Allow static members in interfaces

src/Compiler/Checking/CheckExpressions.fs

@@ -4358,12 +4358,13 @@ and TcTypeOrMeasure kindOpt (cenv: cenv) newOk checkConstraints occ (iwsam: Warn
 
 and CheckIWSAM (cenv: cenv) (env: TcEnv) checkConstraints iwsam m tcref =
     let g = cenv.g
-    let ad = env.eAccessRights
     let ty = generalizedTyconRef g tcref
+
     if iwsam = WarnOnIWSAM.Yes && isInterfaceTy g ty && checkConstraints = CheckCxs then
-        let tcref = tcrefOfAppTy g ty
-        let meths = AllMethInfosOfTypeInScope ResultCollectionSettings.AllResults cenv.infoReader env.NameEnv None ad IgnoreOverrides m ty
+        let meths = AllMethInfosOfTypeInScope ResultCollectionSettings.AllResults cenv.infoReader env.NameEnv None env.eAccessRights IgnoreOverrides m ty
+
         if meths |> List.exists (fun meth -> not meth.IsInstance && meth.IsDispatchSlot && not meth.IsExtensionMember) then
+            let tcref = tcrefOfAppTy g ty
             warning(Error(FSComp.SR.tcUsingInterfaceWithStaticAbstractMethodAsType(tcref.DisplayNameWithStaticParametersAndUnderscoreTypars), m))
 
 and TcLongIdentType kindOpt (cenv: cenv) newOk checkConstraints occ iwsam env tpenv synLongId =
@@ -11080,16 +11081,19 @@ and ApplyAbstractSlotInference (cenv: cenv) (envinner: TcEnv) (_: Val option) (a
 
        [], declaredTypars
 
-and CheckForNonAbstractInterface declKind tcref (memberFlags: SynMemberFlags) m =
+and CheckForNonAbstractInterface (g: TcGlobals) declKind tcref (memberFlags: SynMemberFlags) isMemberStatic m =
     if isInterfaceTyconRef tcref then
         if memberFlags.MemberKind = SynMemberKind.ClassConstructor then
             error(Error(FSComp.SR.tcStaticInitializersIllegalInInterface(), m))
         elif memberFlags.MemberKind = SynMemberKind.Constructor then
             error(Error(FSComp.SR.tcObjectConstructorsIllegalInInterface(), m))
         elif memberFlags.IsOverrideOrExplicitImpl then
             error(Error(FSComp.SR.tcMemberOverridesIllegalInInterface(), m))
-        elif not (declKind=ExtrinsicExtensionBinding || memberFlags.IsDispatchSlot ) then
-            error(Error(FSComp.SR.tcConcreteMembersIllegalInInterface(), m))
+        elif not (declKind = ExtrinsicExtensionBinding || memberFlags.IsDispatchSlot) then
+            if not isMemberStatic then
+                error(Error(FSComp.SR.tcConcreteMembersIllegalInInterface(), m))
+            else
+                checkLanguageFeatureError g.langVersion LanguageFeature.StaticMembersInInterfaces m
 
 //-------------------------------------------------------------------------
 // TcLetrecBindings - AnalyzeAndMakeAndPublishRecursiveValue s
@@ -11135,7 +11139,7 @@ and AnalyzeRecursiveStaticMemberOrValDecl
              memberFlags.IsOverrideOrExplicitImpl ->
 
            CheckMemberFlags intfSlotTyOpt newslotsOK overridesOK memberFlags id.idRange
-           CheckForNonAbstractInterface declKind tcref memberFlags id.idRange
+           CheckForNonAbstractInterface g declKind tcref memberFlags true id.idRange
 
            let isExtrinsic = (declKind = ExtrinsicExtensionBinding)
            let tcrefObjTy, enclosingDeclaredTypars, renaming, _, _ = FreshenObjectArgType cenv mBinding TyparRigidity.WillBeRigid tcref isExtrinsic declaredTyconTypars
@@ -11157,7 +11161,7 @@ and AnalyzeRecursiveStaticMemberOrValDecl
         assert (Option.isNone intfSlotTyOpt)
 
         CheckMemberFlags None newslotsOK overridesOK memberFlags id.idRange
-        CheckForNonAbstractInterface declKind tcref memberFlags id.idRange
+        CheckForNonAbstractInterface g declKind tcref memberFlags true id.idRange
 
         if memberFlags.MemberKind = SynMemberKind.Constructor && tcref.Deref.IsFSharpException then
             error(Error(FSComp.SR.tcConstructorsDisallowedInExceptionAugmentation(), id.idRange))
@@ -11262,7 +11266,7 @@ and AnalyzeRecursiveInstanceMemberDecl
          let argsAndRetTy = NewInferenceType g
          UnifyTypes cenv envinner mBinding ty (mkFunTy g thisTy argsAndRetTy)
 
-         CheckForNonAbstractInterface declKind tcref memberFlags memberId.idRange
+         CheckForNonAbstractInterface g declKind tcref memberFlags false memberId.idRange
 
          // Determine if a uniquely-identified-override exists based on the information
          // at the member signature. If so, we know the type of this member, and the full slotsig

src/Compiler/Checking/CheckExpressions.fsi

@@ -389,7 +389,13 @@ val AnalyzeAndMakeAndPublishRecursiveValue:
 
 /// Check that a member can be included in an interface
 val CheckForNonAbstractInterface:
-    declKind: DeclKind -> tcref: TyconRef -> memberFlags: SynMemberFlags -> m: range -> unit
+    g: TcGlobals ->
+    declKind: DeclKind ->
+    tcref: TyconRef ->
+    memberFlags: SynMemberFlags ->
+    isMemberStatic: bool ->
+    m: range ->
+        unit
 
 /// Check the flags on a member definition for consistency
 val CheckMemberFlags:

src/Compiler/Checking/CheckIncrementalClasses.fs

@@ -128,7 +128,7 @@ let TcImplicitCtorLhs_Phase2A(cenv: cenv, env, tpenv, tcref: TyconRef, vis, attr
         let valSynData = SynValInfo([synArgInfos], SynInfo.unnamedRetVal)
         let id = ident ("new", m)
 
-        CheckForNonAbstractInterface ModuleOrMemberBinding tcref memberFlags id.idRange
+        CheckForNonAbstractInterface g ModuleOrMemberBinding tcref memberFlags false id.idRange
         let memberInfo = MakeMemberDataAndMangledNameForMemberVal(g, tcref, false, attribs, [], memberFlags, valSynData, id, false)
         let prelimValReprInfo = TranslateSynValInfo m (TcAttributes cenv env) valSynData
         let prelimTyschemeG = GeneralizedType(copyOfTyconTypars, ctorTy)
@@ -152,7 +152,7 @@ let TcImplicitCtorLhs_Phase2A(cenv: cenv, env, tpenv, tcref: TyconRef, vis, attr
             let cctorTy = mkFunTy g g.unit_ty g.unit_ty
             let valSynData = SynValInfo([[]], SynInfo.unnamedRetVal)
             let id = ident ("cctor", m)
-            CheckForNonAbstractInterface ModuleOrMemberBinding tcref ClassCtorMemberFlags id.idRange
+            CheckForNonAbstractInterface g ModuleOrMemberBinding tcref ClassCtorMemberFlags false id.idRange
             let memberInfo = MakeMemberDataAndMangledNameForMemberVal(g, tcref, false, [], [], ClassCtorMemberFlags, valSynData, id, false)
             let prelimValReprInfo = TranslateSynValInfo m (TcAttributes cenv env) valSynData
             let prelimTyschemeG = GeneralizedType(copyOfTyconTypars, cctorTy)

src/Compiler/Checking/infos.fs

@@ -866,9 +866,7 @@ type MethInfo =
     member x.IsDispatchSlot =
         match x with
         | ILMeth(_g, ilmeth, _) -> ilmeth.IsVirtual
-        | FSMeth(g, _, vref, _) as x ->
-            isInterfaceTy g x.ApparentEnclosingType  ||
-            vref.MemberInfo.Value.MemberFlags.IsDispatchSlot
+        | FSMeth(_, _, vref, _) -> vref.MemberInfo.Value.MemberFlags.IsDispatchSlot
         | DefaultStructCtor _ -> false
 #if !NO_TYPEPROVIDERS
         | ProvidedMeth _ -> x.IsVirtual // Note: follow same implementation as ILMeth

src/Compiler/FSComp.txt

@@ -717,7 +717,7 @@ tcUnnamedArgumentsDoNotFormPrefix,"The unnamed arguments do not form a prefix of
 865,tcStaticInitializersIllegalInInterface,"Interfaces cannot contain definitions of static initializers"
 866,tcObjectConstructorsIllegalInInterface,"Interfaces cannot contain definitions of object constructors"
 867,tcMemberOverridesIllegalInInterface,"Interfaces cannot contain definitions of member overrides"
-868,tcConcreteMembersIllegalInInterface,"Interfaces cannot contain definitions of concrete members. You may need to define a constructor on your type to indicate that the type is a class."
+868,tcConcreteMembersIllegalInInterface,"Interfaces cannot contain definitions of concrete instance members. You may need to define a constructor on your type to indicate that the type is a class."
 869,tcConstructorsDisallowedInExceptionAugmentation,"Constructors cannot be specified in exception augmentations"
 870,tcStructsCannotHaveConstructorWithNoArguments,"Structs cannot have an object constructor with no arguments. This is a restriction imposed on all CLI languages as structs automatically support a default constructor."
 871,tcConstructorsIllegalForThisType,"Constructors cannot be defined for this type"
@@ -1563,6 +1563,7 @@ featureArithmeticInLiterals,"Allow arithmetic and logical operations in literals
 featureErrorReportingOnStaticClasses,"Error reporting on static classes"
 featureTryWithInSeqExpressions,"Support for try-with in sequence expressions"
 featureWarningWhenCopyAndUpdateRecordChangesAllFields,"Raises warnings when an copy-and-update record expression changes all fields of a record."
+featureStaticMembersInInterfaces,"Static members in interfaces"
 3353,fsiInvalidDirective,"Invalid directive '#%s %s'"
 3354,tcNotAFunctionButIndexerNamedIndexingNotYetEnabled,"This value supports indexing, e.g. '%s.[index]'. The syntax '%s[index]' requires /langversion:preview. See https://aka.ms/fsharp-index-notation."
 3354,tcNotAFunctionButIndexerIndexingNotYetEnabled,"This expression supports indexing, e.g. 'expr.[index]'. The syntax 'expr[index]' requires /langversion:preview. See https://aka.ms/fsharp-index-notation."

src/Compiler/Facilities/LanguageFeatures.fs

@@ -63,6 +63,7 @@ type LanguageFeature =
     | ErrorReportingOnStaticClasses
     | TryWithInSeqExpression
     | WarningWhenCopyAndUpdateRecordChangesAllFields
+    | StaticMembersInInterfaces
 
 /// LanguageVersion management
 type LanguageVersion(versionText) =
@@ -142,6 +143,7 @@ type LanguageVersion(versionText) =
                 LanguageFeature.ErrorReportingOnStaticClasses, previewVersion
                 LanguageFeature.TryWithInSeqExpression, previewVersion
                 LanguageFeature.WarningWhenCopyAndUpdateRecordChangesAllFields, previewVersion
+                LanguageFeature.StaticMembersInInterfaces, previewVersion
 
             ]
 
@@ -258,6 +260,7 @@ type LanguageVersion(versionText) =
         | LanguageFeature.ErrorReportingOnStaticClasses -> FSComp.SR.featureErrorReportingOnStaticClasses ()
         | LanguageFeature.TryWithInSeqExpression -> FSComp.SR.featureTryWithInSeqExpressions ()
         | LanguageFeature.WarningWhenCopyAndUpdateRecordChangesAllFields -> FSComp.SR.featureWarningWhenCopyAndUpdateRecordChangesAllFields ()
+        | LanguageFeature.StaticMembersInInterfaces -> FSComp.SR.featureStaticMembersInInterfaces ()
 
     /// Get a version string associated with the given feature.
     static member GetFeatureVersionString feature =

src/Compiler/Facilities/LanguageFeatures.fsi

@@ -53,6 +53,7 @@ type LanguageFeature =
     | ErrorReportingOnStaticClasses
     | TryWithInSeqExpression
     | WarningWhenCopyAndUpdateRecordChangesAllFields
+    | StaticMembersInInterfaces
 
 /// LanguageVersion management
 type LanguageVersion =

src/Compiler/xlf/FSComp.txt.cs.xlf

@@ -372,6 +372,11 @@
         <target state="translated">vzor s jedním podtržítkem</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureStaticMembersInInterfaces">
+        <source>Static members in interfaces</source>
+        <target state="new">Static members in interfaces</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureStringInterpolation">
         <source>string interpolation</source>
         <target state="translated">interpolace řetězce</target>
@@ -382,19 +387,16 @@
         <target state="translated">reprezentace struktury aktivních vzorů</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureTryWithInSeqExpressions">
         <source>Support for try-with in sequence expressions</source>
         <target state="new">Support for try-with in sequence expressions</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureWarningWhenCopyAndUpdateRecordChangesAllFields">
         <source>Raises warnings when an copy-and-update record expression changes all fields of a record.</source>
         <target state="new">Raises warnings when an copy-and-update record expression changes all fields of a record.</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
         <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
         <target state="translated">Vyvolá upozornění, když se použije „let inline ... =“ společně s atributem [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;]. Funkce není vkládána.</target>
@@ -4626,8 +4628,8 @@
         <note />
       </trans-unit>
       <trans-unit id="tcConcreteMembersIllegalInInterface">
-        <source>Interfaces cannot contain definitions of concrete members. You may need to define a constructor on your type to indicate that the type is a class.</source>
-        <target state="translated">Rozhraní nemůžou obsahovat definice konkrétních členů. Možná bude potřeba definovat u typu konstruktor, který bude vyjadřovat, že jde o třídu.</target>
+        <source>Interfaces cannot contain definitions of concrete instance members. You may need to define a constructor on your type to indicate that the type is a class.</source>
+        <target state="needs-review-translation">Rozhraní nemůžou obsahovat definice konkrétních členů. Možná bude potřeba definovat u typu konstruktor, který bude vyjadřovat, že jde o třídu.</target>
         <note />
       </trans-unit>
       <trans-unit id="tcConstructorsDisallowedInExceptionAugmentation">

src/Compiler/xlf/FSComp.txt.de.xlf

@@ -372,6 +372,11 @@
         <target state="translated">Muster mit einzelnem Unterstrich</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureStaticMembersInInterfaces">
+        <source>Static members in interfaces</source>
+        <target state="new">Static members in interfaces</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureStringInterpolation">
         <source>string interpolation</source>
         <target state="translated">Zeichenfolgeninterpolation</target>
@@ -382,19 +387,16 @@
         <target state="translated">Strukturdarstellung für aktive Muster</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureTryWithInSeqExpressions">
         <source>Support for try-with in sequence expressions</source>
         <target state="new">Support for try-with in sequence expressions</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureWarningWhenCopyAndUpdateRecordChangesAllFields">
         <source>Raises warnings when an copy-and-update record expression changes all fields of a record.</source>
         <target state="new">Raises warnings when an copy-and-update record expression changes all fields of a record.</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
         <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
         <target state="translated">Löst Warnungen aus, wenn „let inline ... =“ zusammen mit dem Attribut [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] verwendet wird. Die Funktion wird nicht inline gesetzt.</target>
@@ -4626,8 +4628,8 @@
         <note />
       </trans-unit>
       <trans-unit id="tcConcreteMembersIllegalInInterface">
-        <source>Interfaces cannot contain definitions of concrete members. You may need to define a constructor on your type to indicate that the type is a class.</source>
-        <target state="translated">Schnittstellen dürfen keine Definitionen konkreter Member enthalten. Sie müssen ggf. einen Konstruktor für den Typ definieren, um anzugeben, dass es sich bei dem Typ um eine Klasse handelt.</target>
+        <source>Interfaces cannot contain definitions of concrete instance members. You may need to define a constructor on your type to indicate that the type is a class.</source>
+        <target state="needs-review-translation">Schnittstellen dürfen keine Definitionen konkreter Member enthalten. Sie müssen ggf. einen Konstruktor für den Typ definieren, um anzugeben, dass es sich bei dem Typ um eine Klasse handelt.</target>
         <note />
       </trans-unit>
       <trans-unit id="tcConstructorsDisallowedInExceptionAugmentation">

src/Compiler/xlf/FSComp.txt.es.xlf

@@ -372,6 +372,11 @@
         <target state="translated">patrón de subrayado simple</target>
         <note />
       </trans-unit>
+      <trans-unit id="featureStaticMembersInInterfaces">
+        <source>Static members in interfaces</source>
+        <target state="new">Static members in interfaces</target>
+        <note />
+      </trans-unit>
       <trans-unit id="featureStringInterpolation">
         <source>string interpolation</source>
         <target state="translated">interpolación de cadena</target>
@@ -382,19 +387,16 @@
         <target state="translated">representación de struct para modelos activos</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureTryWithInSeqExpressions">
         <source>Support for try-with in sequence expressions</source>
         <target state="new">Support for try-with in sequence expressions</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureWarningWhenCopyAndUpdateRecordChangesAllFields">
         <source>Raises warnings when an copy-and-update record expression changes all fields of a record.</source>
         <target state="new">Raises warnings when an copy-and-update record expression changes all fields of a record.</target>
         <note />
       </trans-unit>
-
       <trans-unit id="featureWarningWhenInliningMethodImplNoInlineMarkedFunction">
         <source>Raises warnings when 'let inline ... =' is used together with [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;] attribute. Function is not getting inlined.</source>
         <target state="translated">Genera advertencias cuando se usa "let inline ... =" junto con el atributo [&lt;MethodImpl(MethodImplOptions.NoInlining)&gt;]. La función no se está insertando.</target>
@@ -4626,8 +4628,8 @@
         <note />
       </trans-unit>
       <trans-unit id="tcConcreteMembersIllegalInInterface">
-        <source>Interfaces cannot contain definitions of concrete members. You may need to define a constructor on your type to indicate that the type is a class.</source>
-        <target state="translated">Las interfaces no pueden contener definiciones de miembros concretos. Puede ser necesario definir un constructor en el tipo para indicar que el tipo es una clase.</target>
+        <source>Interfaces cannot contain definitions of concrete instance members. You may need to define a constructor on your type to indicate that the type is a class.</source>
+        <target state="needs-review-translation">Las interfaces no pueden contener definiciones de miembros concretos. Puede ser necesario definir un constructor en el tipo para indicar que el tipo es una clase.</target>
         <note />
       </trans-unit>
       <trans-unit id="tcConstructorsDisallowedInExceptionAugmentation">