From 76d37f6595ba3553dbbbfbc90ee0df57f6327860 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sat, 17 Aug 2024 11:02:38 -0300
Subject: [PATCH] cgen: fix for loop with array fixed returned from fn (#22069)

---
 vlib/v/gen/c/cgen.v                      |  8 +++++++-
 vlib/v/gen/c/for.v                       |  3 +++
 vlib/v/tests/array_fixed_for_loop_test.v | 16 ++++++++++++++++
 3 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/tests/array_fixed_for_loop_test.v

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index ea449dd6215240..95b19558ea923f 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -5784,7 +5784,13 @@ fn (mut g Gen) return_stmt(node ast.Return) {
 						} else {
 							node.types[0]
 						}
-						g.write('memcpy(${tmpvar}.ret_arr, ${g.expr_string(node.exprs[0])}, sizeof(${g.typ(typ)}))')
+						typ_sym := g.table.final_sym(typ)
+						if typ_sym.kind == .array_fixed
+							&& (typ_sym.info as ast.ArrayFixed).is_fn_ret {
+							g.write('memcpy(${tmpvar}.ret_arr, ${g.expr_string(node.exprs[0])}.ret_arr, sizeof(${g.typ(typ)}))')
+						} else {
+							g.write('memcpy(${tmpvar}.ret_arr, ${g.expr_string(node.exprs[0])}, sizeof(${g.typ(typ)}))')
+						}
 					} else if node.exprs[0] in [ast.ArrayInit, ast.StructInit] {
 						if node.exprs[0] is ast.ArrayInit && node.exprs[0].is_fixed
 							&& node.exprs[0].has_init {
diff --git a/vlib/v/gen/c/for.v b/vlib/v/gen/c/for.v
index e12d4c81a56e15..aa0ad7aae41450 100644
--- a/vlib/v/gen/c/for.v
+++ b/vlib/v/gen/c/for.v
@@ -333,6 +333,9 @@ fn (mut g Gen) for_in_stmt(node_ ast.ForInStmt) {
 				} else {
 					g.write(' = ${addr}')
 					g.expr(node.cond)
+					if info.is_fn_ret {
+						g.write('.ret_arr')
+					}
 					g.writeln('[${idx}];')
 				}
 			}
diff --git a/vlib/v/tests/array_fixed_for_loop_test.v b/vlib/v/tests/array_fixed_for_loop_test.v
new file mode 100644
index 00000000000000..514b7c1145f687
--- /dev/null
+++ b/vlib/v/tests/array_fixed_for_loop_test.v
@@ -0,0 +1,16 @@
+fn double() (bool, [4]i16) {
+	return true, [4]i16{}
+}
+
+fn foo() [4]i16 {
+	_, b := double()
+	for i in b {
+		println(i)
+	}
+	return b
+}
+
+fn test_main() {
+	arr := foo()
+	assert arr == [4]i16{}
+}