diff --git a/src/fsharp/infos.fs b/src/fsharp/infos.fs
index 1db4e36b356..63db80bae85 100755
--- a/src/fsharp/infos.fs
+++ b/src/fsharp/infos.fs
@@ -1536,7 +1536,7 @@ type MethInfo =
                     let formalRetTy = ImportReturnTypeFromMetadata amap m ilminfo.RawMetadata.Return.Type ilminfo.RawMetadata.Return.CustomAttrs ftinfo.ILScopeRef ftinfo.TypeInstOfRawMetadata formalMethTyparTys
                     let formalParams =
                         [ [ for p in ilminfo.RawMetadata.Parameters do
-                                let paramType = ImportILTypeFromMetadata amap m ftinfo.ILScopeRef ftinfo.TypeInstOfRawMetadata formalMethTyparTys p.Type
+                                let paramType = ImportILTypeFromMetadataWithAttributes amap m ftinfo.ILScopeRef ftinfo.TypeInstOfRawMetadata formalMethTyparTys p.Type p.CustomAttrs
                                 yield TSlotParam(p.Name, paramType, p.IsIn, p.IsOut, p.IsOptional, []) ] ]
                     formalRetTy, formalParams
 #if !NO_EXTENSIONTYPING
diff --git a/tests/fsharp/Compiler/CompilerAssert.fs b/tests/fsharp/Compiler/CompilerAssert.fs
index 9f0bc09553b..ef0e591a0c1 100644
--- a/tests/fsharp/Compiler/CompilerAssert.fs
+++ b/tests/fsharp/Compiler/CompilerAssert.fs
@@ -8,6 +8,7 @@ open System.Diagnostics
 open System.IO
 open System.Text
 open System.Diagnostics
+open System.Collections.Generic
 open System.Reflection
 open FSharp.Compiler.Text
 open FSharp.Compiler.SourceCodeServices
@@ -17,6 +18,9 @@ open System.Runtime.Loader
 #endif
 open NUnit.Framework
 open System.Reflection.Emit
+open Microsoft.CodeAnalysis
+open Microsoft.CodeAnalysis.CSharp
+open FSharp.Compiler.UnitTests.Utilities
 
 [<Sealed>]
 type ILVerifier (dllFilePath: string) =
@@ -52,12 +56,18 @@ type CompileOutput =
     | Library
     | Exe
 
-type CompilationReference = private CompilationReference of Compilation * staticLink: bool with
+type CompilationReference = 
+    private 
+    | CompilationReference of Compilation * staticLink: bool 
+    | TestCompilationReference of TestCompilation
 
     static member CreateFSharp(cmpl: Compilation, ?staticLink) =
         let staticLink = defaultArg staticLink false
         CompilationReference(cmpl, staticLink)
 
+    static member Create(cmpl: TestCompilation) =
+        TestCompilationReference cmpl
+
 and Compilation = private Compilation of string * SourceKind * CompileOutput * options: string[] * CompilationReference list with
 
     static member Create(source, sourceKind, output, ?options, ?cmplRefs) =
@@ -257,7 +267,14 @@ let main argv = 0"""
                     |> List.map (fun cmpl ->
                             match cmpl with
                             | CompilationReference (cmpl, staticLink) ->
-                                compileCompilationAux disposals ignoreWarnings cmpl, staticLink)
+                                compileCompilationAux disposals ignoreWarnings cmpl, staticLink
+                            | TestCompilationReference (cmpl) -> 
+                                let tmp = Path.GetTempFileName()
+                                disposals.Add({ new IDisposable with 
+                                                    member _.Dispose() = 
+                                                        try File.Delete tmp with | _ -> () })
+                                cmpl.EmitAsFile tmp
+                                (([||], tmp), []), false)
 
                 let compilationRefs =
                     compiledRefs
diff --git a/tests/fsharp/Compiler/Language/ByrefTests.fs b/tests/fsharp/Compiler/Language/ByrefTests.fs
index 2797125d791..d09f9f4cf24 100644
--- a/tests/fsharp/Compiler/Language/ByrefTests.fs
+++ b/tests/fsharp/Compiler/Language/ByrefTests.fs
@@ -4,6 +4,7 @@ namespace FSharp.Compiler.UnitTests
 
 open NUnit.Framework
 open FSharp.Compiler.SourceCodeServices
+open FSharp.Compiler.UnitTests.Utilities
 
 [<TestFixture>]
 module ByrefTests =
@@ -195,4 +196,44 @@ let test1 () =
                     "The value has been copied to ensure the original is not mutated by this operation or because the copy is implicit when returning a struct from a member and another member is then accessed"
                 )
             |]
+#endif
+
+#if NETCOREAPP
+    [<Test>]
+    let ``Consume CSharp interface with a method that has a readonly byref`` () =
+        let cs =
+            """
+using System;
+using System.Buffers;
+
+namespace Example
+{
+    public interface IMessageReader
+    {
+        bool TryParseMessage(in byte input);
+    }
+}
+            """
+        let fs =
+            """
+module Module1
+
+open Example
+
+type MyClass() =
+
+  interface IMessageReader with
+      member this.TryParseMessage(input: inref<byte>): bool = 
+          failwith "Not Implemented"
+            """
+
+        let csCmpl =
+            CompilationUtil.CreateCSharpCompilation(cs, CSharpLanguageVersion.CSharp8, TargetFramework.NetCoreApp30)
+            |> CompilationReference.Create
+
+        let fsCmpl =
+            Compilation.Create(fs, Fsx, Library, cmplRefs = [csCmpl])
+
+        CompilerAssert.Compile fsCmpl
+        
 #endif
\ No newline at end of file
diff --git a/tests/fsharp/Compiler/Utilities.fs b/tests/fsharp/Compiler/Utilities.fs
index 29de21ad3e3..b55707fdb4e 100644
--- a/tests/fsharp/Compiler/Utilities.fs
+++ b/tests/fsharp/Compiler/Utilities.fs
@@ -120,7 +120,7 @@ type CompilationUtil private () =
                 [ CSharpSyntaxTree.ParseText (source, CSharpParseOptions lv) ],
                 references.As<MetadataReference>().AddRange additionalReferences,
                 CSharpCompilationOptions (OutputKind.DynamicallyLinkedLibrary))
-        Some (TestCompilation.CSharp (c, flags))
+        TestCompilation.CSharp (c, flags)
 
     static member CreateILCompilation (source: string) =
         let compute =
@@ -139,4 +139,4 @@ type CompilationUtil private () =
                     try File.Delete ilFilePath with | _ -> ()
                     try File.Delete tmp with | _ -> ()
                     try File.Delete dllFilePath with | _ -> ()
-        Some (TestCompilation.IL (source, compute))
\ No newline at end of file
+        TestCompilation.IL (source, compute)
\ No newline at end of file