[Issue 20033] Deprecation not triggered with foreach + alias this

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20033

--- Comment #2 from Dlang Bot <dlang-bot at dlang.rocks> ---
@Geod24 created vibe-d/vibe.d pull request #2334 "Collection of code cleanup"
mentioning this issue:

- Do not use deprecated alias this in Vibe.d code

  The `alias byKeyValue this` has been deprecated since v0.8.1 (released
2017-08-30).
  However, thanks to issue 20033 the deprecation never triggered for user code.
  This fixes Vibe.d code not to use the deprecated code.
  However, removing the symbol is likely to break user code as the compiler
does
  not show any deprecation message at the moment.

https://github.com/vibe-d/vibe.d/pull/2334

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