diff --git a/compiler/rustc_error_codes/src/error_codes/E0775.md b/compiler/rustc_error_codes/src/error_codes/E0775.md
index beec260e7f1..efbd51e89ea 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0775.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0775.md
@@ -1,3 +1,5 @@
+#### Note: this error code is no longer emitted by the compiler.
+
 `#[cmse_nonsecure_entry]` is only valid for targets with the TrustZone-M
 extension.