diff --git a/diesel/src/pg/expression/functions.rs b/diesel/src/pg/expression/functions.rs
index 07e9aaa13632..494dc174dfe3 100644
--- a/diesel/src/pg/expression/functions.rs
+++ b/diesel/src/pg/expression/functions.rs
@@ -807,11 +807,11 @@ define_sql_function! {
     ///     .get_result::<String>(connection)?;
     /// assert!(String::from("[1:2]").eq(&dims));
     ///
-    /// let dims = diesel::select(array_dims::<Array<Integer>,_>(vec![None::<i32>,Some(2)]))
+    /// let dims = diesel::select(array_dims::<Array<Nullable<Integer>>,_>(vec![None::<i32>,Some(2)]))
     ///     .get_result::<String>(connection)?;
     /// assert!(String::from("[1:2]").eq(&dims));
     ///
-    /// let dims = diesel::select(array_dims::<Array<Integer>,_>(vec![None::<i32>]))
+    /// let dims = diesel::select(array_dims::<Array<Nullable<Integer>>,_>(vec![None::<i32>]))
     ///     .get_result::<String>(connection)?;
     /// assert!(String::from("[1:1]").eq(&dims));
     /// # Ok(())