diff --git a/tests/FSharp.Compiler.ComponentTests/ConstraintSolver/MemberConstraints.fs b/tests/FSharp.Compiler.ComponentTests/ConstraintSolver/MemberConstraints.fs
index 5f424466c2f..9e04bc75dfc 100644
--- a/tests/FSharp.Compiler.ComponentTests/ConstraintSolver/MemberConstraints.fs
+++ b/tests/FSharp.Compiler.ComponentTests/ConstraintSolver/MemberConstraints.fs
@@ -150,6 +150,23 @@ type UnionOfUnions<'T> =
         |> typecheck
         |> shouldSucceed
 
+    // https://github.com/dotnet/fsharp/issues/9878
+    [<Fact>]
+    let ``Issue 9878 - SRTP with phantom type parameter should compile`` () =
+        FSharp
+            """
+type DuCaseName<'T> =
+    static member ToCaseName<'t, 'u>(value: 't) = failwith "delayed resolution"
+    static member ToCaseName(value: 'T) =
+        match FSharp.Reflection.FSharpValue.GetUnionFields(value, typeof<'T>) with case, _ -> case.Name
+    static member inline Invoke(value: 'a) =
+        let inline call (other: ^M, value: ^I) = ((^M or ^I) : (static member ToCaseName: ^I -> string) value)
+        call (Unchecked.defaultof<DuCaseName<_>>, value)
+            """
+        |> asLibrary
+        |> typecheck
+        |> shouldSucceed
+
     // https://github.com/dotnet/fsharp/issues/9382
     [<Fact>]
     let ``Issue 9382 - SRTP stress test with matrix inverse should compile`` () =