[Issue 21591] Mangling problem wrt. backrefs and function types

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21591

--- Comment #4 from Dlang Bot <dlang-bot at dlang.rocks> ---
dlang/dmd pull request #12195 "Merge stable" was merged into master:

- d8668e1afa3c89d2ed50a86d7e495f9aa860e5bf by Martin Kinkelin:
  Fix Issue 21591 - missed backrefs in mangled names wrt. unmerged function
types (#12166)

  TypeFunctions are apparently special and not merged, so make sure to
  use the generic merged function type as backref cache key.

  Unfortunately, this requires special care to prevent an infinite
  recursion, as merging is based on mangling.

https://github.com/dlang/dmd/pull/12195

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