From 066f825dea7b10c4588a17da727d9af39c3c5721 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sun, 15 Dec 2024 17:44:56 -0300
Subject: [PATCH] cgen: fix fixed array option cast with `none` (fix #23164)
 (#23168)

---
 vlib/v/gen/c/cgen.v                           | 10 +++++---
 vlib/v/tests/alias_cast_to_fixed_array_test.v | 24 +++++++++++++++++++
 2 files changed, 31 insertions(+), 3 deletions(-)
 create mode 100644 vlib/v/tests/alias_cast_to_fixed_array_test.v

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index 7b5a03e07d..909660238b 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -5364,10 +5364,14 @@ fn (mut g Gen) cast_expr(node ast.CastExpr) {
 		g.expr(node.expr)
 		g.write('))')
 	} else if sym.kind == .alias && g.table.final_sym(node.typ).kind == .array_fixed {
-		if node.expr is ast.ArrayInit && g.assign_op != .decl_assign {
-			g.write('(${g.styp(node.expr.typ)})')
+		if node.typ.has_flag(.option) {
+			g.expr_with_opt(node.expr, expr_type, node.typ)
+		} else {
+			if node.expr is ast.ArrayInit && g.assign_op != .decl_assign {
+				g.write('(${g.styp(node.expr.typ)})')
+			}
+			g.expr(node.expr)
 		}
-		g.expr(node.expr)
 	} else if expr_type == ast.bool_type && node.typ.is_int() {
 		styp := g.styp(node_typ)
 		g.write('(${styp}[]){(')
diff --git a/vlib/v/tests/alias_cast_to_fixed_array_test.v b/vlib/v/tests/alias_cast_to_fixed_array_test.v
new file mode 100644
index 0000000000..fc3e0eefa3
--- /dev/null
+++ b/vlib/v/tests/alias_cast_to_fixed_array_test.v
@@ -0,0 +1,24 @@
+type Bytes = [3]u8
+type Strs = [3]string
+
+fn test_none() {
+	b := ?Bytes(none)
+	println(b)
+	assert b == none
+
+	c := ?Strs(none)
+	println(c)
+	assert c == none
+}
+
+fn test_non_none() {
+	b := ?Bytes([u8(1), 2, 3]!)
+	println(b)
+	assert b != none
+	assert b?[2] == 3
+
+	c := ?Strs(['a', 'b', 'c']!)
+	println(c)
+	assert c != none
+	assert c?[2] == 'c'
+}