Bump FCS to Rotate [<return: X>] attributes during binding normalization- #20356

CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## [8.0.0-alpha-022] - 2026-08-27
+
+### Added
+
+- Extension members on tuple types, `type (int * int) with ...` and `type struct (int * int) with ...`, format instead of failing. The parser accepts them since [dotnet/fsharp#19602](https://github.com/dotnet/fsharp/pull/19602), and a type definition's name is now any type in the Oak tree rather than only an identifier. The tuple prints as written; no layout decision was added for it. [#3436](https://github.com/fsprojects/fantomas/pull/3436)
+
+### Changed
+
+- Update FCS to 'Rotate [<return: X>] attributes during binding normalization', commit 74ec4f7df70717a162d6ffd23007603cf298fb8b [#3436](https://github.com/fsprojects/fantomas/pull/3436)
+
 ## [8.0.0-alpha-021] - 2026-08-27
 
 ### Fixed

Directory.Build.props

@@ -45,7 +45,7 @@ Some common use cases include:
 
     <!-- Versions -->
     <PropertyGroup>
-        <FCSCommitHash>d05075e098278aedcea3379159504d664628a495</FCSCommitHash>
+        <FCSCommitHash>74ec4f7df70717a162d6ffd23007603cf298fb8b</FCSCommitHash>
     </PropertyGroup>
 
     <PropertyGroup>

src/Fantomas.Core.Tests/SignatureTests.fs

@@ -577,6 +577,31 @@ type T with
     member Foo: int
 """
 
+[<Test>]
+let ``tuple type extension member signature`` () =
+    formatSignatureString
+        """namespace ExtensionParts
+
+type (int * int) with
+    member Sum: int
+
+type struct (int * int) with
+    member Sum: int
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+namespace ExtensionParts
+
+type (int * int) with
+    member Sum: int
+
+type struct (int * int) with
+    member Sum: int
+"""
+
 [<Test>]
 let ``comment above static member, 680`` () =
     formatSignatureString

src/Fantomas.Core.Tests/TypeDeclarationTests.fs

@@ -323,6 +323,44 @@ type System.Int32 with
     member this.FromString(s: string) = System.Int32.Parse(s)
 """
 
+[<Test>]
+let ``tuple type extension`` () =
+    formatSourceString
+        """
+type (int * int) with
+    member this.Sum = fst this + snd this
+
+type (string * int * bool) with
+    member this.Arity = 3
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+type (int * int) with
+    member this.Sum = fst this + snd this
+
+type (string * int * bool) with
+    member this.Arity = 3
+"""
+
+[<Test>]
+let ``struct tuple type extension`` () =
+    formatSourceString
+        """
+type struct (int * int) with
+    member this.Sum = fst this + snd this
+"""
+        config
+    |> prepend newline
+    |> should
+        equal
+        """
+type struct (int * int) with
+    member this.Sum = fst this + snd this
+"""
+
 [<Test>]
 let ``auto property`` () =
     formatSourceString

src/Fantomas.Core/ASTTransformer.fs

@@ -2227,73 +2227,11 @@ let (|OperatorWithStar|_|) (si: SynIdent) =
         ValueSome(IdentifierOrDot.Ident(stn $"( %s{text} )" ident.idRange))
     | _ -> ValueNone
 
-/// The parser moves a `[<return: ...>]` attribute written in front of a binding out of the
-/// binding's attribute list and into the arity information, where nothing prints it. Put those
-/// attributes back in the list they were written in, otherwise they are dropped from the output.
-let restoreRotatedReturnAttributes
-    (attributes: SynAttributes)
-    (SynValData(valInfo = SynValInfo(returnInfo = SynArgInfo(attributes = arityAttributes))))
-    (returnInfo: SynBindingReturnInfo option)
-    : SynAttributes
-    =
-    let sortAttributes (attributes: SynAttribute list) =
-        List.sortBy (fun (a: SynAttribute) -> a.Range.StartLine, a.Range.StartColumn) attributes
-
-    let sortAttributeLists (attributes: SynAttributes) =
-        List.sortBy (fun (al: SynAttributeList) -> al.Range.StartLine, al.Range.StartColumn) attributes
-
-    // A return attribute written on the return type, `let f x : [<return: Foo>] int = x`, ends up in
-    // the arity information as well. That one is printed by the return type node, so leave it there.
-    let returnTypeAttributes =
-        match returnInfo with
-        | None -> []
-        | Some(SynBindingReturnInfo(attributes = attributes)) ->
-            List.collect (fun (al: SynAttributeList) -> al.Attributes) attributes
-
-    let rotated =
-        arityAttributes
-        |> List.collect (fun al -> al.Attributes)
-        |> List.filter (fun a ->
-            not (List.exists (fun (rta: SynAttribute) -> equals rta.Range a.Range) returnTypeAttributes)
-        )
-
-    match rotated with
-    | [] -> attributes
-    | rotated ->
-        let wasWrittenIn (al: SynAttributeList) (a: SynAttribute) =
-            RangeHelpers.rangeContainsRange al.Range a.Range
-
-        let restored =
-            attributes
-            |> List.map (fun al ->
-                match List.filter (wasWrittenIn al) rotated with
-                | [] -> al
-                | inThisList ->
-                    { al with
-                        Attributes = sortAttributes (al.Attributes @ inThisList)
-                    }
-            )
-
-        // An attribute list that held nothing but return attributes was removed altogether, so it
-        // has to be recreated. Its own range is gone, the attribute range is the closest we have.
-        let recreated =
-            rotated
-            |> List.choose (fun a ->
-                if List.exists (fun al -> wasWrittenIn al a) attributes then
-                    None
-                else
-                    Some({ Attributes = [ a ]; Range = a.Range }: SynAttributeList)
-            )
-
-        sortAttributeLists (restored @ recreated)
-
 let mkBinding
     (creationAide: CreationAide)
-    (SynBinding(_, _, _, isMutable, attributes, xmlDoc, valData, pat, returnInfo, expr, _, _, trivia))
+    (SynBinding(_, _, _, isMutable, attributes, xmlDoc, _, pat, returnInfo, expr, _, _, trivia))
     (inKeyword: SingleTextNode option)
     =
-    let attributes = restoreRotatedReturnAttributes attributes valData returnInfo
-
     let mkFunctionName (sli: SynLongIdent) : IdentListNode =
         match sli.IdentsWithTrivia with
         | [ prefix; OperatorWithStar operatorNode ] ->
@@ -2380,16 +2318,12 @@ let mkExternBinding
         accessibility = accessibility
         attributes = attributes
         xmlDoc = xmlDoc
-        valData = valData
         headPat = pat
         returnInfo = returnInfo
         range = range
         trivia = trivia))
     : ExternBindingNode
     =
-    let attributes: SynAttributes =
-        restoreRotatedReturnAttributes attributes valData returnInfo
-
     let m =
         if not xmlDoc.IsEmpty then
             unionRanges xmlDoc.Range pat.Range
@@ -2504,6 +2438,11 @@ let mkXmlDoc (px: PreXmlDoc) =
         let lines = Array.map (sprintf "///%s") xmlDoc.UnprocessedLines
         Some(XmlDocNode(lines, xmlDoc.Range))
 
+let mkModuleName (SynComponentInfo(synType = synType; range = m) as info) : IdentListNode =
+    match synType with
+    | Some(SynType.LongIdent(SynLongIdent(lid, _, _))) -> mkLongIdent lid
+    | _ -> invariantViolationAbout m info "module name is not an identifier"
+
 let mkModuleDecl (creationAide: CreationAide) (decl: SynModuleDecl) =
     let declRange = decl.Range
 
@@ -2535,7 +2474,7 @@ let mkModuleDecl (creationAide: CreationAide) (decl: SynModuleDecl) =
     | SynModuleDecl.ModuleAbbrev(ident, lid, StartRange 6 (mModule, _)) ->
         ModuleAbbrevNode(stn "module" mModule, mkIdent ident, mkLongIdent lid, declRange)
         |> ModuleDecl.ModuleAbbrev
-    | SynModuleDecl.NestedModule(SynComponentInfo(ats, _, _, lid, px, _, ao, _),
+    | SynModuleDecl.NestedModule(SynComponentInfo(ats, _, _, _, px, _, ao, _) as info,
                                  isRecursive,
                                  decls,
                                  _,
@@ -2550,7 +2489,7 @@ let mkModuleDecl (creationAide: CreationAide) (decl: SynModuleDecl) =
             stn "module" mModule,
             mkSynAccess ao,
             isRecursive,
-            mkLongIdent lid,
+            mkModuleName info,
             stn "=" mEq,
             mkModuleDecls creationAide decls id,
             declRange
@@ -3035,16 +2974,24 @@ let mkImplicitCtor
         range
     )
 
+/// The name of a type definition. Besides an identifier this can be a tuple type, for
+/// `type (int * int) with ...` extensions. The parser only leaves it out while recovering from a
+/// missing name, and a parse error never reaches the transformation.
+let mkComponentInfoName (creationAide: CreationAide) (SynComponentInfo(synType = synType; range = m) as info) : Type =
+    match synType with
+    | Some t -> mkType creationAide t
+    | None -> invariantViolationAbout m info "component info without a name"
+
 let mkTypeDefn
     (creationAide: CreationAide)
     (SynTypeDefn(typeInfo, typeRepr, members, implicitConstructor, range, trivia))
     : TypeDefn
     =
     let typeNameNode =
         match typeInfo with
-        | SynComponentInfo(ats, tds, tcs, lid, px, _preferPostfix, ao, _) ->
-            let identifierNode = mkLongIdent lid
-            let mIdentifierNode = identifierNode.Range
+        | SynComponentInfo(ats, tds, tcs, _, px, _preferPostfix, ao, _) ->
+            let identifierNode = mkComponentInfoName creationAide typeInfo
+            let mIdentifierNode = (Type.Node identifierNode).Range
 
             let leadingKeyword =
                 match trivia.LeadingKeyword with
@@ -3905,7 +3852,7 @@ let mkModuleSigDecl (creationAide: CreationAide) (decl: SynModuleSigDecl) =
     | SynModuleSigDecl.ModuleAbbrev(ident, lid, StartRange 6 (mModule, _)) ->
         ModuleAbbrevNode(stn "module" mModule, mkIdent ident, mkLongIdent lid, declRange)
         |> ModuleDecl.ModuleAbbrev
-    | SynModuleSigDecl.NestedModule(SynComponentInfo(ats, _, _, lid, px, _, ao, _),
+    | SynModuleSigDecl.NestedModule(SynComponentInfo(ats, _, _, _, px, _, ao, _) as info,
                                     isRecursive,
                                     decls,
                                     _,
@@ -3919,7 +3866,7 @@ let mkModuleSigDecl (creationAide: CreationAide) (decl: SynModuleSigDecl) =
             stn "module" mModule,
             mkSynAccess ao,
             isRecursive,
-            mkLongIdent lid,
+            mkModuleName info,
             stn "=" mEq,
             mkModuleSigDecls creationAide decls id,
             declRange
@@ -3931,9 +3878,9 @@ let mkModuleSigDecl (creationAide: CreationAide) (decl: SynModuleSigDecl) =
 let mkTypeDefnSig (creationAide: CreationAide) (SynTypeDefnSig(typeInfo, typeRepr, members, range, trivia)) : TypeDefn =
     let typeNameNode =
         match typeInfo with
-        | SynComponentInfo(ats, tds, tcs, lid, px, _preferPostfix, ao, _) ->
-            let identifierNode = mkLongIdent lid
-            let mIdentifierNode = identifierNode.Range
+        | SynComponentInfo(ats, tds, tcs, _, px, _preferPostfix, ao, _) ->
+            let identifierNode = mkComponentInfoName creationAide typeInfo
+            let mIdentifierNode = (Type.Node identifierNode).Range
 
             let leadingKeyword =
                 match trivia.LeadingKeyword with

src/Fantomas.Core/CodePrinter.fs

@@ -4291,7 +4291,7 @@ let genImplicitConstructor (node: ImplicitConstructorNode) =
         )
         node.Self
 
-let hasTriviaAfterLeadingKeyword (identifier: IdentListNode) (accessibility: SingleTextNode option) =
+let hasTriviaAfterLeadingKeyword (identifier: Node) (accessibility: SingleTextNode option) =
     let beforeAccess =
         match accessibility with
         | Some n -> n.HasContentBefore
@@ -4310,7 +4310,7 @@ let genTypeDefn (td: TypeDefn) =
 
         // Workaround for https://github.com/fsprojects/fantomas/issues/628
         let hasTriviaAfterLeadingKeyword =
-            hasTriviaAfterLeadingKeyword typeName.Identifier typeName.Accessibility
+            hasTriviaAfterLeadingKeyword (Type.Node typeName.Identifier) typeName.Accessibility
 
         genXml typeName.XmlDoc
         +> onlyIfNot hasAndKeyword (genAttributes typeName.Attributes)
@@ -4319,7 +4319,7 @@ let genTypeDefn (td: TypeDefn) =
         +> onlyIf hasAndKeyword (sepSpace +> genOnelinerAttributes typeName.Attributes)
         +> sepSpace
         +> genAccessOpt typeName.Accessibility
-        +> genTypeAndParam (genIdentListNode typeName.Identifier) typeName.TypeParameters
+        +> genTypeAndParam (genType typeName.Identifier) typeName.TypeParameters
         +> onlyIfNot typeName.Constraints.IsEmpty (sepSpace +> genTypeConstraints typeName.Constraints)
         +> onlyIf hasTriviaAfterLeadingKeyword unindent
         +> leadingExpressionIsMultiline

src/Fantomas.Core/SyntaxOak.fs

@@ -2598,7 +2598,7 @@ type TypeNameNode
         attributes: MultipleAttributeListNode option,
         leadingKeyword: SingleTextNode,
         ao: SingleTextNode option,
-        identifier: IdentListNode,
+        identifier: Type,
         typeParams: TyparDecls option,
         constraints: TypeConstraint list,
         implicitConstructor: ImplicitConstructorNode option,
@@ -2615,7 +2615,7 @@ type TypeNameNode
             yield! noa attributes
             yield leadingKeyword
             yield! noa ao
-            yield identifier
+            yield Type.Node identifier
             yield! noa (Option.map TyparDecls.Node typeParams)
             yield! List.map TypeConstraint.Node constraints
             yield! noa implicitConstructor