Ensure info() implementation across all SolverBase derived types

Eigen/src/Core/SolverBase.h

@@ -78,6 +78,14 @@ class SolverBase : public EigenBase<Derived> {
   template <typename Derived_>
   friend struct internal::solve_assertion;
 
+  ComputationInfo info() const {
+    // CRTP static dispatch: Calls the 'info()' method on the derived class.
+    // Derived must implement 'ComputationInfo info() const'.
+    // If not implemented, name lookup falls back to this base method, causing
+    // infinite recursion (detectable by -Winfinite-recursion).
+    return derived().info();
+  }
+
   enum {
     RowsAtCompileTime = internal::traits<Derived>::RowsAtCompileTime,
     ColsAtCompileTime = internal::traits<Derived>::ColsAtCompileTime,

Eigen/src/LU/FullPivLU.h

@@ -78,6 +78,17 @@ class FullPivLU : public SolverBase<FullPivLU<MatrixType_, PermutationIndex_> >
   typedef PermutationMatrix<RowsAtCompileTime, MaxRowsAtCompileTime, PermutationIndex> PermutationPType;
   typedef typename MatrixType::PlainObject PlainObject;
 
+  /** \brief Reports whether the LU factorization was successful.
+   *
+   * \note This function always returns \c Success. It is provided for compatibility
+   * with other factorization routines.
+   * \returns \c Success
+   */
+  ComputationInfo info() const {
+    eigen_assert(m_isInitialized && "FullPivLU is not initialized.");
+    return Success;
+  }
+
   /**
    * \brief Default Constructor.
    *

Eigen/src/LU/PartialPivLU.h

@@ -90,6 +90,17 @@ class PartialPivLU : public SolverBase<PartialPivLU<MatrixType_, PermutationInde
   typedef Transpositions<RowsAtCompileTime, MaxRowsAtCompileTime, PermutationIndex> TranspositionType;
   typedef typename MatrixType::PlainObject PlainObject;
 
+  /** \brief Reports whether the LU factorization was successful.
+   *
+   * \note This function always returns \c Success. It is provided for compatibility
+   * with other factorization routines.
+   * \returns \c Success
+   */
+  ComputationInfo info() const {
+    eigen_assert(m_isInitialized && "PartialPivLU is not initialized.");
+    return Success;
+  }
+
   /**
    * \brief Default Constructor.
    *

Eigen/src/QR/FullPivHouseholderQR.h

@@ -82,6 +82,17 @@ class FullPivHouseholderQR : public SolverBase<FullPivHouseholderQR<MatrixType_,
   typedef typename internal::plain_col_type<MatrixType>::type ColVectorType;
   typedef typename MatrixType::PlainObject PlainObject;
 
+  /** \brief Reports whether the QR factorization was successful.
+   *
+   * \note This function always returns \c Success. It is provided for compatibility
+   * with other factorization routines.
+   * \returns \c Success
+   */
+  ComputationInfo info() const {
+    eigen_assert(m_isInitialized && "FullPivHouseholderQR is not initialized.");
+    return Success;
+  }
+
   /** \brief Default Constructor.
    *
    * The default constructor is useful in cases in which the user intends to

Eigen/src/QR/HouseholderQR.h

@@ -75,6 +75,17 @@ class HouseholderQR : public SolverBase<HouseholderQR<MatrixType_>> {
   typedef HouseholderSequence<MatrixType, internal::remove_all_t<typename HCoeffsType::ConjugateReturnType>>
       HouseholderSequenceType;
 
+  /** \brief Reports whether the QR factorization was successful.
+   *
+   * \note This function always returns \c Success. It is provided for compatibility
+   * with other factorization routines.
+   * \returns \c Success
+   */
+  ComputationInfo info() const {
+    eigen_assert(m_isInitialized && "HouseHolderQR is not initialized.");
+    return Success;
+  }
+
   /**
    * \brief Default Constructor.
    *