From 9921598c91d2a2483efb1607c8fcbf0ea2feaaa9 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sat, 17 Dec 2022 13:15:17 -0300
Subject: [PATCH] cgen: fix struct field initialisation with a fixed array
 (#16692)

---
 .../tests/struct_fixed_array_init_test.out     |  3 +++
 .../tests/struct_fixed_array_init_test.vv      | 17 +++++++++++++++++
 vlib/v/gen/c/cgen.v                            | 18 ++++++++++++++++--
 3 files changed, 36 insertions(+), 2 deletions(-)
 create mode 100644 vlib/v/checker/tests/struct_fixed_array_init_test.out
 create mode 100644 vlib/v/checker/tests/struct_fixed_array_init_test.vv

diff --git a/vlib/v/checker/tests/struct_fixed_array_init_test.out b/vlib/v/checker/tests/struct_fixed_array_init_test.out
new file mode 100644
index 000000000..d9899e798
--- /dev/null
+++ b/vlib/v/checker/tests/struct_fixed_array_init_test.out
@@ -0,0 +1,3 @@
+Sample{
+    data: Data([5, 10, 15])
+}
diff --git a/vlib/v/checker/tests/struct_fixed_array_init_test.vv b/vlib/v/checker/tests/struct_fixed_array_init_test.vv
new file mode 100644
index 000000000..84587d92f
--- /dev/null
+++ b/vlib/v/checker/tests/struct_fixed_array_init_test.vv
@@ -0,0 +1,17 @@
+module main
+
+type Data = [3]int | int
+
+struct Sample {
+	data Data
+}
+
+fn test_main() {
+	test := Sample{
+		data: [5, 10, 15]!
+		// data: 5 /* works fine */
+	}
+
+	println(test)
+	assert test.data.str() == 'Data([5, 10, 15])'
+}
diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index a014da9b1..f90424ae5 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -2473,9 +2473,23 @@ fn (mut g Gen) expr_with_cast(expr ast.Expr, got_type_raw ast.Type, expected_typ
 					unwrapped_got_type = unwrapped_got_sym.info.types[g.aggregate_type_idx]
 					unwrapped_got_sym = g.table.sym(unwrapped_got_type)
 				}
+
 				fname := g.get_sumtype_casting_fn(unwrapped_got_type, unwrapped_expected_type)
-				g.call_cfn_for_casting_expr(fname, expr, expected_is_ptr, unwrapped_exp_sym.cname,
-					got_is_ptr, got_is_fn, got_styp)
+
+				if expr is ast.ArrayInit && got_sym.kind == .array_fixed {
+					stmt_str := g.go_before_stmt(0).trim_space()
+					g.empty_line = true
+					tmp_var := g.new_tmp_var()
+					g.write('${got_styp} ${tmp_var} = ')
+					g.expr(expr)
+					g.write(';')
+					g.write(stmt_str)
+					g.write('${fname}(&${tmp_var})')
+					return
+				} else {
+					g.call_cfn_for_casting_expr(fname, expr, expected_is_ptr, unwrapped_exp_sym.cname,
+						got_is_ptr, got_is_fn, got_styp)
+				}
 			}
 			return
 		}
-- 
2.39.5