[Issue 20968] Linker error of uninstantiated templated `opEquals` member of struct when compiled with -preview=in

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20968

FeepingCreature <default_357-line at yahoo.de> changed:

           What    |Removed                     |Added
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                 CC|                            |default_357-line at yahoo.de

--- Comment #3 from FeepingCreature <default_357-line at yahoo.de> ---
May relate to https://issues.dlang.org/show_bug.cgi?id=19091 - sometimes the
compiler doesn't notice misinstantiation of structs. Then the failed struct is
cached for the template parameter and treated as successful.

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