[Issue 17921] allow to use `alias function this` to be used for implicit conversions

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=17921

--- Comment #1 from dlangBugzillaToGithub <robert.schadek at posteo.de> ---
THIS ISSUE HAS BEEN MOVED TO GITHUB

https://github.com/dlang/dmd/issues/19328

DO NOT COMMENT HERE ANYMORE, NOBODY WILL SEE IT, THIS ISSUE HAS BEEN MOVED TO
GITHUB

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