diff --git a/src/fsharp/MethodOverrides.fs b/src/fsharp/MethodOverrides.fs
index 2ba55b7f75f..8a74567bde5 100644
--- a/src/fsharp/MethodOverrides.fs
+++ b/src/fsharp/MethodOverrides.fs
@@ -302,8 +302,7 @@ module DispatchSlotChecking =
                                 |> not
                            
                             if moreThanOnePossibleDispatchSlot then
-                                // Error will be reported below in CheckOverridesAreAllUsedOnce 
-                                ()
+                                noimpl()
 
                             elif argTys.Length <> vargtys.Length then 
                                 fail(Error(FSComp.SR.typrelMemberDoesNotHaveCorrectNumberOfArguments(FormatOverride denv overrideBy, FormatMethInfoSig g amap m denv dispatchSlot), overrideBy.Range))
diff --git a/tests/fsharpqa/Source/Conformance/DeclarationElements/MemberDefinitions/OverloadingMembers/E_OverloadMismatch.fs b/tests/fsharpqa/Source/Conformance/DeclarationElements/MemberDefinitions/OverloadingMembers/E_OverloadMismatch.fs
new file mode 100644
index 00000000000..6a110a839cc
--- /dev/null
+++ b/tests/fsharpqa/Source/Conformance/DeclarationElements/MemberDefinitions/OverloadingMembers/E_OverloadMismatch.fs
@@ -0,0 +1,14 @@
+//<Expects id="FS0366" status="error">No implementation was given for</Expects>
+
+open System
+open System.IO
+type IFoo =
+  abstract member Foo : t:Type * r:TextReader -> obj
+  abstract member Foo<'t> : TextReader -> 't
+
+
+type Foo() =
+  interface IFoo with
+    member x.Foo(t, reader) = obj()
+
+exit 1
diff --git a/tests/fsharpqa/Source/Conformance/DeclarationElements/MemberDefinitions/OverloadingMembers/env.lst b/tests/fsharpqa/Source/Conformance/DeclarationElements/MemberDefinitions/OverloadingMembers/env.lst
index 7a3e95f230e..a7384556634 100644
--- a/tests/fsharpqa/Source/Conformance/DeclarationElements/MemberDefinitions/OverloadingMembers/env.lst
+++ b/tests/fsharpqa/Source/Conformance/DeclarationElements/MemberDefinitions/OverloadingMembers/env.lst
@@ -29,6 +29,7 @@ NOMONO,NoMT	SOURCE=ConsumeOverloadGenericMethods.fs SCFLAGS="-r:lib.dll" PRECMD=
 	SOURCE=SlowOverloadResolution.fs						# SlowOverloadResolution.fs
 
 	SOURCE=E_OverloadCurriedFunc.fs		# E_OverloadCurriedFunc.fs
+	SOURCE=E_OverloadMismatch.fs		# E_OverloadMismatch.fs
 	SOURCE=NoWarningWhenOverloadingInSubClass01.fs SCFLAGS="--warnaserror"		# NoWarningWhenOverloadingInSubClass01.fs
 
 	SOURCE=E_UnsolvableConstraints01.fs     SCFLAGS="--test:ErrorRanges"		# E_UnsolvableConstraints01.fs