[Issue 20246] isCallable fails for template opCall overload

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20246

--- Comment #4 from Max Samukha <maxsamukha at gmail.com> ---
(In reply to Max Samukha from comment #3)

> isCallableWith!(typeof(1))

Typo: isCallableWith!(foo, typeof(1))

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