Add more docs on fix safety

crates/ruff_linter/src/rules/ruff/rules/sort_dunder_all.rs

@@ -54,8 +54,13 @@ use crate::rules::ruff::rules::sequence_sorting::{
 ///
 /// ## Fix safety
 /// This rule's fix is marked as always being safe, in that
-/// it should never alter the semantics of any Python code.
-/// However, note that for multiline `__all__` definitions
+/// it should very rarely alter the semantics of any Python code.
+/// However, note that (although it's rare) the value of `__all__`
+/// could be read by code elsewhere that depends on the exact
+/// iteration order of the items in `__all__`, in which case this
+/// rule's fix could theoretically cause breakage.
+///
+/// Note also that for multiline `__all__` definitions
 /// that include comments on their own line, it can be hard
 /// to tell where the comments should be moved to when sorting
 /// the contents of `__all__`. While this rule's fix will

crates/ruff_linter/src/rules/ruff/rules/sort_dunder_slots.rs

@@ -34,6 +34,26 @@ use itertools::izip;
 /// class Dog:
 ///     __slots__ = "breed", "name"
 /// ```
+///
+/// ## Fix safety
+/// This rule's fix is marked as unsafe whenever Ruff can detect that code
+/// elsewhere in the same file reads the `__slots__` variable in some way.
+/// This is because the order of the items in `__slots__` may have semantic
+/// significance if the `__slots__` of a class is being iterated over, or
+/// being assigned to another value.
+///
+/// In the vast majority of other cases, this rule's fix is unlikely to
+/// cause breakage; as such, Ruff will otherwise mark this rule's fix as
+/// safe. However, note that (although it's rare) the value of `__slots__`
+/// could still be read by code outside of the module in which the
+/// `__slots__` definition occurs, in which case this rule's fix could
+/// theoretically cause breakage.
+///
+/// Additionally, note that for multiline `__slots__` definitions that
+/// include comments on their own line, it can be hard to tell where the
+/// comments should be moved to when sorting the contents of `__slots__`.
+/// While this rule's fix will never delete a comment, it might *sometimes*
+/// move a comment to an unexpected location.
 #[violation]
 pub struct UnsortedDunderSlots {
     class_name: ast::name::Name,