diff --git a/lib/live_ast/common.rb b/lib/live_ast/common.rb
index 094a92a..81a57c0 100644
--- a/lib/live_ast/common.rb
+++ b/lib/live_ast/common.rb
@@ -18,7 +18,12 @@ def arg_to_str2(arg)
     rescue NameError
       thing = arg&.class
 
-      message = "wrong argument type #{thing.inspect} (expected String)"
+      message = if arg.nil?
+                  "wrong argument type #{thing.inspect} (expected String)"
+                else
+                  "no implicit conversion of #{thing.inspect} into String"
+                end
+
       raise TypeError, message
     end
 
diff --git a/test/full/replace_eval_test.rb b/test/full/replace_eval_test.rb
index 6dea861..669c921 100644
--- a/test/full/replace_eval_test.rb
+++ b/test/full/replace_eval_test.rb
@@ -172,7 +172,7 @@ def test_instance_eval_code_argument_type_error_no_block
     end
   end
 
-  def test_instance_eval_filename_argument_type_error_no_block
+  def test_instance_eval_filename_argument_nil_type_error_no_block
     orig = assert_raises TypeError do
       Object.new.live_ast_original_instance_eval("1", nil)
     end
@@ -184,6 +184,18 @@ def test_instance_eval_filename_argument_type_error_no_block
     assert_equal orig.class, live.class
   end
 
+  def test_instance_eval_filename_argument_conversion_type_error_no_block
+    orig = assert_raises TypeError do
+      Object.new.live_ast_original_instance_eval("1", 23)
+    end
+    live = assert_raises TypeError do
+      Object.new.instance_eval("1", 23)
+    end
+
+    assert_equal orig.message, live.message
+    assert_equal orig.class, live.class
+  end
+
   def test_instance_eval_arity_error_with_block
     orig = assert_raises ArgumentError do
       Object.new.live_ast_original_instance_eval(3, 4, 5) { nil }