diff --git a/mlir/docs/OpDefinitions.md b/mlir/docs/OpDefinitions.md
--- a/mlir/docs/OpDefinitions.md
+++ b/mlir/docs/OpDefinitions.md
@@ -576,7 +576,10 @@
 This will generate either `LogicalResult verify()` or
 `LogicalResult verifyRegions()` method declaration on the op class
 that can be defined with any additional verification constraints. These method
-will be invoked on its verification order.
+will be invoked on its verification order. Note that you are not supposed to
+have both of them because no other verifiers will depend on the custom verifier,
+which means `hasVerifier` can always be merged into `hasRegionVerifier` if there
+are regions.
 
 #### Verification Ordering