[hl] add a test for #8299

tests/unit/src/unit/issues/Issue8299.hx

@@ -0,0 +1,11 @@
+package unit.issues;
+
+class Issue8299 extends unit.Test {
+	function test() {
+		eq(-1, foo(1, 2));
+	}
+
+	static function foo<T:Int>(a:T, b:T):Int {
+		return a - b;
+	}
+}