From 5edc4902e2a607b14dc3c2bc75947a5ecf0816dc Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Wed, 15 Apr 2026 05:34:46 +0300
Subject: [PATCH] cgen: fix fixed array with option dynamic elem not compiling
 (fixes #25460)

---
 vlib/v/gen/c/cgen.v                                    | 8 ++++----
 vlib/v/gen/c/testdata/fixed_arr_option_array.out       | 1 +
 vlib/v/gen/c/testdata/fixed_arr_option_array.vv        | 2 ++
 vlib/v/tests/fixed_array_init_with_option_array_test.v | 5 +++++
 4 files changed, 12 insertions(+), 4 deletions(-)
 create mode 100644 vlib/v/gen/c/testdata/fixed_arr_option_array.out
 create mode 100644 vlib/v/gen/c/testdata/fixed_arr_option_array.vv

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index f079c6efb..524f4a130 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -9348,11 +9348,11 @@ fn (mut g Gen) ensure_fixed_array_option_definition(elem_type ast.Type) bool {
 		return false
 	}
 	elem_sym := g.table.final_sym(elem_type.clear_option_and_result())
-	if elem_sym.info !is ast.Struct && elem_sym.info !is ast.Interface
-		&& elem_sym.info !is ast.SumType {
+	if elem_sym.is_builtin() {
 		return false
 	}
 	styp, base := g.option_type_name(elem_type)
+	g.ensure_array_typedef(base)
 	lock g.done_options {
 		if base !in g.done_options {
 			g.done_options << base
@@ -9411,7 +9411,7 @@ fn (mut g Gen) write_types(symbols []&ast.TypeSymbol) {
 			ast.Struct {
 				if !struct_names[name]
 					&& (!g.pref.skip_unused || sym.idx in g.table.used_features.used_syms) {
-					// generate field option types for fixed array of option struct/interface/sumtype
+					// generate field option types for fixed array of option non-builtin types
 					// before the struct declaration
 					opt_fields :=
 						sym.info.fields.filter(g.table.final_sym(it.typ).kind == .array_fixed)
@@ -9542,7 +9542,7 @@ fn (mut g Gen) write_types(symbols []&ast.TypeSymbol) {
 							g.type_definitions.writeln(def_str)
 						} else if elem_sym.info !is ast.ArrayFixed
 							|| (elem_sym.info as ast.ArrayFixed).size > 0 {
-							// fixed array of option struct/interface/sumtype must be defined backwards
+							// fixed array of option non-builtin types must be defined backwards
 							if g.ensure_fixed_array_option_definition(sym.info.elem_type) {
 								g.type_definitions.writeln('typedef ${fixed_elem_name} ${styp} [${len}];')
 							} else if !(resolved_elem_sym.info is ast.ArrayFixed
diff --git a/vlib/v/gen/c/testdata/fixed_arr_option_array.out b/vlib/v/gen/c/testdata/fixed_arr_option_array.out
new file mode 100644
index 000000000..ca1ab1bef
--- /dev/null
+++ b/vlib/v/gen/c/testdata/fixed_arr_option_array.out
@@ -0,0 +1 @@
+[Option(none), Option(none), Option(none)]
diff --git a/vlib/v/gen/c/testdata/fixed_arr_option_array.vv b/vlib/v/gen/c/testdata/fixed_arr_option_array.vv
new file mode 100644
index 000000000..9632709ef
--- /dev/null
+++ b/vlib/v/gen/c/testdata/fixed_arr_option_array.vv
@@ -0,0 +1,2 @@
+a := [3]?[]int{}
+println(a)
diff --git a/vlib/v/tests/fixed_array_init_with_option_array_test.v b/vlib/v/tests/fixed_array_init_with_option_array_test.v
index f327ca678..c94efba1d 100644
--- a/vlib/v/tests/fixed_array_init_with_option_array_test.v
+++ b/vlib/v/tests/fixed_array_init_with_option_array_test.v
@@ -4,3 +4,8 @@ fn test_fixed_array_init_with_option_array() {
 	z := [2][]?int{init: []?int{len: 3}}
 	assert z.str() == '[[Option(none), Option(none), Option(none)], [Option(none), Option(none), Option(none)]]'
 }
+
+fn test_fixed_array_of_option_array() {
+	x := [3]?[]int{}
+	assert '${x}' == '[Option(none), Option(none), Option(none)]'
+}
-- 
2.39.5