This template must be substituted. Replace (((({1))} with ((subst:(({1))}.
Usage
In a template that must be substituted, add the following code at the top:
(( ((#ifeq:((<includeonly>subst:</includeonly>void))|((void))|void|Error:must be substituted))| template name ))
Example: Template:Demo of template that must be substituted (backlinks edit).
((Demo of template that must be substituted)) → This template must be substituted. Replace ((Demo of template that must be substituted with ((subst:Demo of template that must be substituted.Template body
while ((subst:Demo of template that must be substituted)) gives "Template body".