diff --git a/cpp/include/cudf/ast/expressions.hpp b/cpp/include/cudf/ast/expressions.hpp
index bcc9ad1b391..85289a52831 100644
--- a/cpp/include/cudf/ast/expressions.hpp
+++ b/cpp/include/cudf/ast/expressions.hpp
@@ -612,19 +612,19 @@ class tree {
    * @brief get the first expression in the tree
    * @returns the first inserted expression into the tree
    */
-  expression const& front() const { return *expressions.front(); }
+  [[nodiscard]] expression const& front() const { return *expressions.front(); }
 
   /**
    * @brief get the last expression in the tree
    * @returns the last inserted expression into the tree
    */
-  expression const& back() const { return *expressions.back(); }
+  [[nodiscard]] expression const& back() const { return *expressions.back(); }
 
   /**
    * @brief get the number of expressions added to the tree
    * @returns the number of expressions added to the tree
    */
-  size_t size() const { return expressions.size(); }
+  [[nodiscard]] size_t size() const { return expressions.size(); }
 
   /**
    * @brief get the expression at an index in the tree. Index is checked.
diff --git a/cpp/src/io/json/parser_features.cpp b/cpp/src/io/json/parser_features.cpp
index 401a6e992de..e795e8e09d8 100644
--- a/cpp/src/io/json/parser_features.cpp
+++ b/cpp/src/io/json/parser_features.cpp
@@ -109,7 +109,7 @@ struct allnull_column_functor {
   rmm::device_async_resource_ref mr;
 
  private:
-  auto make_zeroed_offsets(size_type size) const
+  [[nodiscard]] auto make_zeroed_offsets(size_type size) const
   {
     auto offsets_buff =
       cudf::detail::make_zeroed_device_uvector_async<size_type>(size + 1, stream, mr);