fix issue 17084 - Can't sort array of structs with alias this

[ghost]

This fix is actually more a workaround. I propose it because it's verifiable by hand that doesPointTo is well @nogc.

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	17084	normal	Can't sort array of structs with alias this: swap can't call non-@nogc function doesPointTo

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub fetch digger
dub run digger -- build "master + phobos#6472"

[wilzbach]

Hmm, how about using assumeNoGC for the line the compiler can't infer correctly?
(though it looks like this should be better fixed in dmd)

[ghost]

I don't know. It uses a delegate, meaning an indirection. AssumeNoGC is rather used when the attribute cant even be put at all.

[edi33416]

Can these be made private or is this what you meant by local?

[ghost]

they can be made private. by

local even static

i meant inside the unittest block. Will make the comment less ambiguous.

[edi33416]

LGTM

[edi33416]

@bbasile could you squash the commits?

Also, what about the doesPointTo overload for shared objects? Would that also require @nogc or is it able to infer it?

[ghost]

what about the doesPointTo overload for shared objects?

Added a test, it works without explicit @nogc.