[Repo Assist] Add regression tests for cross-assembly tooltip resolution (issue #1085) (#1090)

* Add regression tests for cross-assembly tooltip resolution (issue 1085)

Adds two small helper assemblies (CrossAssemblyA, CrossAssemblyB) that
reproduce the type-dependency structure from issue 1085:
- CrossAssemblyA: single-case private DU Did
- CrossAssemblyB: Subject DU and TeamMember record whose fields reference Did

Three new tests in CodeFormatTests.fs:
1. DU case field shows the actual type name (Did) not obj with absolute hash-r paths
2. Record fields from another assembly show correct names with absolute hash-r paths
3. Same verification works with relative hash-r paths when the script is in the
   same directory as the referenced assemblies

All three tests pass against FCS 43.10.100, confirming the current code-path
handles cross-assembly tooltip resolution correctly. The tests serve as
regression guards to detect regressions if future FCS or FSharp.Formatting
changes re-introduce the issue.

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

* ci: trigger checks

* Fix Windows CI: escape backslashes in #r paths embedded in F# source strings

On Windows, absolute paths like D:\a\FSharp.Formatting\... contain sequences
such as \F and \a that are invalid or misinterpreted F# string escape sequences
when the path is embedded directly in an F# source string literal passed to
CodeFormatter.ParseAndCheckSource.

Fix: use .Replace('\\', '/') to convert to forward slashes before embedding.
.NET and FCS accept forward slashes in file paths on all platforms.

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

* ci: trigger checks

---------

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

Author: 3 people

RELEASE_NOTES.md

@@ -10,6 +10,7 @@
 * `fsdocs convert` now accepts the input file as a positional argument (e.g. `fsdocs convert notebook.ipynb -o notebook.html`). [#1019](https://github.com/fsprojects/FSharp.Formatting/pull/1019)
 * `fsdocs convert` infers the output format from the output file extension when `--outputformat` is not specified (e.g. `-o out.md` implies `--outputformat markdown`). [#1019](https://github.com/fsprojects/FSharp.Formatting/pull/1019)
 * `fsdocs convert` now accepts `-o` as a shorthand for `--output`. [#1019](https://github.com/fsprojects/FSharp.Formatting/pull/1019)
+* Add regression tests for cross-assembly tooltip resolution (issue [#1085](https://github.com/fsprojects/FSharp.Formatting/issues/1085)): verify that hover tooltips for types whose fields reference types from other assemblies show the correct type names (not `obj`) when `#r` paths resolve correctly.
 
 ### Changed
 * Tooltip elements (`div.fsdocs-tip`) now use the [Popover API](https://developer.mozilla.org/en-US/docs/Web/API/Popover_API) (Baseline 2024: Chrome 114+, Firefox 125+, Safari 17+). Tooltips are placed in the browser's top layer — no `z-index` needed, always above all other content. Fixes a positioning bug where tooltips appeared offset when the page was scrolled. The previous `display`-toggle fallback has been removed. Tooltips also fade in with a subtle animation. [#422](https://github.com/fsprojects/FSharp.Formatting/issues/422), [#1061](https://github.com/fsprojects/FSharp.Formatting/pull/1061)

tests/FSharp.CodeFormat.Tests/CodeFormatTests.fs

@@ -479,3 +479,152 @@ c.Method()
     // Attribute annotations should not appear in rendered tooltips
     tooltip |> shouldNotContainText "[<Optional"
     tooltip |> shouldNotContainText "[<DefaultParameterValue"
+
+// --------------------------------------------------------------------------------------
+// Tests for cross-assembly type resolution in tooltips (issue #1085)
+// --------------------------------------------------------------------------------------
+
+/// Find the directory where the currently executing test assembly lives.
+/// Both CrossAssemblyA.dll and CrossAssemblyB.dll are copied there as project references.
+let private testBinDir = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location)
+
+/// Return the tooltip text for the first token named `tokenText` that carries a tip.
+let private tipForToken (tokenText: string) (snips: Snippet[]) =
+    snips
+    |> Seq.tryPick (fun (Snippet(_, lines)) ->
+        lines
+        |> Seq.tryPick (fun (Line(_, spans)) ->
+            spans
+            |> Seq.tryPick (function
+                | TokenSpan.Token(_, t, Some tips) when t = tokenText -> Some tips
+                | _ -> None)))
+
+/// Render tooltip spans to a single concatenated string for easy assertion.
+let private renderTips (spans: ToolTipSpans) =
+    spans
+    |> List.map (function
+        | Literal s -> s
+        | Emphasis inner ->
+            inner
+            |> List.map (function
+                | Literal s -> s
+                | _ -> "")
+            |> String.concat ""
+        | HardLineBreak -> "\n")
+    |> String.concat ""
+
+[<Test>]
+let ``Cross-assembly DU field type is shown as actual type name not obj in tooltip`` () =
+    // Reproduce issue #1085: `Subject.Account of Did` should show `Did`, not `obj`
+    // Use forward slashes so the paths are valid F# string literal content on Windows too.
+    let assemblyAPath = System.IO.Path.Combine(testBinDir, "CrossAssemblyA.dll").Replace('\\', '/')
+    let assemblyBPath = System.IO.Path.Combine(testBinDir, "CrossAssemblyB.dll").Replace('\\', '/')
+
+    let source =
+        $"""#r "{assemblyAPath}"
+#r "{assemblyBPath}"
+open CrossAssemblyA
+open CrossAssemblyB
+
+let subject = Subject.Account (CrossAssemblyA.Did.create "test")
+"""
+
+    let snips, errors = CodeFormatter.ParseAndCheckSource("/somewhere/test.fsx", source.Trim(), None, None, ignore)
+
+    errors |> shouldEqual [||]
+
+    // Find the tooltip for the `Subject` identifier and check its text
+    let subjectTip =
+        snips
+        |> tipForToken "Subject"
+        |> Option.map renderTips
+        |> Option.defaultValue ""
+
+    subjectTip |> shouldNotEqual ""
+
+    // The tooltip for Subject should show the actual DU case type, not `obj`
+    subjectTip |> shouldNotContainText "obj"
+    subjectTip |> shouldContainText "Did"
+
+[<Test>]
+let ``Cross-assembly record field types are shown as actual type names not obj in tooltip`` () =
+    // Reproduce issue #1085: `TeamMember` record fields referencing types from another
+    // assembly should show the correct type names (`Did`, `DateTimeOffset option`)
+    // rather than `obj`.
+    // Use forward slashes so the paths are valid F# string literal content on Windows too.
+    let assemblyAPath = System.IO.Path.Combine(testBinDir, "CrossAssemblyA.dll").Replace('\\', '/')
+    let assemblyBPath = System.IO.Path.Combine(testBinDir, "CrossAssemblyB.dll").Replace('\\', '/')
+
+    let source =
+        $"""#r "{assemblyAPath}"
+#r "{assemblyBPath}"
+open CrossAssemblyB
+
+let m : TeamMember = Unchecked.defaultof<TeamMember>
+"""
+
+    let snips, errors = CodeFormatter.ParseAndCheckSource("/somewhere/test.fsx", source.Trim(), None, None, ignore)
+
+    errors |> shouldEqual [||]
+
+    let teamMemberTip =
+        snips
+        |> tipForToken "TeamMember"
+        |> Option.map renderTips
+        |> Option.defaultValue ""
+
+    teamMemberTip |> shouldNotEqual ""
+
+    // Record field types from a different assembly should not appear as `obj`
+    teamMemberTip |> shouldContainText "Did"
+    teamMemberTip |> shouldContainText "DateTimeOffset"
+
+[<Test>]
+let ``Cross-assembly DU field types are correct when using relative hash-r references`` () =
+    // Reproduce the user scenario from issue #1085: using relative #r paths where the
+    // script file is in the same directory as the referenced assemblies.
+    // Set up a temporary directory containing the DLLs and a script path pointing there.
+    let tempDir = System.IO.Path.Combine(System.IO.Path.GetTempPath(), "fsharp-formatting-issue1085")
+    System.IO.Directory.CreateDirectory(tempDir) |> ignore
+
+    try
+        // Copy the test assemblies to the temp directory so relative #r can resolve them.
+        let srcA = System.IO.Path.Combine(testBinDir, "CrossAssemblyA.dll")
+        let srcB = System.IO.Path.Combine(testBinDir, "CrossAssemblyB.dll")
+        System.IO.File.Copy(srcA, System.IO.Path.Combine(tempDir, "CrossAssemblyA.dll"), overwrite = true)
+        System.IO.File.Copy(srcB, System.IO.Path.Combine(tempDir, "CrossAssemblyB.dll"), overwrite = true)
+
+        // Script path is inside the temp dir; FCS uses this to resolve relative #r paths.
+        let scriptPath = System.IO.Path.Combine(tempDir, "test.fsx")
+
+        let source =
+            """#r "CrossAssemblyA.dll"
+#r "CrossAssemblyB.dll"
+open CrossAssemblyA
+open CrossAssemblyB
+
+let subject = Subject.Account (CrossAssemblyA.Did.create "test")
+"""
+
+        let snips, errors = CodeFormatter.ParseAndCheckSource(scriptPath, source.Trim(), None, None, ignore)
+
+        errors |> shouldEqual [||]
+
+        let subjectTip =
+            snips
+            |> tipForToken "Subject"
+            |> Option.map renderTips
+            |> Option.defaultValue ""
+
+        subjectTip |> shouldNotEqual ""
+
+        // With correctly-resolved relative paths the tooltip should show Did, not obj.
+        subjectTip |> shouldNotContainText "of obj"
+        subjectTip |> shouldContainText "Did"
+
+    finally
+        // Clean up
+        try
+            System.IO.Directory.Delete(tempDir, recursive = true)
+        with _ ->
+            ()

tests/FSharp.CodeFormat.Tests/FSharp.CodeFormat.Tests.fsproj

@@ -10,6 +10,8 @@
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\..\src\FSharp.Formatting.CodeFormat\FSharp.Formatting.CodeFormat.fsproj" />
+    <ProjectReference Include="files\CrossAssemblyA\CrossAssemblyA.fsproj" />
+    <ProjectReference Include="files\CrossAssemblyB\CrossAssemblyB.fsproj" />
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="FSharp.Core" />

tests/FSharp.CodeFormat.Tests/files/CrossAssemblyA/CrossAssemblyA.fsproj

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>netstandard2.1</TargetFramework>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="Library.fs" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="FSharp.Core" />
+  </ItemGroup>
+</Project>

tests/FSharp.CodeFormat.Tests/files/CrossAssemblyA/Library.fs

@@ -0,0 +1,9 @@
+namespace CrossAssemblyA
+
+/// A simple single-case discriminated union that is defined in Assembly A.
+/// It is referenced from Assembly B to test cross-assembly tooltip resolution (issue #1085).
+type Did = private Did of string
+
+module Did =
+    /// Construct a Did value.
+    let create (s: string) = Did s

tests/FSharp.CodeFormat.Tests/files/CrossAssemblyB/CrossAssemblyB.fsproj

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFramework>netstandard2.1</TargetFramework>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="Library.fs" />
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="FSharp.Core" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\CrossAssemblyA\CrossAssemblyA.fsproj" />
+  </ItemGroup>
+</Project>

tests/FSharp.CodeFormat.Tests/files/CrossAssemblyB/Library.fs

@@ -0,0 +1,19 @@
+namespace CrossAssemblyB
+
+open CrossAssemblyA
+
+/// A discriminated union in Assembly B whose Account case holds a Did value
+/// from Assembly A.  Used to test cross-assembly tooltip rendering (issue #1085).
+[<RequireQualifiedAccess>]
+type Subject =
+    | Account of Did
+    | Record of string
+
+/// A record in Assembly B whose fields mix types from Assembly A (Did),
+/// primitive types, and generic wrapper types from the BCL.
+/// Used to test cross-assembly tooltip rendering (issue #1085).
+type TeamMember =
+    { Did: Did
+      Name: string
+      Active: bool
+      JoinedAt: System.DateTimeOffset option }