From 935aef383e84bacf08ca8a4ad7ae7b7577897d1b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 18 May 2026 11:22:43 +0000
Subject: [PATCH 1/3] Initial plan


From c16879d9342551dbcb3e25e3f5e8de6dc2d2fc8c Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 18 May 2026 11:41:51 +0000
Subject: [PATCH 2/3] fix: suppress underscore wildcard hover resolution in
 members

Agent-Logs-Url: https://github.com/dotnet/fsharp/sessions/54b93d4d-8821-44a9-8d0e-e45addc62be1

Co-authored-by: T-Gro <46543583+T-Gro@users.noreply.github.com>
---
 src/Compiler/Service/FSharpCheckerResults.fs  |  7 +++++++
 .../TooltipTests.fs                           | 21 +++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/src/Compiler/Service/FSharpCheckerResults.fs b/src/Compiler/Service/FSharpCheckerResults.fs
index 6e9c1ced07..c8f12b2512 100644
--- a/src/Compiler/Service/FSharpCheckerResults.fs
+++ b/src/Compiler/Service/FSharpCheckerResults.fs
@@ -1631,11 +1631,18 @@ type internal TypeCheckInfo
                         | None -> ValueNone
                     | _ -> ValueNone
 
+            let isDiscardIdentifier =
+                match residueOpt, origLongIdentOpt with
+                | None, Some [ "_" ] -> true
+                | _ -> false
+
             match nameResItems with
             | NameResResult.Cancel(denv, m) -> Some([], denv, m)
             | NameResResult.Members(FilterRelevantItems getItem exactMatchResidueOpt (items, denv, m)) ->
                 // lookup based on name resolution results successful
                 Some(items |> List.map (CompletionItem (getType ()) ValueNone), denv, m)
+            | _ when isDiscardIdentifier ->
+                None
             | _ ->
                 match origLongIdentOpt with
                 | None -> None
diff --git a/tests/FSharp.Compiler.Service.Tests/TooltipTests.fs b/tests/FSharp.Compiler.Service.Tests/TooltipTests.fs
index 2947e09f56..7695c9f42f 100644
--- a/tests/FSharp.Compiler.Service.Tests/TooltipTests.fs
+++ b/tests/FSharp.Compiler.Service.Tests/TooltipTests.fs
@@ -399,6 +399,9 @@ let assertNameTagInTooltip expectedTag expectedName (tooltip: ToolTipText) =
     let desc = tags |> Array.map (fun t -> sprintf "(%A, %s)" t.Tag t.Text) |> String.concat ", "
     Assert.True(found, sprintf "Expected tag %A with text '%s' in tooltip, but found: %s" expectedTag expectedName desc)
 
+let assertToolTipIsEmpty (ToolTipText(items)) =
+    Assert.Empty items
+
 let normalize (s: string) = s.Replace("\r\n", "\n").Replace("\n\n", "\n")
 
 [<Fact>]
@@ -594,6 +597,24 @@ let y = normaliz{caret}e' 5
     |> assertAndGetSingleToolTipText
     |> Assert.shouldBeEquivalentTo "val normalize': x: int -> int"
 
+[<Fact>]
+let ``Wildcard lambda parameter inside member with underscore instance identifier has no tooltip`` () =
+    Checker.getTooltip """
+type T () =
+    member _.M () =
+        fun _{caret} -> ()
+"""
+    |> assertToolTipIsEmpty
+
+[<Fact>]
+let ``Wildcard let binding inside member with underscore instance identifier has no tooltip`` () =
+    Checker.getTooltip """
+type T () =
+    member _.N () =
+        let _{caret} = () in ()
+"""
+    |> assertToolTipIsEmpty
+
 // https://github.com/dotnet/fsharp/issues/13194
 [<Fact>]
 let ``Sig file XML doc fallback works for member whose name contains a single quote`` () =

From 1ab81e1259852d009757b4ede83658963265c2de Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Mon, 18 May 2026 12:06:24 +0000
Subject: [PATCH 3/3] style: apply final formatting for wildcard hover fix

Agent-Logs-Url: https://github.com/dotnet/fsharp/sessions/54b93d4d-8821-44a9-8d0e-e45addc62be1

Co-authored-by: T-Gro <46543583+T-Gro@users.noreply.github.com>
---
 src/Compiler/Service/FSharpCheckerResults.fs | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/Compiler/Service/FSharpCheckerResults.fs b/src/Compiler/Service/FSharpCheckerResults.fs
index c8f12b2512..76b8514d8e 100644
--- a/src/Compiler/Service/FSharpCheckerResults.fs
+++ b/src/Compiler/Service/FSharpCheckerResults.fs
@@ -1641,8 +1641,7 @@ type internal TypeCheckInfo
             | NameResResult.Members(FilterRelevantItems getItem exactMatchResidueOpt (items, denv, m)) ->
                 // lookup based on name resolution results successful
                 Some(items |> List.map (CompletionItem (getType ()) ValueNone), denv, m)
-            | _ when isDiscardIdentifier ->
-                None
+            | _ when isDiscardIdentifier -> None
             | _ ->
                 match origLongIdentOpt with
                 | None -> None