Fix overloading for non-pointers and NULL - Lua

Examples/test-suite/lua/overload_null_runme.lua

@@ -0,0 +1,41 @@
+require("import")	-- the import fn
+import("overload_null")	-- import lib into global
+
+o = overload_null.Overload()
+x = overload_null.X()
+
+assert(1 == o:byval1(x))
+assert(2 == o:byval1(nil))
+
+assert(3 == o:byval2(nil))
+assert(4 == o:byval2(x))
+
+assert(5 == o:byref1(x))
+assert(6 == o:byref1(nil))
+
+assert(7 == o:byref2(nil))
+assert(8 == o:byref2(x))
+
+assert(9 == o:byconstref1(x))
+assert(10 == o:byconstref1(nil))
+
+assert(11 == o:byconstref2(nil))
+assert(12 == o:byconstref2(x))
+
+-- const pointer references
+assert(13 == o:byval1cpr(x))
+assert(14 == o:byval1cpr(nil))
+
+assert(15 == o:byval2cpr(nil))
+assert(16 == o:byval2cpr(x))
+
+-- forward class declaration
+assert(17 == o:byval1forwardptr(x))
+assert(18 == o:byval1forwardptr(nil))
+
+assert(19 == o:byval2forwardptr(nil))
+assert(20 == o:byval2forwardptr(x))
+
+assert(21 == o:byval1forwardref(x))
+
+assert(22 == o:byval2forwardref(x))