diff --git a/src/Compiler/TypedTree/TypedTree.fs b/src/Compiler/TypedTree/TypedTree.fs
index 39d090939167a633110670cd362358d36703e99f..b3fcdd6c7d532d00bbd33ef40236a6da0a67cae3 100644
--- a/src/Compiler/TypedTree/TypedTree.fs
+++ b/src/Compiler/TypedTree/TypedTree.fs
@@ -475,6 +475,7 @@ exception UndefinedName of
 
 exception InternalUndefinedItemRef of (string * string * string -> int * string) * string * string * string
 
+[<CustomEquality;NoComparison>]
 type ModuleOrNamespaceKind = 
 
     /// Indicates that a module is compiled to a class with the "Module" suffix added. 
@@ -488,6 +489,22 @@ type ModuleOrNamespaceKind =
         /// Indicates that the sourcecode had a namespace.
         /// If false, this namespace was implicitly constructed during type checking. 
         isExplicit: bool
+        
+    override this.Equals other =
+        match other with
+        | :? ModuleOrNamespaceKind as kind ->
+            match this, kind with
+            | FSharpModuleWithSuffix, FSharpModuleWithSuffix
+            | ModuleOrType, ModuleOrType
+            | Namespace _, Namespace _ -> true
+            | _ -> false
+        | _ -> false
+
+    override this.GetHashCode () =
+        match this with
+        | FSharpModuleWithSuffix -> 0
+        | ModuleOrType -> 1
+        | Namespace _ -> 2
 
 /// A public path records where a construct lives within the global namespace
 /// of a CCU.
diff --git a/src/Compiler/TypedTree/TypedTree.fsi b/src/Compiler/TypedTree/TypedTree.fsi
index 2487daf351700aba3a8ea4796a2be17a1d355db7..d55e5e407067ab0777380c7cd08654b75d94c199 100644
--- a/src/Compiler/TypedTree/TypedTree.fsi
+++ b/src/Compiler/TypedTree/TypedTree.fsi
@@ -294,6 +294,7 @@ exception UndefinedName of depth: int * error: (string -> string) * id: Ident *
 
 exception InternalUndefinedItemRef of (string * string * string -> int * string) * string * string * string
 
+[<CustomEquality; NoComparison>]
 type ModuleOrNamespaceKind =
 
     /// Indicates that a module is compiled to a class with the "Module" suffix added.
diff --git a/tests/FSharp.Compiler.ComponentTests/Conformance/BasicTypeAndModuleDefinitions/ModuleDefinitions/ModuleDefinitions.fs b/tests/FSharp.Compiler.ComponentTests/Conformance/BasicTypeAndModuleDefinitions/ModuleDefinitions/ModuleDefinitions.fs
index af33f5c0f1e5526c62e12f4e3f86488b35c71d62..65d694c96474ce6c1526be3f5e34d3a6e7d1cc4e 100644
--- a/tests/FSharp.Compiler.ComponentTests/Conformance/BasicTypeAndModuleDefinitions/ModuleDefinitions/ModuleDefinitions.fs
+++ b/tests/FSharp.Compiler.ComponentTests/Conformance/BasicTypeAndModuleDefinitions/ModuleDefinitions/ModuleDefinitions.fs
@@ -318,3 +318,36 @@ module ModuleDefinitions =
         |> withReferences [libFoo2; libFoo1]
         |> verifyCompileAndRun
         |> shouldSucceed
+
+    [<Fact>]
+    let ``Regression: compilation error with private types in namespace used in a different file`` () =
+        let types =
+            """
+            namespace FsErrorRepro
+
+            type private Blah = { Number: int }
+            """
+        let example =
+            """
+            [<RequireQualifiedAccess>]
+            module FsErrorRepro.Example
+
+            let dummy (blahNum: int) =
+                let blah : Blah = { Number = blahNum }
+                printf $"%i{blah.Number}"
+            """
+        let program =
+            """
+            module FsErrorRepro.Main
+
+            [<EntryPoint>]
+            let main _ = 
+                Example.dummy 15
+                0
+            """
+
+        FSharp types
+        |> withAdditionalSourceFiles [SourceCodeFileKind.Create("example.fs", example)
+                                      SourceCodeFileKind.Create("program.fs", program)]
+        |> compile
+        |> shouldSucceed