The HermitOS' IO interface is similiar to Unix. Consequently,
this PR synchronize the FD implementation between both.

…es are in scope

These tests might have originally been useful as an implementation aid, but now
they don't provide enough value to justify the burden of updating them as the
underlying code changes.

The code they test is still exercised by the main end-to-end coverage tests.

Using `pub(super)` makes it harder to move code between modules, and doesn't
provide much privacy benefit over `pub(crate)`.

Co-authored-by: Jubilee <[email protected]>

…=nnethercote

Resolve elided lifetimes in assoc const to static if no other lifetimes are in scope

Implements the change to elided lifetime resolution in *associated consts* subject to FCP here: rust-lang#125190 (comment)

Specifically, walk the enclosing lifetime ribs in an associated const, and if we find no other lifetimes, then resolve to `'static`.

Also make it work for traits, but don't lint -- just give a hard error in that case.

docs(change): Don't mention a Cargo 2024 edition change for 1.79

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doc: Added commas where needed

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export std::os::fd module on HermitOS

The HermitOS' IO interface is similiar to Unix. Consequently, this PR synchronize the FD implementation between both.

closes rust-lang#126198

div_euclid, rem_euclid: clarify/extend documentation

…gjubilee

Add codegen test for `Request::provide_*`

Codegen before & after rust-lang#126242: https://gist.github.com/slanterns/3789ee36f59ed834e1a6bd4677b68ed4.

Also adjust an outdated comment since `tag_id` is no longer attached to `TaggedOption` via `Erased`, but stored next to it in `Tagged` under the new implementation.

My first time writing FileCheck xD. Correct me if there is anything that should be amended.

r? libs

coverage: Arrange span extraction/refinement as a series of passes

The old code for extracting/refining coverage spans from MIR has been dismantled and split up into several passes (e.g. see rust-lang#126294), but because this was done incrementally, the resulting code is disorganised.

This PR addresses that by moving the main control-flow into a single function (`coverage::spans::extract_refined_covspans`) that more clearly shows the process as a series of separate steps, most delegated to helper functions in the same file.

This should make it easier to understand and modify the refinement process. It also means that submodule `from_mir` is now only concerned with the details of extracting relevant spans from the various kinds of MIR statement/terminator.

There should be no change to the resulting coverage maps, as demonstrated by the lack of changes to tests.

coverage: Several small improvements to graph code

This PR combines a few small improvements to coverage graph handling code:
- Remove some low-value implementation tests that were getting in the way of other changes.
- Clean up `pub` visibility.
- Flatten some code using let-else.
- Prefer `.copied()` over `.cloned()`.

`@rustbot` label +A-code-coverage