Update RAPx toolchain to nightly-2026-02-05 (#690)

This pr mainly follows the latest verify-rust-std toolchain update.

- Bumped RAPx CI to RAPx 0.7.50 on nightly-2026-02-05.
- Slightly refined several contracts related to Challenge 17 to make
them more compact and accurate.

Author: hxuhack

.github/pull_requests.toml

@@ -18,5 +18,6 @@ members = [
     "btj",
     "rafaelsamenezes",
     "lucasccordeiro",
-    "dkcumming"
+    "dkcumming",
+    "DiuDiu777"
 ]

.github/workflows/rapx.yml

@@ -8,8 +8,8 @@ on:
     branches: [main]
 
 env:
-  RAPX_VERSION: "0.7.38"
-  TOOLCHAIN: "nightly-2025-11-25"
+  RAPX_VERSION: "0.7.50"
+  TOOLCHAIN: "nightly-2026-02-05"
 
 jobs:
   verify-slice:

library/core/src/slice/mod.rs

@@ -649,7 +649,7 @@ impl<T> [T] {
     #[track_caller]
     #[rustc_const_unstable(feature = "const_index", issue = "143775")]
     #[cfg_attr(rapx, rapx::verify)]
-    #[cfg_attr(rapx, rapx::requires(InBound(index_access(self, index))))]
+    #[cfg_attr(rapx, rapx::requires(InBound(self, index)))]
     pub const unsafe fn get_unchecked<I>(&self, index: I) -> &I::Output
     where
         I: [const] SliceIndex<Self>,
@@ -696,7 +696,7 @@ impl<T> [T] {
     #[track_caller]
     #[rustc_const_unstable(feature = "const_index", issue = "143775")]
     #[cfg_attr(rapx, rapx::verify)]
-    #[cfg_attr(rapx, rapx::requires(InBound(index_access(self, index))))]
+    #[cfg_attr(rapx, rapx::requires(InBound(self, index)))]
     pub const unsafe fn get_unchecked_mut<I>(&mut self, index: I) -> &mut I::Output
     where
         I: [const] SliceIndex<Self>,
@@ -5261,7 +5261,7 @@ impl<T> [T] {
     #[inline]
     #[track_caller]
     #[cfg_attr(rapx, rapx::verify)]
-    #[cfg_attr(rapx, rapx::requires(InBound(index_access(self, indices))))]
+    #[cfg_attr(rapx, rapx::requires(InBound(self, indices)))]
     #[cfg_attr(rapx, rapx::requires(NonOverlap(indices)))]
     pub unsafe fn get_disjoint_unchecked_mut<I, const N: usize>(
         &mut self,

library/core/src/slice/raw.rs

@@ -124,7 +124,7 @@ use crate::{array, ptr, ub_checks};
 #[cfg_attr(rapx, rapx::requires(NonNull(data)))]
 #[cfg_attr(rapx, rapx::requires(ValidPtr(data, T, len)))]
 #[cfg_attr(rapx, rapx::requires(Init(data, T, len)))]
-#[cfg_attr(rapx, rapx::requires(Alive(data)))]
+#[cfg_attr(rapx, rapx::requires(Alive(data, 'a)))]
 #[cfg_attr(rapx, rapx::requires(Alias(data)))]
 #[cfg_attr(rapx, rapx::requires(Align(data, T)))]
 #[cfg_attr(rapx, rapx::requires(ValidNum(size_of(T) * len <= isize::MAX)))]
@@ -186,7 +186,7 @@ pub const unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T]
 #[cfg_attr(rapx, rapx::requires(NonNull(data)))]
 #[cfg_attr(rapx, rapx::requires(ValidPtr(data, T, len)))]
 #[cfg_attr(rapx, rapx::requires(Init(data, T, len)))]
-#[cfg_attr(rapx, rapx::requires(Alive(data)))]
+#[cfg_attr(rapx, rapx::requires(Alive(data, 'a)))]
 #[cfg_attr(rapx, rapx::requires(Alias(data)))]
 #[cfg_attr(rapx, rapx::requires(Align(data, T)))]
 #[cfg_attr(rapx, rapx::requires(ValidNum(size_of(T) * len <= isize::MAX)))]