Use extend instead of pushing in a loop

[notriddle]

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[rust-highfive]

r? @alexcrichton

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[alexcrichton]

Thanks for the PR, does this show up in profiling? Or otherwise how were these found? If it's just changing code for changing sake I might say we shouldn't do this?

[notriddle]

I haven't bencharked it, no.

Mostly, it just seems like code cleanup: if it can be phrased as a collect(), it should be, even if it doesn't make things faster, because it better reflects the code's intent.

[alexcrichton]

Hm ok well personally I do not agree and do not want to merge this PR. If others on the Cargo team feel differently they can r+, otherwise I'll close this if no one else wants to pick this up.

[Eh2406]

I do like the collect over the push in a loop. But don't know if it is worth the code cherne.

[weihanglo]

I merged one (#10453) days ago 😅
Although I like the change, I'd suggest not to submit too much this kind of PR unless the readability or performance gains a lot, since it's more like a personal preference.

[alexcrichton]

Thanks for the PR, but I'm going to be stepping down from the Cargo team so I'm going to un-assign myself from this. The Cargo team will help review this when they get a chance.

[notriddle]

Although I like the change, I'd suggest not to submit too much this kind of PR unless the readability or performance gains a lot, since it's more like a personal preference.

That's fine. I understand the concern about wanting to keep the git history readable.