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 rætta).

"{{Demo of template that must be substituted}}" gives "Fyrimynd:Demo of template that must be substituted" [1]

while {{subst:Demo of template that must be substituted}} gives "Template body".

See also

rætta