Merge pull request #8254 from dsyme/pre-ext

pre-cleanup related to #6805

src/fsharp/ConstraintSolver.fsi

@@ -47,34 +47,48 @@ val FreshenMethInfo : range -> MethInfo -> TType list
 [<RequireQualifiedAccess>] 
 /// Information about the context of a type equation.
 type ContextInfo =
-/// No context was given.
-| NoContext
-/// The type equation comes from an IF expression.
-| IfExpression of range
-/// The type equation comes from an omitted else branch.
-| OmittedElseBranch of range
-/// The type equation comes from a type check of the result of an else branch.
-| ElseBranchResult of range
-/// The type equation comes from the verification of record fields.
-| RecordFields
-/// The type equation comes from the verification of a tuple in record fields.
-| TupleInRecordFields
-/// The type equation comes from a list or array constructor
-| CollectionElement of bool * range
-/// The type equation comes from a return in a computation expression.
-| ReturnInComputationExpression
-/// The type equation comes from a yield in a computation expression.
-| YieldInComputationExpression
-/// The type equation comes from a runtime type test.
-| RuntimeTypeTest of bool
-/// The type equation comes from an downcast where a upcast could be used.
-| DowncastUsedInsteadOfUpcast of bool
-/// The type equation comes from a return type of a pattern match clause (not the first clause).
-| FollowingPatternMatchClause of range
-/// The type equation comes from a pattern match guard.
-| PatternMatchGuard of range
-/// The type equation comes from a sequence expression.
-| SequenceExpression of TType
+
+    /// No context was given.
+    | NoContext
+
+    /// The type equation comes from an IF expression.
+    | IfExpression of range
+
+    /// The type equation comes from an omitted else branch.
+    | OmittedElseBranch of range
+
+    /// The type equation comes from a type check of the result of an else branch.
+    | ElseBranchResult of range
+
+    /// The type equation comes from the verification of record fields.
+    | RecordFields
+
+    /// The type equation comes from the verification of a tuple in record fields.
+    | TupleInRecordFields
+
+    /// The type equation comes from a list or array constructor
+    | CollectionElement of bool * range
+
+    /// The type equation comes from a return in a computation expression.
+    | ReturnInComputationExpression
+
+    /// The type equation comes from a yield in a computation expression.
+    | YieldInComputationExpression
+
+    /// The type equation comes from a runtime type test.
+    | RuntimeTypeTest of bool
+
+    /// The type equation comes from an downcast where a upcast could be used.
+    | DowncastUsedInsteadOfUpcast of bool
+
+    /// The type equation comes from a return type of a pattern match clause (not the first clause).
+    | FollowingPatternMatchClause of range
+
+    /// The type equation comes from a pattern match guard.
+    | PatternMatchGuard of range
+
+    /// The type equation comes from a sequence expression.
+    | SequenceExpression of TType
 
 exception ConstraintSolverTupleDiffLengths              of displayEnv: DisplayEnv * TType list * TType list * range * range
 exception ConstraintSolverInfiniteTypes                 of displayEnv: DisplayEnv * contextInfo: ContextInfo * TType * TType * range * range
@@ -116,7 +130,10 @@ type OptionalTrace =
 val SimplifyMeasuresInTypeScheme             : TcGlobals -> bool -> Typars -> TType -> TyparConstraint list -> Typars
 val SolveTyparEqualsType                     : ConstraintSolverEnv -> int -> range -> OptionalTrace -> TType -> TType -> OperationResult<unit>
 val SolveTypeEqualsTypeKeepAbbrevs           : ConstraintSolverEnv -> int -> range -> OptionalTrace -> TType -> TType -> OperationResult<unit>
+
+/// Canonicalize constraints prior to generalization 
 val CanonicalizeRelevantMemberConstraints    : ConstraintSolverEnv -> int -> OptionalTrace -> Typars -> OperationResult<unit>
+
 val ResolveOverloading                       : ConstraintSolverEnv -> OptionalTrace -> string -> ndeep: int -> TraitConstraintInfo option -> int * int -> AccessorDomain -> CalledMeth<Expr> list ->  bool -> TType option -> CalledMeth<Expr> option * OperationResult<unit>
 val UnifyUniqueOverloading                   : ConstraintSolverEnv -> int * int -> string -> AccessorDomain -> CalledMeth<SynExpr> list -> TType -> OperationResult<bool> 
 val EliminateConstraintsForGeneralizedTypars : ConstraintSolverEnv -> OptionalTrace -> Typars -> unit 

src/fsharp/IlxGen.fs

@@ -5273,7 +5273,7 @@ and GenBindingAfterSequencePoint cenv cgbuf eenv sp (TBind(vspec, rhsExpr, _)) s
     // Workaround for .NET and Visual Studio restriction w.r.t debugger type proxys
     // Mark internal constructors in internal classes as public.
     let access =
-        if access = ILMemberAccess.Assembly && vspec.IsConstructor && IsHiddenTycon g eenv.sigToImplRemapInfo vspec.MemberApparentEntity.Deref then
+        if access = ILMemberAccess.Assembly && vspec.IsConstructor && IsHiddenTycon eenv.sigToImplRemapInfo vspec.MemberApparentEntity.Deref then
             ILMemberAccess.Public
         else
             access
@@ -6488,7 +6488,7 @@ and GenModuleBinding cenv (cgbuf: CodeGenBuffer) (qname: QualifiedNameOfFile) la
     GenLetRecBindings cenv cgbuf eenv ([bind], m)
 
   | ModuleOrNamespaceBinding.Module (mspec, mdef) ->
-    let hidden = IsHiddenTycon cenv.g eenv.sigToImplRemapInfo mspec
+    let hidden = IsHiddenTycon eenv.sigToImplRemapInfo mspec
 
     let eenvinner =
         if mspec.IsNamespace then eenv else
@@ -6827,8 +6827,8 @@ and GenTypeDef cenv mgbuf lazyInitInfo eenv m (tycon: Tycon) =
         let ilIntfTys = tycon.ImmediateInterfaceTypesOfFSharpTycon |> List.map (GenType cenv.amap m eenvinner.tyenv)
         let ilTypeName = tref.Name
 
-        let hidden = IsHiddenTycon g eenv.sigToImplRemapInfo tycon
-        let hiddenRepr = hidden || IsHiddenTyconRepr g eenv.sigToImplRemapInfo tycon
+        let hidden = IsHiddenTycon eenv.sigToImplRemapInfo tycon
+        let hiddenRepr = hidden || IsHiddenTyconRepr eenv.sigToImplRemapInfo tycon
         let access = ComputeTypeAccess tref hidden
 
         // The implicit augmentation doesn't actually create CompareTo(object) or Object.Equals
@@ -7411,7 +7411,7 @@ and GenExnDef cenv mgbuf eenv m (exnc: Tycon) =
     | TExnFresh _ ->
         let ilThisTy = GenExnType cenv.amap m eenv.tyenv exncref
         let tref = ilThisTy.TypeRef
-        let isHidden = IsHiddenTycon g eenv.sigToImplRemapInfo exnc
+        let isHidden = IsHiddenTycon eenv.sigToImplRemapInfo exnc
         let access = ComputeTypeAccess tref isHidden
         let reprAccess = ComputeMemberAccess isHidden
         let fspecs = exnc.TrueInstanceFieldsAsList

src/fsharp/InfoReader.fs

@@ -19,7 +19,7 @@ open FSharp.Compiler.Tastops
 open FSharp.Compiler.TcGlobals
 
 /// Use the given function to select some of the member values from the members of an F# type
-let private SelectImmediateMemberVals g optFilter f (tcref: TyconRef) = 
+let SelectImmediateMemberVals g optFilter f (tcref: TyconRef) = 
     let chooser (vref: ValRef) = 
         match vref.MemberInfo with 
         // The 'when' condition is a workaround for the fact that values providing 

src/fsharp/MethodCalls.fs

@@ -498,6 +498,8 @@ type CalledMeth<'T>
 
     member x.TotalNumAssignedNamedArgs = x.ArgSets |> List.sumBy (fun x -> x.NumAssignedNamedArgs)
 
+    override x.ToString() = "call to " + minfo.ToString()
+
 let NamesOfCalledArgs (calledArgs: CalledArg list) = 
     calledArgs |> List.choose (fun x -> x.NameOpt) 
 
@@ -1050,15 +1052,20 @@ let BuildFSharpMethodCall g m (ty, vref: ValRef) valUseFlags minst args =
 /// calls to the type-directed solutions to member constraints.
 let MakeMethInfoCall amap m minfo minst args =
     let valUseFlags = NormalValUse // correct unless if we allow wild trait constraints like "T has a ctor and can be used as a parent class" 
+
     match minfo with 
+
     | ILMeth(g, ilminfo, _) -> 
         let direct = not minfo.IsVirtual
         let isProp = false // not necessarily correct, but this is only used post-creflect where this flag is irrelevant 
         BuildILMethInfoCall g amap m isProp ilminfo valUseFlags minst  direct args |> fst
+
     | FSMeth(g, ty, vref, _) -> 
         BuildFSharpMethodCall g m (ty, vref) valUseFlags minst args |> fst
+
     | DefaultStructCtor(_, ty) -> 
        mkDefault (m, ty)
+
 #if !NO_EXTENSIONTYPING
     | ProvidedMeth(amap, mi, _, m) -> 
         let isProp = false // not necessarily correct, but this is only used post-creflect where this flag is irrelevant 

src/fsharp/NameResolution.fs

@@ -550,15 +550,30 @@ let AllPropInfosOfTypeInScope collectionSettings infoReader nenv optFilter ad fi
     @ ExtensionPropInfosOfTypeInScope collectionSettings infoReader nenv optFilter ad m ty
 
 /// Get the available methods of a type (both declared and inherited)
-let IntrinsicMethInfosOfType (infoReader:InfoReader) optFilter ad allowMultiIntfInst findFlag m ty =
+let IntrinsicMethInfosOfType (infoReader: InfoReader) optFilter ad allowMultiIntfInst findFlag m ty =
     let g = infoReader.g
     let amap = infoReader.amap
     let minfos = GetIntrinsicMethInfoSetsOfType infoReader optFilter ad allowMultiIntfInst findFlag m ty
     let minfos = minfos |> ExcludeHiddenOfMethInfos g amap m
     minfos
 
+let TrySelectExtensionMethInfoOfILExtMem m amap apparentTy (actualParent, minfo, pri) = 
+    match minfo with 
+    | ILMeth(_,ilminfo,_) -> 
+        MethInfo.CreateILExtensionMeth (amap, m, apparentTy, actualParent, Some pri, ilminfo.RawMetadata) |> Some
+    // F#-defined IL-style extension methods are not seen as extension methods in F# code
+    | FSMeth(g,_,vref,_) -> 
+        FSMeth(g, apparentTy, vref, Some pri) |> Some
+#if !NO_EXTENSIONTYPING
+    // // Provided extension methods are not yet supported
+    | ProvidedMeth(amap,providedMeth,_,m) -> 
+        ProvidedMeth(amap, providedMeth, Some pri,m) |> Some
+#endif
+    | DefaultStructCtor _ -> 
+        None
+
 /// Select from a list of extension methods
-let SelectMethInfosFromExtMembers (infoReader:InfoReader) optFilter apparentTy m extMemInfos =
+let SelectMethInfosFromExtMembers (infoReader: InfoReader) optFilter apparentTy m extMemInfos =
     let g = infoReader.g
     // NOTE: multiple "open"'s push multiple duplicate values into eIndexedExtensionMembers
     let seen = HashSet(ExtensionMember.Comparer g)
@@ -575,24 +590,14 @@ let SelectMethInfosFromExtMembers (infoReader:InfoReader) optFilter apparentTy m
                         | _ -> ()
                 | ILExtMem (actualParent, minfo, pri) when (match optFilter with None -> true | Some nm -> nm = minfo.LogicalName) ->
                     // Make a reference to the type containing the extension members
-                    match minfo with
-                    | ILMeth(_, ilminfo, _) ->
-                         yield (MethInfo.CreateILExtensionMeth (infoReader.amap, m, apparentTy, actualParent, Some pri, ilminfo.RawMetadata))
-                    // F#-defined IL-style extension methods are not seen as extension methods in F# code
-                    | FSMeth(g, _, vref, _) ->
-                         yield (FSMeth(g, apparentTy, vref, Some pri))
-#if !NO_EXTENSIONTYPING
-                    // // Provided extension methods are not yet supported
-                    | ProvidedMeth(amap, providedMeth, _, m) ->
-                         yield (ProvidedMeth(amap, providedMeth, Some pri, m))
-#endif
-                    | DefaultStructCtor _ ->
-                         ()
+                    match TrySelectExtensionMethInfoOfILExtMem m infoReader.amap apparentTy (actualParent, minfo, pri) with 
+                    | Some minfo -> yield minfo
+                    | None -> ()
                 | _ -> ()
     ]
 
 /// Query the available extension properties of a methods (including extension methods for inherited types)
-let ExtensionMethInfosOfTypeInScope (collectionSettings:ResultCollectionSettings) (infoReader:InfoReader) (nenv: NameResolutionEnv) optFilter m ty =
+let ExtensionMethInfosOfTypeInScope (collectionSettings: ResultCollectionSettings) (infoReader: InfoReader) (nenv: NameResolutionEnv) optFilter m ty =
     let extMemsDangling = SelectMethInfosFromExtMembers  infoReader optFilter ty  m nenv.eUnindexedExtensionMembers
     if collectionSettings = ResultCollectionSettings.AtMostOneResult && not (isNil extMemsDangling) then 
         extMemsDangling

src/fsharp/NameResolution.fsi

@@ -141,25 +141,68 @@ val ItemWithNoInst : Item -> ItemWithInst
 type FieldResolution = FieldResolution of RecdFieldRef * bool
 
 /// Information about an extension member held in the name resolution environment
-[<Sealed>]
-type ExtensionMember 
+type ExtensionMember =
+   /// F#-style Extrinsic extension member, defined in F# code
+   | FSExtMem of ValRef * ExtensionMethodPriority
+
+   /// ILExtMem(declaringTyconRef, ilMetadata, pri)
+   ///
+   /// IL-style extension member, backed by some kind of method with an [<Extension>] attribute
+   | ILExtMem of TyconRef * MethInfo * ExtensionMethodPriority
+
+   /// Describes the sequence order of the introduction of an extension method. Extension methods that are introduced
+   /// later through 'open' get priority in overload resolution.
+   member Priority : ExtensionMethodPriority
 
 /// The environment of information used to resolve names
 [<NoEquality; NoComparison>]
 type NameResolutionEnv =
-    {eDisplayEnv: DisplayEnv
-     eUnqualifiedItems: LayeredMap<string,Item>
-     ePatItems: NameMap<Item>
-     eModulesAndNamespaces: NameMultiMap<ModuleOrNamespaceRef>
-     eFullyQualifiedModulesAndNamespaces: NameMultiMap<ModuleOrNamespaceRef>
-     eFieldLabels: NameMultiMap<RecdFieldRef>
-     eTyconsByAccessNames: LayeredMultiMap<string,TyconRef>
-     eFullyQualifiedTyconsByAccessNames: LayeredMultiMap<string,TyconRef>
-     eTyconsByDemangledNameAndArity: LayeredMap<NameArityPair,TyconRef>
-     eFullyQualifiedTyconsByDemangledNameAndArity: LayeredMap<NameArityPair,TyconRef>
-     eIndexedExtensionMembers: TyconRefMultiMap<ExtensionMember>
-     eUnindexedExtensionMembers: ExtensionMember list
-     eTypars: NameMap<Typar> }
+    { /// Display environment information for output 
+      eDisplayEnv: DisplayEnv 
+
+      /// Values and Data Tags available by unqualified name 
+      eUnqualifiedItems: LayeredMap<string,Item>
+
+      /// Data Tags and Active Pattern Tags available by unqualified name 
+      ePatItems: NameMap<Item>
+
+      /// Modules accessible via "." notation. Note this is a multi-map. 
+      /// Adding a module abbreviation adds it a local entry to this List.map. 
+      /// Likewise adding a ccu or opening a path adds entries to this List.map. 
+      eModulesAndNamespaces:  NameMultiMap<Tast.ModuleOrNamespaceRef>
+
+      /// Fully qualified modules and namespaces. 'open' does not change this. 
+      eFullyQualifiedModulesAndNamespaces:  NameMultiMap<Tast.ModuleOrNamespaceRef>
+
+      /// RecdField labels in scope.  RecdField labels are those where type are inferred 
+      /// by label rather than by known type annotation. 
+      /// Bools indicate if from a record, where no warning is given on indeterminate lookup 
+      eFieldLabels: NameMultiMap<Tast.RecdFieldRef>
+
+      /// Tycons indexed by the various names that may be used to access them, e.g. 
+      ///     "List" --> multiple TyconRef's for the various tycons accessible by this name. 
+      ///     "List`1" --> TyconRef 
+      eTyconsByAccessNames: LayeredMultiMap<string,TyconRef>
+
+      eFullyQualifiedTyconsByAccessNames: LayeredMultiMap<string,TyconRef>
+
+      /// Tycons available by unqualified, demangled names (i.e. (List,1) --> TyconRef) 
+      eTyconsByDemangledNameAndArity: LayeredMap<NameArityPair,TyconRef>
+
+      /// Tycons available by unqualified, demangled names (i.e. (List,1) --> TyconRef) 
+      eFullyQualifiedTyconsByDemangledNameAndArity: LayeredMap<NameArityPair,TyconRef>
+
+      /// Extension members by type and name 
+      eIndexedExtensionMembers: TyconRefMultiMap<ExtensionMember>
+
+      /// Other extension members unindexed by type
+      eUnindexedExtensionMembers: ExtensionMember list
+
+      /// Typars (always available by unqualified names). Further typars can be 
+      /// in the tpenv, a structure folded through each top-level definition. 
+      eTypars: NameMap<Typar>
+
+    } 
     static member Empty : g:TcGlobals -> NameResolutionEnv
     member DisplayEnv : DisplayEnv
     member FindUnqualifiedItem : string -> Item
@@ -545,3 +588,6 @@ val ResolveCompletionsInType       : NameResolver -> NameResolutionEnv -> Resolv
 val GetVisibleNamespacesAndModulesAtPoint : NameResolver -> NameResolutionEnv -> range -> AccessorDomain -> ModuleOrNamespaceRef list
 
 val IsItemResolvable : NameResolver -> NameResolutionEnv -> range -> AccessorDomain -> string list -> Item -> bool
+
+val TrySelectExtensionMethInfoOfILExtMem : range -> ImportMap -> TType -> TyconRef * MethInfo * ExtensionMethodPriority -> MethInfo option 
+ 

src/fsharp/PostInferenceChecks.fs

@@ -1926,8 +1926,8 @@ let CheckRecdField isUnion cenv env (tycon: Tycon) (rfield: RecdField) =
     let m = rfield.Range
     let fieldTy = stripTyEqns cenv.g rfield.FormalType
     let isHidden = 
-        IsHiddenTycon cenv.g env.sigToImplRemapInfo tycon || 
-        IsHiddenTyconRepr cenv.g env.sigToImplRemapInfo tycon || 
+        IsHiddenTycon env.sigToImplRemapInfo tycon || 
+        IsHiddenTyconRepr env.sigToImplRemapInfo tycon || 
         (not isUnion && IsHiddenRecdField env.sigToImplRemapInfo (tcref.MakeNestedRecdFieldRef rfield))
     let access = AdjustAccess isHidden (fun () -> tycon.CompilationPath) rfield.Accessibility
     CheckTypeForAccess cenv env (fun () -> rfield.Name) access m fieldTy
@@ -2189,7 +2189,7 @@ let CheckEntityDefn cenv env (tycon: Entity) =
             uc.RecdFieldsArray |> Array.iter (CheckRecdField true cenv env tycon))
 
     // Access checks
-    let access =  AdjustAccess (IsHiddenTycon g env.sigToImplRemapInfo tycon) (fun () -> tycon.CompilationPath) tycon.Accessibility
+    let access =  AdjustAccess (IsHiddenTycon env.sigToImplRemapInfo tycon) (fun () -> tycon.CompilationPath) tycon.Accessibility
     let visitType ty = CheckTypeForAccess cenv env (fun () -> tycon.DisplayNameWithStaticParametersAndUnderscoreTypars) access tycon.Range ty    
 
     abstractSlotValsOfTycons [tycon] |> List.iter (typeOfVal >> visitType)