[Issue 21780] alias this preferred over immutable conversion even if alias this is deprecated and de is on

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21780

--- Comment #3 from FeepingCreature <default_357-line at yahoo.de> ---
Oh wait you're right! I thought you were talking about std.typecons.Nullable
for a second.

It's still not a regression - it's a bugfix:
https://issues.dlang.org/show_bug.cgi?id=20033 , I believe.

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