From 4e728758afd54d7203151d58b85bd1dd30e12abc Mon Sep 17 00:00:00 2001
From: Alexis Placet <alexis.placet@quantstack.net>
Date: Fri, 28 Aug 2026 11:00:51 +0200
Subject: [PATCH 1/2] Fix SIMD assignment to xfunctor_view destinations (#2892)

xt::real(e) = w failed to compile with XTENSOR_USE_XSIMD: the SIMD
gate only probed load_simd, but the linear assigner also needs data()
on the destination, which functor views lack. Gate the SIMD paths on
data_interface_expression<E1> instead; functor views fall back to
scalar assignment while containers keep the SIMD path.

Adds a regression test (test_xcomplex.assign_to_real_part).
---
 include/xtensor/core/xassign.hpp |  3 ++-
 test/test_xcomplex.cpp           | 10 ++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/include/xtensor/core/xassign.hpp b/include/xtensor/core/xassign.hpp
index 174ddcdc0..f9a05b183 100644
--- a/include/xtensor/core/xassign.hpp
+++ b/include/xtensor/core/xassign.hpp
@@ -392,7 +392,8 @@ namespace xt
 
         static constexpr bool simd_interface()
         {
-            return has_simd_interface<E1, requested_value_type>()
+            return data_interface_expression<E1>
+                   && has_simd_interface<E1, requested_value_type>()
                    && has_simd_interface<E2, requested_value_type>();
         }
 
diff --git a/test/test_xcomplex.cpp b/test/test_xcomplex.cpp
index 920d21b8e..43d1f856a 100644
--- a/test/test_xcomplex.cpp
+++ b/test/test_xcomplex.cpp
@@ -319,6 +319,16 @@ namespace xt
         EXPECT_EQ(a(4, 4), cmplx(-123.321L, -123.321L));
     }
 
+    TEST(xcomplex, assign_to_real_part)
+    {
+        using cpx = std::complex<double>;
+        xt::xtensor<cpx, 1> a = {cpx(1, 2), cpx(3, 4), cpx(5, 6), cpx(7, 8), cpx(9, 10)};
+        xt::xtensor<double, 1> wr = {11, 12, 13, 14, 15};
+        xt::real(a) = wr;
+        xt::xtensor<cpx, 1> expected = {cpx(11, 2), cpx(12, 4), cpx(13, 6), cpx(14, 8), cpx(15, 10)};
+        EXPECT_EQ(a, expected);
+    }
+
     TEST(xcomplex, build_from_double)
     {
         xt::xarray<double> r = {1., 2., 3.};

From 4597ce51e1aa4a40d6ac912a22a35b83f96a36f1 Mon Sep 17 00:00:00 2001
From: Alexis Placet <alexis.placet@quantstack.net>
Date: Fri, 28 Aug 2026 11:41:50 +0200
Subject: [PATCH 2/2] formatting

---
 include/xtensor/core/xassign.hpp | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/xtensor/core/xassign.hpp b/include/xtensor/core/xassign.hpp
index f9a05b183..e305b19c7 100644
--- a/include/xtensor/core/xassign.hpp
+++ b/include/xtensor/core/xassign.hpp
@@ -392,8 +392,7 @@ namespace xt
 
         static constexpr bool simd_interface()
         {
-            return data_interface_expression<E1>
-                   && has_simd_interface<E1, requested_value_type>()
+            return data_interface_expression<E1> && has_simd_interface<E1, requested_value_type>()
                    && has_simd_interface<E2, requested_value_type>();
         }