diff --git a/lib/ex_marshal/errors/decode_error.ex b/lib/ex_marshal/errors/decode_error.ex
index bd8c678..580ee12 100644
--- a/lib/ex_marshal/errors/decode_error.ex
+++ b/lib/ex_marshal/errors/decode_error.ex
@@ -2,7 +2,7 @@ defmodule ExMarshal.Errors.DecodeError do
   defexception [:reason]
 
   def message(%__MODULE__{} = exception) do
-    case exception.reason() do
+    case exception.reason do
       {:ivar_string_only, term} ->
         "only string ivars are supported: #{inspect(term)}"
       {:invalid_encoding, term} ->
diff --git a/lib/ex_marshal/errors/encode_error.ex b/lib/ex_marshal/errors/encode_error.ex
index 9743424..7b04634 100644
--- a/lib/ex_marshal/errors/encode_error.ex
+++ b/lib/ex_marshal/errors/encode_error.ex
@@ -2,7 +2,7 @@ defmodule ExMarshal.Errors.EncodeError do
   defexception [:reason]
 
   def message(%__MODULE__{} = exception) do
-    case exception.reason() do
+    case exception.reason do
       {:not_supported, term} ->
         "the following type is not supported: #{inspect(term)}"
     end