diff --git a/docs/error-codes.md b/docs/error-codes.md
index 50ed380bc786..220dc06d0e38 100644
--- a/docs/error-codes.md
+++ b/docs/error-codes.md
@@ -35,6 +35,8 @@ the error code. For example:
 
 #### `IL1007`: Missing predefined 'type' type
 
+- Consider adding the missing reference to your project or pass `--disable-opt unreachablebodies` to ignore.
+
 #### `IL1008`: Could not find constructor on 'type'
 
 #### `IL1009`: Assembly reference 'name' could not be resolved
@@ -1979,4 +1981,4 @@ void TestMethod()
     // IL3003: Member 'Implementation.TestMethod()' with 'RequiresAssemblyFilesAttribute' implements interface member 'IRAF.TestMethod()' without 'RequiresAssemblyFilesAttribute'. For all interfaces and overrides the implementation attribute must match the definition attribute.
     public void TestMethod () { }
   }
-  ```
\ No newline at end of file
+  ```