diff --git a/src/librustc_error_codes/error_codes/E0399.md b/src/librustc_error_codes/error_codes/E0399.md
index 71482c3ca64c..55e1774d9ca9 100644
--- a/src/librustc_error_codes/error_codes/E0399.md
+++ b/src/librustc_error_codes/error_codes/E0399.md
@@ -1,9 +1,11 @@
+Note: This error code is no longer emitted by the compiler.
+
 You implemented a trait, overriding one or more of its associated types but did
 not reimplement its default methods.
 
 Example of erroneous code:
 
-```compile_fail,E0399
+```ignore
 #![feature(associated_type_defaults)]
 
 pub trait Foo {
@@ -20,7 +22,7 @@ impl Foo for i32 {
 
 To fix this, add an implementation for each default method from the trait:
 
-```
+```ignore
 #![feature(associated_type_defaults)]
 
 pub trait Foo {