diff --git a/failtest/const_qualified_block_method_retval_0.cpp b/failtest/const_qualified_block_method_retval_0.cpp
index 08b5d3c78..6d19bb4bc 100644
--- a/failtest/const_qualified_block_method_retval_0.cpp
+++ b/failtest/const_qualified_block_method_retval_0.cpp
@@ -8,6 +8,9 @@
 
 using namespace Eigen;
 
-void foo(CV_QUALIFIER Matrix3d &m) { Block<Matrix3d, 3, 3> b(m.block<3, 3>(0, 0)); }
+void foo(CV_QUALIFIER Matrix3d &m) {
+  Block<Matrix3d, 3, 3> b(m.block<3, 3>(0, 0));
+  EIGEN_UNUSED_VARIABLE(b);
+}
 
 int main() {}
diff --git a/failtest/const_qualified_block_method_retval_1.cpp b/failtest/const_qualified_block_method_retval_1.cpp
index 06e12c7f8..d58a01832 100644
--- a/failtest/const_qualified_block_method_retval_1.cpp
+++ b/failtest/const_qualified_block_method_retval_1.cpp
@@ -8,6 +8,9 @@
 
 using namespace Eigen;
 
-void foo(CV_QUALIFIER Matrix3d &m) { Block<Matrix3d> b(m.block(0, 0, 3, 3)); }
+void foo(CV_QUALIFIER Matrix3d &m) {
+  Block<Matrix3d> b(m.block(0, 0, 3, 3));
+  EIGEN_UNUSED_VARIABLE(b);
+}
 
 int main() {}
diff --git a/failtest/const_qualified_diagonal_method_retval.cpp b/failtest/const_qualified_diagonal_method_retval.cpp
index f3acba625..a10796ae8 100644
--- a/failtest/const_qualified_diagonal_method_retval.cpp
+++ b/failtest/const_qualified_diagonal_method_retval.cpp
@@ -8,6 +8,9 @@
 
 using namespace Eigen;
 
-void foo(CV_QUALIFIER Matrix3d &m) { Diagonal<Matrix3d> b(m.diagonal()); }
+void foo(CV_QUALIFIER Matrix3d &m) {
+  Diagonal<Matrix3d> b(m.diagonal());
+  EIGEN_UNUSED_VARIABLE(b);
+}
 
 int main() {}
diff --git a/failtest/const_qualified_transpose_method_retval.cpp b/failtest/const_qualified_transpose_method_retval.cpp
index 394f64a64..33200a97b 100644
--- a/failtest/const_qualified_transpose_method_retval.cpp
+++ b/failtest/const_qualified_transpose_method_retval.cpp
@@ -8,6 +8,9 @@
 
 using namespace Eigen;
 
-void foo(CV_QUALIFIER Matrix3d &m) { Transpose<Matrix3d> b(m.transpose()); }
+void foo(CV_QUALIFIER Matrix3d &m) {
+  Transpose<Matrix3d> b(m.transpose());
+  EIGEN_UNUSED_VARIABLE(b);
+}
 
 int main() {}