From 76f6f4ff417c8d3adc1bdfac19a484a9a2d03591 Mon Sep 17 00:00:00 2001
From: conrad <conrad@localhost.localdomain>
Date: Fri, 11 Jun 2021 15:31:58 +1000
Subject: [PATCH] warn on unused object access

---
 include/armadillo_bits/field_bones.hpp | 36 +++++++++++++-------------
 include/armadillo_bits/field_meat.hpp  | 18 +++++++++++++
 2 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/include/armadillo_bits/field_bones.hpp b/include/armadillo_bits/field_bones.hpp
index 3bf03152..e0ccb456 100644
--- a/include/armadillo_bits/field_bones.hpp
+++ b/include/armadillo_bits/field_bones.hpp
@@ -86,33 +86,33 @@ class field
   template<typename oT2>
   inline void copy_size(const field<oT2>& x);
   
-  arma_inline       oT& operator[](const uword i);
-  arma_inline const oT& operator[](const uword i) const;
+  arma_inline arma_warn_unused       oT& operator[](const uword i);
+  arma_inline arma_warn_unused const oT& operator[](const uword i) const;
   
-  arma_inline       oT&         at(const uword i);
-  arma_inline const oT&         at(const uword i) const;
+  arma_inline arma_warn_unused       oT&         at(const uword i);
+  arma_inline arma_warn_unused const oT&         at(const uword i) const;
   
-  arma_inline       oT& operator()(const uword i);
-  arma_inline const oT& operator()(const uword i) const;
+  arma_inline arma_warn_unused       oT& operator()(const uword i);
+  arma_inline arma_warn_unused const oT& operator()(const uword i) const;
   
-  arma_inline       oT&         at(const uword row, const uword col);
-  arma_inline const oT&         at(const uword row, const uword col) const;
+  arma_inline arma_warn_unused       oT&         at(const uword row, const uword col);
+  arma_inline arma_warn_unused const oT&         at(const uword row, const uword col) const;
 
-  arma_inline       oT&         at(const uword row, const uword col, const uword slice);
-  arma_inline const oT&         at(const uword row, const uword col, const uword slice) const;
+  arma_inline arma_warn_unused       oT&         at(const uword row, const uword col, const uword slice);
+  arma_inline arma_warn_unused const oT&         at(const uword row, const uword col, const uword slice) const;
   
-  arma_inline       oT& operator()(const uword row, const uword col);
-  arma_inline const oT& operator()(const uword row, const uword col) const;
+  arma_inline arma_warn_unused       oT& operator()(const uword row, const uword col);
+  arma_inline arma_warn_unused const oT& operator()(const uword row, const uword col) const;
 
-  arma_inline       oT& operator()(const uword row, const uword col, const uword slice);
-  arma_inline const oT& operator()(const uword row, const uword col, const uword slice) const;
+  arma_inline arma_warn_unused       oT& operator()(const uword row, const uword col, const uword slice);
+  arma_inline arma_warn_unused const oT& operator()(const uword row, const uword col, const uword slice) const;
   
   
-  arma_inline       oT& front();
-  arma_inline const oT& front() const;
+  arma_inline arma_warn_unused       oT& front();
+  arma_inline arma_warn_unused const oT& front() const;
   
-  arma_inline       oT& back();
-  arma_inline const oT& back() const;
+  arma_inline arma_warn_unused       oT& back();
+  arma_inline arma_warn_unused const oT& back() const;
   
   
   arma_cold inline field_injector<field> operator<<(const oT& val);
diff --git a/include/armadillo_bits/field_meat.hpp b/include/armadillo_bits/field_meat.hpp
index 95e53a87..ad9036f0 100644
--- a/include/armadillo_bits/field_meat.hpp
+++ b/include/armadillo_bits/field_meat.hpp
@@ -470,6 +470,7 @@ field<oT>::copy_size(const field<oT2>& x)
 //! linear element accessor (treats the field as a vector); no bounds check
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::operator[] (const uword i)
   {
@@ -481,6 +482,7 @@ field<oT>::operator[] (const uword i)
 //! linear element accessor (treats the field as a vector); no bounds check
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::operator[] (const uword i) const
   {
@@ -492,6 +494,7 @@ field<oT>::operator[] (const uword i) const
 //! linear element accessor (treats the field as a vector); no bounds check
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::at(const uword i)
   {
@@ -503,6 +506,7 @@ field<oT>::at(const uword i)
 //! linear element accessor (treats the field as a vector); no bounds check
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::at(const uword i) const
   {
@@ -514,6 +518,7 @@ field<oT>::at(const uword i) const
 //! linear element accessor (treats the field as a vector); bounds checking not done when ARMA_NO_DEBUG is defined
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::operator() (const uword i)
   {
@@ -527,6 +532,7 @@ field<oT>::operator() (const uword i)
 //! linear element accessor (treats the field as a vector); bounds checking not done when ARMA_NO_DEBUG is defined
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::operator() (const uword i) const
   {
@@ -540,6 +546,7 @@ field<oT>::operator() (const uword i) const
 //! element accessor; bounds checking not done when ARMA_NO_DEBUG is defined
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::operator() (const uword in_row, const uword in_col)
   {
@@ -553,6 +560,7 @@ field<oT>::operator() (const uword in_row, const uword in_col)
 //! element accessor; bounds checking not done when ARMA_NO_DEBUG is defined
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::operator() (const uword in_row, const uword in_col) const
   {
@@ -566,6 +574,7 @@ field<oT>::operator() (const uword in_row, const uword in_col) const
 //! element accessor; bounds checking not done when ARMA_NO_DEBUG is defined
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::operator() (const uword in_row, const uword in_col, const uword in_slice)
   {
@@ -579,6 +588,7 @@ field<oT>::operator() (const uword in_row, const uword in_col, const uword in_sl
 //! element accessor; bounds checking not done when ARMA_NO_DEBUG is defined
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::operator() (const uword in_row, const uword in_col, const uword in_slice) const
   {
@@ -592,6 +602,7 @@ field<oT>::operator() (const uword in_row, const uword in_col, const uword in_sl
 //! element accessor; no bounds check
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::at(const uword in_row, const uword in_col)
   {
@@ -603,6 +614,7 @@ field<oT>::at(const uword in_row, const uword in_col)
 //! element accessor; no bounds check
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::at(const uword in_row, const uword in_col) const
   {
@@ -614,6 +626,7 @@ field<oT>::at(const uword in_row, const uword in_col) const
 //! element accessor; no bounds check
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::at(const uword in_row, const uword in_col, const uword in_slice)
   {
@@ -625,6 +638,7 @@ field<oT>::at(const uword in_row, const uword in_col, const uword in_slice)
 //! element accessor; no bounds check
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::at(const uword in_row, const uword in_col, const uword in_slice) const
   {
@@ -635,6 +649,7 @@ field<oT>::at(const uword in_row, const uword in_col, const uword in_slice) cons
 
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::front()
   {
@@ -647,6 +662,7 @@ field<oT>::front()
 
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::front() const
   {
@@ -659,6 +675,7 @@ field<oT>::front() const
 
 template<typename oT>
 arma_inline
+arma_warn_unused
 oT&
 field<oT>::back()
   {
@@ -671,6 +688,7 @@ field<oT>::back()
 
 template<typename oT>
 arma_inline
+arma_warn_unused
 const oT&
 field<oT>::back() const
   {