Don't run MIR unsafeck at all when using -Zthir-unsafeck

[LeSeulArtichaut]

I don't know how I missed this :D
r? @oli-obk

[oli-obk]

Huh 😄

how does it then work that we don't see MIR unsafeck messages with -Zthir-unsafeck? Do we abort compilation before we get there if there are any errors?

[LeSeulArtichaut]

That's because the unsafety_check_result query doesn't actually report any errors, that is left to the check_unsafety function:

rust/compiler/rustc_mir/src/transform/check_unsafety.rs

Lines 506 to 570 in aea2e44

	pub fn check_unsafety(tcx: TyCtxt<'_>, def_id: LocalDefId) {
	debug!("check_unsafety({:?})", def_id);
	// closures are handled by their parent fn.
	if tcx.is_closure(def_id.to_def_id()) {
	return;
	}
	let UnsafetyCheckResult { violations, unsafe_blocks } = tcx.unsafety_check_result(def_id);
	for &UnsafetyViolation { source_info, lint_root, kind, details } in violations.iter() {
	let (description, note) = details.description_and_note();
	// Report an error.
	let unsafe_fn_msg =
	if unsafe_op_in_unsafe_fn_allowed(tcx, lint_root) { " function or" } else { "" };
	match kind {
	UnsafetyViolationKind::General => {
	// once
	struct_span_err!(
	tcx.sess,
	source_info.span,
	E0133,
	"{} is unsafe and requires unsafe{} block",
	description,
	unsafe_fn_msg,
	)
	.span_label(source_info.span, description)
	.note(note)
	.emit();
	}
	UnsafetyViolationKind::UnsafeFn => tcx.struct_span_lint_hir(
	UNSAFE_OP_IN_UNSAFE_FN,
	lint_root,
	source_info.span,
	|lint| {
	lint.build(&format!(
	"{} is unsafe and requires unsafe block (error E0133)",
	description,
	))
	.span_label(source_info.span, description)
	.note(note)
	.emit();
	},
	),
	}
	}
	let (mut unsafe_used, mut unsafe_unused): (FxHashSet<_>, Vec<_>) = Default::default();
	for &(block_id, is_used) in unsafe_blocks.iter() {
	if is_used {
	unsafe_used.insert(block_id);
	} else {
	unsafe_unused.push(block_id);
	}
	}
	// The unused unsafe blocks might not be in source order; sort them so that the unused unsafe
	// error messages are properly aligned and the issue-45107 and lint-unused-unsafe tests pass.
	unsafe_unused.sort_by_cached_key(|hir_id| tcx.hir().span(*hir_id));
	for &block_id in &unsafe_unused {
	report_unused_unsafe(tcx, &unsafe_used, block_id);
	}
	}

[oli-obk]

@bors r+

[bors]

📌 Commit 40b57be has been approved by oli-obk