[Issue 21228] Templated toString silently ignored when it can't be instantiated

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21228

--- Comment #4 from Joseph Rushton Wakeling <joseph.wakeling at webdrake.net> ---
One thing I don't understand here: why is the missing symbol not detected
_anyway_ regardless of whether any attempt is made to instantiate the template
or not?  This feels like a more general problem where bugs in templates remain
unflagged by the compiler if the templated code is not used.

It strikes me that if it's possible to address that, it might address the
observed problem more robustly than just addressing how phobos consumes the
errors.

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