[Repo Assist] Fix #734: ReturnInfo.ReturnType is None for getter+setter properties (#1012)

* Fix #734: ReturnInfo.ReturnType is None for getter+setter properties

For properties with both a getter and a setter, the CurriedParameterGroups
from FCS reflects the getter's unit parameter as an empty list [[]]. The
previous pattern matching code would fall through to the catch-all setter
branch (which returns None), discarding the getter's return type.

Adding | [ [] ], _, true -> [], Some retType as a more specific pattern
before the catch-all setter case correctly returns the getter's return type
for getter+setter (and setter-only-with-no-args) properties.

Also adds a test type Test_Issue734 with GetterOnly, SetterOnly, and
GetterAndSetter properties, and a test verifying ReturnInfo.ReturnType is
Some for each.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* ci: trigger CI checks

---------

Co-authored-by: Repo Assist <repo-assist@github.com>
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Co-authored-by: Don Syme <dsyme@users.noreply.github.com>

Author: 4 people

RELEASE_NOTES.md

@@ -7,6 +7,7 @@
 * Add `{{fsdocs-logo-alt}}` substitution (configurable via `<FsDocsLogoAlt>` MSBuild property, defaults to `Logo`) for accessible alt text on the header logo image. [#626](https://github.com/fsprojects/FSharp.Formatting/issues/626)
 
 ### Fixed
+* Fix `ApiDocMember.Details.ReturnInfo.ReturnType` returning `None` for properties that have both a getter and a setter. [#734](https://github.com/fsprojects/FSharp.Formatting/issues/734)
 * Improve error message when a named code snippet is not found (e.g. `(*** include:name ***)` with undefined name now reports the missing name clearly). [#982](https://github.com/fsprojects/FSharp.Formatting/pull/982)
 * HTML-encode XML doc text nodes and unresolved `<see cref>` values to prevent HTML injection and fix broken output when docs contain characters like `<`, `>`, or backticks in generic type notation. [#748](https://github.com/fsprojects/FSharp.Formatting/issues/748)
 * Add uppercase output kind extension (e.g. `HTML`, `IPYNB`) to `ConditionalDefines` so that `#if HTML` and `(*** condition: HTML ***)` work alongside their lowercase variants. [#693](https://github.com/fsprojects/FSharp.Formatting/issues/693)

src/FSharp.Formatting.ApiDocs/GenerateModel.fs

@@ -1538,6 +1538,7 @@ module internal SymbolReader =
         let argInfos, retType =
             match argInfos, v.HasGetterMethod, v.HasSetterMethod with
             | [ AllAndLast(args, last) ], _, true -> [ args ], Some last.Type
+            | [ [] ], _, true -> [], Some retType
             | _, _, true -> argInfos, None
             | [ [] ], true, _ -> [], Some retType
             | _, _, _ -> argInfos, Some retType

tests/FSharp.ApiDocs.Tests/ApiDocsTests.fs

@@ -455,12 +455,40 @@ let ``ApiDocs model generation works on two sample F# assemblies`` (_format: Out
     model.Collection.Namespaces.[0].Entities
     |> List.filter (fun c -> c.IsTypeDefinition)
     |> function
-        | x -> x.Length |> shouldEqual 10
+        | x -> x.Length |> shouldEqual 11
 
     let assemblies = [ for t in model.Collection.Namespaces.[0].Entities -> t.Assembly.Name ]
 
     assemblies |> List.distinct |> List.sort |> shouldEqual [ "FsLib1"; "FsLib2" ]
 
+[<Test>]
+let ``ApiDocs ReturnInfo.ReturnType is Some for properties with setters (issue 734)`` () =
+    let libraries = [ testBin </> "FsLib2.dll" ]
+    let inputs = [ for lib in libraries -> ApiDocInput.FromFile(lib, mdcomments = true) ]
+
+    let model =
+        ApiDocs.GenerateModel(inputs, collectionName = "FsLib", substitutions = substitutions, libDirs = [ testBin ])
+
+    let typeEntity =
+        model.Collection.Namespaces.[0].Entities
+        |> List.find (fun e -> e.Name = "Test_Issue734")
+
+    let members = typeEntity.AllMembers
+
+    let getReturnType name =
+        members
+        |> List.tryFind (fun m -> m.Name = name)
+        |> Option.bind (fun m -> m.ReturnInfo.ReturnType)
+
+    // Getter-only: ReturnType should be Some string
+    getReturnType "GetterOnly" |> Option.isSome |> shouldEqual true
+
+    // Getter+setter: ReturnType should be Some string
+    getReturnType "GetterAndSetter" |> Option.isSome |> shouldEqual true
+
+    // Setter-only: ReturnType should be Some string (value type)
+    getReturnType "SetterOnly" |> Option.isSome |> shouldEqual true
+
 [<Test>]
 [<TestCaseSource("formats")>]
 let ``ApiDocs generates Go to GitHub source links`` (format: OutputFormat) =

tests/FSharp.ApiDocs.Tests/files/FsLib2/Library2.fs

@@ -129,6 +129,22 @@ module ``Space-Missing`` =
     type ``Implicit-Cast``(value: int) = class end
 
 
+/// Test type with setter-only and getter+setter properties (issue #734)
+type Test_Issue734() =
+    let mutable _value = ""
+
+    /// Getter-only property
+    member _.GetterOnly = "getter"
+
+    /// Setter-only property
+    member _.SetterOnly
+        with set (value: string) = _value <- value
+
+    /// Getter and setter property
+    member _.GetterAndSetter
+        with get () = _value
+        and set (value: string) = _value <- value
+
 module CommentExamples =
     /// <summary>this does the thing</summary>
     /// <example>this is an example