[Issue 17444] std.traits.isCallable doesn't recognize struct member function if return type is 'auto'.

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=17444

--- Comment #3 from uplink.coder at googlemail.com ---
I would classify this as a bug, however it seems like a fix for this would
break other situations.

for now the best workaround is to not use functions returning auto inside that
struct.

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