diff --git a/vlib/v/parser/parse_type.v b/vlib/v/parser/parse_type.v
index 6ad3c961cc..44e968e130 100644
--- a/vlib/v/parser/parse_type.v
+++ b/vlib/v/parser/parse_type.v
@@ -136,7 +136,7 @@ pub fn (mut p Parser) parse_type() table.Type {
 	if p.tok.kind != .lcbr {
 		pos := p.tok.position()
 		typ = p.parse_any_type(language, nr_muls > 0)
-		if typ == table.void_type {
+		if typ == table.void_type && is_optional {
 			p.error_with_pos('use `?` instead of `?void`', pos)
 		}
 	}
diff --git a/vlib/v/tests/inout/c_fn_can_return_void_type.out b/vlib/v/tests/inout/c_fn_can_return_void_type.out
new file mode 100644
index 0000000000..9766475a41
--- /dev/null
+++ b/vlib/v/tests/inout/c_fn_can_return_void_type.out
@@ -0,0 +1 @@
+ok
diff --git a/vlib/v/tests/inout/c_fn_can_return_void_type.vv b/vlib/v/tests/inout/c_fn_can_return_void_type.vv
new file mode 100644
index 0000000000..f10bea8f42
--- /dev/null
+++ b/vlib/v/tests/inout/c_fn_can_return_void_type.vv
@@ -0,0 +1,4 @@
+fn C.some_c_function(int) void
+fn main() {
+	println('ok')
+}