diff --git a/src/Elm.elm b/src/Elm.elm
index 4b7389f..0240686 100644
--- a/src/Elm.elm
+++ b/src/Elm.elm
@@ -2183,7 +2183,12 @@ portIncoming nameStr arg =
                         , typeAnnotation =
                             Compiler.nodify
                                 (Annotation.FunctionTypeAnnotation
-                                    (Compiler.nodify (Compiler.getInnerAnnotation index arg))
+                                    (Compiler.nodify
+                                        (Annotation.FunctionTypeAnnotation
+                                            (Compiler.nodify (Compiler.getInnerAnnotation index arg))
+                                            (Compiler.nodify (Annotation.GenericType "msg"))
+                                        )
+                                    )
                                     (Compiler.nodify sub)
                                 )
                         }
@@ -2459,4 +2464,3 @@ typeConstructorIsExposed name (Node _ node) =
 
         Expose.TypeExpose myType ->
             name == myType.name
-
diff --git a/tests/Declare.elm b/tests/Declare.elm
index f91331a..bb4f285 100644
--- a/tests/Declare.elm
+++ b/tests/Declare.elm
@@ -22,6 +22,7 @@ suite =
         , customTypeTest
         , customTypeWithTest
         , newStyleTest
+        , ports
         ]
 
 
@@ -396,3 +397,19 @@ makeAndCaseGenerationFullyDynamic =
                             """
                 ]
                 ()
+
+
+ports : Test
+ports =
+    describe "ports"
+        [ test "incoming" <|
+            \_ ->
+                Elm.portIncoming "receive" Type.int
+                    |> Elm.Expect.declarationAs
+                        "port receive : (Int -> msg) -> Sub msg"
+        , test "outgoing" <|
+            \_ ->
+                Elm.portOutgoing "send" Type.int
+                    |> Elm.Expect.declarationAs
+                        "port send : Int -> Cmd msg"
+        ]