From 0cf3a445b73e558b1eb97b8875d7ab483073d862 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Fri, 11 Oct 2024 13:31:18 -0300
Subject: [PATCH] cgen: fix spawn generic codegen (fix #22484) (#22491)

---
 vlib/v/gen/c/spawn_and_go.v                | 10 ++++----
 vlib/v/tests/generics/generic_spawn_test.v | 29 ++++++++++++++++++++++
 2 files changed, 34 insertions(+), 5 deletions(-)
 create mode 100644 vlib/v/tests/generics/generic_spawn_test.v

diff --git a/vlib/v/gen/c/spawn_and_go.v b/vlib/v/gen/c/spawn_and_go.v
index 32117885aa0c59..ad29c5bbc79b28 100644
--- a/vlib/v/gen/c/spawn_and_go.v
+++ b/vlib/v/gen/c/spawn_and_go.v
@@ -248,12 +248,12 @@ fn (mut g Gen) spawn_and_go_expr(node ast.SpawnExpr, mode SpawnGoMode) {
 				}
 			} else {
 				if f := g.table.find_fn(node.call_expr.name) {
-					mut muttable := unsafe { &ast.Table(g.table) }
-					return_type := muttable.convert_generic_type(f.return_type, f.generic_names,
-						node.call_expr.concrete_types) or { f.return_type }
+					concrete_types := node.call_expr.concrete_types.map(g.unwrap_generic(it))
+					return_type := g.table.convert_generic_type(f.return_type, f.generic_names,
+						concrete_types) or { f.return_type }
 					mut arg_types := f.params.map(it.typ)
-					arg_types = arg_types.map(muttable.convert_generic_type(it, f.generic_names,
-						node.call_expr.concrete_types) or { it })
+					arg_types = arg_types.map(g.table.convert_generic_type(it, f.generic_names,
+						concrete_types) or { it })
 					for i, typ in arg_types {
 						mut typ_sym := g.table.sym(typ)
 						for {
diff --git a/vlib/v/tests/generics/generic_spawn_test.v b/vlib/v/tests/generics/generic_spawn_test.v
new file mode 100644
index 00000000000000..b746b92829c3de
--- /dev/null
+++ b/vlib/v/tests/generics/generic_spawn_test.v
@@ -0,0 +1,29 @@
+module main
+
+struct In[T] {
+	source chan T
+}
+
+fn emit[T](s In[T], ar []T) {
+	for _, i in ar {
+		s.source <- i
+	}
+}
+
+fn from[T](ar []T) In[T] {
+	s := In[T]{}
+
+	spawn emit(s, ar)
+
+	return s
+}
+
+fn (i In[T]) get() T {
+	return <-i.source
+}
+
+fn test_main() {
+	v := from[int]([1]).get()
+
+	assert v == 1
+}