r? @thomcc

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Hey! It looks like you've submitted a new PR for the library teams!

If this PR contains changes to any rust-lang/rust public library APIs then please comment with @rustbot label T-libs-api -T-libs to tag it appropriately. If this PR contains changes to any unstable APIs please edit the PR description to add a link to the relevant API Change Proposal or create one if you haven't already. If you're unsure where your change falls no worries, just leave it as is and the reviewer will take a look and make a decision to forward on if necessary.

Examples of T-libs-api changes:

• Stabilizing library features
• Introducing insta-stable changes such as new implementations of existing stable traits on existing stable types
• Introducing new or changing existing unstable library APIs (excluding permanently unstable features / features without a tracking issue)
• Changing public documentation in ways that create new stability guarantees
• Changing observable runtime behavior of library APIs

@rustbot label T-libs-api -T-libs

The job x86_64-gnu-llvm-13 failed! Check out the build log: (web) (plain)

error[E0133]: call to unsafe function is unsafe and requires unsafe block
  --> library/core/src/str/raw.rs:95:60
   |
89 |     unsafe {
   |     ------ items do not inherit unsafety from separate enclosing items
...
95 |                 && super::validations::run_utf8_validation(crate::slice::from_raw_parts(data, len)).is_ok()
   |
   = note: consult the function's documentation for information on how to avoid undefined behavior

error[E0133]: call to unsafe function is unsafe and requires unsafe block
error[E0133]: call to unsafe function is unsafe and requires unsafe block
   --> library/core/src/str/raw.rs:145:60
    |
139 |     unsafe {
    |     ------ items do not inherit unsafety from separate enclosing items
...
145 |                 && super::validations::run_utf8_validation(crate::slice::from_raw_parts(data, len)).is_ok()
    |
    = note: consult the function's documentation for information on how to avoid undefined behavior

For more information about this error, try `rustc --explain E0133`.

Can you file an ACP? NM, see rust-lang/libs-team#167.

For the docs could you add something like, "if there is any doubt that the incoming data may not be UTF-8, prefer str::from_utf8(slice::from_raw_parts(ptr, len)) instead", to point people in the right diretion?

Also, I think it would be better to provide a short summary of the safety requirements and then point to slice::from_raw_parts{mut} for the details rather than duplicating the documentation.

any update on this? would be very nice to have

I've opened a tracking issue: #119206