[Issue 19057] 2.079 changelog variadic template and default arguments

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19057

--- Comment #8 from Steven Schveighoffer <schveiguy at yahoo.com> ---
I think we need to find a way to change this behavior, and soon. As it stands
now, it doesn't make sense, as it's only useful in the __FILE__ and __LINE__
context. It could easily be generalized to fit all contexts, even in a way
where the original behavior is valid. I'd flag this as a regression if it were
up to me.

The change that allows default parameters to work is reasonable. The change
that makes them NEVER match IFTI-passed arguments is very bad and not
intuitive.

I'd absolutely expect this to work like anyone would think it should:

Exception genErr(A...)(A args, string file = __FILE__, size_t line = __LINE__)

Exception genSpecificError(string file = __FILE__, size_t line = __LINE)
{
   return genErr(1, 2, 3, file, line);
}

And the workaround is NOT pleasant.

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