Avoid a cast in `ptr::slice_from_raw_parts(_mut)` by scottmcm · Pull Request #124795

Avoid a cast in `ptr::slice_from_raw_parts(_mut)` by scottmcm · Pull Request #124795 · rust-lang/rust

Casting to `*const ()` or `*mut ()` just bloats the MIR, so let's not.

If ACP#362 goes through we can keep calling `ptr::from_raw_parts(_mut)` in these also without the cast, but that hasn't had any libs-api attention yet, so I'm not waiting on it.

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May 6, 2024

bors added a commit to rust-lang-ci/rust that referenced this pull request

May 7, 2024

…ts, r=<try>

Avoid a cast in `ptr::slice_from_raw_parts(_mut)`

Casting to `*const ()` or `*mut ()` is no longer needed after rust-lang#123840 so let's make the MIR smaller (and more inline-able, as seen in the tests).

If [ACP#362](rust-lang/libs-team#362) goes through we can keep calling `ptr::from_raw_parts(_mut)` in these also without the cast, but that hasn't had any libs-api attention yet, so I'm not waiting on it.

bors added S-waiting-on-bors

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and removed S-waiting-on-review

Status: Awaiting review from the assignee but also interested parties.

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May 8, 2024

scottmcm deleted the simplify-slice-from-raw-parts branch

May 9, 2024 16:46

fmease added a commit to fmease/rust that referenced this pull request

May 29, 2024

…=WaffleLapkin

[ACP 362] genericize `ptr::from_raw_parts`

This implements rust-lang/libs-team#362

As such, it can partially undo rust-lang#124795 , letting `slice_from_raw_parts` just call `from_raw_parts` again without re-introducing the unnecessary cast to MIR.

By doing this it also removes a spurious cast from `str::from_raw_parts`.  And I think it does a good job of showing the value of the ACP, since the only thing that needed new turbofishing because of this is inside `ptr::null(_mut)`, but only because `ptr::without_provenance(_mut)` doesn't support pointers to extern types, which it absolutely could (without even changing the implementation).

fmease added a commit to fmease/rust that referenced this pull request

May 29, 2024

…=WaffleLapkin

[ACP 362] genericize `ptr::from_raw_parts`

This implements rust-lang/libs-team#362

As such, it can partially undo rust-lang#124795 , letting `slice_from_raw_parts` just call `from_raw_parts` again without re-introducing the unnecessary cast to MIR.

By doing this it also removes a spurious cast from `str::from_raw_parts`.  And I think it does a good job of showing the value of the ACP, since the only thing that needed new turbofishing because of this is inside `ptr::null(_mut)`, but only because `ptr::without_provenance(_mut)` doesn't support pointers to extern types, which it absolutely could (without even changing the implementation).

rust-timer added a commit to rust-lang-ci/rust that referenced this pull request

May 30, 2024

Rollup merge of rust-lang#125701 - scottmcm:generic-from-raw-parts, r=WaffleLapkin

[ACP 362] genericize `ptr::from_raw_parts`

This implements rust-lang/libs-team#362

As such, it can partially undo rust-lang#124795 , letting `slice_from_raw_parts` just call `from_raw_parts` again without re-introducing the unnecessary cast to MIR.

By doing this it also removes a spurious cast from `str::from_raw_parts`.  And I think it does a good job of showing the value of the ACP, since the only thing that needed new turbofishing because of this is inside `ptr::null(_mut)`, but only because `ptr::without_provenance(_mut)` doesn't support pointers to extern types, which it absolutely could (without even changing the implementation).

flip1995 pushed a commit to flip1995/rust-clippy that referenced this pull request

Jun 28, 2024

…pkin

[ACP 362] genericize `ptr::from_raw_parts`

This implements rust-lang/libs-team#362

As such, it can partially undo rust-lang/rust#124795 , letting `slice_from_raw_parts` just call `from_raw_parts` again without re-introducing the unnecessary cast to MIR.

By doing this it also removes a spurious cast from `str::from_raw_parts`.  And I think it does a good job of showing the value of the ACP, since the only thing that needed new turbofishing because of this is inside `ptr::null(_mut)`, but only because `ptr::without_provenance(_mut)` doesn't support pointers to extern types, which it absolutely could (without even changing the implementation).