Suppose Template:X contained the string "{{#if:{{{1|}}}|1 was set|1 wasn't set}}". If {{X|foo<ref>bar</ref>}} is used, the reference to bar shouldn't show up in <references />, but it currently does (along with a broken backlink). The far more common case of this happening is on the English Wikipedia, where infobox labels contain a reference that should only appear if data for the label exists. Hacks in lua have been written to avoid looking at parameters to work around this problem. A much cleaner solution would be to only display references in the reference list if they've been unstripped during the page's parsing (or some equivalent way of checking that).
Version: unspecified
Severity: enhancement