Merge branch 'fix/stanheaders' into patch/stanheaders

Author: eddelbuettel

ChangeLog

@@ -1,12 +1,20 @@
+
 2026-10-07  Steve Bronder  <sbronder@flatironinstitute.org>
 
-	* inst/include/Eigen/src/Core/Fill.h: Apply upstream commit e246f9cb
-	to use memset only if !NumTraits<Scalar>::RequireInitialization
 	* inst/include/Eigen/src/Core/arch/AVX/TypeCasting.h: Apply upstream
 	commit 43a01f06 to support gcc < 10.1 and clang < 10
 	* inst/include/Eigen/src/Core/arch/AVX512/PacketMath.h: Idem
 	* inst/include/Eigen/src/Core/arch/AVX512/TypeCasting.h: Idem
 
+2026-10-06  Dirk Eddelbuettel  <edd@debian.org>
+
+	* patches/eigen-5.0.1-stan.diff: Document previous commit as diff
+
+2026-10-01  Dirk Eddelbuettel  <edd@debian.org>
+
+	* inst/include/Eigen/src/Core/Fill.h: Apply upstream commit e246f9cb
+	to use memset only if !NumTraits<Scalar>::RequireInitialization
+
 2026-07-27  Dirk Eddelbuettel  <edd@debian.org>
 
 	* configure.ac: Conditionally adding compilation flags

DESCRIPTION

@@ -1,8 +1,8 @@
 Package: RcppEigen
 Type: Package
 Title: 'Rcpp' Integration for the 'Eigen' Templated Linear Algebra Library
-Version: 0.4.9.9-2
-Date: 2026-06-04
+Version: 0.4.9.9-4
+Date: 2026-10-01
 Authors@R: c(person("Doug", "Bates", role = "aut",
                     comment = c(ORCID = "0000-0001-8316-9503")),
              person("Dirk", "Eddelbuettel", role = c("aut", "cre"), email = "edd@debian.org",

patches/eigen-5.0.1-stan.diff

@@ -0,0 +1,17 @@
+diff --git o/inst/include/Eigen/src/Core/Fill.h w/inst/include/Eigen/src/Core/Fill.h
+index 779ef26..6f45935 100644
+--- o/inst/include/Eigen/src/Core/Fill.h
++++ w/inst/include/Eigen/src/Core/Fill.h
+@@ -93,8 +93,10 @@ struct eigen_fill_impl<Xpr, /*use_fill*/ true> {
+ 
+ template <typename Xpr>
+ struct eigen_memset_helper {
+-  static constexpr bool value =
+-      std::is_trivially_copyable<typename Xpr::Scalar>::value && eigen_fill_helper<Xpr>::value;
++  using Scalar = typename Xpr::Scalar;
++  static constexpr bool value = std::is_trivially_copyable<Scalar>::value &&
++                                !static_cast<bool>(NumTraits<Scalar>::RequireInitialization) &&
++                                eigen_fill_helper<Xpr>::value;
+ };
+ 
+ template <typename Xpr>