From f27181e81b464fcd58dd543c0c1f809be364286d Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Wed, 25 Dec 2024 07:05:53 -0300
Subject: [PATCH] cgen: fix thread struct name for same fn var name on
 different scope (fix #21746) (#23261)

---
 vlib/v/gen/c/spawn_and_go.v           |  5 +++++
 vlib/v/tests/chan_same_fn_name_test.v | 24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+)
 create mode 100644 vlib/v/tests/chan_same_fn_name_test.v

diff --git a/vlib/v/gen/c/spawn_and_go.v b/vlib/v/gen/c/spawn_and_go.v
index 833b7891b..f16285eab 100644
--- a/vlib/v/gen/c/spawn_and_go.v
+++ b/vlib/v/gen/c/spawn_and_go.v
@@ -30,6 +30,11 @@ fn (mut g Gen) spawn_and_go_expr(node ast.SpawnExpr, mode SpawnGoMode) {
 	mut use_tmp_fn_var := false
 	tmp_fn := g.new_tmp_var()
 
+	if expr.is_fn_var {
+		// generate a name different for same var fn name declared in another scope
+		name = '${name}_${node.pos.pos}'
+	}
+
 	if expr.concrete_types.len > 0 {
 		name = g.generic_fn_name(expr.concrete_types, name)
 	} else if expr.is_fn_var && expr.fn_var_type.has_flag(.generic) {
diff --git a/vlib/v/tests/chan_same_fn_name_test.v b/vlib/v/tests/chan_same_fn_name_test.v
new file mode 100644
index 000000000..fee61dd91
--- /dev/null
+++ b/vlib/v/tests/chan_same_fn_name_test.v
@@ -0,0 +1,24 @@
+fn a() chan string {
+	ch_out := chan string{}
+	f := fn (a chan string) {
+		a <- 'foo'
+	}
+	spawn f(ch_out)
+	return ch_out
+}
+
+fn b(ch_in chan string) string {
+	f := fn (a chan string, b chan string) {
+		val := <-a
+		{}
+		b <- val
+	}
+	ch_out := chan string{}
+	spawn f(ch_in, ch_out)
+	return <-ch_out
+}
+
+fn test_main() {
+	ch0 := a()
+	assert b(ch0) == 'foo'
+}
-- 
2.39.5