From 023fd9234d0d1629b74c1e7df9bfc5374e3b0a2b Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Sat, 7 Sep 2024 00:54:14 +0800
Subject: [PATCH] cgen: fix struct field with default optional value (fix
 #11119) (#22167)

---
 vlib/v/gen/c/struct.v                         |  8 ++++++
 ...struct_field_default_value_optional_test.v | 27 +++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 vlib/v/tests/structs/struct_field_default_value_optional_test.v

diff --git a/vlib/v/gen/c/struct.v b/vlib/v/gen/c/struct.v
index a87ab460e3..b5da913481 100644
--- a/vlib/v/gen/c/struct.v
+++ b/vlib/v/gen/c/struct.v
@@ -415,6 +415,14 @@ fn (mut g Gen) zero_struct_field(field ast.StructField) bool {
 					g.struct_init(default_init)
 				}
 				return true
+			} else if sym.language == .v && !field.typ.is_ptr() && sym.mod != 'builtin'
+				&& !sym.info.is_empty_struct() {
+				default_init := ast.StructInit{
+					typ: field.typ
+				}
+				g.write('.${field_name} = ')
+				g.struct_init(default_init)
+				return true
 			}
 		}
 	}
diff --git a/vlib/v/tests/structs/struct_field_default_value_optional_test.v b/vlib/v/tests/structs/struct_field_default_value_optional_test.v
new file mode 100644
index 0000000000..dfaa021002
--- /dev/null
+++ b/vlib/v/tests/structs/struct_field_default_value_optional_test.v
@@ -0,0 +1,27 @@
+import regex
+
+struct RegexCache {
+mut:
+	tag_script_start regex.RE = regex.regex_opt(r'^script.*>') or { panic(err) }
+}
+
+pub struct Tokenizer {
+mut:
+	regex_cache RegexCache = RegexCache{}
+}
+
+fn new_parser() &Parser {
+	mut parser := &Parser{}
+	return parser
+}
+
+pub struct Parser {
+mut:
+	tnzr Tokenizer
+}
+
+fn test_struct_field_default_value_optional() {
+	p := new_parser()
+	println(p)
+	assert true
+}