Clean up warnings + unsafe_op_in_unsafe_fn when building std for armv6k-nintendo-3ds

[ian-h-chamberlain]

See #127747

ping @AzureMarker @Meziu

I could only find one instance needing an extra unsafe that was not also shared with many other unix targets (presumably these will get covered in larger sweeping changes, I didn't want to introduce churn that would potentially conflict with those). The one codepath I found is shared with vita however, so also pinging @nikarh @pheki @zetanumbers just to make sure they're aware of this change.

Also removed one unused import from process_unsupported which should simply fix the warning for any target that uses it.

[rustbot]

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[tgross35]

What/when does this flag? It seems like either it should apply to only a couple objects, or the whole module should be disabled in some cases

[ian-h-chamberlain]

Fair point, actually revisiting this I am surprised it warned at all:

error: struct `stat` is never constructed
  --> library/std/src/os/horizon/raw.rs:41:12
   |
41 | pub struct stat {
   |            ^^^^
   |
   = note: `stat` has a derived impl for the trait `Clone`, but this is intentionally ignored during dead code analysis
   = note: `-D dead-code` implied by `-D warnings`
   = help: to override `-D warnings` add `#[allow(dead_code)]`

warning: `std` (lib) generated 1 warning

Shouldn't pub struct normally avoid emitting a dead_code warning?

I can move the attribute to just that struct, but is this actually some kind of compiler regression or am I missing something?

[Meziu]

Shouldn't pub struct normally avoid emitting a dead_code warning?

@ian-h-chamberlain The raw module is only exported at a crate-level. As such, if never built, the compiler will complain about unused members (such as the stat struct) because they aren't actually publicly accessible API.

[tgross35]

Oh, I see - most os crates have their raw module public, Horizon is special in pub(crate) since this module was added after std::os::raw was already deprecated. So I guess it's just around for consistency, per #95897 (comment).

So this seems fine to me, but could you add a note explaining this? Or just update the crate's docstring.

Has this just been a warning for a while then? Assuming nothing in this PR is making it suddenly start to fire.

[ian-h-chamberlain]

Yes, I think this warning has been present since the module was added — at the time, there were a lot of other warnings when building for this target, but they've mostly been cleaned up now and this was the last remaining warning.

I've moved the #[allow] to be more specific and added a comment.

[tgross35]

Thanks for the change!

[tgross35]

One other thing, could you add a #![forbid(unsafe_op_in_unsafe_fn)] in library/std/src/os/horizon/mod.rs to match the others that have been updating?

[tgross35]

@bors r+

[bors]

📌 Commit dba6b74 has been approved by tgross35

It is now in the queue for this repository.

[tgross35]

@bors rollup