Add `Duration::from_nanos_u128` #139243

omanirudh · 2025-04-02T08:48:52Z

Feature gate: #![feature(duration_from_nanos_u128)]
ACP: rust-lang/libs-team#567
Tracking issue: #139201

rustbot · 2025-04-02T08:48:56Z

rustbot has assigned @tgross35.
They will have a look at your PR within the next two weeks and either review your PR or reassign to another reviewer.

Use r? to explicitly pick a reviewer

library/core/src/time.rs

RalfJung · 2025-04-02T12:06:56Z

Thanks for taking this over!
However, this needs a libs reviewer. I just proposed the API. :)

r? libs

omanirudh · 2025-04-02T15:08:45Z

Thanks for taking this over! However, this needs a libs reviewer. I just proposed the API. :)

r? libs

Happy to take this up. noted.

library/core/src/time.rs

tgross35 · 2025-04-02T18:06:31Z

@rustbot author

rustbot · 2025-04-02T18:06:36Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

library/core/src/time.rs

tgross35 · 2025-07-03T19:49:18Z

It looks like you did a merge rather than a rebase - that will need to get fixed since this branch still contains some weird history. Were you able to try what was suggested in rustc-dev-guide (linked above)?

omanirudh · 2025-07-04T01:49:27Z

Hey Trevor Yes I did do a rebase. However CI wasn't getting triggered. Core Test's time.rs file had an additional #test which I resolved and merged on github The same thing I did in local and pushed to my branch but CI wasn't picking it up. It was stuck with "conflicts" in the file. No worries I will take a look and rebase again if needed. The other weird thing would be two commits with cargo.lock both times my repo was 500+ commits behind upstream master. I will squish these and keep just two commits 1) for the function 2) for the tests

…

On Fri, 4 Jul, 2025, 1:19 am Trevor Gross, ***@***.***> wrote: *tgross35* left a comment (rust-lang/rust#139243) <#139243 (comment)> It looks like you did a merge rather than a rebase - that will need to get fixed since this branch still contains some weird history. Were you able to try what was suggested in rustc-dev-guide (linked above)? — Reply to this email directly, view it on GitHub <#139243 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BPJEXXODJKQGXOSI7ALFVRD3GWCNLAVCNFSM6AAAAAB2I6KI7OVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTAMZTGQZTCOJYHE> . You are receiving this because you were mentioned.Message ID: ***@***.***>

alex-semenyuk · 2025-08-10T06:48:48Z

@omanirudh
Thanks for your contribution.
Form wg-triage. Any updates on this PR?

omanirudh · 2025-08-10T06:51:47Z

Hey all. I'm unable to manage the git merge conflict the logic is simple and done. I tried figuring out the git part in vain. Please take this over. I no longer can give time to this. Thanks all for the assistance

…

On Sun, 10 Aug, 2025, 12:19 pm alexey semenyuk, ***@***.***> wrote: *alex-semenyuk* left a comment (rust-lang/rust#139243) <#139243 (comment)> @omanirudh <https://github.com/omanirudh> Thanks for your contribution. Form wg-triage. Any updates on this PR? — Reply to this email directly, view it on GitHub <#139243 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/BPJEXXMEJYBTE5Y76HJVZJT3M3TOPAVCNFSM6AAAAAB2I6KI7OVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTCNZSGQYTMMRSGE> . You are receiving this because you were mentioned.Message ID: ***@***.***>

Tracking issue: RUST-139201

rust-log-analyzer · 2025-08-10T07:52:04Z

The job aarch64-gnu-llvm-19-2 failed! Check out the build log: (web) (plain enhanced) (plain)

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

[RUSTC-TIMING] rand_core test:false 0.228
[RUSTC-TIMING] rand_xorshift test:false 0.112
[RUSTC-TIMING] rand test:false 0.956
[RUSTC-TIMING] vec_deque_alloc_error test:true 0.288
error[E0425]: cannot find value `NANOS_PER_SEC` in this scope
##[error]  --> coretests/tests/time.rs:51:32
   |
51 |     let overflow = (u64::MAX * NANOS_PER_SEC) + (NANOS_PER_SEC - 1) + 1;
   |                                ^^^^^^^^^^^^^ not found in this scope

error[E0425]: cannot find value `NANOS_PER_SEC` in this scope
##[error]  --> coretests/tests/time.rs:51:50
   |
51 |     let overflow = (u64::MAX * NANOS_PER_SEC) + (NANOS_PER_SEC - 1) + 1;
   |                                                  ^^^^^^^^^^^^^ not found in this scope

[RUSTC-TIMING] allocbenches test:true 8.617
[RUSTC-TIMING] alloctests test:true 16.962
[RUSTC-TIMING] alloctests test:true 17.263
[RUSTC-TIMING] corebenches test:true 8.790
error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]  --> coretests/tests/time.rs:52:13
   |
52 |     let _ = Duration::from_nanos_u128(overflow);
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
   = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
   = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

error[E0308]: mismatched types
##[error]   --> coretests/tests/time.rs:52:39
    |
 52 |     let _ = Duration::from_nanos_u128(overflow);
    |             ------------------------- ^^^^^^^^ expected `u128`, found `u64`
    |             |
    |             arguments to this function are incorrect
    |
note: associated function defined here
   --> /checkout/library/core/src/time.rs:331:18
    |
331 |     pub const fn from_nanos_u128(nanos: u128) -> Duration {
    |                  ^^^^^^^^^^^^^^^
help: you can convert a `u64` to a `u128`
    |
 52 |     let _ = Duration::from_nanos_u128(overflow.into());
    |                                               +++++++

error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]  --> coretests/tests/time.rs:91:16
   |
91 |     assert_eq!(Duration::from_nanos_u128(999_999_999).as_secs(), 0);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
   = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
   = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]  --> coretests/tests/time.rs:92:16
   |
92 |     assert_eq!(Duration::from_nanos_u128(1_000_000_001).as_secs(), 1);
   |                ^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
   = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
   = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]   --> coretests/tests/time.rs:107:16
    |
107 |     assert_eq!(Duration::from_nanos_u128(999_999_999).subsec_millis(), 999);
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
    = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
    = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]   --> coretests/tests/time.rs:108:16
    |
108 |     assert_eq!(Duration::from_nanos_u128(1_001_000_001).subsec_millis(), 1);
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
    = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
    = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]   --> coretests/tests/time.rs:123:16
    |
123 |     assert_eq!(Duration::from_nanos_u128(999_999_999).subsec_micros(), 999_999);
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
    = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
    = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]   --> coretests/tests/time.rs:124:16
    |
124 |     assert_eq!(Duration::from_nanos_u128(1_000_001_000).subsec_micros(), 1);
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
    = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
    = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]   --> coretests/tests/time.rs:139:16
    |
139 |     assert_eq!(Duration::from_nanos_u128(999_999_999).subsec_nanos(), 999_999_999);
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
    = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
    = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

error[E0658]: use of unstable library feature `duration_from_nanos_u128`
##[error]   --> coretests/tests/time.rs:140:16
    |
140 |     assert_eq!(Duration::from_nanos_u128(1_000_000_001).subsec_nanos(), 1);
    |                ^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #139201 <https://github.com/rust-lang/rust/issues/139201> for more information
    = help: add `#![feature(duration_from_nanos_u128)]` to the crate attributes to enable
    = note: this compiler was built on 2025-08-10; consider upgrading it if it is out of date

Some errors have detailed explanations: E0308, E0425, E0658.
For more information about an error, try `rustc --explain E0308`.
[RUSTC-TIMING] coretests test:true 51.353
error: could not compile `coretests` (test "coretests") due to 12 previous errors
env -u RUSTC_WRAPPER CARGO_ENCODED_RUSTDOCFLAGS="-Csymbol-mangling-version=v0\u{1f}-Zrandomize-layout\u{1f}-Zunstable-options\u{1f}--check-cfg=cfg(bootstrap)\u{1f}--check-cfg=cfg(llvm_enzyme)\u{1f}-Dwarnings\u{1f}-Wrustdoc::invalid_codeblock_attributes\u{1f}--crate-version\u{1f}1.91.0-nightly\t(f7211377d\t2025-08-10)" CARGO_ENCODED_RUSTFLAGS="-Csymbol-mangling-version=v0\u{1f}-Zrandomize-layout\u{1f}-Zunstable-options\u{1f}--check-cfg=cfg(bootstrap)\u{1f}--check-cfg=cfg(llvm_enzyme)\u{1f}-Zmacro-backtrace\u{1f}-Csplit-debuginfo=off\u{1f}-Clink-arg=-L/usr/lib/llvm-19/lib\u{1f}-Cllvm-args=-import-instr-limit=10\u{1f}-Clink-args=-Wl,-z,origin\u{1f}-Clink-args=-Wl,-rpath,$ORIGIN/../lib\u{1f}-Alinker-messages\u{1f}--cap-lints=allow\u{1f}--cfg\u{1f}randomized_layouts" RUSTC="/checkout/obj/build/aarch64-unknown-linux-gnu/stage1-tools/cg_clif/dist/rustc-clif" RUSTDOC="/checkout/obj/build/aarch64-unknown-linux-gnu/stage1-tools/cg_clif/dist/rustdoc-clif" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage0/bin/cargo" "test" "--manifest-path" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage1-tools/cg_clif/build/sysroot_tests/Cargo.toml" "--target-dir" "/checkout/obj/build/aarch64-unknown-linux-gnu/stage1-tools/cg_clif/build/sysroot_tests_target" "--locked" "--target" "aarch64-unknown-linux-gnu" "-p" "coretests" "-p" "alloctests" "--tests" "--" "-q" exited with status ExitStatus(unix_wait_status(25856))
Command has failed. Rerun with -v to see more details.
Build completed unsuccessfully in 0:07:36
  local time: Sun Aug 10 07:51:55 UTC 2025
  network time: Sun, 10 Aug 2025 07:51:55 GMT
##[error]Process completed with exit code 1.
Post job cleanup.

tgross35 · 2025-08-10T07:53:55Z

Okay yeah that history was a mess, there were two merge commits going opposite directions. For future reference, you can usually fix these kind of situations with

git reset "$(git merge-base HEAD master)"

Which wipes away history but leaves the files unstaged. So your repo will be reset to wherever you branched from master (the merge-base), and it will look like you just edited the files. Then you recreate a single commit with git commit -a and force push, and everything is back to normal :)

I did this for you and force pushed your branch so you don't need to worry about it. This just needs a few small changes if you are interested in finishing it up, now that git shouldn't be a problem.

tgross35 · 2025-08-10T07:50:20Z

library/core/src/time.rs

+    /// Panics if the given number of nanoseconds is greater than what Duration can handle,
+    /// which is `(u64::MAX * NANOS_PER_SEC) + NANOS_PER_SEC - 1`


Suggested change

/// Panics if the given number of nanoseconds is greater than what Duration can handle,

/// which is `(u64::MAX * NANOS_PER_SEC) + NANOS_PER_SEC - 1`

/// Panics if the given number of nanoseconds is greater than [`Duration::MAX`].

Technically we say this can vary by platform, so we don't need to give specifics.

tgross35 · 2025-08-10T07:51:15Z

library/core/src/time.rs

+    /// Use this function if you need to specify time greater than what can fit in u64
+    /// (around 584 years).


Suggested change

/// Use this function if you need to specify time greater than what can fit in u64

/// (around 584 years).

I think this is reasonably straightforward

tgross35 · 2025-08-10T07:51:50Z

library/core/src/time.rs

+        const NANOS_PER_SEC: u128 = self::NANOS_PER_SEC as u128;
+        let secs: u128 = nanos / NANOS_PER_SEC;
+        if secs > u64::MAX as u128 {
+            panic!("overflow in duration in Duration::from_nanos_u128");


Suggested change

panic!("overflow in duration in Duration::from_nanos_u128");

panic!("overflow in `Duration::from_nanos_u128`");

tgross35 · 2025-08-10T07:52:23Z

library/core/src/time.rs

+    #[unstable(feature = "duration_from_nanos_u128", issue = "139201")]
+    #[must_use]
+    #[inline]
+    pub const fn from_nanos_u128(nanos: u128) -> Duration {


Suggested change

pub const fn from_nanos_u128(nanos: u128) -> Duration {

#[track_caller]

pub const fn from_nanos_u128(nanos: u128) -> Duration {

Makes the panic message show where this was called, rather than reporting std's time.rs as the panic location

tgross35 · 2025-08-10T07:55:07Z

library/coretests/tests/time.rs

You'll need to add #![feature(duration_from_nanos_u128)] to coretests/tests/lib.rs, even for testing the unstable feature needs to be enabled (this is your CI failure)

tgross35 · 2025-08-10T07:56:17Z

library/coretests/tests/time.rs

@@ -123,6 +136,8 @@ fn nanos() {
    assert_eq!(Duration::from_micros(1_000_001).subsec_nanos(), 1000);
    assert_eq!(Duration::from_nanos(999_999_999).subsec_nanos(), 999_999_999);
    assert_eq!(Duration::from_nanos(1_000_000_001).subsec_nanos(), 1);
+    assert_eq!(Duration::from_nanos_u128(999_999_999).subsec_nanos(), 999_999_999);
+    assert_eq!(Duration::from_nanos_u128(1_000_000_001).subsec_nanos(), 1);
 }



Please also add a test to duration_const below (look for const NANOS)

…28, r=tgross35 Add Duration::from_nanos_u128 Feature Gate: `#![feature(duration_from_nanos_u128)]` ACP: rust-lang/libs-team#567 Tracking issue: rust-lang#139201 Recreated from rust-lang#139243

Rollup merge of #145969 - actuallylost:duration-from-nanos-128, r=tgross35 Add Duration::from_nanos_u128 Feature Gate: `#![feature(duration_from_nanos_u128)]` ACP: rust-lang/libs-team#567 Tracking issue: #139201 Recreated from #139243

bors · 2025-08-30T14:46:18Z

☔ The latest upstream changes (presumably #146026) made this pull request unmergeable. Please resolve the merge conflicts.

GuillaumeGomez · 2025-08-30T14:53:44Z

It was done in #145969 so this PR can be closed.

…28, r=tgross35 Add Duration::from_nanos_u128 Feature Gate: `#![feature(duration_from_nanos_u128)]` ACP: rust-lang/libs-team#567 Tracking issue: rust-lang#139201 Recreated from rust-lang#139243

rustbot assigned tgross35 Apr 2, 2025

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Apr 2, 2025

rustbot assigned RalfJung and unassigned tgross35 Apr 2, 2025

This comment has been minimized.

Sign in to view

madhav-madhusoodanan reviewed Apr 2, 2025

View reviewed changes

library/core/src/time.rs Show resolved Hide resolved

madhav-madhusoodanan reviewed Apr 2, 2025

View reviewed changes

library/core/src/time.rs Outdated Show resolved Hide resolved

This comment has been minimized.

Sign in to view

rustbot assigned joboet and unassigned RalfJung Apr 2, 2025

tgross35 requested changes Apr 2, 2025

View reviewed changes

library/core/src/time.rs Outdated Show resolved Hide resolved

library/core/src/time.rs Outdated Show resolved Hide resolved

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Apr 2, 2025

This comment has been minimized.

Sign in to view

madhav-madhusoodanan reviewed Apr 3, 2025

View reviewed changes

library/core/src/time.rs Show resolved Hide resolved

This comment has been minimized.

Sign in to view

omanirudh marked this pull request as ready for review April 10, 2025 15:53

rustbot added the has-merge-commits PR has merge commits, merge with caution. label Apr 10, 2025

Add Duration::from_nanos_u128

27d11bc

Tracking issue: RUST-139201

tgross35 changed the title ~~Add Duration from nanos u128~~ Add Duration::from_nanos_u128 Aug 10, 2025

tgross35 force-pushed the duration-from-nanos-u128 branch from 18ce05f to 27d11bc Compare August 10, 2025 07:37

tgross35 requested changes Aug 10, 2025

View reviewed changes

tgross35 mentioned this pull request Aug 27, 2025

Tracking Issue for Duration::from_nanos_u128 #139201

Open

3 tasks

actuallylost added a commit to actuallylost/rust that referenced this pull request Aug 28, 2025

fix(core): update doctest; address pr(rust-lang#139243) comments

469d6a8

tgross35 mentioned this pull request Aug 28, 2025

Add Duration::from_nanos_u128 #145969

Merged

GuillaumeGomez closed this Aug 30, 2025

rustbot removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Aug 30, 2025

		/// Panics if the given number of nanoseconds is greater than what Duration can handle,
		/// which is `(u64::MAX * NANOS_PER_SEC) + NANOS_PER_SEC - 1`

		/// Use this function if you need to specify time greater than what can fit in u64
		/// (around 584 years).

	panic!("overflow in duration in Duration::from_nanos_u128");
	panic!("overflow in `Duration::from_nanos_u128`");

	pub const fn from_nanos_u128(nanos: u128) -> Duration {
	#[track_caller]
	pub const fn from_nanos_u128(nanos: u128) -> Duration {

Add Duration::from_nanos_u128 #139243

Add Duration::from_nanos_u128 #139243

Uh oh!

Conversation

omanirudh commented Apr 2, 2025 • edited by tgross35 Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

rustbot commented Apr 2, 2025

Uh oh!

This comment has been minimized.

Uh oh!

Uh oh!

This comment has been minimized.

RalfJung commented Apr 2, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

omanirudh commented Apr 2, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Uh oh!

Uh oh!

tgross35 commented Apr 2, 2025

Uh oh!

rustbot commented Apr 2, 2025

Uh oh!

This comment has been minimized.

Uh oh!

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

tgross35 commented Jul 3, 2025

Uh oh!

omanirudh commented Jul 4, 2025 via email

Uh oh!

alex-semenyuk commented Aug 10, 2025

Uh oh!

omanirudh commented Aug 10, 2025 via email

Uh oh!

rust-log-analyzer commented Aug 10, 2025

Uh oh!

tgross35 commented Aug 10, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

tgross35 Aug 10, 2025

Choose a reason for hiding this comment

Uh oh!

tgross35 Aug 10, 2025

Choose a reason for hiding this comment

Uh oh!

tgross35 Aug 10, 2025

Choose a reason for hiding this comment

Uh oh!

tgross35 Aug 10, 2025

Choose a reason for hiding this comment

Uh oh!

tgross35 Aug 10, 2025

Choose a reason for hiding this comment

Uh oh!

tgross35 Aug 10, 2025

Choose a reason for hiding this comment

Uh oh!

bors commented Aug 30, 2025

Uh oh!

GuillaumeGomez commented Aug 30, 2025

Uh oh!

Uh oh!

Add `Duration::from_nanos_u128` #139243

Add `Duration::from_nanos_u128` #139243

omanirudh commented Apr 2, 2025 •

edited by tgross35

Loading

RalfJung commented Apr 2, 2025 •

edited

Loading

omanirudh commented Apr 2, 2025 •

edited

Loading

tgross35 commented Aug 10, 2025 •

edited

Loading