Rename Unsafe to Safety

[spastorino]

Alternative to #124455, which is to just have one Safety enum to use everywhere, this opens the posibility of adding ast::Safety::Safe that's useful for unsafe extern blocks.

This leaves us today with:

enum ast::Safety {
    Unsafe(Span),
    Default,
    // Safe (going to be added for unsafe extern blocks)
}

enum hir::Safety {
    Unsafe,
    Safe,
}

We would convert from ast::Safety::Default into the right Safety level according the context.

[rustbot]

r? @petrochenkov

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[rustbot]

Some changes occurred in need_type_info.rs

cc @lcnr

Some changes occurred in compiler/rustc_codegen_cranelift

cc @bjorn3

Some changes occurred to MIR optimizations

cc @rust-lang/wg-mir-opt

Some changes occurred in compiler/rustc_codegen_gcc

cc @antoyo, @GuillaumeGomez

Some changes occurred in src/librustdoc/clean/types.rs

cc @camelid

Some changes occurred in src/tools/rustfmt

cc @rust-lang/rustfmt

Some changes occurred in src/tools/clippy

cc @rust-lang/clippy

This PR changes Stable MIR

cc @oli-obk, @celinval, @ouz-a

HIR ty lowering was modified

cc @fmease

changes to the core type system

cc @compiler-errors, @lcnr

[spastorino]

r? @cjgillot

[spastorino]

I'm going to wait on a review and decision about this or #124455 or any other alternative before fixing CI and possible conflicts as it is a lot of work to keep all these in a mergeable state.

[bors]

☔ The latest upstream changes (presumably #125179) made this pull request unmergeable. Please resolve the merge conflicts.

[rustbot]

rust-analyzer is developed in its own repository. If possible, consider making this change to rust-lang/rust-analyzer instead.

cc @rust-lang/rust-analyzer

[jackh726]

r? jackh726

@bors r+

[bors]

📌 Commit 6b46a91 has been approved by jackh726

It is now in the queue for this repository.

[bors]

⌛ Testing commit 6b46a91 with merge eb1a5c9...

[bors]

☀️ Test successful - checks-actions
Approved by: jackh726
Pushing eb1a5c9 to master...

[rust-timer]

Finished benchmarking commit (eb1a5c9): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results (primary 3.3%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	3.3%	[3.3%, 3.3%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.3%	[3.3%, 3.3%]	1

Cycles

Results (primary 5.2%, secondary 6.3%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	5.2%	[5.2%, 5.2%]	1
Regressions ❌ (secondary)	6.3%	[5.7%, 6.8%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	5.2%	[5.2%, 5.2%]	1

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 669.868s -> 667.962s (-0.28%)
Artifact size: 316.05 MiB -> 316.23 MiB (0.06%)