This template must be substituted. Replace {{{{{1}}}|content=< redirect's contents >}} with {{subst:{{{1}}}|content= < redirect's contents >}}.
 | This is the template sandbox page for Template:Error:must be substituted (diff). See also the companion subpage for test cases. |
Usage edit
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".