Partially stabilize duration_consts_2

[jhpratt]

Methods that were only blocked on const_panic have been stabilized.
The remaining methods of duration_consts_2 are all related to floats,
and as such have been placed behind the duration_consts_float feature
gate.

[rust-highfive]

r? @dtolnay

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[dtolnay]

Stabilize the following methods as const:

impl Duration {
    pub const fn new(secs: u64, nanos: u32) -> Duration;
    pub const fn checked_add(self, rhs: Duration) -> Option<Duration>;
    pub const fn saturating_add(self, rhs: Duration) -> Duration;
    pub const fn checked_sub(self, rhs: Duration) -> Option<Duration>;
    pub const fn saturating_sub(self, rhs: Duration) -> Duration;
    pub const fn checked_mul(self, rhs: u32) -> Option<Duration>;
    pub const fn saturating_mul(self, rhs: u32) -> Duration;
    pub const fn checked_div(self, rhs: u32) -> Option<Duration>;
}

All of these are stable signatures already, but this PR is making them stably callable in const.

@rust-lang/libs-api
@rfcbot fcp merge

[rfcbot]

Team member @dtolnay has proposed to merge this. The next step is review by the rest of the tagged team members:

• @Amanieu
• @BurntSushi
• @dtolnay
• @joshtriplett
• @m-ou-se
• @yaahc

No concerns currently listed.

Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up!

See this document for info about what commands tagged team members can give me.

[rfcbot]

🔔 This is now entering its final comment period, as per the review above. 🔔

[bors]

☔ The latest upstream changes (presumably #89767) made this pull request unmergeable. Please resolve the merge conflicts.

[rfcbot]

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

[joshtriplett]

@bors r+

[bors]

📌 Commit 14bb025 has been approved by joshtriplett

[oli-obk]

@bors r+

[bors]

📌 Commit 88b0d7c has been approved by oli-obk

[bors]

⌛ Testing commit 88b0d7c with merge 84852792e31fdd32cb16d0d277da9c673e004113...

[rust-log-analyzer]

The job x86_64-gnu-tools failed! Check out the build log: (web) (plain)

Click to see the possible cause of the failure (guessed by this bot)

......... (50/53)
...        (53/53)


/checkout/src/test/rustdoc-gui/toggle-click-deadspace.goml toggle-click-deadspace... FAILED
[ERROR] (line 8) Error: Evaluation failed: assert didn't fail: for command `assert-attribute-false: (".impl-items .rustdoc-toggle", {"open": ""})`



command did not execute successfully: "/node-v14.4.0-linux-x64/bin/node" "/checkout/src/tools/rustdoc-gui/tester.js" "--jobs" "16" "--doc-folder" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/rustdoc-gui/doc" "--tests-folder" "/checkout/src/test/rustdoc-gui"


Build completed unsuccessfully in 0:00:16

[bors]

💔 Test failed - checks-actions

[jhpratt]

Test failure is unrelated.

[oli-obk]

@bors retry