Update cursor.rs #67415

LuoZijun · 2019-12-19T05:40:23Z

impl<T: AsMut<[u8]>> std::io::Write for std::io::Cursor { }

rust-highfive · 2019-12-19T05:40:26Z

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @kennytm (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

rust-highfive · 2019-12-19T05:51:01Z

The job mingw-check of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

2019-12-19T05:41:01.4106296Z ##[command]git remote add origin https://github.com/rust-lang/rust
2019-12-19T05:41:01.4335186Z ##[command]git config gc.auto 0
2019-12-19T05:41:01.4412772Z ##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
2019-12-19T05:41:01.4468277Z ##[command]git config --get-all http.proxy
2019-12-19T05:41:01.4614289Z ##[command]git -c http.extraheader="AUTHORIZATION: basic ***" fetch --force --tags --prune --progress --no-recurse-submodules --depth=2 origin +refs/heads/*:refs/remotes/origin/* +refs/pull/67415/merge:refs/remotes/pull/67415/merge
---
2019-12-19T05:46:38.8601067Z Successfully built 2673061d01f0
2019-12-19T05:46:38.9889455Z Successfully tagged rust-ci:latest
2019-12-19T05:46:39.0402304Z Built container sha256:2673061d01f0c246c4a386ff392cde3ea35463dcb23994c380a6c60e1c7d9514
2019-12-19T05:46:39.0429263Z Uploading finished image to https://rust-lang-ci-sccache2.s3.amazonaws.com/docker/a4e8b7e8bb02ac2100a242c404ec9cad308c2d13ab7005efa7a2f5ca462ea44fe3b309afeb06c439a0091371f6a14487ea26f96e8916366f1b586cbeecbe4c35
2019-12-19T05:47:40.6389396Z upload failed: - to s3://rust-lang-ci-sccache2/docker/a4e8b7e8bb02ac2100a242c404ec9cad308c2d13ab7005efa7a2f5ca462ea44fe3b309afeb06c439a0091371f6a14487ea26f96e8916366f1b586cbeecbe4c35 An error occurred (InvalidAccessKeyId) when calling the CreateMultipartUpload operation: The AWS Access Key Id you provided does not exist in our records.
2019-12-19T05:47:41.7731642Z [CI_JOB_NAME=mingw-check]
2019-12-19T05:47:41.7766323Z == clock drift check ==
2019-12-19T05:47:41.7809427Z   local time: Thu Dec 19 05:47:41 UTC 2019
2019-12-19T05:47:41.9250935Z   network time: Thu, 19 Dec 2019 05:47:41 GMT
---
2019-12-19T05:49:33.7254129Z     Checking panic_abort v0.0.0 (/checkout/src/libpanic_abort)
2019-12-19T05:49:33.7730646Z     Checking rustc-std-workspace-alloc v1.99.0 (/checkout/src/tools/rustc-std-workspace-alloc)
2019-12-19T05:49:33.9648721Z     Checking backtrace v0.3.40
2019-12-19T05:49:34.1810075Z     Checking panic_unwind v0.0.0 (/checkout/src/libpanic_unwind)
2019-12-19T05:49:36.6745333Z error[E0520]: `write` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6747023Z    --> src/libstd/io/cursor.rs:337:5
2019-12-19T05:49:36.6747509Z     |
2019-12-19T05:49:36.6748382Z 337 | /     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6748968Z 338 | |         slice_write(&mut self.pos, self.inner, buf)
2019-12-19T05:49:36.6749583Z 339 | |     }
2019-12-19T05:49:36.6750044Z     | |_____^ cannot specialize default item `write`
2019-12-19T05:49:36.6750390Z ...
2019-12-19T05:49:36.6750845Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6751274Z 397 | |     #[inline]
2019-12-19T05:49:36.6751743Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6752563Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6753306Z ...   |
2019-12-19T05:49:36.6753799Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6754675Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6755067Z     |
2019-12-19T05:49:36.6755067Z     |
2019-12-19T05:49:36.6755928Z     = note: to specialize, `write` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6756199Z 
2019-12-19T05:49:36.6763734Z error[E0520]: `write_vectored` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6764063Z    --> src/libstd/io/cursor.rs:342:5
2019-12-19T05:49:36.6764273Z     |
2019-12-19T05:49:36.6764596Z 342 | /     fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
2019-12-19T05:49:36.6764928Z 343 | |         slice_write_vectored(&mut self.pos, self.inner, bufs)
2019-12-19T05:49:36.6765190Z 344 | |     }
2019-12-19T05:49:36.6766011Z     | |_____^ cannot specialize default item `write_vectored`
2019-12-19T05:49:36.6766286Z ...
2019-12-19T05:49:36.6766786Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6767170Z 397 | |     #[inline]
2019-12-19T05:49:36.6767514Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6767836Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6768371Z ...   |
2019-12-19T05:49:36.6768715Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6769863Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6770552Z     |
2019-12-19T05:49:36.6770552Z     |
2019-12-19T05:49:36.6770909Z     = note: to specialize, `write_vectored` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6770967Z 
2019-12-19T05:49:36.6790165Z error[E0520]: `flush` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6790651Z    --> src/libstd/io/cursor.rs:347:5
2019-12-19T05:49:36.6791051Z     |
2019-12-19T05:49:36.6791470Z 347 |       fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6792130Z     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `flush`
2019-12-19T05:49:36.6792496Z ...
2019-12-19T05:49:36.6792909Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6793337Z 397 | |     #[inline]
2019-12-19T05:49:36.6793788Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6794226Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6794592Z ...   |
2019-12-19T05:49:36.6795030Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6796561Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6796991Z     |
2019-12-19T05:49:36.6796991Z     |
2019-12-19T05:49:36.6797487Z     = note: to specialize, `flush` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6797697Z 
2019-12-19T05:49:36.6803036Z error[E0520]: `write` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6808839Z    --> src/libstd/io/cursor.rs:352:5
2019-12-19T05:49:36.6813036Z     |
2019-12-19T05:49:36.6814099Z 352 | /     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6814671Z 353 | |         vec_write(&mut self.pos, self.inner, buf)
2019-12-19T05:49:36.6816120Z 354 | |     }
2019-12-19T05:49:36.6816527Z     | |_____^ cannot specialize default item `write`
2019-12-19T05:49:36.6816759Z ...
2019-12-19T05:49:36.6817647Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6817963Z 397 | |     #[inline]
2019-12-19T05:49:36.6818538Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6818870Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6819431Z ...   |
2019-12-19T05:49:36.6820150Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6820688Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6820859Z     |
2019-12-19T05:49:36.6820859Z     |
2019-12-19T05:49:36.6821740Z     = note: to specialize, `write` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6821806Z 
2019-12-19T05:49:36.6822074Z error[E0520]: `write_vectored` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6822275Z    --> src/libstd/io/cursor.rs:356:5
2019-12-19T05:49:36.6822455Z     |
2019-12-19T05:49:36.6822724Z 356 | /     fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
2019-12-19T05:49:36.6823013Z 357 | |         vec_write_vectored(&mut self.pos, self.inner, bufs)
2019-12-19T05:49:36.6823273Z 358 | |     }
2019-12-19T05:49:36.6823532Z     | |_____^ cannot specialize default item `write_vectored`
2019-12-19T05:49:36.6823694Z ...
2019-12-19T05:49:36.6824150Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6824568Z 397 | |     #[inline]
2019-12-19T05:49:36.6824862Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6825130Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6825331Z ...   |
2019-12-19T05:49:36.6826019Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6826817Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6827054Z     |
2019-12-19T05:49:36.6827054Z     |
2019-12-19T05:49:36.6827362Z     = note: to specialize, `write_vectored` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6827401Z 
2019-12-19T05:49:36.6827808Z error[E0520]: `flush` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6828064Z    --> src/libstd/io/cursor.rs:361:5
2019-12-19T05:49:36.6828404Z     |
2019-12-19T05:49:36.6828726Z 361 |       fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6829265Z     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `flush`
2019-12-19T05:49:36.6829455Z ...
2019-12-19T05:49:36.6829708Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6829942Z 397 | |     #[inline]
2019-12-19T05:49:36.6830225Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6830477Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6830694Z ...   |
2019-12-19T05:49:36.6830953Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6831419Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6831586Z     |
2019-12-19T05:49:36.6831586Z     |
2019-12-19T05:49:36.6831822Z     = note: to specialize, `flush` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6831868Z 
2019-12-19T05:49:36.6832110Z error[E0520]: `write` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6832319Z    --> src/libstd/io/cursor.rs:366:5
2019-12-19T05:49:36.6832500Z     |
2019-12-19T05:49:36.6832762Z 366 | /     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6833024Z 367 | |         vec_write(&mut self.pos, &mut self.inner, buf)
2019-12-19T05:49:36.6833266Z 368 | |     }
2019-12-19T05:49:36.6833510Z     | |_____^ cannot specialize default item `write`
2019-12-19T05:49:36.6833666Z ...
2019-12-19T05:49:36.6833930Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6834168Z 397 | |     #[inline]
2019-12-19T05:49:36.6834544Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6834837Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6835028Z ...   |
2019-12-19T05:49:36.6835300Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6836227Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6836967Z     |
2019-12-19T05:49:36.6836967Z     |
2019-12-19T05:49:36.6837280Z     = note: to specialize, `write` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6837318Z 
2019-12-19T05:49:36.6873747Z error[E0520]: `write_vectored` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6874077Z    --> src/libstd/io/cursor.rs:370:5
2019-12-19T05:49:36.6874274Z     |
2019-12-19T05:49:36.6874656Z 370 | /     fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
2019-12-19T05:49:36.6874960Z 371 | |         vec_write_vectored(&mut self.pos, &mut self.inner, bufs)
2019-12-19T05:49:36.6875248Z 372 | |     }
2019-12-19T05:49:36.6875923Z     | |_____^ cannot specialize default item `write_vectored`
2019-12-19T05:49:36.6876182Z ...
2019-12-19T05:49:36.6876520Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6876822Z 397 | |     #[inline]
2019-12-19T05:49:36.6877160Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6877501Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6877753Z ...   |
2019-12-19T05:49:36.6878086Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6878687Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6878920Z     |
2019-12-19T05:49:36.6878920Z     |
2019-12-19T05:49:36.6879393Z     = note: to specialize, `write_vectored` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6879428Z 
2019-12-19T05:49:36.6879676Z error[E0520]: `flush` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6879915Z    --> src/libstd/io/cursor.rs:375:5
2019-12-19T05:49:36.6880087Z     |
2019-12-19T05:49:36.6880471Z 375 |       fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6880849Z     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `flush`
2019-12-19T05:49:36.6881198Z ...
2019-12-19T05:49:36.6881479Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6881728Z 397 | |     #[inline]
2019-12-19T05:49:36.6882188Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6882614Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6882834Z ...   |
2019-12-19T05:49:36.6883118Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6883636Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6883821Z     |
2019-12-19T05:49:36.6883821Z     |
2019-12-19T05:49:36.6884103Z     = note: to specialize, `flush` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6884183Z 
2019-12-19T05:49:36.6907540Z error[E0520]: `write` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6908430Z    --> src/libstd/io/cursor.rs:381:5
2019-12-19T05:49:36.6909124Z     |
2019-12-19T05:49:36.6909819Z 381 | /     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6910303Z 382 | |         slice_write(&mut self.pos, &mut self.inner, buf)
2019-12-19T05:49:36.6910707Z 383 | |     }
2019-12-19T05:49:36.6911152Z     | |_____^ cannot specialize default item `write`
2019-12-19T05:49:36.6911661Z ...
2019-12-19T05:49:36.6912105Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6912540Z 397 | |     #[inline]
2019-12-19T05:49:36.6912982Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6913431Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6913790Z ...   |
2019-12-19T05:49:36.6914212Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6915184Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6915964Z     |
2019-12-19T05:49:36.6915964Z     |
2019-12-19T05:49:36.6916671Z     = note: to specialize, `write` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6916909Z 
2019-12-19T05:49:36.6917531Z error[E0520]: `write_vectored` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6918055Z    --> src/libstd/io/cursor.rs:386:5
2019-12-19T05:49:36.6918515Z     |
2019-12-19T05:49:36.6919253Z 386 | /     fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
2019-12-19T05:49:36.6919863Z 387 | |         slice_write_vectored(&mut self.pos, &mut self.inner, bufs)
2019-12-19T05:49:36.6920305Z 388 | |     }
2019-12-19T05:49:36.6920725Z     | |_____^ cannot specialize default item `write_vectored`
2019-12-19T05:49:36.6921064Z ...
2019-12-19T05:49:36.6921472Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6921878Z 397 | |     #[inline]
2019-12-19T05:49:36.6922300Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6922723Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6923093Z ...   |
2019-12-19T05:49:36.6923514Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6924328Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6924650Z     |
2019-12-19T05:49:36.6924650Z     |
2019-12-19T05:49:36.6925072Z     = note: to specialize, `write_vectored` in the parent `impl` must be marked `default`
2019-12-19T05:49:36.6925223Z 
2019-12-19T05:49:36.6925610Z error[E0520]: `flush` specializes an item from a parent `impl`, but that item is not marked `default`
2019-12-19T05:49:36.6926520Z    --> src/libstd/io/cursor.rs:391:5
2019-12-19T05:49:36.6926935Z     |
2019-12-19T05:49:36.6927455Z 391 |       fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6928262Z     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot specialize default item `flush`
2019-12-19T05:49:36.6928748Z ...
2019-12-19T05:49:36.6929427Z 396 | / impl<T: AsMut<[u8]>> Write for Cursor<T> {
2019-12-19T05:49:36.6929995Z 397 | |     #[inline]
2019-12-19T05:49:36.6930446Z 398 | |     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
2019-12-19T05:49:36.6930959Z 399 | |         self.inner.as_mut().write(buf)
2019-12-19T05:49:36.6931400Z ...   |
2019-12-19T05:49:36.6931815Z 408 | |     fn flush(&mut self) -> io::Result<()> { Ok(()) }
2019-12-19T05:49:36.6932952Z     | |_- parent `impl` is here
2019-12-19T05:49:36.6933120Z     |
2019-12-19T05:49:36.6933120Z     |
2019-12-19T05:49:36.6933378Z     = note: to specialize, `flush` in the parent `impl` must be marked `default`
2019-12-19T05:49:38.0510388Z error: aborting due to 12 previous errors
2019-12-19T05:49:38.0511028Z 
2019-12-19T05:49:38.0511573Z For more information about this error, try `rustc --explain E0520`.
2019-12-19T05:49:38.0641661Z error: could not compile `std`.
---
2019-12-19T05:49:38.0772107Z   local time: Thu Dec 19 05:49:38 UTC 2019
2019-12-19T05:49:38.3520683Z   network time: Thu, 19 Dec 2019 05:49:38 GMT
2019-12-19T05:49:38.3525152Z == end clock drift check ==
2019-12-19T05:49:46.1078948Z 
2019-12-19T05:49:46.1191887Z ##[error]Bash exited with code '1'.
2019-12-19T05:49:46.1223432Z ##[section]Starting: Checkout
2019-12-19T05:49:46.1225487Z ==============================================================================
2019-12-19T05:49:46.1225548Z Task         : Get sources
2019-12-19T05:49:46.1225597Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

kennytm · 2019-12-19T06:12:11Z

Please explain why this impl should be added to std in the PR description (I've found no associated issues or RFCs or IRLO posts). Also please use a better PR title.

This new AsMut-based impl will take over all four existing impls. They need to be removed before this PR passes.

impl Write for Cursor<&mut [u8]> {}
impl Write for Cursor<&mut Vec<u8>> {}
impl Write for Cursor<Vec<u8>> {}
impl Write for Cursor<Box<[u8]>> {}

The feature name should not be rust1. This new AsMut is not stabilized at 1.0.0.

cc #27197, #27897, rust-lang/futures-rs#1109.

r? @alexcrichton

dtolnay · 2020-01-10T07:37:31Z

r? dtolnay

dtolnay

This breaks the existing implementations for Cursor<&mut Vec<u8>> and Cursor<Vec<u8>>, whose Write impl currently grows the Vec if needed. Converting those to go through &mut [u8]'s Write impl via AsMut<[u8]> loses the ability to grow the backing Vec.

Thanks anyway!

…lnay Implement `Write for Cursor<[u8; N]>`, plus `A: Allocator` cursor support This implements `Write for Cursor<[u8; N]>`, and also adds support for generic `A: Allocator` in `Box` and `Vec` cursors. This was inspired by a user questioning why they couldn't write a `Cursor<[u8; N]>`: https://users.rust-lang.org/t/why-vec-and-not-u8-makes-cursor-have-write/68210 Related history: - rust-lang#27197 switched `AsRef<[u8]>` for reading and seeking - rust-lang#67415 tried to use `AsMut<[u8]>` for writing, but did not specialize `Vec`.

Update cursor.rs

78571d3

rust-highfive assigned kennytm Dec 19, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Dec 19, 2019

kennytm added needs-fcp This change is insta-stable, so needs a completed FCP to proceed. T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. labels Dec 19, 2019

rust-highfive assigned alexcrichton and unassigned kennytm Dec 19, 2019

Dylan-DPC-zz 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 Dec 21, 2019

dtolnay reviewed Jan 10, 2020

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dtolnay assigned dtolnay and unassigned alexcrichton Jan 10, 2020

dtolnay closed this Jan 10, 2020

cuviper mentioned this pull request Jan 8, 2022

Implement Write for Cursor<[u8; N]>, plus A: Allocator cursor support #92663

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Update cursor.rs #67415

Update cursor.rs #67415

LuoZijun commented Dec 19, 2019

rust-highfive commented Dec 19, 2019

rust-highfive commented Dec 19, 2019

kennytm commented Dec 19, 2019

dtolnay commented Jan 10, 2020

dtolnay left a comment

Update cursor.rs #67415

Update cursor.rs #67415

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LuoZijun commented Dec 19, 2019

rust-highfive commented Dec 19, 2019

rust-highfive commented Dec 19, 2019

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