CheckExpressions.fsi

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

module internal FSharp.Compiler.CheckExpressions

open System
open Internal.Utilities.Collections
open Internal.Utilities.Library
open FSharp.Compiler
open FSharp.Compiler.AbstractIL.IL
open FSharp.Compiler.AccessibilityLogic
open FSharp.Compiler.ConstraintSolver
open FSharp.Compiler.InfoReader
open FSharp.Compiler.Infos
open FSharp.Compiler.MethodOverrides
open FSharp.Compiler.NameResolution
open FSharp.Compiler.PatternMatchCompilation
open FSharp.Compiler.Syntax
open FSharp.Compiler.TcGlobals
open FSharp.Compiler.Text
open FSharp.Compiler.Xml
open FSharp.Compiler.TypedTree
open FSharp.Compiler.TypedTreeOps
open FSharp.Compiler.CheckBasics

#if !NO_TYPEPROVIDERS
open FSharp.Compiler.TypeProviders
#endif

//-------------------------------------------------------------------------
// Some of the exceptions arising from type checking. These should be moved to
// use DiagnosticsLogger.
//-------------------------------------------------------------------------

exception BakedInMemberConstraintName of string * range

exception FunctionExpected of DisplayEnv * TType * range

exception NotAFunction of DisplayEnv * TType * range * range

exception NotAFunctionButIndexer of DisplayEnv * TType * string option * range * range * bool

exception Recursion of DisplayEnv * Ident * TType * TType * range

exception RecursiveUseCheckedAtRuntime of DisplayEnv * ValRef * range

exception LetRecEvaluatedOutOfOrder of DisplayEnv * ValRef * ValRef * range

exception LetRecCheckedAtRuntime of range

exception LetRecUnsound of DisplayEnv * ValRef list * range

exception TyconBadArgs of DisplayEnv * TyconRef * int * range

exception UnionCaseWrongArguments of DisplayEnv * int * int * range

exception UnionCaseWrongNumberOfArgs of DisplayEnv * int * int * range

exception FieldsFromDifferentTypes of DisplayEnv * RecdFieldRef * RecdFieldRef * range

exception FieldGivenTwice of DisplayEnv * RecdFieldRef * range

exception MissingFields of string list * range

exception UnitTypeExpected of DisplayEnv * TType * range

exception UnitTypeExpectedWithEquality of DisplayEnv * TType * range

exception UnitTypeExpectedWithPossiblePropertySetter of DisplayEnv * TType * string * string * range

exception UnitTypeExpectedWithPossibleAssignment of DisplayEnv * TType * bool * string * range

exception FunctionValueUnexpected of DisplayEnv * TType * range

exception UnionPatternsBindDifferentNames of range

exception VarBoundTwice of Ident

exception ValueRestriction of DisplayEnv * InfoReader * Val * Typar * range

exception ValNotMutable of DisplayEnv * ValRef * range

exception ValNotLocal of DisplayEnv * ValRef * range

exception InvalidRuntimeCoercion of DisplayEnv * TType * TType * range

exception IndeterminateRuntimeCoercion of DisplayEnv * TType * TType * range

exception IndeterminateStaticCoercion of DisplayEnv * TType * TType * range

exception StaticCoercionShouldUseBox of DisplayEnv * TType * TType * range

exception RuntimeCoercionSourceSealed of DisplayEnv * TType * range

exception CoercionTargetSealed of DisplayEnv * TType * range

exception UpcastUnnecessary of range

exception TypeTestUnnecessary of range

exception SelfRefObjCtor of bool * range

exception VirtualAugmentationOnNullValuedType of range

exception NonVirtualAugmentationOnNullValuedType of range

exception UseOfAddressOfOperator of range

exception DeprecatedThreadStaticBindingWarning of range

exception IntfImplInIntrinsicAugmentation of range

exception IntfImplInExtrinsicAugmentation of range

exception OverrideInIntrinsicAugmentation of range

exception OverrideInExtrinsicAugmentation of range

exception NonUniqueInferredAbstractSlot of TcGlobals * DisplayEnv * string * MethInfo * MethInfo * range

exception StandardOperatorRedefinitionWarning of string * range

exception InvalidInternalsVisibleToAssemblyName of badName: string * fileName: string option

val TcFieldInit: range -> ILFieldInit -> Const

val LightweightTcValForUsingInBuildMethodCall:
    g: TcGlobals -> vref: ValRef -> vrefFlags: ValUseFlag -> vrefTypeInst: TTypes -> m: range -> Expr * TType

/// Indicates whether a syntactic type is allowed to include new type variables
/// not declared anywhere, e.g. `let f (x: 'T option) = x.Value`
type ImplicitlyBoundTyparsAllowed =
    | NewTyparsOKButWarnIfNotRigid
    | NewTyparsOK
    | NoNewTypars

//-------------------------------------------------------------------------
// The rest are all helpers needed for declaration checking (CheckDeclarations.fs)
//-------------------------------------------------------------------------

val permitInferTypars: ExplicitTyparInfo

val dontInferTypars: ExplicitTyparInfo

val noArgOrRetAttribs: ArgAndRetAttribs

/// The results of applying let-style generalization after type checking.
type PrelimVal2 =
    | PrelimVal2 of
        id: Ident *
        prelimType: GeneralizedType *
        prelimValReprInfo: PrelimValReprInfo option *
        memberInfoOpt: PrelimMemberInfo option *
        isMutable: bool *
        inlineFlag: ValInline *
        baseOrThisInfo: ValBaseOrThisInfo *
        argAttribs: ArgAndRetAttribs *
        visibility: SynAccess option *
        isCompGen: bool *
        hasDeclaredTypars: bool

/// Represents information about the module or type in which a member or value is declared.
type MemberOrValContainerInfo =
    | MemberOrValContainerInfo of
        tcref: TyconRef *
        intfSlotTyOpt: (TType * SlotImplSet) option *
        baseValOpt: Val option *
        safeInitInfo: SafeInitData *
        declaredTyconTypars: Typars

/// Provides information about the context for a value or member definition.
type ContainerInfo =
    | ContainerInfo of ParentRef * MemberOrValContainerInfo option

    member ParentRef: ParentRef

val ExprContainerInfo: ContainerInfo

/// Indicates if member declarations are allowed to be abstract members.
type NewSlotsOK =
    | NewSlotsOK
    | NoNewSlots

/// Indicates if member declarations are allowed to be override members.
type OverridesOK =
    | OverridesOK
    | WarnOnOverrides
    | ErrorOnOverrides

/// A flag to represent the sort of bindings are we processing.
type DeclKind =
    /// A binding in a module, or a member
    | ModuleOrMemberBinding

    /// Extensions to a type within the same assembly
    | IntrinsicExtensionBinding

    /// Extensions to a type in a different assembly
    | ExtrinsicExtensionBinding

    /// A binding in a class
    | ClassLetBinding of isStatic: bool

    /// A binding in an object expression
    | ObjectExpressionOverrideBinding

    /// A binding in an expression
    | ExpressionBinding

    member CanOverrideOrImplement: OverridesOK

/// Indicates whether the position being checked is precisely the r.h.s. of a "'T :> ***" constraint or a similar
/// places where IWSAM types do not generate a warning
[<RequireQualifiedAccess>]
type WarnOnIWSAM =
    | Yes
    | No

/// Indicates if a member binding is an object expression binding
type IsObjExprBinding =
    | ObjExprBinding
    | ValOrMemberBinding

/// Represents the initial information about a recursive binding
type RecDefnBindingInfo =
    | RecDefnBindingInfo of
        containerInfo: ContainerInfo *
        newslotsOk: NewSlotsOK *
        declKind: DeclKind *
        synBinding: SynBinding

/// The result of checking a value or member signature
type ValSpecResult =
    | ValSpecResult of
        altActualParent: ParentRef *
        memberInfoOpt: PrelimMemberInfo option *
        id: Ident *
        enclosingDeclaredTypars: Typars *
        declaredTypars: Typars *
        ty: TType *
        prelimValReprInfo: PrelimValReprInfo *
        declKind: DeclKind

/// An empty environment of type variables with implicit scope
val emptyUnscopedTyparEnv: UnscopedTyparEnv

/// NormalizedBindingRhs records the r.h.s. of a binding after some munging just before type checking.
type NormalizedBindingRhs =
    | NormalizedBindingRhs of
        simplePats: SynSimplePats list *
        returnTyOpt: SynBindingReturnInfo option *
        rhsExpr: SynExpr

/// Represents a syntactic, unchecked binding after the resolution of the name resolution status of pattern
/// constructors and after "pushing" all complex patterns to the right hand side.
type NormalizedBinding =
    | NormalizedBinding of
        visibility: SynAccess option *
        kind: SynBindingKind *
        shouldInline: bool *
        isMutable: bool *
        attribs: SynAttribute list *
        xmlDoc: XmlDoc *
        typars: SynValTyparDecls *
        valSynData: SynValData *
        pat: SynPat *
        rhsExpr: NormalizedBindingRhs *
        mBinding: range *
        spBinding: DebugPointAtBinding

/// RecursiveBindingInfo - flows through initial steps of TcLetrec
type RecursiveBindingInfo =
    | RecursiveBindingInfo of
        recBindIndex: int *  // index of the binding in the recursive group
        containerInfo: ContainerInfo *
        enclosingDeclaredTypars: Typars *
        inlineFlag: ValInline *
        vspec: Val *
        explicitTyparInfo: ExplicitTyparInfo *
        prelimValReprInfo: PrelimValReprInfo *
        memberInfoOpt: PrelimMemberInfo option *
        baseValOpt: Val option *
        safeThisValOpt: Val option *
        safeInitInfo: SafeInitData *
        visibility: SynAccess option *
        ty: TType *
        declKind: DeclKind

    member Val: Val
    member EnclosingDeclaredTypars: Typar list
    member Index: int

/// Represents the results of the first phase of preparing bindings
[<Sealed>]
type CheckedBindingInfo

/// Represents the results of the second phase of checking simple values
type ValScheme =
    | ValScheme of
        id: Ident *
        typeScheme: GeneralizedType *
        valReprInfo: ValReprInfo option *
        valReprInfoForDisplay: ValReprInfo option *
        memberInfo: PrelimMemberInfo option *
        isMutable: bool *
        inlineInfo: ValInline *
        baseOrThisInfo: ValBaseOrThisInfo *
        visibility: SynAccess option *
        isCompGen: bool *
        isIncrClass: bool *
        isTyFunc: bool *
        hasDeclaredTypars: bool

/// Represents a recursive binding after it has been normalized but before it's info has been put together
type NormalizedRecBindingDefn =
    | NormalizedRecBindingDefn of
        containerInfo: ContainerInfo *
        newslotsOk: NewSlotsOK *
        declKind: DeclKind *
        binding: NormalizedBinding

/// Represents a recursive binding after it has been normalized but before it has been checked
type PreCheckingRecursiveBinding =
    { SyntacticBinding: NormalizedBinding
      RecBindingInfo: RecursiveBindingInfo }

/// Represents a recursive binding after it has been checked but prior to generalization
type PreGeneralizationRecursiveBinding =
    { ExtraGeneralizableTypars: Typars
      CheckedBinding: CheckedBindingInfo
      RecBindingInfo: RecursiveBindingInfo }

/// Represents the usage points of a recursive binding that need later adjustment once the
/// type of the member of value is fully inferred.
[<Sealed>]
type RecursiveUseFixupPoints

/// Represents a recursive binding after it has been both checked and generalized
type PostGeneralizationRecursiveBinding =
    { ValScheme: ValScheme
      CheckedBinding: CheckedBindingInfo
      RecBindingInfo: RecursiveBindingInfo }

    member GeneralizedTypars: Typar list

/// Represents a recursive binding after it has been both checked and generalized and after
/// the special adjustments for 'as this' class initialization checks have been inserted into members.
type PostSpecialValsRecursiveBinding =
    { ValScheme: ValScheme
      Binding: Binding }

/// Represents a recursive binding after it has been both checked and generalized, but
/// before initialization recursion has been rewritten
type PreInitializationGraphEliminationBinding =
    { FixupPoints: RecursiveUseFixupPoints
      Binding: Binding }

/// Record the entire contents of a module or namespace type as not-generalizable, that is
/// if any type variables occur free in the module or namespace type (because type inference
/// is not yet complete), then they can't be generalized.
val addFreeItemOfModuleTy: ModuleOrNamespaceType -> UngeneralizableItem list -> UngeneralizableItem list

/// Merge together lists of type variables to generalize, keeping canonical order
val unionGeneralizedTypars: typarSets: Typar list list -> Typar list

/// Add a list of explicitly declared type variables to the environment, producing a new environment
val AddDeclaredTypars: check: CheckForDuplicateTyparFlag -> typars: Typar list -> env: TcEnv -> TcEnv

/// Add a value to the environment, producing a new environment. Report to the sink.
val AddLocalVal: g: TcGlobals -> TcResultsSink -> scopem: range -> v: Val -> TcEnv -> TcEnv

/// Add a value to the environment, producing a new environment
val AddLocalValPrimitive: g: TcGlobals -> v: Val -> TcEnv -> TcEnv

/// Add a list of values to the environment, producing a new environment. Report to the sink.
val AddLocalVals: g: TcGlobals -> tcSink: TcResultsSink -> scopem: range -> vals: Val list -> env: TcEnv -> TcEnv

/// Set the type of a 'Val' after it has been fully inferred.
val AdjustRecType: v: Val -> vscheme: ValScheme -> unit

/// Process a normalized recursive binding and prepare for progressive generalization
val AnalyzeAndMakeAndPublishRecursiveValue:
    overridesOK: OverridesOK ->
    isGeneratedEventVal: bool ->
    cenv: TcFileState ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv * recBindIdx: int ->
        NormalizedRecBindingDefn ->
            (PreCheckingRecursiveBinding list * Val list) * (UnscopedTyparEnv * int)

/// Check that a member can be included in an interface
val CheckForNonAbstractInterface:
    g: TcGlobals ->
    declKind: DeclKind ->
    tcref: TyconRef ->
    memberFlags: SynMemberFlags ->
    isMemberStatic: bool ->
    m: range ->
        unit

/// Check the flags on a member definition for consistency
val CheckMemberFlags:
    intfSlotTyOpt: 'a option ->
    newslotsOK: NewSlotsOK ->
    overridesOK: OverridesOK ->
    memberFlags: SynMemberFlags ->
    m: range ->
        unit

/// Check a super type is valid
val CheckSuperType: cenv: TcFileState -> ty: TType -> m: range -> unit

/// After inference, view a set of declared type parameters in a canonical way.
val ChooseCanonicalDeclaredTyparsAfterInference:
    g: TcGlobals -> denv: DisplayEnv -> declaredTypars: Typar list -> m: range -> Typar list

/// After inference, view a ValSchem in a canonical way.
val ChooseCanonicalValSchemeAfterInference:
    g: TcGlobals -> denv: DisplayEnv -> vscheme: ValScheme -> m: range -> ValScheme

/// Check if the type annotations and inferred type information in a value give a
/// full and complete generic type for a value. If so, enable generic recursion.
val ComputeIsComplete: enclosingDeclaredTypars: Typar list -> declaredTypars: Typar list -> ty: TType -> bool

/// Compute the available access rights from a particular location in code
val ComputeAccessRights:
    eAccessPath: CompilationPath ->
    eInternalsVisibleCompPaths: CompilationPath list ->
    eFamilyType: TyconRef option ->
        AccessorDomain

/// Compute the available access rights and module/entity compilation path for a paricular location in code
val ComputeAccessAndCompPath:
    g: TcGlobals ->
    env: TcEnv ->
    declKindOpt: DeclKind option ->
    m: range ->
    vis: SynAccess option ->
    overrideVis: Accessibility option ->
    actualParent: ParentRef ->
        Accessibility * CompilationPath option

/// Get the expression resulting from turning an expression into an enumerable value, e.g. at 'for' loops
val ConvertArbitraryExprToEnumerable: cenv: TcFileState -> ty: TType -> env: TcEnv -> expr: Expr -> Expr * TType

/// Invoke pattern match compilation
val CompilePatternForMatchClauses:
    cenv: TcFileState ->
    env: TcEnv ->
    mExpr: range ->
    mMatch: range ->
    warnOnUnused: bool ->
    actionOnFailure: ActionOnFailure ->
    inputExprOpt: Expr option ->
    inputTy: TType ->
    resultTy: TType ->
    tclauses: MatchClause list ->
        Val * Expr

/// Process recursive bindings so that initialization is through laziness and is checked.
/// The bindings may be either plain 'let rec' bindings or mutually recursive nestings of modules and types.
/// The functions must iterate the actual bindings and process them to the overall result.
val EliminateInitializationGraphs:
    g: TcGlobals ->
    mustHaveValReprInfo: bool ->
    denv: DisplayEnv ->
    bindings: 'Binding list ->
    iterBindings: ((PreInitializationGraphEliminationBinding list -> unit) -> 'Binding list -> unit) ->
    buildLets: (Binding list -> 'Result) ->
    mapBindings: ((PreInitializationGraphEliminationBinding list -> Binding list) -> 'Binding list -> 'Result list) ->
    bindsm: range ->
        'Result list

/// Adjust a recursive binding after generalization
val FixupLetrecBind:
    cenv: TcFileState ->
    denv: DisplayEnv ->
    generalizedTyparsForRecursiveBlock: Typars ->
    bind: PostSpecialValsRecursiveBinding ->
        PreInitializationGraphEliminationBinding

/// Produce a fresh view of an object type, e.g. 'List<T>' becomes 'List<?>' for new
/// inference variables with the given rigidity.
val FreshenObjectArgType:
    cenv: TcFileState ->
    m: range ->
    rigid: TyparRigidity ->
    tcref: TyconRef ->
    isExtrinsic: bool ->
    declaredTyconTypars: Typar list ->
        TType * Typar list * TyparInstantiation * TType * TType

/// Get the accumulated module/namespace type for the current module/namespace being processed.
val GetCurrAccumulatedModuleOrNamespaceType: env: TcEnv -> ModuleOrNamespaceType

/// Get the "this" variable from the lambda for an instance member binding
val GetInstanceMemberThisVariable: vspec: Val * expr: Expr -> Val option

/// Build the full ValReprInfo one type inference is complete.
val InferGenericArityFromTyScheme: GeneralizedType -> prelimValReprInfo: PrelimValReprInfo -> ValReprInfo

/// Locate the environment within a particular namespace path, used to process a
/// 'namespace' declaration.
val LocateEnv: isModule: bool -> ccu: CcuThunk -> env: TcEnv -> enclosingNamespacePath: Ident list -> TcEnv

/// Make the check for safe initialization of a member
val MakeCheckSafeInit:
    g: TcGlobals -> tinst: TypeInst -> safeInitInfo: SafeInitData -> reqExpr: Expr -> expr: Expr -> Expr

/// Make an initial 'Val' and publish it to the environment and mutable module type accumulator.
val MakeAndPublishVal:
    cenv: TcFileState ->
    env: TcEnv ->
    altActualParent: ParentRef *
    inSig: bool *
    declKind: DeclKind *
    valRecInfo: ValRecursiveScopeInfo *
    vscheme: ValScheme *
    attrs: Attribs *
    xmlDoc: XmlDoc *
    konst: Const option *
    isGeneratedEventVal: bool ->
        Val

/// Make an initial 'base' value
val MakeAndPublishBaseVal: cenv: TcFileState -> env: TcEnv -> Ident option -> TType -> Val option

/// Make simple values (which are not recursive nor members)
val MakeAndPublishSimpleVals:
    cenv: TcFileState -> env: TcEnv -> names: NameMap<PrelimVal1> -> NameMap<Val * GeneralizedType> * NameMap<Val>

/// Make an initial implicit safe initialization value
val MakeAndPublishSafeThisVal: cenv: TcFileState -> env: TcEnv -> thisIdOpt: Ident option -> thisTy: TType -> Val option

/// Make initial information for a member value
val MakeMemberDataAndMangledNameForMemberVal:
    g: TcGlobals *
    tcref: TyconRef *
    isExtrinsic: bool *
    attrs: Attribs *
    implSlotTys: TType list *
    memberFlags: SynMemberFlags *
    valSynData: SynValInfo *
    id: Ident *
    isCompGen: bool ->
        PrelimMemberInfo

/// Return a new environment suitable for processing declarations in the interior of a type definition
val MakeInnerEnvForTyconRef: env: TcEnv -> tcref: TyconRef -> isExtrinsicExtension: bool -> TcEnv

/// Return a new environment suitable for processing declarations in the interior of a module definition
/// including creating an accumulator for the module type.
val MakeInnerEnv:
    addOpenToNameEnv: bool ->
    env: TcEnv ->
    nm: Ident ->
    moduleKind: ModuleOrNamespaceKind ->
        TcEnv * ModuleOrNamespaceType ref

/// Return a new environment suitable for processing declarations in the interior of a module definition
/// given that the accumulator for the module type already exisits.
val MakeInnerEnvWithAcc:
    addOpenToNameEnv: bool ->
    env: TcEnv ->
    nm: Ident ->
    moduleTyAcc: ModuleOrNamespaceType ref ->
    moduleKind: ModuleOrNamespaceKind ->
        TcEnv

/// Produce a post-generalization type scheme for a simple type where no type inference generalization
/// is appplied.
val NonGenericTypeScheme: ty: TType -> GeneralizedType

/// Publish a module definition to the module/namespace type accumulator.
val PublishModuleDefn: cenv: TcFileState -> env: TcEnv -> mspec: ModuleOrNamespace -> unit

/// Publish a type definition to the module/namespace type accumulator.
val PublishTypeDefn: cenv: TcFileState -> env: TcEnv -> mspec: Tycon -> unit

/// Publish a value definition to the module/namespace type accumulator.
val PublishValueDefn: cenv: TcFileState -> env: TcEnv -> declKind: DeclKind -> vspec: Val -> unit

/// Publish a value definition to the module/namespace type accumulator.
val PublishValueDefnMaybeInclCompilerGenerated:
    cenv: TcFileState -> env: TcEnv -> inclCompilerGenerated: bool -> declKind: DeclKind -> vspec: Val -> unit

/// Mark a typar as no longer being an inference type variable
val SetTyparRigid: DisplayEnv -> range -> Typar -> unit

/// Check and publish a value specification (in a signature or 'abstract' member) to the
/// module/namespace type accumulator and return the resulting Val(s).  Normally only one
/// 'Val' results but CLI events may produce both and add_Event and _remove_Event Val.
val TcAndPublishValSpec:
    cenv: TcFileState *
    env: TcEnv *
    containerInfo: ContainerInfo *
    declKind: DeclKind *
    memFlagsOpt: SynMemberFlags option *
    tpenv: UnscopedTyparEnv *
    synValSig: SynValSig ->
        Val list * UnscopedTyparEnv

/// Check a set of attributes
val TcAttributes:
    cenv: TcFileState -> env: TcEnv -> attrTgt: AttributeTargets -> synAttribs: SynAttribute list -> Attrib list

/// Check a set of attributes and allow failure because a later phase of type realization
/// may successfully check the attributes (if the attribute type or its arguments is in the
/// same recursive group)
val TcAttributesCanFail:
    cenv: TcFileState ->
    env: TcEnv ->
    attrTgt: AttributeTargets ->
    synAttribs: SynAttribute list ->
        Attrib list * (unit -> Attribs)

/// Check a set of attributes which can only target specific elements
val TcAttributesWithPossibleTargets:
    canFail: bool ->
    cenv: TcFileState ->
    env: TcEnv ->
    attrTgt: AttributeTargets ->
    synAttribs: SynAttribute list ->
        (AttributeTargets * Attrib) list * bool

/// Check a constant value, e.g. a literal
val TcConst: cenv: TcFileState -> overallTy: TType -> m: range -> env: TcEnv -> synConst: SynConst -> Const

/// Check a syntactic expression and convert it to a typed tree expression
val TcExpr:
    cenv: TcFileState ->
    ty: OverallTy ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    synExpr: SynExpr ->
        Expr * UnscopedTyparEnv

/// Check that 'args' have the correct number of elements for a tuple expression.
/// If not, use 'tcArgs' to type check the given elements to show
/// their correct types (if known) in the error message and raise the error
val CheckTupleIsCorrectLength:
    g: TcGlobals -> env: TcEnv -> m: range -> tupleTy: TType -> args: 'a list -> tcArgs: (TType list -> unit) -> unit

/// Converts 'a..b' to a call to the '(..)' operator in FSharp.Core
/// Converts 'a..b..c' to a call to the '(.. ..)' operator in FSharp.Core
val RewriteRangeExpr: synExpr: SynExpr -> SynExpr option

/// Check a syntactic expression and convert it to a typed tree expression
val TcExprOfUnknownType:
    cenv: TcFileState -> env: TcEnv -> tpenv: UnscopedTyparEnv -> synExpr: SynExpr -> Expr * TType * UnscopedTyparEnv

/// Check a syntactic expression and convert it to a typed tree expression. Possibly allow for subsumption flexibility
/// and insert a coercion if necessary.
val TcExprFlex:
    cenv: TcFileState ->
    flex: bool ->
    compat: bool ->
    desiredTy: TType ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    synExpr: SynExpr ->
        Expr * UnscopedTyparEnv

/// Process a leaf construct where the actual type of that construct is already pre-known,
/// and the overall type can be eagerly propagated into the actual type, including pre-calculating
/// any type-directed conversion.
val TcPropagatingExprLeafThenConvert:
    cenv: TcFileState ->
    overallTy: OverallTy ->
    actualTy: TType ->
    env: TcEnv ->
    m: range ->
    f: (unit -> Expr * UnscopedTyparEnv) ->
        Expr * UnscopedTyparEnv

/// Check a syntactic statement and convert it to a typed tree expression.
val TcStmtThatCantBeCtorBody:
    cenv: TcFileState -> env: TcEnv -> tpenv: UnscopedTyparEnv -> synExpr: SynExpr -> Expr * UnscopedTyparEnv

/// Check a syntactic expression and convert it to a typed tree expression
val TcExprUndelayed:
    cenv: TcFileState ->
    overallTy: OverallTy ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    synExpr: SynExpr ->
        Expr * UnscopedTyparEnv

/// Check a linear expression (e.g. a sequence of 'let') in a tail-recursive way
/// and convert it to a typed tree expression, using the bodyChecker to check the parts
/// that are not linear.
val TcLinearExprs:
    bodyChecker: (OverallTy -> TcEnv -> UnscopedTyparEnv -> SynExpr -> Expr * UnscopedTyparEnv) ->
    cenv: TcFileState ->
    env: TcEnv ->
    overallTy: OverallTy ->
    tpenv: UnscopedTyparEnv ->
    isCompExpr: bool ->
    synExpr: SynExpr ->
    cont: (Expr * UnscopedTyparEnv -> Expr * UnscopedTyparEnv) ->
        Expr * UnscopedTyparEnv

/// Try to check a syntactic statement and indicate if it's type is not unit without emitting a warning
val TryTcStmt:
    cenv: TcFileState -> env: TcEnv -> tpenv: UnscopedTyparEnv -> synExpr: SynExpr -> bool * TType * Expr * UnscopedTyparEnv

/// Check a pattern being used as a pattern match
val TcMatchPattern:
    cenv: TcFileState ->
    inputTy: TType ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    synPat: SynPat ->
    synWhenExprOpt: SynExpr option ->
        Pattern * Expr option * Val list * TcEnv * UnscopedTyparEnv

[<return: Struct>]
val (|BinOpExpr|_|): SynExpr -> (Ident * SynExpr * SynExpr) voption

/// Check a set of let bindings in a class or module
val TcLetBindings:
    cenv: TcFileState ->
    env: TcEnv ->
    containerInfo: ContainerInfo ->
    declKind: DeclKind ->
    tpenv: UnscopedTyparEnv ->
    binds: SynBinding list * bindsm: range * scopem: range ->
        ModuleOrNamespaceContents list * TcEnv * UnscopedTyparEnv

/// Check an individual `let rec` binding
val TcLetrecBinding:
    cenv: TcFileState *
    envRec: TcEnv *
    scopem: range *
    extraGeneralizableTypars: Typars *
    reqdThisValTyOpt: TType option ->
        envNonRec: TcEnv *
        generalizedRecBinds: PostGeneralizationRecursiveBinding list *
        preGeneralizationRecBinds: PreGeneralizationRecursiveBinding list *
        tpenv: UnscopedTyparEnv *
        uncheckedRecBindsTable: Map<Stamp, PreCheckingRecursiveBinding> ->
            rbind: PreCheckingRecursiveBinding ->
                TcEnv *
                PostGeneralizationRecursiveBinding list *
                PreGeneralizationRecursiveBinding list *
                UnscopedTyparEnv *
                Map<Stamp, PreCheckingRecursiveBinding>

/// Get the binding for the implicit safe initialziation check value if it is being used
val TcLetrecComputeCtorSafeThisValBind: cenv: TcFileState -> safeThisValOpt: Val option -> Binding option

/// Check a collection of `let rec` bindings
val TcLetrecBindings:
    overridesOK: OverridesOK ->
    cenv: TcFileState ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    binds: RecDefnBindingInfo list * bindsm: range * scopem: range ->
        Bindings * TcEnv * UnscopedTyparEnv

/// Part of check a collection of recursive bindings that might include members
val TcLetrecAdjustMemberForSpecialVals:
    cenv: TcFileState -> pgrbind: PostGeneralizationRecursiveBinding -> PostSpecialValsRecursiveBinding

/// Check an inheritance expression or other 'new XYZ()' expression
val TcNewExpr:
    cenv: TcFileState ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    objTy: TType ->
    mObjTyOpt: range option ->
    superInit: bool ->
    arg: SynExpr ->
    mWholeExprOrObjTy: range ->
        Expr * UnscopedTyparEnv

/// Check a 'nameof' expression
val TcNameOfExpr: cenv: TcFileState -> env: TcEnv -> tpenv: UnscopedTyparEnv -> synArg: SynExpr -> Expr

#if !NO_TYPEPROVIDERS
/// Check the application of a provided type to static args
val TcProvidedTypeAppToStaticConstantArgs:
    cenv: TcFileState ->
    env: TcEnv ->
    generatedTypePathOpt: string list option ->
    tpenv: UnscopedTyparEnv ->
    tcref: TyconRef ->
    args: SynType list ->
    m: range ->
        bool * Tainted<ProvidedType> * (unit -> unit)
#endif

/// Check a set of explicitly declared constraints on type parameters
val TcTyparConstraints:
    cenv: TcFileState ->
    newOk: ImplicitlyBoundTyparsAllowed ->
    checkConstraints: CheckConstraints ->
    occ: ItemOccurence ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    synConstraints: SynTypeConstraint list ->
        UnscopedTyparEnv

/// Check a collection of type parameters declarations
val TcTyparDecls: cenv: TcFileState -> env: TcEnv -> synTypars: SynTyparDecl list -> Typar list

/// Check a syntactic type
val TcType:
    cenv: TcFileState ->
    newOk: ImplicitlyBoundTyparsAllowed ->
    checkConstraints: CheckConstraints ->
    occ: ItemOccurence ->
    iwsam: WarnOnIWSAM ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    ty: SynType ->
        TType * UnscopedTyparEnv

/// Check a syntactic type or unit of measure
val TcTypeOrMeasureAndRecover:
    kindOpt: TyparKind option ->
    cenv: TcFileState ->
    newOk: ImplicitlyBoundTyparsAllowed ->
    checkConstraints: CheckConstraints ->
    occ: ItemOccurence ->
    iwsam: WarnOnIWSAM ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    ty: SynType ->
        TType * UnscopedTyparEnv

/// Check a syntactic type (with error recovery)
val TcTypeAndRecover:
    cenv: TcFileState ->
    newOk: ImplicitlyBoundTyparsAllowed ->
    checkConstraints: CheckConstraints ->
    occ: ItemOccurence ->
    iwsam: WarnOnIWSAM ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    ty: SynType ->
        TType * UnscopedTyparEnv

/// Check a specification of a value or member in a signature or an abstract member
val TcValSpec:
    cenv: TcFileState ->
    env: TcEnv ->
    declKind: DeclKind ->
    newOk: ImplicitlyBoundTyparsAllowed ->
    containerInfo: ContainerInfo ->
    memFlagsOpt: SynMemberFlags option ->
    thisTyOpt: TType option ->
    tpenv: UnscopedTyparEnv ->
    SynValSig ->
    Attrib list ->
        ValSpecResult list * UnscopedTyparEnv

/// Given the declaration of a function or member, process it to produce the ValReprInfo
/// giving the names and attributes relevant to arguments and return, but before type
/// parameters have been fully inferred via generalization.
val TranslateSynValInfo:
    cenv: TcFileState ->
    range ->
    tcAttributes: (AttributeTargets -> SynAttribute list -> Attrib list) ->
    synValInfo: SynValInfo ->
        PrelimValReprInfo

/// Given the declaration of a function or member, complete the processing of its ValReprInfo
/// once type parameters have been fully inferred via generalization.
val TranslatePartialValReprInfo: tps: Typar list -> PrelimValReprInfo -> ValReprInfo

/// Constrain two types to be equal within this type checking context
val UnifyTypes: cenv: TcFileState -> env: TcEnv -> m: range -> expectedTy: TType -> actualTy: TType -> unit

val TcRuntimeTypeTest:
    isCast: bool ->
    isOperator: bool ->
    cenv: TcFileState ->
    denv: DisplayEnv ->
    m: range ->
    tgtTy: TType ->
    srcTy: TType ->
        unit

/// Allow the inference of structness from the known type, e.g.
///    let (x: struct (int * int)) = (3,4)
val UnifyTupleTypeAndInferCharacteristics:
    contextInfo: ContextInfo ->
    cenv: TcFileState ->
    denv: DisplayEnv ->
    m: range ->
    knownTy: TType ->
    isExplicitStruct: bool ->
    'T list ->
        TupInfo * TTypes

/// Helper used to check both record expressions and record patterns
val BuildFieldMap:
    cenv: TcFileState ->
    env: TcEnv ->
    isPartial: bool ->
    ty: TType ->
    flds: ((Ident list * Ident) * 'T) list ->
    m: range ->
        (TypeInst * TyconRef * Map<string, 'T> * (string * 'T) list) option

/// Check a long identifier 'Case' or 'Case argsR' that has been resolved to an active pattern case
val TcPatLongIdentActivePatternCase:
    warnOnUpper: WarnOnUpperFlag ->
    cenv: TcFileState ->
    env: TcEnv ->
    vFlags: TcPatValFlags ->
    patEnv: TcPatLinearEnv ->
    ty: TType ->
    mLongId: range * item: Item * apref: ActivePatternElemRef * args: SynPat list * m: range ->
        (TcPatPhase2Input -> Pattern) * TcPatLinearEnv

/// The pattern syntax can also represent active pattern arguments. This routine
/// converts from the pattern syntax to the expression syntax.
///
/// Note we parse arguments to parameterized pattern labels as patterns, not expressions.
/// This means the range of syntactic expression forms that can be used here is limited.
val ConvSynPatToSynExpr: synPat: SynPat -> SynExpr

val TcVal:
    checkAttributes: bool ->
    cenv: TcFileState ->
    env: TcEnv ->
    tpenv: UnscopedTyparEnv ->
    vref: ValRef ->
    instantiationInfoOpt: (ValUseFlag * (UnscopedTyparEnv -> TyparKind list -> TypeInst * UnscopedTyparEnv)) option ->
    optAfterResolution: AfterResolution option ->
    m: range ->
        Typar list * Expr * bool * TType * TType list * UnscopedTyparEnv

module GeneralizationHelpers =

    /// Given an environment, compute the set of inference type variables which may not be
    /// generalised, because they appear somewhere in the types of the constructs availabe
    /// in the environment.
    val ComputeUngeneralizableTypars: env: TcEnv -> Zset<Typar>

    /// Given an environment, compute the set of trait solutions which must appear before
    /// the current location, not after (to prevent use-before definitiosn and
    /// forward calls via type inference filling in trait solutions).
    val ComputeUnabstractableTraitSolutions: env: TcEnv -> FreeLocals

    /// Given an environment, compute the set of type definitions which must appear before
    /// the current location, not after (to prevent use-before-definition of type definitions
    /// via type inference).
    val ComputeUnabstractableTycons: env: TcEnv -> FreeTycons

// Logically extends System.AttributeTargets for F# constructs
module AttributeTargets =
    /// The allowed attribute targets for an F# field declaration
    val FieldDecl: AttributeTargets

    /// The allowed attribute targets for an F# field declaration once it's known to be targeting
    /// a field not a property (see useGenuineField)
    val FieldDeclRestricted: AttributeTargets

    /// The allowed attribute targets for an F# union case declaration
    val UnionCaseDecl: AttributeTargets

    /// The allowed attribute targets for an F# type declaration
    val TyconDecl: AttributeTargets

    /// The allowed attribute targets for an F# exception declaration
    val ExnDecl: AttributeTargets

    /// The allowed attribute targets for an F# module declaration
    val ModuleDecl: AttributeTargets

    /// The allowed attribute targets for an F# top level 'do' expression
    val Top: AttributeTargets

module BindingNormalization =
    /// Take a syntactic binding and do the very first processing step to normalize it.
    val NormalizeBinding:
        isObjExprBinding: IsObjExprBinding ->
        cenv: TcFileState ->
        env: TcEnv ->
        binding: SynBinding ->
            NormalizedBinding