.GetString(SR.QfailedToBindAssembly), a.ToString()))
            | assembly -> assembly

    let u_NamedType st =
        let a, b = u_tup2 u_string u_assemblyRef st
        let mutable idx = 0
        // From FSharp.Core for F# 4.0+ (4.4.0.0+), referenced type definitions can be integer indexes into a table of type definitions provided on quotation
        // deserialization, avoiding the need for System.Reflection.Assembly.Load
        if System.Int32.TryParse(a, &idx) && b = "" then
            st.referencedTypeDefs.[idx]
        else
            // escape commas found in type name, which are not already escaped
            // '\' is not valid in a type name except as an escape character, so logic can be pretty simple
            let escapedTcName =
                System.Text.RegularExpressions.Regex.Replace(a, @"(?<!\\), ", @"\, ")

            let assemblyRef = decodeAssemblyRef st b
            mkNamedTycon (escapedTcName, assemblyRef)

    let u_tyconstSpec st =
        let tag = u_byte_as_int st

        match tag with
        | 1 -> u_void st |> (fun () -> decodeFunTy)
        | 2 -> u_NamedType st |> decodeNamedTy
        | 3 -> u_int st |> decodeArrayTy
        | _ -> failwith "u_tyconstSpec"

    let appL fs env =
        List.map (fun f -> f env) fs

    let rec u_dtype st : (int -> Type) -> Type =
        let tag = u_byte_as_int st

        match tag with
        | 0 -> u_int st |> (fun x env -> env x)
        | 1 -> u_tup2 u_tyconstSpec (u_list u_dtype) st |> (fun (a, b) env -> a (appL b env))
        | _ -> failwith "u_dtype"

    let u_dtypes st =
        let a = u_list u_dtype st in appL a

    let (|NoTyArgs|) input =
        match input with
        | [] -> ()
        | _ -> failwith "incorrect number of arguments during deserialization"

    let (|OneTyArg|) input =
        match input with
        | [ x ] -> x
        | _ -> failwith "incorrect number of arguments during deserialization"

    [<NoEquality; NoComparison>]
    type BindingEnv =
        {
            /// Mapping from variable index to Var object for the variable
            vars: Map<int, Var>
            /// The number of indexes in the mapping
            varn: int
            /// The active type instantiation for generic type parameters
            typeInst: int -> Type
        }

    let addVar env v =
        { env with
            vars = env.vars.Add(env.varn, v)
            varn = env.varn + 1
        }

    let mkTyparSubst (tyargs: Type[]) =
        let n = tyargs.Length

        fun idx ->
            if idx < n then
                tyargs.[idx]
            else
                invalidOp (SR.GetString(SR.QtypeArgumentOutOfRange))

    let envClosed (spliceTypes: Type[]) =
        {
            vars = Map.empty
            varn = 0
            typeInst = mkTyparSubst spliceTypes
        }

    type Bindable<'T> = BindingEnv -> 'T

    let rec u_Expr st =
        let tag = u_byte_as_int st

        match tag with
        | 0 ->
            let a = u_constSpec st
            let b = u_dtypes st
            let args = u_list u_Expr st

            (fun (env: BindingEnv) ->
                let args = List.map (fun e -> e env) args

                let a =
                    match a with
                    | Unique v -> v
                    | Ambiguous f ->
                        let argTys = List.map typeOf args
                        f argTys

                let tyargs = b env.typeInst
                E(CombTerm(a tyargs (ValueSome args.Length), args)))
        | 1 ->
            let x = u_VarRef st
            (fun env -> E(VarTerm(x env)))
        | 2 ->
            let a = u_VarDecl st
            let b = u_Expr st
            (fun env -> let v = a env in E(LambdaTerm(v, b (addVar env v))))
        | 3 ->
            let a = u_dtype st
            let idx = u_int st
            (fun env -> E(HoleTerm(a env.typeInst, idx)))
        | 4 ->
            let a = u_Expr st
            (fun env -> mkQuote (a env, true))
        | 5 ->
            let a = u_Expr st
            let attrs = u_list u_Expr st
            (fun env -> let e = (a env) in EA(e.Tree, (e.CustomAttributes @ List.map (fun attrf -> attrf env) attrs)))
        | 6 ->
            let a = u_dtype st
            (fun env -> mkVar (Var.Global("this", a env.typeInst)))
        | 7 ->
            let a = u_Expr st
            (fun env -> mkQuote (a env, false))
        | _ -> failwith "u_Expr"

    and u_VarDecl st =
        let s, b, mut = u_tup3 u_string u_dtype u_bool st
        (fun env -> new Var(s, b env.typeInst, mut))

    and u_VarRef st =
        let i = u_int st
        (fun env -> env.vars.[i])

    and u_RecdField st =
        let ty, nm = u_tup2 u_NamedType u_string st
        (fun tyargs -> getRecordProperty (mkNamedType (ty, tyargs), nm))

    and u_UnionCaseInfo st =
        let ty, nm = u_tup2 u_NamedType u_string st
        (fun tyargs -> getUnionCaseInfo (mkNamedType (ty, tyargs), nm))

    and u_UnionCaseField st =
        let case, i = u_tup2 u_UnionCaseInfo u_int st
        (fun tyargs -> getUnionCaseInfoField (case tyargs, i))

    and u_ModuleDefn witnessInfo st =
        let (ty, nm, isProp) = u_tup3 u_NamedType u_string u_bool st

        if isProp then
            Unique(StaticPropGetOp(bindModuleProperty (ty, nm)))
        else
            let meths =
                ty.GetMethods staticBindingFlags |> Array.filter (fun mi -> mi.Name = nm)

            match meths with
            | [||] -> invalidOp (String.Format(SR.GetString(SR.QcannotBindFunction), nm, ty.ToString()))
            | [| minfo |] ->
                match witnessInfo with
                | None -> Unique(StaticMethodCallOp(minfo))
                | Some (nmW, nWitnesses) ->
                    let methsW =
                        ty.GetMethods(staticBindingFlags) |> Array.filter (fun mi -> mi.Name = nmW)

                    match methsW with
                    | [||] -> invalidOp (String.Format(SR.GetString(SR.QcannotBindFunction), nmW, ty.ToString()))
                    | [| minfoW |] -> Unique(StaticMethodCallWOp(minfo, minfoW, nWitnesses))
                    | _ ->
                        Ambiguous(fun argTypes tyargs ->
                            let minfoW = bindModuleFunctionWithCallSiteArgs (ty, nm, argTypes, tyargs)
                            StaticMethodCallWOp(minfo, minfoW, nWitnesses))
            | _ ->
                Ambiguous(fun argTypes tyargs ->
                    match witnessInfo with
                    | None ->
                        let minfo = bindModuleFunctionWithCallSiteArgs (ty, nm, argTypes, tyargs)
                        StaticMethodCallOp minfo
                    | Some (nmW, nWitnesses) ->
                        let minfo =
                            bindModuleFunctionWithCallSiteArgs (ty, nm, List.skip nWitnesses argTypes, tyargs)

                        let minfoW = bindModuleFunctionWithCallSiteArgs (ty, nmW, argTypes, tyargs)
                        StaticMethodCallWOp(minfo, minfoW, nWitnesses))

    and u_MethodInfoData st =
        u_tup5 u_NamedType (u_list u_dtype) u_dtype u_string u_int st

    and u_PropInfoData st =
        u_tup4 u_NamedType u_string u_dtype u_dtypes st

    and u_CtorInfoData st =
        u_tup2 u_NamedType u_dtypes st

    and u_MethodBase st =
        let tag = u_byte_as_int st

        match tag with
        | 0 ->
            match u_ModuleDefn None st with
            | Unique (StaticMethodCallOp minfo) -> (minfo :> MethodBase)
            | Unique (StaticPropGetOp pinfo) -> (pinfo.GetGetMethod true :> MethodBase)
            | Ambiguous (_) -> raise (System.Reflection.AmbiguousMatchException())
            | _ -> failwith "unreachable"
        | 1 ->
            let ((genericType, _, _, methName, _) as data) = u_MethodInfoData st

            if methName = ".cctor" then
                let cinfo = bindGenericCctor genericType
                (cinfo :> MethodBase)
            else
                let minfo = bindGenericMeth (ValueNone, data)
                (minfo :> MethodBase)
        | 2 ->
            let data = u_CtorInfoData st
            let cinfo = bindGenericCtor data
            (cinfo :> MethodBase)
        | 3 ->
            let methNameW = u_string st
            let nWitnesses = u_int st

            match u_ModuleDefn (Some(methNameW, nWitnesses)) st with
            | Unique (StaticMethodCallOp (minfo)) -> (minfo :> MethodBase)
            | Unique (StaticMethodCallWOp (_minfo, minfoW, _)) -> (minfoW :> MethodBase)
            | Unique (StaticPropGetOp (pinfo)) -> (pinfo.GetGetMethod(true) :> MethodBase)
            | Ambiguous (_) -> raise (System.Reflection.AmbiguousMatchException())
            | _ -> failwith "unreachable"
        | _ -> failwith "u_MethodBase"

    and instModuleDefnOp r tyargs _ =
        match r with
        | StaticMethodCallOp (minfo) -> StaticMethodCallOp(instMeth (minfo, tyargs))
        | StaticMethodCallWOp (minfo, minfoW, n) ->
            StaticMethodCallWOp(instMeth (minfo, tyargs), instMeth (minfoW, tyargs), n)
        // OK to throw away the tyargs here since this only non-generic values in modules get represented by static properties
        | x -> x

    and u_constSpec st =
        let tag = u_byte_as_int st

        if tag = 1 then
            match u_ModuleDefn None st with
            | Unique r -> Unique(instModuleDefnOp r)
            | Ambiguous f -> Ambiguous(fun argTypes tyargs -> instModuleDefnOp (f argTypes tyargs) tyargs)
        elif tag = 51 then
            let nmW = u_string st
            let nWitnesses = u_int st

            match u_ModuleDefn (Some(nmW, nWitnesses)) st with
            | Unique r -> Unique(instModuleDefnOp r)
            | Ambiguous f -> Ambiguous(fun argTypes tyargs -> instModuleDefnOp (f argTypes tyargs) tyargs)
        else
            let constSpec =
                match tag with
                | 0 -> u_void st |> (fun () NoTyArgs _ -> IfThenElseOp)
                // 1 taken above
                | 2 -> u_void st |> (fun () NoTyArgs _ -> LetRecOp)
                | 3 -> u_NamedType st |> (fun x tyargs _ -> NewRecordOp(mkNamedType (x, tyargs)))
                | 4 -> u_RecdField st |> (fun prop tyargs _ -> InstancePropGetOp(prop tyargs))
                | 5 ->
                    u_UnionCaseInfo st
                    |> (fun unionCase tyargs _ -> NewUnionCaseOp(unionCase tyargs))
                | 6 -> u_UnionCaseField st |> (fun prop tyargs _ -> InstancePropGetOp(prop tyargs))
                | 7 ->
                    u_UnionCaseInfo st
                    |> (fun unionCase tyargs _ -> UnionCaseTestOp(unionCase tyargs))
                | 8 -> u_void st |> (fun () (OneTyArg tyarg) _ -> NewTupleOp tyarg)
                | 9 -> u_int st |> (fun x (OneTyArg tyarg) _ -> TupleGetOp(tyarg, x))
                // Note, these get type args because they may be the result of reading literal field constants
                | 11 -> u_bool st |> (fun x (OneTyArg tyarg) _ -> mkLiftedValueOpG (x, tyarg))
                | 12 -> u_string st |> (fun x (OneTyArg tyarg) _ -> mkLiftedValueOpG (x, tyarg))
                | 13 -> u_float32 st |> (fun x (OneTyArg tyarg) _ -> mkLiftedValueOpG (x, tyarg))
                | 14 -> u_double st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 15 -> u_char st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 16 -> u_sbyte st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 17 -> u_byte st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 18 -> u_int16 st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 19 -> u_uint16 st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 20 -> u_int32 st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 21 -> u_uint32 st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 22 -> u_int64 st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 23 -> u_uint64 st |> (fun a (OneTyArg tyarg) _ -> mkLiftedValueOpG (a, tyarg))
                | 24 -> u_void st |> (fun () NoTyArgs _ -> mkLiftedValueOpG ((), typeof<unit>))
                | 25 ->
                    u_PropInfoData st
                    |> (fun (a, b, c, d) tyargs _ ->
                        let pinfo = bindProp (a, b, c, d, tyargs) in

                        if pinfoIsStatic pinfo then
                            StaticPropGetOp pinfo
                        else
                            InstancePropGetOp pinfo)
                | 26 ->
                    u_CtorInfoData st
                    |> (fun (a, b) tyargs _ -> NewObjectOp(bindCtor (a, b, tyargs)))
                | 28 -> u_void st |> (fun () (OneTyArg ty) _ -> CoerceOp ty)
                | 29 -> u_void st |> (fun () NoTyArgs _ -> SequentialOp)
                | 30 -> u_void st |> (fun () NoTyArgs _ -> ForIntegerRangeLoopOp)
                | 31 ->
                    u_MethodInfoData st
                    |> (fun p tyargs knownArgCount ->
                        let minfo = bindMeth (knownArgCount, p, tyargs) in

                        if minfo.IsStatic then
                            StaticMethodCallOp minfo
                        else
                            InstanceMethodCallOp minfo)
                | 32 -> u_void st |> (fun () (OneTyArg ty) _ -> NewArrayOp ty)
                | 33 -> u_void st |> (fun () (OneTyArg ty) _ -> NewDelegateOp ty)
                | 34 -> u_void st |> (fun () NoTyArgs _ -> WhileLoopOp)
                | 35 -> u_void st |> (fun () NoTyArgs _ -> LetOp)
                | 36 -> u_RecdField st |> (fun prop tyargs _ -> InstancePropSetOp(prop tyargs))
                | 37 ->
                    u_tup2 u_NamedType u_string st
                    |> (fun (a, b) tyargs _ ->
                        let finfo = bindField (a, b, tyargs) in

                        if finfo.IsStatic then
                            StaticFieldGetOp finfo
                        else
                            InstanceFieldGetOp finfo)
                | 38 -> u_void st |> (fun () NoTyArgs _ -> LetRecCombOp)
                | 39 -> u_void st |> (fun () NoTyArgs _ -> AppOp)
                | 40 -> u_void st |> (fun () (OneTyArg ty) _ -> ValueOp(null, ty, None))
                | 41 -> u_void st |> (fun () (OneTyArg ty) _ -> DefaultValueOp ty)
                | 42 ->
                    u_PropInfoData st
                    |> (fun (a, b, c, d) tyargs _ ->
                        let pinfo = bindProp (a, b, c, d, tyargs) in

                        if pinfoIsStatic pinfo then
                            StaticPropSetOp pinfo
                        else
                            InstancePropSetOp pinfo)
                | 43 ->
                    u_tup2 u_NamedType u_string st
                    |> (fun (a, b) tyargs _ ->
                        let finfo = bindField (a, b, tyargs) in

                        if finfo.IsStatic then
                            StaticFieldSetOp finfo
                        else
                            InstanceFieldSetOp finfo)
                | 44 -> u_void st |> (fun () NoTyArgs _ -> AddressOfOp)
                | 45 -> u_void st |> (fun () NoTyArgs _ -> AddressSetOp)
                | 46 -> u_void st |> (fun () (OneTyArg ty) _ -> TypeTestOp ty)
                | 47 -> u_void st |> (fun () NoTyArgs _ -> TryFinallyOp)
                | 48 -> u_void st |> (fun () NoTyArgs _ -> TryWithOp)
                | 49 -> u_void st |> (fun () NoTyArgs _ -> VarSetOp)
                | 50 ->
                    let m1 = u_MethodInfoData st
                    let m2 = u_MethodInfoData st
                    let n = u_int st

                    (fun tyargs _ ->
                        let minfo = bindMeth (ValueNone, m1, tyargs)
                        let minfoW = bindMeth (ValueNone, m2, tyargs)

                        if minfo.IsStatic then
                            StaticMethodCallWOp(minfo, minfoW, n)
                        else
                            InstanceMethodCallWOp(minfo, minfoW, n))
                // 51 taken above
                | _ -> failwith ("u_constSpec, unrecognized tag " + string tag)

            Unique constSpec

    let u_ReflectedDefinition = u_tup2 u_MethodBase u_Expr

    let u_ReflectedDefinitions = u_list u_ReflectedDefinition

    let unpickleExpr (localType: Type) referencedTypes bytes =
        unpickleObj localType.Assembly referencedTypes u_Expr bytes

    let unpickleReflectedDefns localAssembly referencedTypes bytes =
        unpickleObj localAssembly referencedTypes u_ReflectedDefinitions bytes

    //--------------------------------------------------------------------------
    // General utilities that will eventually be folded into
    // Microsoft.FSharp.Quotations.Typed
    //--------------------------------------------------------------------------

    /// Fill the holes in an Expr
    let rec fillHolesInRawExpr (l: Expr[]) (E t as e) =
        match t with
        | VarTerm _ -> e
        | LambdaTerm (v, b) -> EA(LambdaTerm(v, fillHolesInRawExpr l b), e.CustomAttributes)
        | CombTerm (op, args) -> EA(CombTerm(op, args |> List.map (fillHolesInRawExpr l)), e.CustomAttributes)
        | HoleTerm (ty, idx) ->
            if idx < 0 || idx >= l.Length then
                failwith "hole index out of range"

            let h = l.[idx]

            match typeOf h with
            | expected when expected <> ty ->
                invalidArg "receivedType" (String.Format(SR.GetString(SR.QtmmRaw), expected, ty))
            | _ -> h

    let rec freeInExprAcc bvs acc (E t) =
        match t with
        | HoleTerm _ -> acc
        | CombTerm (_, ag) -> ag |> List.fold (freeInExprAcc bvs) acc
        | VarTerm v ->
            if Set.contains v bvs || Set.contains v acc then
                acc
            else
                Set.add v acc
        | LambdaTerm (v, b) -> freeInExprAcc (Set.add v bvs) acc b

    and freeInExpr e =
        freeInExprAcc Set.empty Set.empty e

    [<NoEquality; NoComparison>]
    exception Clash of Var

    /// Replace type variables and expression variables with parameters using the
    /// given substitution functions/maps.
    let rec substituteInExpr bvs tmsubst (E t as e) =
        match t with
        | CombTerm (c, args) ->
            let substargs = args |> List.map (fun arg -> substituteInExpr bvs tmsubst arg)
            EA(CombTerm(c, substargs), e.CustomAttributes)
        | VarTerm v ->
            match tmsubst v with
            | None -> e
            | Some e2 ->
                let fvs = freeInExpr e2
                let clashes = Set.intersect fvs bvs in

                if clashes.IsEmpty then
                    e2
                else
                    raise (Clash(clashes.MinimumElement))
        | LambdaTerm (v, b) ->
            try
                EA(LambdaTerm(v, substituteInExpr (Set.add v bvs) tmsubst b), e.CustomAttributes)
            with Clash bv ->
                if v = bv then
                    let v2 = new Var(v.Name, v.Type)
                    let v2exp = E(VarTerm v2)
                    let b2 = substituteInExpr bvs (fun v -> if v = bv then Some v2exp else tmsubst v) b
                    EA(LambdaTerm(v2, b2), e.CustomAttributes)
                else
                    reraise ()
        | HoleTerm _ -> e

    let substituteRaw tmsubst e =
        substituteInExpr Set.empty tmsubst e

    let readToEnd (s: Stream) =
        let n = int s.Length
        let res = Array.zeroCreate n
        let mutable i = 0

        while (i < n) do
            i <- i + s.Read(res, i, (n - i))

        res

    let decodedTopResources =
        new Dictionary<Assembly * string, int>(10, HashIdentity.Structural)

    [<StructuralEquality; NoComparison>]
    type ReflectedDefinitionTableKey =
        | Key of ModuleHandle * int

        static member GetKey(methodBase: MethodBase) =
            Key(methodBase.Module.ModuleHandle, methodBase.MetadataToken)

    [<NoEquality; NoComparison>]
    type ReflectedDefinitionTableEntry = Entry of Bindable<Expr>

    let reflectedDefinitionTable =
        new Dictionary<ReflectedDefinitionTableKey, ReflectedDefinitionTableEntry>(10, HashIdentity.Structural)

    let registerReflectedDefinitions (assem, resourceName, bytes, referencedTypes) =
        let defns = unpickleReflectedDefns assem referencedTypes bytes

        defns
        |> List.iter (fun (minfo, exprBuilder) ->
            let key = ReflectedDefinitionTableKey.GetKey minfo
            lock reflectedDefinitionTable (fun () -> reflectedDefinitionTable.Add(key, Entry exprBuilder)))

        decodedTopResources.Add((assem, resourceName), 0)

    let isReflectedDefinitionResourceName (resourceName: string) =
        resourceName.StartsWith(ReflectedDefinitionsResourceNameBase, StringComparison.Ordinal)

    /// Get the reflected definition at the given (always generic) instantiation
    let tryGetReflectedDefinition (methodBase: MethodBase, tyargs: Type[]) =
        checkNonNull "methodBase" methodBase

        let data =
            let assem = methodBase.DeclaringType.Assembly
            let key = ReflectedDefinitionTableKey.GetKey methodBase

            let ok, res =
                lock reflectedDefinitionTable (fun () -> reflectedDefinitionTable.TryGetValue key)

            if ok then
                Some res
            else

                let qdataResources =
                    // dynamic assemblies don't support the GetManifestResourceNames
                    match assem with
                    | a when a.FullName = "System.Reflection.Emit.AssemblyBuilder" -> []
                    | null
                    | _ ->
                        let resources =
                            // This raises NotSupportedException for dynamic assemblies
                            try
                                assem.GetManifestResourceNames()
                            with :? NotSupportedException ->
                                [||]

                        [
                            for resourceName in resources do
                                if
                                    isReflectedDefinitionResourceName resourceName
                                    && not (decodedTopResources.ContainsKey((assem, resourceName)))
                                then

                                    let cmaAttribForResource =
                                        assem.GetCustomAttributes(typeof<CompilationMappingAttribute>, false)
                                        |> (function
                                        | null -> [||]
                                        | x -> x)
                                        |> Array.tryPick (fun ca ->
                                            match ca with
                                            | :? CompilationMappingAttribute as cma when cma.ResourceName = resourceName ->
                                                Some cma
                                            | _ -> None)

                                    let resourceBytes = readToEnd (assem.GetManifestResourceStream resourceName)

                                    let referencedTypes =
                                        match cmaAttribForResource with
                                        | None -> [||]
                                        | Some cma -> cma.TypeDefinitions

                                    yield (resourceName, unpickleReflectedDefns assem referencedTypes resourceBytes)
                        ]

                // ok, add to the table
                let ok, res =
                    lock reflectedDefinitionTable (fun () ->
                        // check another thread didn't get in first
                        if not (reflectedDefinitionTable.ContainsKey key) then
                            qdataResources
                            |> List.iter (fun (resourceName, defns) ->
                                defns
                                |> List.iter (fun (methodBase, exprBuilder) ->
                                    reflectedDefinitionTable.[ReflectedDefinitionTableKey.GetKey methodBase] <-
                                        Entry exprBuilder)

                                decodedTopResources.[(assem, resourceName)] <- 0)
                        // we know it's in the table now, if it's ever going to be there
                        reflectedDefinitionTable.TryGetValue key)

                if ok then Some res else None

        match data with
        | Some (Entry exprBuilder) ->
            let expectedNumTypars =
                getNumGenericArguments (methodBase.DeclaringType)
                + (match methodBase with
                   | :? MethodInfo as minfo ->
                       if minfo.IsGenericMethod then
                           minfo.GetGenericArguments().Length
                       else
                           0
                   | _ -> 0)

            if (expectedNumTypars <> tyargs.Length) then
                invalidArg
                    "tyargs"
                    (String.Format(
                        SR.GetString(SR.QwrongNumOfTypeArgs),
                        methodBase.Name,
                        expectedNumTypars.ToString(),
                        tyargs.Length.ToString()
                    ))

            Some(exprBuilder (envClosed tyargs))
        | None -> None

    /// Get the reflected definition at the generic instantiation
    let tryGetReflectedDefinitionInstantiated (methodBase: MethodBase) =
        checkNonNull "methodBase" methodBase

        match methodBase with
        | :? MethodInfo as minfo ->
            let tyargs =
                Array.append
                    (getGenericArguments minfo.DeclaringType)
                    (if minfo.IsGenericMethod then
                         minfo.GetGenericArguments()
                     else
                         [||])

            tryGetReflectedDefinition (methodBase, tyargs)
        | :? ConstructorInfo as cinfo ->
            let tyargs = getGenericArguments cinfo.DeclaringType
            tryGetReflectedDefinition (methodBase, tyargs)
        | _ -> tryGetReflectedDefinition (methodBase, [||])

    let deserialize (localAssembly, referencedTypeDefs, spliceTypes, spliceExprs, bytes) : Expr =
        let expr =
            unpickleExpr localAssembly referencedTypeDefs bytes (envClosed spliceTypes)

        fillHolesInRawExpr spliceExprs expr

    let cast (expr: Expr) : Expr<'T> =
        checkTypesSR (typeof<'T>) (typeOf expr) "expr" (SR.GetString(SR.QtmmExprHasWrongType))
        new Expr<'T>(expr.Tree, expr.CustomAttributes)

open Patterns

type Expr with

    member x.Substitute substitution =
        substituteRaw substitution x

    member x.GetFreeVars() =
        (freeInExpr x :> seq<_>)

    member x.Type = typeOf x

    static member AddressOf(target: Expr) =
        mkAddressOf target

    static member AddressSet(target: Expr, value: Expr) =
        mkAddressSet (target, value)

    static member Application(functionExpr: Expr, argument: Expr) =
        mkApplication (functionExpr, argument)

    static member Applications(functionExpr: Expr, arguments) =
        mkApplications (functionExpr, arguments)

    static member Call(methodInfo: MethodInfo, arguments) =
        checkNonNull "methodInfo" methodInfo
        mkStaticMethodCall (methodInfo, arguments)

    static member Call(obj: Expr, methodInfo: MethodInfo, arguments) =
        checkNonNull "methodInfo" methodInfo
        mkInstanceMethodCall (obj, methodInfo, arguments)

    static member CallWithWitnesses(methodInfo: MethodInfo, methodInfoWithWitnesses: MethodInfo, witnesses, arguments) =
        checkNonNull "methodInfo" methodInfo
        checkNonNull "methodInfoWithWitnesses" methodInfoWithWitnesses
        mkStaticMethodCallW (methodInfo, methodInfoWithWitnesses, List.length witnesses, witnesses @ arguments)

    static member CallWithWitnesses
        (
            obj: Expr,
            methodInfo: MethodInfo,
            methodInfoWithWitnesses: MethodInfo,
            witnesses,
            arguments
        ) =
        checkNonNull "methodInfo" methodInfo
        checkNonNull "methodInfoWithWitnesses" methodInfoWithWitnesses
        mkInstanceMethodCallW (obj, methodInfo, methodInfoWithWitnesses, List.length witnesses, witnesses @ arguments)

    static member Coerce(source: Expr, target: Type) =
        checkNonNull "target" target
        mkCoerce (target, source)

    static member IfThenElse(guard: Expr, thenExpr: Expr, elseExpr: Expr) =
        mkIfThenElse (guard, thenExpr, elseExpr)

    static member ForIntegerRangeLoop(loopVariable, start: Expr, endExpr: Expr, body: Expr) =
        mkForLoop (loopVariable, start, endExpr, body)

    static member FieldGet(fieldInfo: FieldInfo) =
        checkNonNull "fieldInfo" fieldInfo
        mkStaticFieldGet fieldInfo

    static member FieldGet(obj: Expr, fieldInfo: FieldInfo) =
        checkNonNull "fieldInfo" fieldInfo
        mkInstanceFieldGet (obj, fieldInfo)

    static member FieldSet(fieldInfo: FieldInfo, value: Expr) =
        checkNonNull "fieldInfo" fieldInfo
        mkStaticFieldSet (fieldInfo, value)

    static member FieldSet(obj: Expr, fieldInfo: FieldInfo, value: Expr) =
        checkNonNull "fieldInfo" fieldInfo
        mkInstanceFieldSet (obj, fieldInfo, value)

    static member Lambda(parameter: Var, body: Expr) =
        mkLambda (parameter, body)

    static member Let(letVariable: Var, letExpr: Expr, body: Expr) =
        mkLet (letVariable, letExpr, body)

    static member LetRecursive(bindings, body: Expr) =
        mkLetRec (bindings, body)

    static member NewObject(constructorInfo: ConstructorInfo, arguments) =
        checkNonNull "constructorInfo" constructorInfo
        mkCtorCall (constructorInfo, arguments)

    static member DefaultValue(expressionType: Type) =
        checkNonNull "expressionType" expressionType
        mkDefaultValue expressionType

    static member NewTuple elements =
        mkNewTuple elements

    static member NewStructTuple(asm: Assembly, elements) =
        mkNewStructTuple (asm, elements)

    static member NewStructTuple elements =
        mkNewStructTupleNetStandard elements

    static member NewRecord(recordType: Type, elements) =
        checkNonNull "recordType" recordType
        mkNewRecord (recordType, elements)

    static member NewArray(elementType: Type, elements) =
        checkNonNull "elementType" elementType
        mkNewArray (elementType, elements)

    static member NewDelegate(delegateType: Type, parameters: Var list, body: Expr) =
        checkNonNull "delegateType" delegateType
        mkNewDelegate (delegateType, mkIteratedLambdas (parameters, body))

    static member NewUnionCase(unionCase, arguments) =
        mkNewUnionCase (unionCase, arguments)

    static member PropertyGet(obj: Expr, property: PropertyInfo, ?indexerArgs) =
        checkNonNull "property" property
        mkInstancePropGet (obj, property, defaultArg indexerArgs [])

    static member PropertyGet(property: PropertyInfo, ?indexerArgs) =
        checkNonNull "property" property
        mkStaticPropGet (property, defaultArg indexerArgs [])

    static member PropertySet(obj: Expr, property: PropertyInfo, value: Expr, ?indexerArgs) =
        checkNonNull "property" property
        mkInstancePropSet (obj, property, defaultArg indexerArgs [], value)

    static member PropertySet(property: PropertyInfo, value: Expr, ?indexerArgs) =
        mkStaticPropSet (property, defaultArg indexerArgs [], value)

    static member Quote(inner: Expr) =
        mkQuote (inner, true)

    static member QuoteRaw(inner: Expr) =
        mkQuote (inner, false)

    static member QuoteTyped(inner: Expr) =
        mkQuote (inner, true)

    static member Sequential(first: Expr, second: Expr) =
        mkSequential (first, second)

    static member TryWith(body: Expr, filterVar: Var, filterBody: Expr, catchVar: Var, catchBody: Expr) =
        mkTryWith (body, filterVar, filterBody, catchVar, catchBody)

    static member TryFinally(body: Expr, compensation: Expr) =
        mkTryFinally (body, compensation)

    static member TupleGet(tuple: Expr, index: int) =
        mkTupleGet (typeOf tuple, index, tuple)

    static member TypeTest(source: Expr, target: Type) =
        checkNonNull "target" target
        mkTypeTest (source, target)

    static member UnionCaseTest(source: Expr, unionCase: UnionCaseInfo) =
        mkUnionCaseTest (unionCase, source)

    static member Value(value: 'T) =
        mkValue (box value, typeof<'T>)

    static member Value(value: obj, expressionType: Type) =
        checkNonNull "expressionType" expressionType
        mkValue (value, expressionType)

    static member ValueWithName(value: 'T, name: string) =
        checkNonNull "name" name
        mkValueWithName (box value, typeof<'T>, name)

    static member ValueWithName(value: obj, expressionType: Type, name: string) =
        checkNonNull "expressionType" expressionType
        checkNonNull "name" name
        mkValueWithName (value, expressionType, name)

    static member WithValue(value: 'T, definition: Expr<'T>) =
        let raw = mkValueWithDefn (box value, typeof<'T>, definition)
        new Expr<'T>(raw.Tree, raw.CustomAttributes)

    static member WithValue(value: obj, expressionType: Type, definition: Expr) =
        checkNonNull "expressionType" expressionType
        mkValueWithDefn (value, expressionType, definition)

    static member Var variable =
        mkVar variable

    static member VarSet(variable, value: Expr) =
        mkVarSet (variable, value)

    static member WhileLoop(guard: Expr, body: Expr) =
        mkWhileLoop (guard, body)

    static member TryGetReflectedDefinition(methodBase: MethodBase) =
        checkNonNull "methodBase" methodBase
        tryGetReflectedDefinitionInstantiated methodBase

    static member Cast(source: Expr) =
        cast source

    static member Deserialize(qualifyingType: Type, spliceTypes, spliceExprs, bytes: byte[]) =
        checkNonNull "qualifyingType" qualifyingType
        checkNonNull "bytes" bytes
        deserialize (qualifyingType, [||], Array.ofList spliceTypes, Array.ofList spliceExprs, bytes)

    static member Deserialize40(qualifyingType: Type, referencedTypes, spliceTypes, spliceExprs, bytes: byte[]) =
        checkNonNull "spliceExprs" spliceExprs
        checkNonNull "spliceTypes" spliceTypes
        checkNonNull "referencedTypeDefs" referencedTypes
        checkNonNull "qualifyingType" qualifyingType
        checkNonNull "bytes" bytes
        deserialize (qualifyingType, referencedTypes, spliceTypes, spliceExprs, bytes)

    static member RegisterReflectedDefinitions(assembly, resource, serializedValue) =
        Expr.RegisterReflectedDefinitions(assembly, resource, serializedValue, [||])

    static member RegisterReflectedDefinitions(assembly, resource, serializedValue, referencedTypes) =
        checkNonNull "assembly" assembly
        registerReflectedDefinitions (assembly, resource, serializedValue, referencedTypes)

    static member GlobalVar<'T>(name) : Expr<'T> =
        checkNonNull "name" name
        Expr.Var(Var.Global(name, typeof<'T>)) |> Expr.Cast

[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
module DerivedPatterns =
    open Patterns

    [<CompiledName("BoolPattern")>]
    let (|Bool|_|) input =
        match input with
        | ValueObj (:? bool as v) -> Some v
        | _ -> None

    [<CompiledName("StringPattern")>]
    let (|String|_|) input =
        match input with
        | ValueObj (:? string as v) -> Some v
        | _ -> None

    [<CompiledName("SinglePattern")>]
    let (|Single|_|) input =
        match input with
        | ValueObj (:? single as v) -> Some v
        | _ -> None

    [<CompiledName("DoublePattern")>]
    let (|Double|_|) input =
        match input with
        | ValueObj (:? double as v) -> Some v
        | _ -> None

    [<CompiledName("CharPattern")>]
    let (|Char|_|) input =
        match input with
        | ValueObj (:? char as v) -> Some v
        | _ -> None

    [<CompiledName("SBytePattern")>]
    let (|SByte|_|) input =
        match input with
        | ValueObj (:? sbyte as v) -> Some v
        | _ -> None

    [<CompiledName("BytePattern")>]
    let (|Byte|_|) input =
        match input with
        | ValueObj (:? byte as v) -> Some v
        | _ -> None

    [<CompiledName("Int16Pattern")>]
    let (|Int16|_|) input =
        match input with
        | ValueObj (:? int16 as v) -> Some v
        | _ -> None

    [<CompiledName("UInt16Pattern")>]
    let (|UInt16|_|) input =
        match input with
        | ValueObj (:? uint16 as v) -> Some v
        | _ -> None

    [<CompiledName("Int32Pattern")>]
    let (|Int32|_|) input =
        match input with
        | ValueObj (:? int32 as v) -> Some v
        | _ -> None

    [<CompiledName("UInt32Pattern")>]
    let (|UInt32|_|) input =
        match input with
        | ValueObj (:? uint32 as v) -> Some v
        | _ -> None

    [<CompiledName("Int64Pattern")>]
    let (|Int64|_|) input =
        match input with
        | ValueObj (:? int64 as v) -> Some v
        | _ -> None

    [<CompiledName("UInt64Pattern")>]
    let (|UInt64|_|) input =
        match input with
        | ValueObj (:? uint64 as v) -> Some v
        | _ -> None

    [<CompiledName("UnitPattern")>]
    let (|Unit|_|) input =
        match input with
        | Comb0 (ValueOp (_, ty, None)) when ty = typeof<unit> -> Some()
        | _ -> None

    /// (fun (x, y) -> z) is represented as 'fun p -> let x = p#0 let y = p#1' etc.
    /// This reverses this encoding.
    let (|TupledLambda|_|) (lam: Expr) =
        /// Strip off the 'let' bindings for an TupledLambda
        let rec stripSuccessiveProjLets (p: Var) n expr =
            match expr with
            | Let (v1, TupleGet (Var pA, m), rest) when p = pA && m = n ->
                let restvs, b = stripSuccessiveProjLets p (n + 1) rest
                v1 :: restvs, b
            | _ -> ([], expr)

        match lam.Tree with
        | LambdaTerm (v, body) ->
            match stripSuccessiveProjLets v 0 body with
            | [], b -> Some([ v ], b)
            | letvs, b -> Some(letvs, b)
        | _ -> None

    let (|TupledApplication|_|) e =
        match e with
        | Application (f, x) ->
            match x with
            | Unit -> Some(f, [])
            | NewTuple x -> Some(f, x)
            | x -> Some(f, [ x ])
        | _ -> None

    [<CompiledName("LambdasPattern")>]
    let (|Lambdas|_|) (input: Expr) =
        qOneOrMoreRLinear (|TupledLambda|_|) input

    [<CompiledName("ApplicationsPattern")>]
    let (|Applications|_|) (input: Expr) =
        qOneOrMoreLLinear (|TupledApplication|_|) input

    /// Reverse the compilation of And and Or
    [<CompiledName("AndAlsoPattern")>]
    let (|AndAlso|_|) input =
        match input with
        | IfThenElse (x, y, Bool false) -> Some(x, y)
        | _ -> None

    [<CompiledName("OrElsePattern")>]
    let (|OrElse|_|) input =
        match input with
        | IfThenElse (x, Bool true, y) -> Some(x, y)
        | _ -> None

    [<CompiledName("SpecificCallPattern")>]
    let (|SpecificCall|_|) templateParameter =
        // Note: precomputation
        match templateParameter with
        | (Lambdas (_, Call (_, minfo1, _)) | Call (_, minfo1, _)) ->
            let isg1 = minfo1.IsGenericMethod

            let gmd =
                if isg1 then
                    minfo1.GetGenericMethodDefinition()
                else
                    null

            // end-of-precomputation

            (fun tm ->
                match tm with
                | Call (obj, minfo2, args) when
#if FX_NO_REFLECTION_METADATA_TOKENS
                    ( // if metadata tokens are not available we'll rely only on equality of method references
#else
                    (minfo1.MetadataToken = minfo2.MetadataToken
                     &&
#endif
                    if isg1 then
                        minfo2.IsGenericMethod && gmd = minfo2.GetGenericMethodDefinition()
                    else
                        minfo1 = minfo2)
                    ->
                    Some(obj, (minfo2.GetGenericArguments() |> Array.toList), args)
                | _ -> None)
        | _ -> invalidArg "templateParameter" (SR.GetString(SR.QunrecognizedMethodCall))

    let private new_decimal_info =
        methodhandleof (fun (low, medium, high, isNegative, scale) ->
            LanguagePrimitives.IntrinsicFunctions.MakeDecimal low medium high isNegative scale)
        |> System.Reflection.MethodInfo.GetMethodFromHandle
        :?> MethodInfo

    [<CompiledName("DecimalPattern")>]
    let (|Decimal|_|) input =
        match input with
        | Call (None, mi, [ Int32 low; Int32 medium; Int32 high; Bool isNegative; Byte scale ]) when
            mi.Name = new_decimal_info.Name
            && mi.DeclaringType.FullName = new_decimal_info.DeclaringType.FullName
            ->
            Some(LanguagePrimitives.IntrinsicFunctions.MakeDecimal low medium high isNegative scale)
        | _ -> None

    [<CompiledName("MethodWithReflectedDefinitionPattern")>]
    let (|MethodWithReflectedDefinition|_|) (methodBase) =
        Expr.TryGetReflectedDefinition methodBase

    [<CompiledName("PropertyGetterWithReflectedDefinitionPattern")>]
    let (|PropertyGetterWithReflectedDefinition|_|) (propertyInfo: System.Reflection.PropertyInfo) =
        Expr.TryGetReflectedDefinition(propertyInfo.GetGetMethod true)

    [<CompiledName("PropertySetterWithReflectedDefinitionPattern")>]
    let (|PropertySetterWithReflectedDefinition|_|) (propertyInfo: System.Reflection.PropertyInfo) =
        Expr.TryGetReflectedDefinition(propertyInfo.GetSetMethod true)

[<CompilationRepresentation(CompilationRepresentationFlags.ModuleSuffix)>]
module ExprShape =
    open Patterns

    let RebuildShapeCombination (shape: obj, arguments) =
        // preserve the attributes
        let op, attrs = unbox<ExprConstInfo * Expr list> (shape)

        let e =
            match op, arguments with
            | AppOp, [ f; x ] -> mkApplication (f, x)
            | IfThenElseOp, [ g; t; e ] -> mkIfThenElse (g, t, e)
            | LetRecOp, [ e1 ] -> mkLetRecRaw e1
            | LetRecCombOp, _ -> mkLetRecCombRaw arguments
            | LetOp, [ e1; e2 ] -> mkLetRawWithCheck (e1, e2)
            | NewRecordOp ty, _ -> mkNewRecord (ty, arguments)
            | NewUnionCaseOp unionCase, _ -> mkNewUnionCase (unionCase, arguments)
            | UnionCaseTestOp unionCase, [ arg ] -> mkUnionCaseTest (unionCase, arg)
            | NewTupleOp ty, _ -> mkNewTupleWithType (ty, arguments)
            | TupleGetOp (ty, i), [ arg ] -> mkTupleGet (ty, i, arg)
            | InstancePropGetOp pinfo, (obj :: args) -> mkInstancePropGet (obj, pinfo, args)
            | StaticPropGetOp pinfo, _ -> mkStaticPropGet (pinfo, arguments)
            | InstancePropSetOp pinfo, obj :: (FrontAndBack (args, v)) -> mkInstancePropSet (obj, pinfo, args, v)
            | StaticPropSetOp pinfo, (FrontAndBack (args, v)) -> mkStaticPropSet (pinfo, args, v)
            | InstanceFieldGetOp finfo, [ obj ] -> mkInstanceFieldGet (obj, finfo)
            | StaticFieldGetOp finfo, [] -> mkStaticFieldGet (finfo)
            | InstanceFieldSetOp finfo, [ obj; v ] -> mkInstanceFieldSet (obj, finfo, v)
            | StaticFieldSetOp finfo, [ v ] -> mkStaticFieldSet (finfo, v)
            | NewObjectOp minfo, _ -> mkCtorCall (minfo, arguments)
            | DefaultValueOp ty, _ -> mkDefaultValue ty
            | StaticMethodCallOp minfo, _ -> mkStaticMethodCall (minfo, arguments)
            | InstanceMethodCallOp minfo, obj :: args -> mkInstanceMethodCall (obj, minfo, args)
            | StaticMethodCallWOp (minfo, minfoW, n), _ -> mkStaticMethodCallW (minfo, minfoW, n, arguments)
            | InstanceMethodCallWOp (minfo, minfoW, n), obj :: args ->
                mkInstanceMethodCallW (obj, minfo, minfoW, n, args)
            | CoerceOp ty, [ arg ] -> mkCoerce (ty, arg)
            | NewArrayOp ty, _ -> mkNewArray (ty, arguments)
            | NewDelegateOp ty, [ arg ] -> mkNewDelegate (ty, arg)
            | SequentialOp, [ e1; e2 ] -> mkSequential (e1, e2)
            | TypeTestOp ty, [ e1 ] -> mkTypeTest (e1, ty)
            | AddressOfOp, [ e1 ] -> mkAddressOf e1
            | VarSetOp, [ E (VarTerm v); e ] -> mkVarSet (v, e)
            | AddressSetOp, [ e1; e2 ] -> mkAddressSet (e1, e2)
            | ForIntegerRangeLoopOp, [ e1; e2; E (LambdaTerm (v, e3)) ] -> mkForLoop (v, e1, e2, e3)
            | WhileLoopOp, [ e1; e2 ] -> mkWhileLoop (e1, e2)
            | TryFinallyOp, [ e1; e2 ] -> mkTryFinally (e1, e2)
            | TryWithOp, [ e1; Lambda (v1, e2); Lambda (v2, e3) ] -> mkTryWith (e1, v1, e2, v2, e3)
            | QuoteOp flg, [ e1 ] -> mkQuote (e1, flg)
            | ValueOp (v, ty, None), [] -> mkValue (v, ty)
            | ValueOp (v, ty, Some nm), [] -> mkValueWithName (v, ty, nm)
            | WithValueOp (v, ty), [ e ] -> mkValueWithDefn (v, ty, e)
            | _ -> invalidOp (SR.GetString(SR.QillFormedAppOrLet))

        EA(e.Tree, attrs)

    [<CompiledName("ShapePattern")>]
    let rec (|ShapeVar|ShapeLambda|ShapeCombination|) input =
        let rec loop expr =
            let (E t) = expr

            match t with
            | VarTerm v -> ShapeVar v
            | LambdaTerm (v, b) -> ShapeLambda(v, b)
            | CombTerm (op, args) -> ShapeCombination(box<ExprConstInfo * Expr list> (op, expr.CustomAttributes), args)
            | HoleTerm _ -> invalidArg "expr" (SR.GetString(SR.QunexpectedHole))

        loop (input :> Expr)
