[Issue 19807] undefined reference involving separate compilation, `unittest`, `double`

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=19807

kinke at gmx.net changed:

           What    |Removed                     |Added
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                 CC|                            |kinke at gmx.net

--- Comment #1 from kinke at gmx.net ---
The `double` field is required to make the Tuple struct template
non-zero-initialized, so that the init symbol is actually required. You'd have
the same issue with an `int expand = 1` field.

For some reason, the TypeInfo for Tuple is emitted into the `main` module, but
the init symbol isn't.

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