diff --git a/mex/sources/libkorder/tl/t_polynomial.hh b/mex/sources/libkorder/tl/t_polynomial.hh
index dcadee020..f8f7f22f4 100644
--- a/mex/sources/libkorder/tl/t_polynomial.hh
+++ b/mex/sources/libkorder/tl/t_polynomial.hh
@@ -202,7 +202,7 @@ public:
     PowerProvider pwp(xval);
     for (int i = 1; i <= tp.maxdim; i++)
       {
-        const _Stype& xpow = pwp.getNext<_Stype>();
+        const auto& xpow = pwp.getNext<_Stype>();
         for (int j = 0; j <= tp.maxdim - i; j++)
           if (tp.check(Symmetry {i + j}))
             {