From f82d41bc9a60f12ff4905b40dafd67d775432083 Mon Sep 17 00:00:00 2001
From: Gustavo Konrad <g.konrad@outlook.com>
Date: Sat, 28 Feb 2026 12:33:57 -0300
Subject: [PATCH] fix #6344: field-first index writes on #soa[dynamic]T and
 #soa[]T

---
 src/llvm_backend_expr.cpp         |  6 ++-
 tests/issues/run.sh               |  2 +
 tests/issues/test_issue_6344.odin | 72 +++++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+), 2 deletions(-)
 create mode 100644 tests/issues/test_issue_6344.odin

diff --git a/src/llvm_backend_expr.cpp b/src/llvm_backend_expr.cpp
index 81d7a4e36..35464af21 100644
--- a/src/llvm_backend_expr.cpp
+++ b/src/llvm_backend_expr.cpp
@@ -4654,6 +4654,8 @@ gb_internal lbAddr lb_build_addr_index_expr(lbProcedure *p, Ast *expr) {
 			}
 		}
 		lbValue val = lb_emit_ptr_offset(p, field, index);
+		// make sure it's ^T and not [^]T
+		val.type = alloc_type_multi_pointer_to_pointer(val.type);
 		return lb_addr(val);
 	}
 
@@ -5795,8 +5797,8 @@ gb_internal lbAddr lb_build_addr_internal(lbProcedure *p, Ast *expr) {
 					if (sub_sel.index.count > 0) {
 						item = lb_emit_deep_field_gep(p, item, sub_sel);
 					}
-					// make sure it's ^T and not [^]T
-					item.type = alloc_type_multi_pointer_to_pointer(item.type);
+				// make sure it's ^T and not [^]T
+				item.type = alloc_type_multi_pointer_to_pointer(item.type);
 
 					return lb_addr(item);
 				} else if (addr.kind == lbAddr_Swizzle) {
diff --git a/tests/issues/run.sh b/tests/issues/run.sh
index 73d0d9587..a5323dc45 100755
--- a/tests/issues/run.sh
+++ b/tests/issues/run.sh
@@ -36,6 +36,8 @@ $ODIN test ../test_issue_5699.odin $COMMON
 $ODIN test ../test_issue_6068.odin $COMMON
 $ODIN test ../test_issue_6101.odin $COMMON
 $ODIN test ../test_issue_6165.odin $COMMON
+$ODIN test ../test_issue_6344.odin $COMMON
+$ODIN test ../test_issue_6344.odin $COMMON -o:speed
 set +x
 
 popd
diff --git a/tests/issues/test_issue_6344.odin b/tests/issues/test_issue_6344.odin
new file mode 100644
index 000000000..834ca25db
--- /dev/null
+++ b/tests/issues/test_issue_6344.odin
@@ -0,0 +1,72 @@
+// Tests issue #6344 https://github.com/odin-lang/Odin/issues/6344
+package test_issues
+
+import "core:testing"
+
+@(test)
+test_soa_dynamic_field_write :: proc(t: ^testing.T) {
+	V :: struct {
+		x: f32,
+		y: f32,
+	}
+
+	array := make(#soa[dynamic]V, 4, 8)
+	defer delete(array)
+
+	for i in 0 ..< 4 {
+		array[i] = V{f32(i), f32(i) * 2}
+	}
+
+	// Simple write through field-first indexing (was: compiler panic)
+	for i in 0 ..< 4 {
+		array.x[i] = f32(i) * 10
+	}
+	testing.expect_value(t, array[0].x, 0)
+	testing.expect_value(t, array[1].x, 10)
+	testing.expect_value(t, array[2].x, 20)
+	testing.expect_value(t, array[3].x, 30)
+
+	// Compound write through field-first indexing (was: compiler panic)
+	for i in 0 ..< 4 {
+		array.x[i] += array.y[i]
+	}
+	testing.expect_value(t, array[0].x, 0)
+	testing.expect_value(t, array[1].x, 12)
+	testing.expect_value(t, array[2].x, 24)
+	testing.expect_value(t, array[3].x, 36)
+}
+
+@(test)
+test_soa_slice_field_write :: proc(t: ^testing.T) {
+	V :: struct {
+		x: f32,
+		y: f32,
+	}
+
+	array := make(#soa[dynamic]V, 4, 8)
+	defer delete(array)
+
+	for i in 0 ..< 4 {
+		array[i] = V{f32(i), f32(i) * 2}
+	}
+
+	slice := array[:]
+
+	// Write through slice field-first indexing (was: compiler panic)
+	for i in 0 ..< 4 {
+		slice.x[i] = f32(i) * 10
+	}
+	testing.expect_value(t, array[0].x, 0)
+	testing.expect_value(t, array[1].x, 10)
+	testing.expect_value(t, array[2].x, 20)
+	testing.expect_value(t, array[3].x, 30)
+
+	// Compound write through slice field-first indexing
+	for i in 0 ..< 4 {
+		slice.x[i] += slice.y[i]
+	}
+	testing.expect_value(t, array[0].x, 0)
+	testing.expect_value(t, array[1].x, 12)
+	testing.expect_value(t, array[2].x, 24)
+	testing.expect_value(t, array[3].x, 36)
+}