diff --git a/mlir/docs/Diagnostics.md b/mlir/docs/Diagnostics.md
--- a/mlir/docs/Diagnostics.md
+++ b/mlir/docs/Diagnostics.md
@@ -26,7 +26,7 @@
 can be interfaced with via an `MLIRContext` instance.
 
 ```c++
-DiagnosticEngine engine = ctx->getDiagEngine();
+DiagnosticEngine& engine = ctx->getDiagEngine();
 
 /// Handle the reported diagnostic.
 // Return success to signal that the diagnostic has either been fully processed,