From b0f906419e84b7750895dd654666038bce957f66 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nuno=20Gon=C3=A7alves?= <nunojpg@gmail.com>
Date: Fri, 19 Jan 2024 18:49:53 +0000
Subject: [PATCH] add missing constexpr qualifier

---
 Eigen/src/Core/PlainObjectBase.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Eigen/src/Core/PlainObjectBase.h b/Eigen/src/Core/PlainObjectBase.h
index a8307c7ae..f9bf737ca 100644
--- a/Eigen/src/Core/PlainObjectBase.h
+++ b/Eigen/src/Core/PlainObjectBase.h
@@ -204,7 +204,9 @@ class PlainObjectBase : public internal::dense_xpr_base<Derived>::type
    * provided to by-pass the creation of an evaluator of the expression, thus saving compilation efforts.
    *
    * See DenseCoeffsBase<Derived,ReadOnlyAccessors>::coeff(Index) const for details. */
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Scalar& coeff(Index index) const { return m_storage.data()[index]; }
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE constexpr const Scalar& coeff(Index index) const {
+    return m_storage.data()[index];
+  }
 
   /** This is an overloaded version of DenseCoeffsBase<Derived,WriteAccessors>::coeffRef(Index,Index) const
    * provided to by-pass the creation of an evaluator of the expression, thus saving compilation efforts.