on a signed deref check, mention the right pointer in the error

RalfJung · RalfJung · commit 34d25b051e28 · 2024-08-01T14:25:19.000+02:00
diff --git a/src/alloc_addresses/mod.rs b/src/alloc_addresses/mod.rs
@@ -105,15 +105,17 @@ impl<'tcx> EvalContextExtPriv<'tcx> for crate::MiriInterpCx<'tcx> {}
 trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
     // Returns the exposed `AllocId` that corresponds to the specified addr,
     // or `None` if the addr is out of bounds
-    fn alloc_id_from_addr(&self, addr: u64) -> Option<AllocId> {
+    fn alloc_id_from_addr(&self, addr: u64, size: i64) -> Option<AllocId> {
         let ecx = self.eval_context_ref();
         let global_state = ecx.machine.alloc_addresses.borrow();
         assert!(global_state.provenance_mode != ProvenanceMode::Strict);
 
+        // We always search the allocation to the right of this address. So if the size is structly
+        // negative, we have to search for `addr-1` instead.
+        let addr = if size >= 0 { addr } else { addr.saturating_sub(1) };
         let pos = global_state.int_to_ptr_map.binary_search_by_key(&addr, |(addr, _)| *addr);
 
         // Determine the in-bounds provenance for this pointer.
-        // (This is only called on an actual access, so in-bounds is the only possible kind of provenance.)
         let alloc_id = match pos {
             Ok(pos) => Some(global_state.int_to_ptr_map[pos].1),
             Err(0) => None,
@@ -318,7 +320,11 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
 
     /// When a pointer is used for a memory access, this computes where in which allocation the
     /// access is going.
-    fn ptr_get_alloc(&self, ptr: interpret::Pointer<Provenance>) -> Option<(AllocId, Size)> {
+    fn ptr_get_alloc(
+        &self,
+        ptr: interpret::Pointer<Provenance>,
+        size: i64,
+    ) -> Option<(AllocId, Size)> {
         let ecx = self.eval_context_ref();
 
         let (tag, addr) = ptr.into_parts(); // addr is absolute (Tag provenance)
@@ -327,7 +333,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
             alloc_id
         } else {
             // A wildcard pointer.
-            ecx.alloc_id_from_addr(addr.bytes())?
+            ecx.alloc_id_from_addr(addr.bytes(), size)?
         };
 
         // This cannot fail: since we already have a pointer with that provenance, adjust_alloc_root_pointer
diff --git a/src/borrow_tracker/stacked_borrows/mod.rs b/src/borrow_tracker/stacked_borrows/mod.rs
@@ -673,7 +673,7 @@ trait EvalContextPrivExt<'tcx, 'ecx>: crate::MiriInterpCxExt<'tcx> {
             // attempt to use it for a non-zero-sized access.
             // Dangling slices are a common case here; it's valid to get their length but with raw
             // pointer tagging for example all calls to get_unchecked on them are invalid.
-            if let Ok((alloc_id, base_offset, orig_tag)) = this.ptr_try_get_alloc_id(place.ptr()) {
+            if let Ok((alloc_id, base_offset, orig_tag)) = this.ptr_try_get_alloc_id(place.ptr(), 0) {
                 log_creation(this, Some((alloc_id, base_offset, orig_tag)))?;
                 // Still give it the new provenance, it got retagged after all.
                 return Ok(Some(Provenance::Concrete { alloc_id, tag: new_tag }));
@@ -685,7 +685,7 @@ trait EvalContextPrivExt<'tcx, 'ecx>: crate::MiriInterpCxExt<'tcx> {
             }
         }
 
-        let (alloc_id, base_offset, orig_tag) = this.ptr_get_alloc_id(place.ptr())?;
+        let (alloc_id, base_offset, orig_tag) = this.ptr_get_alloc_id(place.ptr(), 0)?;
         log_creation(this, Some((alloc_id, base_offset, orig_tag)))?;
 
         trace!(
diff --git a/src/borrow_tracker/tree_borrows/mod.rs b/src/borrow_tracker/tree_borrows/mod.rs
@@ -223,7 +223,7 @@ trait EvalContextPrivExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         };
 
         trace!("Reborrow of size {:?}", ptr_size);
-        let (alloc_id, base_offset, parent_prov) = match this.ptr_try_get_alloc_id(place.ptr()) {
+        let (alloc_id, base_offset, parent_prov) = match this.ptr_try_get_alloc_id(place.ptr(), 0) {
             Ok(data) => {
                 // Unlike SB, we *do* a proper retag for size 0 if can identify the allocation.
                 // After all, the pointer may be lazily initialized outside this initial range.
diff --git a/src/concurrency/data_race.rs b/src/concurrency/data_race.rs
@@ -1180,7 +1180,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
         // We avoid `get_ptr_alloc` since we do *not* want to run the access hooks -- the actual
         // access will happen later.
         let (alloc_id, _offset, _prov) = this
-            .ptr_try_get_alloc_id(place.ptr())
+            .ptr_try_get_alloc_id(place.ptr(), 0)
             .expect("there are no zero-sized atomic accesses");
         if this.get_alloc_mutability(alloc_id)? == Mutability::Not {
             // See if this is fine.
@@ -1307,7 +1307,7 @@ trait EvalContextPrivExt<'tcx>: MiriInterpCxExt<'tcx> {
         if let Some(data_race) = &this.machine.data_race {
             if data_race.race_detecting() {
                 let size = place.layout.size;
-                let (alloc_id, base_offset, _prov) = this.ptr_get_alloc_id(place.ptr())?;
+                let (alloc_id, base_offset, _prov) = this.ptr_get_alloc_id(place.ptr(), 0)?;
                 // Load and log the atomic operation.
                 // Note that atomic loads are possible even from read-only allocations, so `get_alloc_extra_mut` is not an option.
                 let alloc_meta = this.get_alloc_extra(alloc_id)?.data_race.as_ref().unwrap();
diff --git a/src/concurrency/weak_memory.rs b/src/concurrency/weak_memory.rs
@@ -468,7 +468,7 @@ pub(super) trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         init: Scalar,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
-        let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr())?;
+        let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr(), 0)?;
         if let (
             crate::AllocExtra { weak_memory: Some(alloc_buffers), .. },
             crate::MiriMachine { data_race: Some(global), threads, .. },
@@ -495,7 +495,7 @@ pub(super) trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
     ) -> InterpResult<'tcx, Scalar> {
         let this = self.eval_context_ref();
         if let Some(global) = &this.machine.data_race {
-            let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr())?;
+            let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr(), 0)?;
             if let Some(alloc_buffers) = this.get_alloc_extra(alloc_id)?.weak_memory.as_ref() {
                 if atomic == AtomicReadOrd::SeqCst {
                     global.sc_read(&this.machine.threads);
@@ -535,7 +535,7 @@ pub(super) trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         init: Scalar,
     ) -> InterpResult<'tcx> {
         let this = self.eval_context_mut();
-        let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(dest.ptr())?;
+        let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(dest.ptr(), 0)?;
         if let (
             crate::AllocExtra { weak_memory: Some(alloc_buffers), .. },
             crate::MiriMachine { data_race: Some(global), threads, .. },
@@ -585,7 +585,7 @@ pub(super) trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 global.sc_read(&this.machine.threads);
             }
             let size = place.layout.size;
-            let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr())?;
+            let (alloc_id, base_offset, ..) = this.ptr_get_alloc_id(place.ptr(), 0)?;
             if let Some(alloc_buffers) = this.get_alloc_extra(alloc_id)?.weak_memory.as_ref() {
                 let buffer = alloc_buffers
                     .get_or_create_store_buffer(alloc_range(base_offset, size), init)?;
diff --git a/src/machine.rs b/src/machine.rs
@@ -1198,19 +1198,23 @@ impl<'tcx> Machine<'tcx> for MiriMachine<'tcx> {
         }
     }
 
-    /// Convert a pointer with provenance into an allocation-offset pair,
-    /// or a `None` with an absolute address if that conversion is not possible.
+    /// Convert a pointer with provenance into an allocation-offset pair and extra provenance info.
+    /// `size` says how many bytes of memory are expected at that pointer. The *sign* of `size` can
+    /// be used to disambiguate situations where a wildcard pointer sits right in between two
+    /// allocations.
     ///
-    /// This is called when a pointer is about to be used for memory access,
-    /// an in-bounds check, or anything else that requires knowing which allocation it points to.
+    /// If `ptr.provenance.get_alloc_id()` is `Some(p)`, the returned `AllocId` must be `p`.
     /// The resulting `AllocId` will just be used for that one step and the forgotten again
     /// (i.e., we'll never turn the data returned here back into a `Pointer` that might be
     /// stored in machine state).
+    ///
+    /// When this fails, that means the pointer does not point to a live allocation.
     fn ptr_get_alloc(
         ecx: &MiriInterpCx<'tcx>,
         ptr: StrictPointer,
+        size: i64,
     ) -> Option<(AllocId, Size, Self::ProvenanceExtra)> {
-        let rel = ecx.ptr_get_alloc(ptr);
+        let rel = ecx.ptr_get_alloc(ptr, size);
 
         rel.map(|(alloc_id, size)| {
             let tag = match ptr.provenance {
diff --git a/src/shims/backtrace.rs b/src/shims/backtrace.rs
@@ -116,7 +116,7 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
 
         let ptr = this.read_pointer(ptr)?;
         // Take apart the pointer, we need its pieces. The offset encodes the span.
-        let (alloc_id, offset, _prov) = this.ptr_get_alloc_id(ptr)?;
+        let (alloc_id, offset, _prov) = this.ptr_get_alloc_id(ptr, 0)?;
 
         // This has to be an actual global fn ptr, not a dlsym function.
         let fn_instance = if let Some(GlobalAlloc::Function { instance, .. }) =
diff --git a/src/shims/foreign_items.rs b/src/shims/foreign_items.rs
@@ -278,7 +278,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
             "miri_get_alloc_id" => {
                 let [ptr] = this.check_shim(abi, Abi::Rust, link_name, args)?;
                 let ptr = this.read_pointer(ptr)?;
-                let (alloc_id, _, _) = this.ptr_get_alloc_id(ptr).map_err(|_e| {
+                let (alloc_id, _, _) = this.ptr_get_alloc_id(ptr, 0).map_err(|_e| {
                     err_machine_stop!(TerminationInfo::Abort(format!(
                         "pointer passed to `miri_get_alloc_id` must not be dangling, got {ptr:?}"
                     )))
@@ -311,7 +311,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
             "miri_static_root" => {
                 let [ptr] = this.check_shim(abi, Abi::Rust, link_name, args)?;
                 let ptr = this.read_pointer(ptr)?;
-                let (alloc_id, offset, _) = this.ptr_get_alloc_id(ptr)?;
+                let (alloc_id, offset, _) = this.ptr_get_alloc_id(ptr, 0)?;
                 if offset != Size::ZERO {
                     throw_unsup_format!(
                         "pointer passed to `miri_static_root` must point to beginning of an allocated block"
@@ -392,7 +392,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
                         "`miri_promise_symbolic_alignment`: pointer is not actually aligned"
                     );
                 }
-                if let Ok((alloc_id, offset, ..)) = this.ptr_try_get_alloc_id(ptr) {
+                if let Ok((alloc_id, offset, ..)) = this.ptr_try_get_alloc_id(ptr, 0) {
                     let (_size, alloc_align, _kind) = this.get_alloc_info(alloc_id);
                     // If the newly promised alignment is bigger than the native alignment of this
                     // allocation, and bigger than the previously promised alignment, then set it.
@@ -584,8 +584,8 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 let n = Size::from_bytes(this.read_target_usize(n)?);
 
                 // C requires that this must always be a valid pointer (C18 §7.1.4).
-                this.ptr_get_alloc_id(left)?;
-                this.ptr_get_alloc_id(right)?;
+                this.ptr_get_alloc_id(left, 0)?;
+                this.ptr_get_alloc_id(right, 0)?;
 
                 let result = {
                     let left_bytes = this.read_bytes_ptr_strip_provenance(left, n)?;
@@ -612,7 +612,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 let val = val as u8;
 
                 // C requires that this must always be a valid pointer (C18 §7.1.4).
-                this.ptr_get_alloc_id(ptr)?;
+                this.ptr_get_alloc_id(ptr, 0)?;
 
                 if let Some(idx) = this
                     .read_bytes_ptr_strip_provenance(ptr, Size::from_bytes(num))?
@@ -639,7 +639,7 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 let val = val as u8;
 
                 // C requires that this must always be a valid pointer (C18 §7.1.4).
-                this.ptr_get_alloc_id(ptr)?;
+                this.ptr_get_alloc_id(ptr, 0)?;
 
                 let idx = this
                     .read_bytes_ptr_strip_provenance(ptr, Size::from_bytes(num))?
@@ -681,8 +681,8 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
 
                 // C requires that this must always be a valid pointer, even if `n` is zero, so we better check that.
                 // (This is more than Rust requires, so `mem_copy` is not sufficient.)
-                this.ptr_get_alloc_id(ptr_dest)?;
-                this.ptr_get_alloc_id(ptr_src)?;
+                this.ptr_get_alloc_id(ptr_dest, 0)?;
+                this.ptr_get_alloc_id(ptr_src, 0)?;
 
                 this.mem_copy(ptr_src, ptr_dest, Size::from_bytes(n), true)?;
                 this.write_pointer(ptr_dest, dest)?;
diff --git a/tests/fail-dep/libc/affinity.stderr b/tests/fail-dep/libc/affinity.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: memory access failed: expected a pointer to 129 bytes of memory, but got ALLOC and there are only 128 bytes starting at that pointer
+error: Undefined Behavior: memory access failed: expected a pointer to 129 bytes of memory, but got ALLOC which is only 128 bytes from the end of the allocation
   --> $DIR/affinity.rs:LL:CC
    |
 LL |     let err = unsafe { sched_setaffinity(PID, size_of::<cpu_set_t>() + 1, &cpuset) };
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: expected a pointer to 129 bytes of memory, but got ALLOC and there are only 128 bytes starting at that pointer
+   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: expected a pointer to 129 bytes of memory, but got ALLOC which is only 128 bytes from the end of the allocation
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/both_borrows/issue-miri-1050-1.stack.stderr b/tests/fail/both_borrows/issue-miri-1050-1.stack.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC and there are only 2 bytes starting at that pointer
+error: Undefined Behavior: out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC which is only 2 bytes from the end of the allocation
   --> RUSTLIB/alloc/src/boxed.rs:LL:CC
    |
 LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC and there are only 2 bytes starting at that pointer
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC which is only 2 bytes from the end of the allocation
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/both_borrows/issue-miri-1050-1.tree.stderr b/tests/fail/both_borrows/issue-miri-1050-1.tree.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC and there are only 2 bytes starting at that pointer
+error: Undefined Behavior: out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC which is only 2 bytes from the end of the allocation
   --> RUSTLIB/alloc/src/boxed.rs:LL:CC
    |
 LL |         Box(unsafe { Unique::new_unchecked(raw) }, alloc)
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC and there are only 2 bytes starting at that pointer
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC which is only 2 bytes from the end of the allocation
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/dangling_pointers/out_of_bounds_project.stderr b/tests/fail/dangling_pointers/out_of_bounds_project.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: out-of-bounds pointer arithmetic: expected a pointer to 8 bytes of memory, but got ALLOC and there are only 4 bytes starting at that pointer
+error: Undefined Behavior: out-of-bounds pointer arithmetic: expected a pointer to 8 bytes of memory, but got ALLOC which is only 4 bytes from the end of the allocation
   --> $DIR/out_of_bounds_project.rs:LL:CC
    |
 LL |         let _field = addr_of!((*ptr).2);
-   |                      ^^^^^^^^^^^^^^^^^^ out-of-bounds pointer arithmetic: expected a pointer to 8 bytes of memory, but got ALLOC and there are only 4 bytes starting at that pointer
+   |                      ^^^^^^^^^^^^^^^^^^ out-of-bounds pointer arithmetic: expected a pointer to 8 bytes of memory, but got ALLOC which is only 4 bytes from the end of the allocation
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/intrinsics/out_of_bounds_ptr_1.stderr b/tests/fail/intrinsics/out_of_bounds_ptr_1.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: out-of-bounds pointer arithmetic: expected a pointer to 5 bytes of memory, but got ALLOC and there are only 4 bytes starting at that pointer
+error: Undefined Behavior: out-of-bounds pointer arithmetic: expected a pointer to 5 bytes of memory, but got ALLOC which is only 4 bytes from the end of the allocation
   --> $DIR/out_of_bounds_ptr_1.rs:LL:CC
    |
 LL |     let x = unsafe { x.offset(5) };
-   |                      ^^^^^^^^^^^ out-of-bounds pointer arithmetic: expected a pointer to 5 bytes of memory, but got ALLOC and there are only 4 bytes starting at that pointer
+   |                      ^^^^^^^^^^^ out-of-bounds pointer arithmetic: expected a pointer to 5 bytes of memory, but got ALLOC which is only 4 bytes from the end of the allocation
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/intrinsics/out_of_bounds_ptr_3.rs b/tests/fail/intrinsics/out_of_bounds_ptr_3.rs
@@ -1,6 +1,6 @@
 fn main() {
     let v = [0i8; 4];
     let x = &v as *const i8;
-    let x = unsafe { x.offset(-1) }; //~ERROR: expected a pointer to 1 byte of memory
+    let x = unsafe { x.offset(-1) }; //~ERROR: expected a pointer to the end of 1 byte of memory
     panic!("this should never print: {:?}", x);
 }
diff --git a/tests/fail/intrinsics/out_of_bounds_ptr_3.stderr b/tests/fail/intrinsics/out_of_bounds_ptr_3.stderr
@@ -1,8 +1,8 @@
-error: Undefined Behavior: out-of-bounds pointer arithmetic: expected a pointer to 1 byte of memory, but got ALLOC-0x1 which points to before the beginning of the allocation
+error: Undefined Behavior: out-of-bounds pointer arithmetic: expected a pointer to the end of 1 byte of memory, but got ALLOC which is at the beginning of the allocation
   --> $DIR/out_of_bounds_ptr_3.rs:LL:CC
    |
 LL |     let x = unsafe { x.offset(-1) };
-   |                      ^^^^^^^^^^^^ out-of-bounds pointer arithmetic: expected a pointer to 1 byte of memory, but got ALLOC-0x1 which points to before the beginning of the allocation
+   |                      ^^^^^^^^^^^^ out-of-bounds pointer arithmetic: expected a pointer to the end of 1 byte of memory, but got ALLOC which is at the beginning of the allocation
    |
    = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
    = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
diff --git a/tests/fail/intrinsics/ptr_offset_from_different_ints.stderr b/tests/fail/intrinsics/ptr_offset_from_different_ints.stderr

Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,8 @@`
`1`		`-error: Undefined Behavior: memory access failed: expected a pointer to 129 bytes of memory, but got ALLOC and there are only 128 bytes starting at that pointer`
	`1`	`+error: Undefined Behavior: memory access failed: expected a pointer to 129 bytes of memory, but got ALLOC which is only 128 bytes from the end of the allocation`
`2`	`2`	`--> $DIR/affinity.rs:LL:CC`
`3`	`3`	`\|`
`4`	`4`	`LL \| let err = unsafe { sched_setaffinity(PID, size_of::<cpu_set_t>() + 1, &cpuset) };`
`5`		`- \| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: expected a pointer to 129 bytes of memory, but got ALLOC and there are only 128 bytes starting at that pointer`
	`5`	`+ \| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: expected a pointer to 129 bytes of memory, but got ALLOC which is only 128 bytes from the end of the allocation`
`6`	`6`	`\|`
`7`	`7`	`= help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior`
`8`	`8`	`= help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information`
Original file line number	Diff line number	Diff line change
`@@ -1,8 +1,8 @@`
`1`		`-error: Undefined Behavior: out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC and there are only 2 bytes starting at that pointer`
	`1`	`+error: Undefined Behavior: out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC which is only 2 bytes from the end of the allocation`
`2`	`2`	`--> RUSTLIB/alloc/src/boxed.rs:LL:CC`
`3`	`3`	`\|`
`4`	`4`	`LL \| Box(unsafe { Unique::new_unchecked(raw) }, alloc)`
`5`		`- \| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC and there are only 2 bytes starting at that pointer`
	`5`	`+ \| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ out-of-bounds pointer use: expected a pointer to 4 bytes of memory, but got ALLOC which is only 2 bytes from the end of the allocation`
`6`	`6`	`\|`
`7`	`7`	`= help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior`
`8`	`8`	`= help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information`