diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 8d38867ab1f99..7fe94c2e82ba6 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -754,6 +754,7 @@ symbols! {
         enable,
         encode,
         end,
+        enumerate_method,
         env,
         env_CFG_RELEASE: env!("CFG_RELEASE"),
         eprint_macro,
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index 7c1c6122efe4d..cee99e28b5a97 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -974,6 +974,7 @@ pub trait Iterator {
     #[inline]
     #[stable(feature = "rust1", since = "1.0.0")]
     #[rustc_do_not_const_check]
+    #[cfg_attr(not(test), rustc_diagnostic_item = "enumerate_method")]
     fn enumerate(self) -> Enumerate<Self>
     where
         Self: Sized,