Attribute targets on records

docs/release-notes/.FSharp.Compiler.Service/8.0.400.md

@@ -1,5 +1,6 @@
 ### Fixed
 
+* Enforce `AttributeTargets` on records. ([PR #17207](https://github.com/dotnet/fsharp/pull/17207))
 * Extended #help directive in fsi to show documentation in the REPL. ([PR #17140](https://github.com/dotnet/fsharp/pull/17140))
 * Fix internal error when dotting into delegates with multiple type parameters. ([PR #17227](https://github.com/dotnet/fsharp/pull/17227))
 * Error for partial implementation of interface with static and non-static abstract members. ([Issue #17138](https://github.com/dotnet/fsharp/issues/17138), [PR #17160](https://github.com/dotnet/fsharp/pull/17160))

docs/release-notes/.FSharp.Core/8.0.400.md

@@ -6,3 +6,4 @@
 
 * Cache delegate in query extensions. ([PR #17130](https://github.com/dotnet/fsharp/pull/17130))
 * Update `AllowNullLiteralAttribute` to also use `AttributeTargets.Interface` ([PR #17173](https://github.com/dotnet/fsharp/pull/17173))
+* Update `StructAttribute ` to also use `AttributeTargets.Class` ([PR #17207](https://github.com/dotnet/fsharp/pull/17207))

src/Compiler/Checking/CheckDeclarations.fs

@@ -428,6 +428,7 @@ module TcRecdUnionAndEnumDeclarations =
         let g = cenv.g
         let m = id.idRange
         let attrs, _ = TcAttributesWithPossibleTargets false cenv env AttributeTargets.FieldDecl synAttrs
+
         let attrsForProperty, attrsForField = attrs |> List.partition (fun (attrTargets, _) -> (attrTargets &&& AttributeTargets.Property) <> enum 0) 
         let attrsForProperty = (List.map snd attrsForProperty) 
         let attrsForField = (List.map snd attrsForField)
@@ -2840,6 +2841,8 @@ module EstablishTypeDefinitionCores =
         // Allow failure of constructor resolution because Vals for members in the same recursive group are not yet available
         let attrs, getFinalAttrs = TcAttributesCanFail cenv envinner AttributeTargets.TyconDecl synAttrs
         let hasMeasureAttr = HasFSharpAttribute g g.attrib_MeasureAttribute attrs
+        let hasStructAttr = HasFSharpAttribute g g.attrib_StructAttribute attrs
+        let hasRQAAttr = HasFSharpAttribute g g.attrib_RequireQualifiedAccessAttribute attrs
 
         let isStructRecordOrUnionType = 
             match synTyconRepr with
@@ -2896,6 +2899,16 @@ module EstablishTypeDefinitionCores =
 
                 // Run InferTyconKind to raise errors on inconsistent attribute sets
                 InferTyconKind g (SynTypeDefnKind.Record, attrs, [], [], inSig, true, m) |> ignore
+
+                if g.langVersion.SupportsFeature(LanguageFeature.EnforceAttributeTargets) then
+                    if hasStructAttr then
+                        // To ensure that we can still use the RequiredQualifiedAccessAttribute on classes and structs we need to allow both AttributeTargets.Class ||| AttributeTargets.Struct.
+                        if hasRQAAttr then
+                            TcAttributesWithPossibleTargets false cenv envinner (AttributeTargets.Class ||| AttributeTargets.Struct) synAttrs |> ignore
+                        else
+                            TcAttributesWithPossibleTargets false cenv envinner AttributeTargets.Struct synAttrs |> ignore
+                    else
+                        TcAttributesWithPossibleTargets false cenv envinner AttributeTargets.Class synAttrs |> ignore
 
                 // Note: the table of record fields is initially empty
                 TFSharpTyconRepr (Construct.NewEmptyFSharpTyconData TFSharpRecord)

src/FSharp.Core/prim-types.fs

@@ -180,7 +180,7 @@ namespace Microsoft.FSharp.Core
         inherit Attribute()
         member _.CompiledName = compiledName
 
-    [<AttributeUsage (AttributeTargets.Struct ||| AttributeTargets.ReturnValue, AllowMultiple=false)>]  
+    [<AttributeUsage (AttributeTargets.Class ||| AttributeTargets.Struct ||| AttributeTargets.ReturnValue, AllowMultiple=false)>]  
     [<Sealed>]
     type StructAttribute() =
         inherit Attribute()

src/FSharp.Core/prim-types.fsi

@@ -199,7 +199,7 @@ namespace Microsoft.FSharp.Core
     /// <summary>Adding this attribute to a type causes it to be represented using a CLI struct.</summary>
     ///
     /// <category>Attributes</category>
-    [<AttributeUsage (AttributeTargets.Struct ||| AttributeTargets.ReturnValue ,AllowMultiple=false)>]  
+    [<AttributeUsage (AttributeTargets.Class ||| AttributeTargets.Struct ||| AttributeTargets.ReturnValue ,AllowMultiple=false)>]  
     [<Sealed>]
     type StructAttribute =
         inherit Attribute

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/CustomAttributes/AttributeUsage/AttributeTargetsIsClass.fs

@@ -24,3 +24,11 @@ type SemanticClassificationItem =
 type ILTableName(idx: int) =
     member __.Index = idx
     static member FromIndex n = ILTableName n
+
+[<RequireQualifiedAccess>]
+[<CustomClass>]
+type Record = { Prop: string }
+
+[<RequireQualifiedAccess>]
+[<Struct>]
+type StructRecord = { Prop: string }

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/CustomAttributes/AttributeUsage/AttributeTargetsIsProperty.fs

@@ -7,4 +7,4 @@ type PropertyLevelAttribute() =
 
 type U =
     | [<PropertyLevel>] A
-    | [<PropertyLevel>] B
+    | [<PropertyLevel>] B

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/CustomAttributes/AttributeUsage/AttributeUsage.fs

@@ -638,4 +638,25 @@ type InterruptibleLazy<'T> private (valueFactory: unit -> 'T) =
             (Error 842, Line 14, Col 3, Line 14, Col 15, "This attribute is not valid for use on this language element")
             (Error 842, Line 18, Col 3, Line 18, Col 14, "This attribute is not valid for use on this language element")
             (Error 842, Line 19, Col 3, Line 19, Col 15, "This attribute is not valid for use on this language element")
+        ]
+
+    // SOURCE= E_AttributeTargetIsClass02.fs	# E_AttributeTargetIsClass02.fs
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"E_AttributeTargetIsClass02.fs"|])>]
+    let ``E_AttributeTargetIsClass02_fs`` compilation =
+        compilation
+        |> verifyCompile
+        |> shouldSucceed
+
+    // SOURCE=E_AttributeTargetIsClass02.fs	# E_AttributeTargetIsClass02.fs
+    [<Theory; Directory(__SOURCE_DIRECTORY__, Includes=[|"E_AttributeTargetIsClass02.fs"|])>]
+    let ``E_AttributeTargetIsClass02_fs preview`` compilation =
+        compilation
+        |> withLangVersionPreview
+        |> verifyCompile
+        |> shouldFail
+        |> withDiagnostics [
+            (Error 842, Line 15, Col 3, Line 15, Col 18, "This attribute is not valid for use on this language element")
+            (Error 842, Line 16, Col 3, Line 16, Col 15, "This attribute is not valid for use on this language element")
+            (Error 842, Line 20, Col 3, Line 20, Col 14, "This attribute is not valid for use on this language element")
+            (Error 842, Line 21, Col 3, Line 21, Col 18, "This attribute is not valid for use on this language element")
         ]

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/CustomAttributes/AttributeUsage/E_AttributeTargetIsClass02.fs

@@ -0,0 +1,24 @@
+open System
+
+[<AttributeUsage(AttributeTargets.Class)>]
+type ClassTargetAttribute() =
+    inherit Attribute()
+
+[<AttributeUsage(AttributeTargets.Interface)>]
+type InterfaceTargetAttribute() =
+    inherit Attribute()
+
+[<AttributeUsage(AttributeTargets.Struct)>]
+type StructTargetAttribute() =
+    inherit Attribute()
+
+[<InterfaceTarget>]
+[<StructTarget>]
+[<ClassTarget>]
+type Record = { Prop: string }
+
+[<ClassTarget>]
+[<InterfaceTarget>]
+[<StructTarget>]
+[<Struct>]
+type StructRecord = { Prop: string }

tests/FSharp.Compiler.ComponentTests/Conformance/BasicGrammarElements/CustomAttributes/AttributeUsage/E_AttributeTargetIsProperty01.fs

@@ -12,4 +12,5 @@ type PropertyOrFieldLevelAttribute() =
 
 type SomeUnion =
 | [<PropertyLevel>] Case1 of int // Should fail
-| [<PropertyOrFieldLevel>] Case2 of int // Should fail
+| [<PropertyOrFieldLevel>] Case2 of int // Should fail
+