public static void add_type_conversion_from_defined(type_node from, type_node to,
			function_node convertion_method,type_compare comp,bool is_implicit,bool is_generated)
		{
			type_intersection_node tin=from.get_type_intersection(to);
			if (tin==null)
			{
				tin=new type_intersection_node(comp);
				from.add_intersection_node(to,tin,is_generated);
			}
#if (DEBUG)
			else
			{
				if (tin.this_to_another!=null)
				{
					throw new PascalABCCompiler.TreeConverter.CompilerInternalError("Duplicate type conversion added");
				}
			}
#endif
			tin.this_to_another=new type_conversion(convertion_method,!is_implicit);		
		}