diff --git a/compiler/rustc_hir/src/attrs/data_structures.rs b/compiler/rustc_hir/src/attrs/data_structures.rs
index 5d154cef66a6..2968083c7d72 100644
--- a/compiler/rustc_hir/src/attrs/data_structures.rs
+++ b/compiler/rustc_hir/src/attrs/data_structures.rs
@@ -1233,6 +1233,9 @@ pub enum AttributeKind {
     /// Represents `#[rustc_diagnostic_item]`
     RustcDiagnosticItem(Symbol),
 
+    /// Represents `#[rustc_diagnostic_item]`
+    RustcDiagnosticItem(Symbol),
+
     /// Represents `#[rustc_do_not_const_check]`
     RustcDoNotConstCheck,