From 52a055b6bc7211a439d05e92d323353e52c1de5f Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Wed, 12 Jul 2023 20:48:04 +0800
Subject: [PATCH] cgen: fix option map with fn type value (#18849)

---
 vlib/v/gen/c/cgen.v                          |  8 +++++++-
 vlib/v/tests/option_map_fn_type_value_test.v | 13 +++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/tests/option_map_fn_type_value_test.v

diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index 2b997d037f..c0dac59a0d 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -1065,9 +1065,12 @@ fn (mut g Gen) expr_string_surround(prepend string, expr ast.Expr, append string
 // all unified in one place so that it doesnt break
 // if one location changes
 fn (mut g Gen) option_type_name(t ast.Type) (string, string) {
-	base := g.base_type(t)
+	mut base := g.base_type(t)
 	mut styp := ''
 	sym := g.table.sym(t)
+	if sym.info is ast.FnType {
+		base = 'anon_fn_${g.table.fn_type_signature(sym.info.func)}'
+	}
 	if sym.language == .c && sym.kind == .struct_ {
 		styp = '${c.option_name}_${base.replace(' ', '_')}'
 	} else {
@@ -1087,6 +1090,9 @@ fn (mut g Gen) result_type_name(t ast.Type) (string, string) {
 	}
 	mut styp := ''
 	sym := g.table.sym(t)
+	if sym.info is ast.FnType {
+		base = 'anon_fn_${g.table.fn_type_signature(sym.info.func)}'
+	}
 	if sym.language == .c && sym.kind == .struct_ {
 		styp = '${c.result_name}_${base.replace(' ', '_')}'
 	} else {
diff --git a/vlib/v/tests/option_map_fn_type_value_test.v b/vlib/v/tests/option_map_fn_type_value_test.v
new file mode 100644
index 0000000000..2ba561109a
--- /dev/null
+++ b/vlib/v/tests/option_map_fn_type_value_test.v
@@ -0,0 +1,13 @@
+const mouse_action_to_function_map = {
+	1: handle_mouse_down_signal
+}
+
+fn handle_mouse_down_signal() string {
+	return 'hello'
+}
+
+fn test_option_map_fn_type_value() {
+	t := mouse_action_to_function_map[1] or { return }
+	println(t())
+	assert t() == 'hello'
+}