From 5f4e74532e01c94087658f5236bdf903e0f47ab9 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Tue, 14 Apr 2026 12:45:28 +0300
Subject: [PATCH] cgen: cgen error when changing the signature of a function
 with a specialized generic struct parameter, that is not called (fixes
 #23014)

---
 ...s_unused_specialized_fn_array_param_test.v | 30 +++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 vlib/v/tests/generics/generics_unused_specialized_fn_array_param_test.v

diff --git a/vlib/v/tests/generics/generics_unused_specialized_fn_array_param_test.v b/vlib/v/tests/generics/generics_unused_specialized_fn_array_param_test.v
new file mode 100644
index 000000000..6e9b27a27
--- /dev/null
+++ b/vlib/v/tests/generics/generics_unused_specialized_fn_array_param_test.v
@@ -0,0 +1,30 @@
+struct Context[U] {
+	name string
+	x    U
+}
+
+type Handler[U] = fn (ctx Context[U]) ?
+
+fn f1[U](ctx Context[U]) ? {}
+
+fn f2[U](ctx Context[U]) ? {}
+
+// Keep these unused specialized signatures distinct; issue #23014 failed in cgen here.
+fn f3(ctx Context[int]) ? {}
+
+fn f4(ctx Context[u8]) ? {}
+
+struct App[U] {
+	x U
+}
+
+fn (mut app App[U]) get(prefix string, handlers []Handler[U]) {
+	assert prefix.len > 0
+	assert handlers.len == 2
+}
+
+fn test_generics_unused_specialized_fn_array_param() {
+	mut app := App[u64]{}
+	app.get('abc', [f1[u64], f2[u64]])
+	assert true
+}
-- 
2.39.5