From ad83973bbd73fb5bf922a797b8f6d4248b22b5c3 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Wed, 24 May 2023 14:55:53 -0600
Subject: [PATCH] Also check PETSc TS and SNES requirements on matrices.

---
 include/deal.II/lac/petsc_snes.h | 11 +++++++++--
 include/deal.II/lac/petsc_ts.h   | 11 +++++++++--
 2 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/include/deal.II/lac/petsc_snes.h b/include/deal.II/lac/petsc_snes.h
index 6167b0d9cd..1ef8c9cb77 100644
--- a/include/deal.II/lac/petsc_snes.h
+++ b/include/deal.II/lac/petsc_snes.h
@@ -238,8 +238,15 @@ namespace PETScWrappers
   template <typename VectorType  = PETScWrappers::VectorBase,
             typename PMatrixType = PETScWrappers::MatrixBase,
             typename AMatrixType = PMatrixType>
-  DEAL_II_CXX20_REQUIRES((concepts::is_dealii_petsc_vector_type<VectorType> ||
-                          std::constructible_from<VectorType, Vec>))
+  DEAL_II_CXX20_REQUIRES(
+    (concepts::is_dealii_petsc_vector_type<VectorType> ||
+     std::constructible_from<
+       VectorType,
+       Vec>)&&(concepts::is_dealii_petsc_matrix_type<PMatrixType> ||
+               std::constructible_from<
+                 PMatrixType,
+                 Mat>)&&(concepts::is_dealii_petsc_matrix_type<AMatrixType> ||
+                         std::constructible_from<AMatrixType, Mat>))
   class NonlinearSolver
   {
   public:
diff --git a/include/deal.II/lac/petsc_ts.h b/include/deal.II/lac/petsc_ts.h
index 9a45ffc5be..60641ba51b 100644
--- a/include/deal.II/lac/petsc_ts.h
+++ b/include/deal.II/lac/petsc_ts.h
@@ -295,8 +295,15 @@ namespace PETScWrappers
   template <typename VectorType  = PETScWrappers::VectorBase,
             typename PMatrixType = PETScWrappers::MatrixBase,
             typename AMatrixType = PMatrixType>
-  DEAL_II_CXX20_REQUIRES((concepts::is_dealii_petsc_vector_type<VectorType> ||
-                          std::constructible_from<VectorType, Vec>))
+  DEAL_II_CXX20_REQUIRES(
+    (concepts::is_dealii_petsc_vector_type<VectorType> ||
+     std::constructible_from<
+       VectorType,
+       Vec>)&&(concepts::is_dealii_petsc_matrix_type<PMatrixType> ||
+               std::constructible_from<
+                 PMatrixType,
+                 Mat>)&&(concepts::is_dealii_petsc_matrix_type<AMatrixType> ||
+                         std::constructible_from<AMatrixType, Mat>))
   class TimeStepper
   {
   public:
-- 
2.39.5