Refactor extension attribute addition for modules and types.

src/Compiler/Checking/CheckDeclarations.fs

@@ -1203,11 +1203,13 @@ module MutRecBindingChecking =
                     if cenv.g.langVersion.SupportsFeature(LanguageFeature.CSharpExtensionAttributeNotRequired) then
                         tyconOpt
                         |> Option.map (fun tycon ->
-                            tryAddExtensionAttributeIfNotAlreadyPresent
+                            tryAddExtensionAttributeIfNotAlreadyPresentForType
+                                g
                                 (fun tryFindExtensionAttribute ->
                                     tycon.MembersOfFSharpTyconSorted
                                     |> Seq.tryPick (fun m -> tryFindExtensionAttribute m.Attribs)
                                 )
+                                envForTycon.eModuleOrNamespaceTypeAccumulator
                                 tycon
                         )
                     else
@@ -1437,7 +1439,25 @@ module MutRecBindingChecking =
 
                             let innerState = (tpenv, envInstance, envStatic, envNonRec, generalizedRecBinds, preGeneralizationRecBinds, uncheckedRecBindsTable)
                             Phase2BMember rbind.RecBindingInfo.Index, innerState)
-
+
+                let tyconOpt =
+                    if not(cenv.g.langVersion.SupportsFeature(LanguageFeature.CSharpExtensionAttributeNotRequired)) then
+                        tyconOpt
+                    else
+                        // We need to redo this check, which already happened in TcMutRecBindings_Phase2A_CreateRecursiveValuesAndCheckArgumentPatterns
+                        // Because the environment is being reset in the case of recursive modules.
+                        tyconOpt
+                        |> Option.map (fun tycon ->
+                            tryAddExtensionAttributeIfNotAlreadyPresentForType
+                                g
+                                (fun tryFindExtensionAttribute ->
+                                    tycon.MembersOfFSharpTyconSorted
+                                    |> Seq.tryPick (fun m -> tryFindExtensionAttribute m.Attribs)
+                                )
+                                envForTycon.eModuleOrNamespaceTypeAccumulator
+                                tycon
+                        )
+
                 let defnBs = MutRecShape.Tycon (TyconBindingsPhase2B(tyconOpt, tcref, defnBs))
                 let outerState = (tpenv, generalizedRecBinds, preGeneralizationRecBinds, uncheckedRecBindsTable, envNonRec)
                 defnBs, outerState)
@@ -4528,16 +4548,20 @@ module TcDeclarations =
                 |> List.map (function
                     | MutRecShape.Tycon (Some tycon, bindings) ->
                         let tycon =
-                            tryAddExtensionAttributeIfNotAlreadyPresent
+                            tryAddExtensionAttributeIfNotAlreadyPresentForType
+                                g
                                 (fun tryFindExtensionAttribute ->
                                     tycon.MembersOfFSharpTyconSorted
                                     |> Seq.tryPick (fun m -> tryFindExtensionAttribute m.Attribs)
                                 )
+                                envFinal.eModuleOrNamespaceTypeAccumulator
                                 tycon
+
                         MutRecShape.Tycon (Some tycon, bindings)
                     | MutRecShape.Module ((MutRecDefnsPhase2DataForModule(moduleOrNamespaceType, entity), env), shapes) ->
                         let entity =
-                            tryAddExtensionAttributeIfNotAlreadyPresent
+                            tryAddExtensionAttributeIfNotAlreadyPresentForModule
+                                g
                                 (fun tryFindExtensionAttribute ->
                                     moduleOrNamespaceType.Value.AllValsAndMembers
                                     |> Seq.filter(fun v -> v.IsModuleBinding)
@@ -4659,8 +4683,28 @@ module TcDeclarations =
                 let envForTycon = AddDeclaredTypars CheckForDuplicateTypars declaredTyconTypars envForDecls
                 let envForTycon = MakeInnerEnvForTyconRef envForTycon tcref (declKind = ExtrinsicExtensionBinding) 
 
-                TcTyconMemberSpecs cenv envForTycon (TyconContainerInfo(innerParent, tcref, declaredTyconTypars, NoSafeInitInfo)) declKind tpenv members)
+                let vals, env = TcTyconMemberSpecs cenv envForTycon (TyconContainerInfo(innerParent, tcref, declaredTyconTypars, NoSafeInitInfo)) declKind tpenv members
+                if not(cenv.g.langVersion.SupportsFeature(LanguageFeature.CSharpExtensionAttributeNotRequired)) then
+                    vals, env
+                else
+                    // Check if any of the vals has the `[<Extension>]` attribute
+                    // If this is the case, add it to the type in the env.
+                    let extensionAttributeOnVals =
+                        vals
+                        |> List.tryPick (fun v -> tryFindExtensionAttribute g v.Attribs)
+
+                    let typeEntity =
+                        envForTycon.eModuleOrNamespaceTypeAccumulator.Value.AllEntitiesByLogicalMangledName.TryFind(tcref.LogicalName)
 
+                    match extensionAttributeOnVals, typeEntity with
+                    | Some extensionAttribute, Some typeEntity ->
+                        if Option.isNone (tryFindExtensionAttribute g typeEntity.Attribs) then
+                            typeEntity.entity_attribs <- extensionAttribute :: typeEntity.Attribs
+                    | _ -> ()
+
+                    vals, env
+
+            )
             // Do this for each 'val' declaration in a module
             (fun envForDecls (containerInfo, valSpec) -> 
                 let tpenv = emptyUnscopedTyparEnv
@@ -5130,7 +5174,8 @@ let rec TcModuleOrNamespaceElementNonMutRec (cenv: cenv) parent typeNames scopem
                     //
                     //[<System.Runtime.CompilerServices.Extension>]
                     //let PlusOne (a:int) = a + 1
-                    tryAddExtensionAttributeIfNotAlreadyPresent
+                    tryAddExtensionAttributeIfNotAlreadyPresentForModule
+                        g
                         (fun tryFindExtensionAttribute ->
                             match moduleContents with
                             | ModuleOrNamespaceContents.TMDefs(defs) ->

src/Compiler/TypedTree/TypedTreeOps.fs

@@ -10591,23 +10591,42 @@ let (|EmptyModuleOrNamespaces|_|) (moduleOrNamespaceContents: ModuleOrNamespaceC
             None
     | _ -> None
 
-let tryAddExtensionAttributeIfNotAlreadyPresent
+let tryFindExtensionAttribute (g: TcGlobals) (attribs: Attrib list): Attrib option =
+    attribs
+    |> List.tryFind (IsMatchingFSharpAttribute g g.attrib_ExtensionAttribute)
+
+let tryAddExtensionAttributeIfNotAlreadyPresentForModule
+    (g: TcGlobals)
+    (tryFindExtensionAttributeIn: (Attrib list -> Attrib option) -> Attrib option)
+    (moduleEntity: Entity)
+    : Entity
+    =
+    if Option.isSome (tryFindExtensionAttribute g moduleEntity.Attribs) then
+        moduleEntity
+    else
+        match tryFindExtensionAttributeIn (tryFindExtensionAttribute g) with
+        | None -> moduleEntity
+        | Some extensionAttrib ->
+            { moduleEntity with entity_attribs = extensionAttrib :: moduleEntity.Attribs }
+
+let tryAddExtensionAttributeIfNotAlreadyPresentForType
+    (g: TcGlobals)
     (tryFindExtensionAttributeIn: (Attrib list -> Attrib option) -> Attrib option)
-    (entity: Entity)
+    (moduleOrNamespaceTypeAccumulator: ModuleOrNamespaceType ref)
+    (typeEntity: Entity)
     : Entity
     =
-    let tryFindExtensionAttribute (attribs: Attrib list): Attrib option =
-         List.tryFind
-             (fun (a: Attrib) ->
-                a.TyconRef.CompiledRepresentationForNamedType.BasicQualifiedName = "System.Runtime.CompilerServices.ExtensionAttribute")
-             attribs
-
-    if Option.isSome (tryFindExtensionAttribute entity.Attribs) then
-        entity
+    if Option.isSome (tryFindExtensionAttribute g typeEntity.Attribs) then
+        typeEntity
     else
-        match tryFindExtensionAttributeIn tryFindExtensionAttribute with
-        | None -> entity
-        | Some extensionAttrib -> { entity with entity_attribs = extensionAttrib :: entity.Attribs }
+        match tryFindExtensionAttributeIn (tryFindExtensionAttribute g) with
+        | None -> typeEntity
+        | Some extensionAttrib ->
+            moduleOrNamespaceTypeAccumulator.Value.AllEntitiesByLogicalMangledName.TryFind(typeEntity.LogicalName)
+            |> Option.iter (fun e ->
+                e.entity_attribs <- extensionAttrib :: e.Attribs
+            )
+            typeEntity
 
 type TypedTreeNode =
     {

src/Compiler/TypedTree/TypedTreeOps.fsi

@@ -2727,9 +2727,22 @@ type TraitConstraintInfo with
 val (|EmptyModuleOrNamespaces|_|):
     moduleOrNamespaceContents: ModuleOrNamespaceContents -> (ModuleOrNamespace list) option
 
-/// Add an System.Runtime.CompilerServices.ExtensionAttribute to the Entity if found via predicate and not already present.
-val tryAddExtensionAttributeIfNotAlreadyPresent:
-    tryFindExtensionAttributeIn: ((Attrib list -> Attrib option) -> Attrib option) -> entity: Entity -> Entity
+val tryFindExtensionAttribute: g: TcGlobals -> attribs: Attrib list -> Attrib option
+
+/// Add an System.Runtime.CompilerServices.ExtensionAttribute to the module Entity if found via predicate and not already present.
+val tryAddExtensionAttributeIfNotAlreadyPresentForModule:
+    g: TcGlobals ->
+    tryFindExtensionAttributeIn: ((Attrib list -> Attrib option) -> Attrib option) ->
+    moduleEntity: Entity ->
+        Entity
+
+/// Add an System.Runtime.CompilerServices.ExtensionAttribute to the type Entity if found via predicate and not already present.
+val tryAddExtensionAttributeIfNotAlreadyPresentForType:
+    g: TcGlobals ->
+    tryFindExtensionAttributeIn: ((Attrib list -> Attrib option) -> Attrib option) ->
+    moduleOrNamespaceTypeAccumulator: ModuleOrNamespaceType ref ->
+    typeEntity: Entity ->
+        Entity
 
 /// Serialize an entity to a very basic json structure.
 val serializeEntity: path: string -> entity: Entity -> unit

tests/FSharp.Compiler.ComponentTests/Language/ExtensionMethodTests.fs

@@ -648,3 +648,40 @@ module M =
            |> withReferences [ csharp ]
 
         fsharp |> compile |> shouldSucceed
+
+    [<Fact>]
+    let ``F# CSharpStyleExtensionMethod consumed in F#`` () =
+        let producer =
+            FSharp
+                """
+namespace Producer
+
+open System.Runtime.CompilerServices
+
+type WidgetBuilder<'msg, 'marker>() = class end
+
+type IMarkerOne = interface end
+
+// Commenting out [<Extension>] breaks
+//[<Extension>]
+type WidgetBuilderExtensions =
+    [<Extension>]
+    static member inline one(this: WidgetBuilder<'msg, #IMarkerOne>) = this
+"""
+            |> withLangVersion80
+            |> withName "FSLibProducer"
+
+        let fsharp2 =
+            FSharp
+                """
+namespace Consumer
+
+open Producer
+
+module FSLibConsumer =   
+    let x = WidgetBuilder<int, IMarkerOne>().one()
+"""
+            |> withName "FSLibConsumer"
+            |> withReferences [ producer ]
+
+        fsharp2 |> compile |> shouldSucceed