tests: add checks_for_operator_overrides_should_happen_on_the_concrete_types_when_using_generics_test.v

vlib/v/tests/checks_for_operator_overrides_should_happen_on_the_concrete_types_when_using_generics_test.v

@@ -0,0 +1,31 @@
+module main
+
+import datatypes
+
+struct Item {
+	priority int
+}
+
+fn (a Item) < (b Item) bool {
+	return a.priority < b.priority
+}
+
+fn (a Item) == (b Item) bool {
+	return a.priority == b.priority
+}
+
+// Issue https://github.com/vlang/v/issues/13318
+fn test_comparison_operator_override_works_with_generic_datatypes() {
+	mut heap := datatypes.MinHeap<Item>{}
+	heap.insert(Item{10})
+	assert heap.peek()?.priority == 10
+	heap.insert(Item{100})
+	assert heap.peek()?.priority == 10
+	heap.insert(Item{2})
+	assert heap.peek()?.priority == 2
+	heap.insert(Item{5})
+	assert heap.peek()?.priority == 2
+	heap.insert(Item{1})
+	assert heap.peek()?.priority == 1
+	println(heap)
+}