Merge main to release/dev17.5

src/Compiler/Driver/CompilerConfig.fs

@@ -300,7 +300,7 @@ type ImportedAssembly =
         IsProviderGenerated: bool
         mutable TypeProviders: Tainted<ITypeProvider> list
 #endif
-        FSharpOptimizationData: Microsoft.FSharp.Control.Lazy<Option<Optimizer.LazyModuleInfo>>
+        FSharpOptimizationData: Microsoft.FSharp.Control.Lazy<Optimizer.LazyModuleInfo option>
     }
 
 type AvailableImportedAssembly =

src/Compiler/Driver/CompilerImports.fs

@@ -338,7 +338,7 @@ type ImportedAssembly =
         IsProviderGenerated: bool
         mutable TypeProviders: Tainted<ITypeProvider> list
 #endif
-        FSharpOptimizationData: Microsoft.FSharp.Control.Lazy<Option<Optimizer.LazyModuleInfo>>
+        FSharpOptimizationData: Microsoft.FSharp.Control.Lazy<Optimizer.LazyModuleInfo option>
     }
 
 type AvailableImportedAssembly =

src/Compiler/Driver/CompilerImports.fsi

@@ -116,7 +116,7 @@ type ImportedAssembly =
       IsProviderGenerated: bool
       mutable TypeProviders: Tainted<ITypeProvider> list
 #endif
-      FSharpOptimizationData: Lazy<Option<LazyModuleInfo>> }
+      FSharpOptimizationData: Lazy<LazyModuleInfo option> }
 
 /// Tables of assembly resolutions
 [<Sealed>]

src/Compiler/Driver/CompilerOptions.fs

@@ -69,7 +69,7 @@ and CompilerOption =
         name: string *
         argumentDescriptionString: string *
         actionSpec: OptionSpec *
-        deprecationError: Option<exn> *
+        deprecationError: exn option *
         helpText: string option
 
 and CompilerOptionBlock =

src/Compiler/Driver/CompilerOptions.fsi

@@ -36,7 +36,7 @@ and CompilerOption =
         name: string *
         argumentDescriptionString: string *
         actionSpec: OptionSpec *
-        deprecationError: Option<exn> *
+        deprecationError: exn option *
         helpText: string option
 
 and CompilerOptionBlock =

src/Compiler/Service/FSharpCheckerResults.fs

@@ -834,7 +834,7 @@ type internal TypeCheckInfo
             if p >= 0 then Some p else None
 
     /// Build a CompetionItem
-    let CompletionItem (ty: ValueOption<TyconRef>) (assemblySymbol: ValueOption<AssemblySymbol>) (item: ItemWithInst) =
+    let CompletionItem (ty: TyconRef voption) (assemblySymbol: AssemblySymbol voption) (item: ItemWithInst) =
         let kind =
             match item.Item with
             | Item.FakeInterfaceCtor _

src/Compiler/Service/ServiceParseTreeWalk.fs

@@ -594,7 +594,7 @@ module SyntaxTraversal =
 
                 | SynExpr.TypeApp (synExpr, _, _synTypeList, _commas, _, _, _range) -> traverseSynExpr synExpr
 
-                | SynExpr.LetOrUse (_, isRecursive, synBindingList, synExpr, range, _) ->
+                | SynExpr.LetOrUse (isRecursive, _, synBindingList, synExpr, range, _) ->
                     match visitor.VisitLetOrUse(path, isRecursive, traverseSynBinding path, synBindingList, range) with
                     | None ->
                         [

src/Compiler/TypedTree/TypedTreeOps.fs

@@ -1604,13 +1604,13 @@ type TyconRefMultiMap<'T>(contents: TyconRefMap<'T list>) =
 //--------------------------------------------------------------------------
 
 /// Try to create a EntityRef suitable for accessing the given Entity from another assembly 
-let tryRescopeEntity viewedCcu (entity: Entity) : ValueOption<EntityRef> = 
+let tryRescopeEntity viewedCcu (entity: Entity) : EntityRef voption =
     match entity.PublicPath with 
     | Some pubpath -> ValueSome (ERefNonLocal (rescopePubPath viewedCcu pubpath))
     | None -> ValueNone
 
 /// Try to create a ValRef suitable for accessing the given Val from another assembly 
-let tryRescopeVal viewedCcu (entityRemap: Remap) (vspec: Val) : ValueOption<ValRef> =
+let tryRescopeVal viewedCcu (entityRemap: Remap) (vspec: Val) : ValRef voption =
     match vspec.PublicPath with 
     | Some (ValPubPath(p, fullLinkageKey)) -> 
         // The type information in the val linkage doesn't need to keep any information to trait solutions.

src/Compiler/TypedTree/TypedTreeOps.fsi

@@ -665,7 +665,7 @@ val isTyparTy: TcGlobals -> TType -> bool
 
 val isAnyParTy: TcGlobals -> TType -> bool
 
-val tryAnyParTy: TcGlobals -> TType -> ValueOption<Typar>
+val tryAnyParTy: TcGlobals -> TType -> Typar voption
 
 val tryAnyParTyOption: TcGlobals -> TType -> Typar option
 
@@ -679,26 +679,26 @@ val isProvenUnionCaseTy: TType -> bool
 
 val isAppTy: TcGlobals -> TType -> bool
 
-val tryAppTy: TcGlobals -> TType -> ValueOption<TyconRef * TypeInst>
+val tryAppTy: TcGlobals -> TType -> (TyconRef * TypeInst) voption
 
 val destAppTy: TcGlobals -> TType -> TyconRef * TypeInst
 
 val tcrefOfAppTy: TcGlobals -> TType -> TyconRef
 
-val tryTcrefOfAppTy: TcGlobals -> TType -> ValueOption<TyconRef>
+val tryTcrefOfAppTy: TcGlobals -> TType -> TyconRef voption
 
-val tryDestTyparTy: TcGlobals -> TType -> ValueOption<Typar>
+val tryDestTyparTy: TcGlobals -> TType -> Typar voption
 
-val tryDestFunTy: TcGlobals -> TType -> ValueOption<TType * TType>
+val tryDestFunTy: TcGlobals -> TType -> (TType * TType) voption
 
-val tryDestAnonRecdTy: TcGlobals -> TType -> ValueOption<AnonRecdTypeInfo * TType list>
+val tryDestAnonRecdTy: TcGlobals -> TType -> (AnonRecdTypeInfo * TType list) voption
 
 val argsOfAppTy: TcGlobals -> TType -> TypeInst
 
 val mkInstForAppTy: TcGlobals -> TType -> TyparInstantiation
 
 /// Try to get a TyconRef for a type without erasing type abbreviations
-val tryNiceEntityRefOfTy: TType -> ValueOption<TyconRef>
+val tryNiceEntityRefOfTy: TType -> TyconRef voption
 
 val tryNiceEntityRefOfTyOption: TType -> TyconRef option
 
@@ -1089,7 +1089,7 @@ val tagEntityRefName: xref: EntityRef -> name: string -> TaggedText
 /// Return the full text for an item as we want it displayed to the user as a fully qualified entity
 val fullDisplayTextOfModRef: ModuleOrNamespaceRef -> string
 
-val fullDisplayTextOfParentOfModRef: ModuleOrNamespaceRef -> ValueOption<string>
+val fullDisplayTextOfParentOfModRef: ModuleOrNamespaceRef -> string voption
 
 val fullDisplayTextOfValRef: ValRef -> string
 
@@ -1303,10 +1303,10 @@ val wrapModuleOrNamespaceTypeInNamespace:
 val wrapModuleOrNamespaceType: Ident -> CompilationPath -> ModuleOrNamespaceType -> ModuleOrNamespace
 
 /// Given a namespace, module or type definition, try to produce a reference to that entity.
-val tryRescopeEntity: CcuThunk -> Entity -> ValueOption<EntityRef>
+val tryRescopeEntity: CcuThunk -> Entity -> EntityRef voption
 
 /// Given a value definition, try to produce a reference to that value. Fails for local values.
-val tryRescopeVal: CcuThunk -> Remap -> Val -> ValueOption<ValRef>
+val tryRescopeVal: CcuThunk -> Remap -> Val -> ValRef voption
 
 /// Make the substitution (remapping) table for viewing a module or namespace 'from the outside'
 ///
@@ -1526,7 +1526,7 @@ val isOptionTy: TcGlobals -> TType -> bool
 val destOptionTy: TcGlobals -> TType -> TType
 
 /// Try to take apart an option type
-val tryDestOptionTy: TcGlobals -> TType -> ValueOption<TType>
+val tryDestOptionTy: TcGlobals -> TType -> TType voption
 
 /// Try to take apart an option type
 val destValueOptionTy: TcGlobals -> TType -> TType
@@ -1535,7 +1535,7 @@ val destValueOptionTy: TcGlobals -> TType -> TType
 val isNullableTy: TcGlobals -> TType -> bool
 
 /// Try to take apart a System.Nullable type
-val tryDestNullableTy: TcGlobals -> TType -> ValueOption<TType>
+val tryDestNullableTy: TcGlobals -> TType -> TType voption
 
 /// Take apart a System.Nullable type
 val destNullableTy: TcGlobals -> TType -> TType

src/FSharp.Core/fslib-extra-pervasives.fs

@@ -51,10 +51,7 @@ module ExtraTopLevelOperators =
             makeSafeKey: 'Key -> 'SafeKey,
             getKey: 'SafeKey -> 'Key
         ) =
-#if NETSTANDARD
-        static let emptyEnumerator =
-            (Array.empty<KeyValuePair<'Key, 'T>> :> seq<_>).GetEnumerator()
-#endif
+
         member _.Count = t.Count
 
         // Give a read-only view of the dictionary
@@ -169,47 +166,8 @@ module ExtraTopLevelOperators =
             member _.GetEnumerator() =
                 // We use an array comprehension here instead of seq {} as otherwise we get incorrect
                 // IEnumerator.Reset() and IEnumerator.Current semantics.
-                // Coreclr has a bug with SZGenericEnumerators --- implement a correct enumerator.  On desktop use the desktop implementation because it's ngened.
-#if !NETSTANDARD
                 let kvps = [| for (KeyValue (k, v)) in t -> KeyValuePair(getKey k, v) |] :> seq<_>
                 kvps.GetEnumerator()
-#else
-                let endIndex = t.Count
-
-                if endIndex = 0 then
-                    emptyEnumerator
-                else
-                    let kvps = [| for (KeyValue (k, v)) in t -> KeyValuePair(getKey k, v) |]
-                    let mutable index = -1
-
-                    let current () =
-                        if index < 0 then
-                            raise <| InvalidOperationException(SR.GetString(SR.enumerationNotStarted))
-
-                        if index >= endIndex then
-                            raise <| InvalidOperationException(SR.GetString(SR.enumerationAlreadyFinished))
-
-                        kvps.[index]
-
-                    { new IEnumerator<_> with
-                        member _.Current = current ()
-                      interface System.Collections.IEnumerator with
-                          member _.Current = box (current ())
-
-                          member _.MoveNext() =
-                              if index < endIndex then
-                                  index <- index + 1
-                                  index < endIndex
-                              else
-                                  false
-
-                          member _.Reset() =
-                              index <- -1
-                      interface System.IDisposable with
-                          member _.Dispose() =
-                              ()
-                    }
-#endif
 
         interface System.Collections.IEnumerable with
             member _.GetEnumerator() =

src/FSharp.Core/result.fsi

@@ -281,7 +281,7 @@ module Result =
     /// </code>
     /// </example>
     [<CompiledName("ToList")>]
-    val toList: result: Result<'T, 'Error> -> List<'T>
+    val toList: result: Result<'T, 'Error> -> 'T list
 
     /// <summary>Convert the result to an Option value.</summary>
     ///
@@ -296,7 +296,7 @@ module Result =
     /// </code>
     /// </example>
     [<CompiledName("ToOption")>]
-    val toOption: result: Result<'T, 'Error> -> Option<'T>
+    val toOption: result: Result<'T, 'Error> -> 'T option
 
     /// <summary>Convert the result to an Option value.</summary>
     ///
@@ -311,4 +311,4 @@ module Result =
     /// </code>
     /// </example>
     [<CompiledName("ToValueOption")>]
-    val toValueOption: result: Result<'T, 'Error> -> ValueOption<'T>
+    val toValueOption: result: Result<'T, 'Error> -> 'T voption

tests/FSharp.Core.UnitTests/FSharp.Core/Microsoft.FSharp.Core/ExtraTopLevelOperatorsTests.fs

@@ -8,7 +8,7 @@ open System.Collections.Generic
 type DictTests () =
 
     [<Fact>]
-    member this.IEnumerable() =
+    member this.IEnumerableOnDict() =
         // Legit IE
         let ie = (dict [|(1,1);(2,4);(3,9)|]) :> IEnumerable
         let enum = ie.GetEnumerator()
@@ -38,7 +38,7 @@ type DictTests () =
         CheckThrowsInvalidOperationExn(fun () -> enum.Current |> ignore)
 
     [<Fact>]
-    member this.IEnumerable_T() =
+    member this.IEnumerable_T_OnDict() =
         // Legit IE
         let ie = (dict [|(1,1);(2,4);(3,9)|]) :> IEnumerable<KeyValuePair<_,_>>
         let enum = ie.GetEnumerator()

tests/service/TreeVisitorTests.fs

@@ -58,4 +58,20 @@ let ``Visit enum definition test`` () =
 
     match SyntaxTraversal.Traverse(pos0, parseTree, visitor) with
     | Some [ SynEnumCase (_, SynIdent(id1,_), _, _, _, _, _); SynEnumCase (_, SynIdent(id2,_), _, _, _, _, _) ] when id1.idText = "A" && id2.idText = "B" -> ()
-    | _ -> failwith "Did not visit enum definition"
+    | _ -> failwith "Did not visit enum definition"
+
+[<Test>]
+let ``Visit recursive let binding`` () =
+    let visitor =
+        { new SyntaxVisitorBase<_>() with
+            member x.VisitExpr(_, _, defaultTraverse, expr) = defaultTraverse expr
+            member x.VisitLetOrUse(_, isRecursive, _, bindings, _) =
+                if not isRecursive then failwith $"{nameof isRecursive} should be true"
+                Some bindings }
+
+    let source = "let rec fib n = if n < 2 then n else fib (n - 1) + fib (n - 2) in fib 10"
+    let parseTree = parseSourceCode("C:\\test.fs", source)
+
+    match SyntaxTraversal.Traverse(pos0, parseTree, visitor) with
+    | Some [ SynBinding(valData = SynValData(valInfo = SynValInfo(curriedArgInfos = [ [ SynArgInfo(ident = Some id) ] ]))) ] when id.idText = "n" -> ()
+    | _ -> failwith "Did not visit recursive let binding"