Enforce AttributeTargets.Class and AttributeTargets.Struct (#16790)

* Enforce AttributeTargets.Class and AttributeTargets.Struct

* Enforce AttributeTargets.Class properly in the compiler

* Enforce AttributeTargets.Class properly in the compiler

* update tests

* Fix test

* release-notes

* Extend AutoOpenAttribute and RequireQualifiedAccessAttribute to use AttributeTargets.Struct

* Put back AutoOpen and RequireQualifiedAccess

* Update tests

* Release notes

* release notes

* Extend attributes targets

* Update prim-types.fs

* Update 8.0.300.md

---------

Co-authored-by: Kevin Ransom (msft) <[email protected]>
Co-authored-by: Vlad Zarytovskii <[email protected]>
Co-authored-by: Petr <[email protected]>

Author: 4 people

docs/release-notes/.FSharp.Compiler.Service/8.0.300.md

@@ -16,6 +16,7 @@
 * Enforce AttributeTargets on let values and functions. ([PR #16692](https://github.com/dotnet/fsharp/pull/16692))
 * Enforce AttributeTargets on union case declarations. ([PR #16764](https://github.com/dotnet/fsharp/pull/16764))
 * Disallow using base to invoke an abstract base method. ([Issue #13926](https://github.com/dotnet/fsharp/issues/13926), [PR #16773](https://github.com/dotnet/fsharp/pull/16773))
+* Enforce AttributeTargets on structs and classes ([PR #16790](https://github.com/dotnet/fsharp/pull/16790))
 * Parser: fix pattern range for idents with trivia ([PR #16824](https://github.com/dotnet/fsharp/pull/16824))
 * Fix broken code completion after a record type declaration ([PR #16813](https://github.com/dotnet/fsharp/pull/16813))
 

docs/release-notes/.FSharp.Core/8.0.300.md

@@ -6,3 +6,4 @@
 ### Fixed
 
 * Preserve original stack traces in resumable state machines generated code if available. ([PR #16568](https://github.com/dotnet/fsharp/pull/16568))
+* Enforce AttributeTargets on structs and classes. Also update `RequireQualifiedAccessAttribute` and `AutoOpenAttribute` to use `AttributeTargets.Struct` ([PR #16790](https://github.com/dotnet/fsharp/pull/16790))

docs/release-notes/.Language/preview.md

@@ -11,6 +11,7 @@
 * Allow extension methods without type attribute work for types from imported assemblies. ([PR #16368](https://github.com/dotnet/fsharp/pull/16368))
 * Enforce AttributeTargets on let values and functions. ([PR #16692](https://github.com/dotnet/fsharp/pull/16692))
 * Enforce AttributeTargets on union case declarations. ([PR #16764](https://github.com/dotnet/fsharp/pull/16764))
+* Enforce AttributeTargets on structs and classes ([PR #16790](https://github.com/dotnet/fsharp/pull/16790))
 
 ### Changed
 

src/Compiler/Checking/CheckDeclarations.fs

@@ -2926,10 +2926,16 @@ module EstablishTypeDefinitionCores =
                 | _ -> 
                     let kind = 
                         match kind with
-                        | SynTypeDefnKind.Class -> TFSharpClass
+                        | SynTypeDefnKind.Class ->
+                            if g.langVersion.SupportsFeature(LanguageFeature.EnforceAttributeTargetsOnStructAndClasses) then
+                                TcAttributesWithPossibleTargets false cenv envinner AttributeTargets.Class synAttrs |> ignore
+                            TFSharpClass
                         | SynTypeDefnKind.Interface -> TFSharpInterface
                         | SynTypeDefnKind.Delegate _ -> TFSharpDelegate (MakeSlotSig("Invoke", g.unit_ty, [], [], [], None))
-                        | SynTypeDefnKind.Struct -> TFSharpStruct 
+                        | SynTypeDefnKind.Struct ->
+                            if g.langVersion.SupportsFeature(LanguageFeature.EnforceAttributeTargetsOnStructAndClasses) then
+                                TcAttributesWithPossibleTargets false cenv envinner AttributeTargets.Struct synAttrs |> ignore
+                            TFSharpStruct 
                         | _ -> error(InternalError("should have inferred tycon kind", m))
 
                     TFSharpTyconRepr (Construct.NewEmptyFSharpTyconData kind)

src/Compiler/FSComp.txt

@@ -1596,6 +1596,7 @@ featureBooleanReturningAndReturnTypeDirectedPartialActivePattern,"Boolean-return
 featureEnforceAttributeTargetsOnFunctions,"Enforce AttributeTargets on functions"
 featureEnforceAttributeTargetsUnionCaseDeclarations,"Enforce AttributeTargets on union case declarations"
 featureLowerInterpolatedStringToConcat,"Optimizes interpolated strings in certain cases, by lowering to concatenation"
+featureEnforceAttributeTargetsOnStructAndClasses,"Enforce AttributeTargets on structs and classes"
 featureLowerIntegralRangesToFastLoops,"Optimizes certain uses of the integral range (..) and range-step (.. ..) operators to fast while-loops."
 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

@@ -88,6 +88,7 @@ type LanguageFeature =
     | EnforceAttributeTargetsOnFunctions
     | EnforceAttributeTargetsUnionCaseDeclarations
     | LowerInterpolatedStringToConcat
+    | EnforceAttributeTargetsOnStructAndClasses
     | LowerIntegralRangesToFastLoops
 
 /// LanguageVersion management
@@ -204,6 +205,7 @@ type LanguageVersion(versionText) =
                 LanguageFeature.EnforceAttributeTargetsOnFunctions, previewVersion
                 LanguageFeature.EnforceAttributeTargetsUnionCaseDeclarations, previewVersion
                 LanguageFeature.LowerInterpolatedStringToConcat, previewVersion
+                LanguageFeature.EnforceAttributeTargetsOnStructAndClasses, previewVersion
                 LanguageFeature.LowerIntegralRangesToFastLoops, previewVersion
             ]
 
@@ -351,6 +353,7 @@ type LanguageVersion(versionText) =
         | LanguageFeature.EnforceAttributeTargetsOnFunctions -> FSComp.SR.featureEnforceAttributeTargetsOnFunctions ()
         | LanguageFeature.EnforceAttributeTargetsUnionCaseDeclarations -> FSComp.SR.featureEnforceAttributeTargetsUnionCaseDeclarations ()
         | LanguageFeature.LowerInterpolatedStringToConcat -> FSComp.SR.featureLowerInterpolatedStringToConcat ()
+        | LanguageFeature.EnforceAttributeTargetsOnStructAndClasses -> FSComp.SR.featureEnforceAttributeTargetsOnStructAndClasses ()
         | LanguageFeature.LowerIntegralRangesToFastLoops -> FSComp.SR.featureLowerIntegralRangesToFastLoops ()
 
     /// Get a version string associated with the given feature.

src/Compiler/Facilities/LanguageFeatures.fsi

@@ -79,6 +79,7 @@ type LanguageFeature =
     | EnforceAttributeTargetsOnFunctions
     | EnforceAttributeTargetsUnionCaseDeclarations
     | LowerInterpolatedStringToConcat
+    | EnforceAttributeTargetsOnStructAndClasses
     | LowerIntegralRangesToFastLoops
 
 /// LanguageVersion management