diff --git a/src/tools/miri/src/helpers.rs b/src/tools/miri/src/helpers.rs
index 2b27400e9e362..308455feaf619 100644
--- a/src/tools/miri/src/helpers.rs
+++ b/src/tools/miri/src/helpers.rs
@@ -919,7 +919,9 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         if fn_abi.conv != exp_abi {
             throw_ub_format!(
                 "calling a function with ABI {:?} using caller ABI {:?}",
-                exp_abi, fn_abi.conv);
+                exp_abi,
+                fn_abi.conv
+            );
         }
         interp_ok(())
     }
@@ -964,6 +966,21 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
                 return interp_ok(());
             }
 
+            if ["__rust_alloc", "__rust_alloc_zeroed", "__rust_realloc", "__rust_dealloc"]
+                .contains(&link_name.as_str())
+            {
+                let attrs = self.eval_context_ref().tcx.codegen_fn_attrs(instance.def_id());
+                if attrs
+                    .linkage
+                    .map_or(false, |linkage| linkage == rustc_middle::mir::mono::Linkage::WeakAny)
+                    && attrs.flags.contains(CodegenFnAttrFlags::RUSTC_STD_INTERNAL_SYMBOL)
+                {
+                    // We intentionally intercept the allocator methods even though libstd provides
+                    // default implementations.
+                    return interp_ok(());
+                }
+            }
+
             throw_machine_stop!(TerminationInfo::SymbolShimClashing {
                 link_name,
                 span: body.span.data(),
diff --git a/src/tools/miri/src/shims/alloc.rs b/src/tools/miri/src/shims/alloc.rs
index 4dc9ba354a05a..25c0b52d0618b 100644
--- a/src/tools/miri/src/shims/alloc.rs
+++ b/src/tools/miri/src/shims/alloc.rs
@@ -1,6 +1,7 @@
 use std::iter;
 
 use rustc_abi::{Align, Size};
+use rustc_ast::expand::allocator::AllocatorKind;
 
 use crate::*;
 
@@ -51,6 +52,34 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
         Align::from_bytes(prev_power_of_two(size)).unwrap()
     }
 
+    /// Emulates calling the internal __rust_* allocator functions
+    fn emulate_allocator(
+        &mut self,
+        default: impl FnOnce(&mut MiriInterpCx<'tcx>) -> InterpResult<'tcx>,
+    ) -> InterpResult<'tcx, EmulateItemResult> {
+        let this = self.eval_context_mut();
+
+        let Some(allocator_kind) = this.tcx.allocator_kind(()) else {
+            // in real code, this symbol does not exist without an allocator
+            return interp_ok(EmulateItemResult::NotSupported);
+        };
+
+        match allocator_kind {
+            AllocatorKind::Global => {
+                // When `#[global_allocator]` is used, `__rust_*` is defined by the macro expansion
+                // of this attribute. As such we have to call an exported Rust function,
+                // and not execute any Miri shim. Somewhat unintuitively doing so is done
+                // by returning `NotSupported`, which triggers the `lookup_exported_symbol`
+                // fallback case in `emulate_foreign_item`.
+                interp_ok(EmulateItemResult::NotSupported)
+            }
+            AllocatorKind::Default => {
+                default(this)?;
+                interp_ok(EmulateItemResult::NeedsReturn)
+            }
+        }
+    }
+
     fn malloc(&mut self, size: u64, zero_init: bool) -> InterpResult<'tcx, Pointer> {
         let this = self.eval_context_mut();
         let align = this.malloc_align(size);
diff --git a/src/tools/miri/src/shims/foreign_items.rs b/src/tools/miri/src/shims/foreign_items.rs
index 6ac7310ea2d2f..09c77267717e4 100644
--- a/src/tools/miri/src/shims/foreign_items.rs
+++ b/src/tools/miri/src/shims/foreign_items.rs
@@ -1,5 +1,6 @@
 use std::collections::hash_map::Entry;
 use std::io::Write;
+use std::iter;
 use std::path::Path;
 
 use rustc_abi::{Align, AlignFromBytesError, Size};
@@ -501,33 +502,124 @@ trait EvalContextExtPriv<'tcx>: crate::MiriInterpCxExt<'tcx> {
             }
 
             // Rust allocation
-            "miri_alloc" => {
-                let [size, align] = this.check_shim(abi, Conv::Rust, link_name, args)?;
-                let size = this.read_target_usize(size)?;
-                let align = this.read_target_usize(align)?;
+            "__rust_alloc" | "miri_alloc" => {
+                let default = |ecx: &mut MiriInterpCx<'tcx>| {
+                    // Only call `check_shim` when `#[global_allocator]` isn't used. When that
+                    // macro is used, we act like no shim exists, so that the exported function can run.
+                    let [size, align] = ecx.check_shim(abi, Conv::Rust, link_name, args)?;
+                    let size = ecx.read_target_usize(size)?;
+                    let align = ecx.read_target_usize(align)?;
+
+                    ecx.check_rustc_alloc_request(size, align)?;
+
+                    let memory_kind = match link_name.as_str() {
+                        "__rust_alloc" => MiriMemoryKind::Rust,
+                        "miri_alloc" => MiriMemoryKind::Miri,
+                        _ => unreachable!(),
+                    };
 
-                this.check_rustc_alloc_request(size, align)?;
+                    let ptr = ecx.allocate_ptr(
+                        Size::from_bytes(size),
+                        Align::from_bytes(align).unwrap(),
+                        memory_kind.into(),
+                    )?;
 
-                let ptr = this.allocate_ptr(
-                    Size::from_bytes(size),
-                    Align::from_bytes(align).unwrap(),
-                    MiriMemoryKind::Miri.into(),
-                )?;
+                    ecx.write_pointer(ptr, dest)
+                };
 
-                this.write_pointer(ptr, dest)?;
+                match link_name.as_str() {
+                    "__rust_alloc" => return this.emulate_allocator(default),
+                    "miri_alloc" => {
+                        default(this)?;
+                        return interp_ok(EmulateItemResult::NeedsReturn);
+                    }
+                    _ => unreachable!(),
+                }
             }
-            "miri_dealloc" => {
-                let [ptr, old_size, align] = this.check_shim(abi, Conv::Rust, link_name, args)?;
-                let ptr = this.read_pointer(ptr)?;
-                let old_size = this.read_target_usize(old_size)?;
-                let align = this.read_target_usize(align)?;
+            "__rust_alloc_zeroed" => {
+                return this.emulate_allocator(|this| {
+                    // See the comment for `__rust_alloc` why `check_shim` is only called in the
+                    // default case.
+                    let [size, align] = this.check_shim(abi, Conv::Rust, link_name, args)?;
+                    let size = this.read_target_usize(size)?;
+                    let align = this.read_target_usize(align)?;
 
-                // No need to check old_size/align; we anyway check that they match the allocation.
-                this.deallocate_ptr(
-                    ptr,
-                    Some((Size::from_bytes(old_size), Align::from_bytes(align).unwrap())),
-                    MiriMemoryKind::Miri.into(),
-                )?;
+                    this.check_rustc_alloc_request(size, align)?;
+
+                    let ptr = this.allocate_ptr(
+                        Size::from_bytes(size),
+                        Align::from_bytes(align).unwrap(),
+                        MiriMemoryKind::Rust.into(),
+                    )?;
+
+                    // We just allocated this, the access is definitely in-bounds.
+                    this.write_bytes_ptr(
+                        ptr.into(),
+                        iter::repeat(0u8).take(usize::try_from(size).unwrap()),
+                    )
+                    .unwrap();
+                    this.write_pointer(ptr, dest)
+                });
+            }
+            "__rust_dealloc" | "miri_dealloc" => {
+                let default = |ecx: &mut MiriInterpCx<'tcx>| {
+                    // See the comment for `__rust_alloc` why `check_shim` is only called in the
+                    // default case.
+                    let [ptr, old_size, align] =
+                        ecx.check_shim(abi, Conv::Rust, link_name, args)?;
+                    let ptr = ecx.read_pointer(ptr)?;
+                    let old_size = ecx.read_target_usize(old_size)?;
+                    let align = ecx.read_target_usize(align)?;
+
+                    let memory_kind = match link_name.as_str() {
+                        "__rust_dealloc" => MiriMemoryKind::Rust,
+                        "miri_dealloc" => MiriMemoryKind::Miri,
+                        _ => unreachable!(),
+                    };
+
+                    // No need to check old_size/align; we anyway check that they match the allocation.
+                    ecx.deallocate_ptr(
+                        ptr,
+                        Some((Size::from_bytes(old_size), Align::from_bytes(align).unwrap())),
+                        memory_kind.into(),
+                    )
+                };
+
+                match link_name.as_str() {
+                    "__rust_dealloc" => {
+                        return this.emulate_allocator(default);
+                    }
+                    "miri_dealloc" => {
+                        default(this)?;
+                        return interp_ok(EmulateItemResult::NeedsReturn);
+                    }
+                    _ => unreachable!(),
+                }
+            }
+            "__rust_realloc" => {
+                return this.emulate_allocator(|this| {
+                    // See the comment for `__rust_alloc` why `check_shim` is only called in the
+                    // default case.
+                    let [ptr, old_size, align, new_size] =
+                        this.check_shim(abi, Conv::Rust, link_name, args)?;
+                    let ptr = this.read_pointer(ptr)?;
+                    let old_size = this.read_target_usize(old_size)?;
+                    let align = this.read_target_usize(align)?;
+                    let new_size = this.read_target_usize(new_size)?;
+                    // No need to check old_size; we anyway check that they match the allocation.
+
+                    this.check_rustc_alloc_request(new_size, align)?;
+
+                    let align = Align::from_bytes(align).unwrap();
+                    let new_ptr = this.reallocate_ptr(
+                        ptr,
+                        Some((Size::from_bytes(old_size), align)),
+                        Size::from_bytes(new_size),
+                        align,
+                        MiriMemoryKind::Rust.into(),
+                    )?;
+                    this.write_pointer(new_ptr, dest)
+                });
             }
 
             // C memory handling functions
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.stderr b/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.stderr
new file mode 100644
index 0000000000000..f07db3c62c91d
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/deallocate-bad-alignment.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 1 and alignment ALIGN
+  --> tests/fail/alloc/deallocate-bad-alignment.rs:LL:CC
+   |
+LL |         dealloc(x, Layout::from_size_align_unchecked(1, 2));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 1 and alignment ALIGN
+   |
+   = 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
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/alloc/deallocate-bad-alignment.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-bad-size.stderr b/src/tools/miri/tests/fail/alloc/deallocate-bad-size.stderr
new file mode 100644
index 0000000000000..c913bde04cc91
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/deallocate-bad-size.stderr
@@ -0,0 +1,15 @@
+error: Undefined Behavior: incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 2 and alignment ALIGN
+  --> tests/fail/alloc/deallocate-bad-size.rs:LL:CC
+   |
+LL |         dealloc(x, Layout::from_size_align_unchecked(2, 1));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 2 and alignment ALIGN
+   |
+   = 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
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/alloc/deallocate-bad-size.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/deallocate-twice.stderr b/src/tools/miri/tests/fail/alloc/deallocate-twice.stderr
index 344dd5689c6eb..9e6ce3d45a726 100644
--- a/src/tools/miri/tests/fail/alloc/deallocate-twice.stderr
+++ b/src/tools/miri/tests/fail/alloc/deallocate-twice.stderr
@@ -1,8 +1,8 @@
 error: Undefined Behavior: memory access failed: ALLOC has been freed, so this pointer is dangling
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> tests/fail/alloc/deallocate-twice.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: ALLOC has been freed, so this pointer is dangling
+LL |         dealloc(x, Layout::from_size_align_unchecked(1, 1));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: ALLOC has been freed, so this pointer is dangling
    |
    = 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
@@ -17,13 +17,7 @@ help: ALLOC was deallocated here:
 LL |         dealloc(x, Layout::from_size_align_unchecked(1, 1));
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: BACKTRACE (of the first span):
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `main`
-  --> tests/fail/alloc/deallocate-twice.rs:LL:CC
-   |
-LL |         dealloc(x, Layout::from_size_align_unchecked(1, 1));
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: inside `main` at tests/fail/alloc/deallocate-twice.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/alloc/global_system_mixup.stderr b/src/tools/miri/tests/fail/alloc/global_system_mixup.stderr
new file mode 100644
index 0000000000000..4c355c511ef45
--- /dev/null
+++ b/src/tools/miri/tests/fail/alloc/global_system_mixup.stderr
@@ -0,0 +1,21 @@
+error: Undefined Behavior: deallocating ALLOC, which is Rust heap memory, using PLATFORM heap deallocation operation
+  --> RUSTLIB/std/src/sys/alloc/PLATFORM.rs:LL:CC
+   |
+LL |         FREE();
+   | ^ deallocating ALLOC, which is Rust heap memory, using PLATFORM heap deallocation operation
+   |
+   = 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
+   = note: BACKTRACE:
+   = note: inside `std::sys::alloc::PLATFORM::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/PLATFORM.rs:LL:CC
+   = note: inside `<std::alloc::System as std::alloc::Allocator>::deallocate` at RUSTLIB/std/src/alloc.rs:LL:CC
+note: inside `main`
+  --> tests/fail/alloc/global_system_mixup.rs:LL:CC
+   |
+LL |     unsafe { System.deallocate(ptr, l) };
+   | ^
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+
diff --git a/src/tools/miri/tests/fail/alloc/reallocate-bad-size.stderr b/src/tools/miri/tests/fail/alloc/reallocate-bad-size.stderr
index 24e97383b979a..6f6c8850603d4 100644
--- a/src/tools/miri/tests/fail/alloc/reallocate-bad-size.stderr
+++ b/src/tools/miri/tests/fail/alloc/reallocate-bad-size.stderr
@@ -1,21 +1,15 @@
-error: memory leaked: ALLOC (C heap, size: 1, align: 1), allocated here:
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+error: Undefined Behavior: incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 2 and alignment ALIGN
+  --> tests/fail/alloc/reallocate-bad-size.rs:LL:CC
    |
-LL |             unsafe { libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8 }
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |         let _y = realloc(x, Layout::from_size_align_unchecked(2, 1), 1);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ incorrect layout on deallocation: ALLOC has size 1 and alignment ALIGN, but gave size 2 and alignment ALIGN
    |
+   = 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
    = note: BACKTRACE:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::realloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_realloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `main`
-  --> tests/fail/alloc/reallocate-bad-size.rs:LL:CC
-   |
-LL | ...   let _y = realloc(x, Layout::from_size_align_unchecked(2, 1), 1);
-   |                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: inside `main` at tests/fail/alloc/reallocate-bad-size.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
-note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
-
 error: aborting due to 1 previous error
 
diff --git a/src/tools/miri/tests/fail/alloc/reallocate-dangling.stderr b/src/tools/miri/tests/fail/alloc/reallocate-dangling.stderr
index dfe5cd024b512..06960380f6c94 100644
--- a/src/tools/miri/tests/fail/alloc/reallocate-dangling.stderr
+++ b/src/tools/miri/tests/fail/alloc/reallocate-dangling.stderr
@@ -1,8 +1,8 @@
 error: Undefined Behavior: memory access failed: ALLOC has been freed, so this pointer is dangling
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> tests/fail/alloc/reallocate-dangling.rs:LL:CC
    |
-LL |             unsafe { libc::realloc(ptr as *mut libc::c_void, new_size) as *mut u8 }
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: ALLOC has been freed, so this pointer is dangling
+LL |         let _z = realloc(x, Layout::from_size_align_unchecked(1, 1), 1);
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ memory access failed: ALLOC has been freed, so this pointer is dangling
    |
    = 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
@@ -17,13 +17,7 @@ help: ALLOC was deallocated here:
 LL |         dealloc(x, Layout::from_size_align_unchecked(1, 1));
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: BACKTRACE (of the first span):
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::realloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_realloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `main`
-  --> tests/fail/alloc/reallocate-dangling.rs:LL:CC
-   |
-LL |         let _z = realloc(x, Layout::from_size_align_unchecked(1, 1), 1);
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: inside `main` at tests/fail/alloc/reallocate-dangling.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/alloc/stack_free.stderr b/src/tools/miri/tests/fail/alloc/stack_free.stderr
index 2885151e7113f..7d7cee133c653 100644
--- a/src/tools/miri/tests/fail/alloc/stack_free.stderr
+++ b/src/tools/miri/tests/fail/alloc/stack_free.stderr
@@ -1,14 +1,12 @@
-error: Undefined Behavior: deallocating ALLOC, which is stack variable memory, using C heap deallocation operation
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+error: Undefined Behavior: deallocating ALLOC, which is stack variable memory, using Rust heap deallocation operation
+  --> RUSTLIB/alloc/src/boxed.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating ALLOC, which is stack variable memory, using C heap deallocation operation
+LL |                 self.1.deallocate(From::from(ptr.cast()), layout);
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating ALLOC, which is stack variable memory, using Rust heap deallocation operation
    |
    = 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
    = note: BACKTRACE:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
    = note: inside `<std::boxed::Box<i32> as std::ops::Drop>::drop` at RUSTLIB/alloc/src/boxed.rs:LL:CC
    = note: inside `std::ptr::drop_in_place::<std::boxed::Box<i32>> - shim(Some(std::boxed::Box<i32>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
    = note: inside `std::mem::drop::<std::boxed::Box<i32>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
diff --git a/src/tools/miri/tests/fail/alloc/too_large.stderr b/src/tools/miri/tests/fail/alloc/too_large.stderr
index 3a3c239261903..03e54088e3b50 100644
--- a/src/tools/miri/tests/fail/alloc/too_large.stderr
+++ b/src/tools/miri/tests/fail/alloc/too_large.stderr
@@ -1,29 +1,13 @@
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
-unsafe precondition(s) violated: Layout::from_size_align_unchecked requires that align is a power of 2 and the rounded-up allocation size does not exceed isize::MAX
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
-thread caused non-unwinding panic. aborting.
-error: abnormal termination: the program aborted execution
-  --> RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
-   |
-LL |     unsafe { libc::abort() }
-   |              ^^^^^^^^^^^^^ the program aborted execution
-   |
-   = note: BACKTRACE:
-   = note: inside `std::sys::pal::PLATFORM::abort_internal` at RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
-   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `std::sys::backtrace::__rust_end_short_backtrace::<{closure@std::panicking::begin_panic_handler::{closure#0}}, !>` at RUSTLIB/std/src/sys/backtrace.rs:LL:CC
-   = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `core::panicking::panic_nounwind` at RUSTLIB/core/src/panicking.rs:LL:CC
-   = note: inside `std::alloc::Layout::from_size_align_unchecked::precondition_check` at RUSTLIB/core/src/ub_checks.rs:LL:CC
-   = note: inside `std::alloc::Layout::from_size_align_unchecked` at RUSTLIB/core/src/ub_checks.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_alloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `main`
+error: Undefined Behavior: creating an allocation larger than half the address space
   --> tests/fail/alloc/too_large.rs:LL:CC
    |
 LL |         __rust_alloc(bytes, 1);
-   |         ^^^^^^^^^^^^^^^^^^^^^^
+   |         ^^^^^^^^^^^^^^^^^^^^^^ creating an allocation larger than half the address space
+   |
+   = 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
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/alloc/too_large.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/alloc/unsupported_big_alignment.stderr b/src/tools/miri/tests/fail/alloc/unsupported_big_alignment.stderr
index 4bbda6c4ed846..8eb71f5ce8459 100644
--- a/src/tools/miri/tests/fail/alloc/unsupported_big_alignment.stderr
+++ b/src/tools/miri/tests/fail/alloc/unsupported_big_alignment.stderr
@@ -1,138 +1,14 @@
-thread 'rustc' panicked at src/tools/miri/src/shims/alloc.rs:LL:CC:
-called `Result::unwrap()` on an `Err` value: `1073741824` is too large
-stack backtrace:
-   0: rust_begin_unwind
- at RUSTLIB/std/src/panicking.rs:LL:CC
-   1: core::panicking::panic_fmt
- at RUSTLIB/core/src/panicking.rs:LL:CC
-   2: core::result::unwrap_failed
- at RUSTLIB/core/src/result.rs:LL:CC
-   3: <core::result::Result<rustc_abi::Align, rustc_abi::AlignFromBytesError>>::unwrap
- at RUSTLIB/core/src/result.rs:LL:CC
-   4: <rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine> as miri::shims::alloc::EvalContextExt>::posix_memalign
- at ./src/shims/alloc.rs:LL:CC
-   5: <rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine> as miri::shims::unix::foreign_items::EvalContextExt>::emulate_foreign_item_inner
- at ./src/shims/unix/foreign_items.rs:LL:CC
-   6: <rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine> as miri::shims::foreign_items::EvalContextExtPriv>::emulate_foreign_item_inner
- at ./src/shims/foreign_items.rs:LL:CC
-   7: <rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine> as miri::shims::foreign_items::EvalContextExt>::emulate_foreign_item
- at ./src/shims/foreign_items.rs:LL:CC
-   8: <miri::machine::MiriMachine as rustc_const_eval::interpret::machine::Machine>::find_mir_or_eval_fn
- at ./src/machine.rs:LL:CC
-   9: <rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine>>::init_fn_call
- at /home/gh-bjorn3/rust/compiler/rustc_const_eval/src/interpret/call.rs:LL:CC
-  10: <rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine>>::eval_terminator
- at /home/gh-bjorn3/rust/compiler/rustc_const_eval/src/interpret/step.rs:LL:CC
-  11: <rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine>>::step
- at /home/gh-bjorn3/rust/compiler/rustc_const_eval/src/interpret/step.rs:LL:CC
-  12: <rustc_const_eval::interpret::eval_context::InterpCx<miri::machine::MiriMachine> as miri::concurrency::thread::EvalContextExt>::run_threads
- at ./src/concurrency/thread.rs:LL:CC
-  13: miri::eval::eval_entry::{closure#0}
- at ./src/eval.rs:LL:CC
-  14: <miri::eval::eval_entry::{closure#0} as core::ops::function::FnOnce<()>>::call_once
- at RUSTLIB/core/src/ops/function.rs:LL:CC
-  15: <core::panic::unwind_safe::AssertUnwindSafe<miri::eval::eval_entry::{closure#0}> as core::ops::function::FnOnce<()>>::call_once
- at RUSTLIB/core/src/panic/unwind_safe.rs:LL:CC
-  16: std::panicking::try::do_call
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  17: std::panicking::try
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  18: std::panic::catch_unwind
- at RUSTLIB/std/src/panic.rs:LL:CC
-  19: miri::eval::eval_entry
- at ./src/eval.rs:LL:CC
-  20: <miri::MiriCompilerCalls as rustc_driver_impl::Callbacks>::after_analysis
- at ./src/bin/miri.rs:LL:CC
-  21: rustc_driver_impl::run_compiler::{closure#0}::{closure#2}
- at /home/gh-bjorn3/rust/compiler/rustc_driver_impl/src/lib.rs:LL:CC
-  22: rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}::{closure#0}
- at /home/gh-bjorn3/rust/compiler/rustc_interface/src/passes.rs:LL:CC
-  23: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt::{closure#3}
- at /home/gh-bjorn3/rust/compiler/rustc_middle/src/ty/context.rs:LL:CC
-  24: rustc_middle::ty::context::tls::enter_context::{closure#0}
- at /home/gh-bjorn3/rust/compiler/rustc_middle/src/ty/context/tls.rs:LL:CC
-  25: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::try_with
- at RUSTLIB/std/src/thread/local.rs:LL:CC
-  26: <std::thread::local::LocalKey<core::cell::Cell<*const ()>>>::with
- at RUSTLIB/std/src/thread/local.rs:LL:CC
-  27: rustc_middle::ty::context::tls::enter_context
- at /home/gh-bjorn3/rust/compiler/rustc_middle/src/ty/context/tls.rs:LL:CC
-  28: <rustc_middle::ty::context::TyCtxt>::create_global_ctxt
- at /home/gh-bjorn3/rust/compiler/rustc_middle/src/ty/context.rs:LL:CC
-  29: rustc_interface::passes::create_and_enter_global_ctxt::{closure#2}
- at /home/gh-bjorn3/rust/compiler/rustc_interface/src/passes.rs:LL:CC
-  30: <rustc_interface::passes::create_and_enter_global_ctxt<core::option::Option<rustc_interface::queries::Linker>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}>::{closure#2} as core::ops::function::FnOnce<(&rustc_interface::interface::Compiler, &std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2})>>::call_once::{shim:vtable#0}
- at RUSTLIB/core/src/ops/function.rs:LL:CC
-  31: <alloc::boxed::Box<dyn for<'a> core::ops::function::FnOnce<(&'a rustc_interface::interface::Compiler, &'a std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt<'a>>, &'a rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena<'a>>, &'a rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena<'a>>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2}), Output = core::option::Option<rustc_interface::queries::Linker>>> as core::ops::function::FnOnce<(&rustc_interface::interface::Compiler, &std::sync::once_lock::OnceLock<rustc_middle::ty::context::GlobalCtxt>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_middle::arena::Arena>, &rustc_data_structures::sync::worker_local::WorkerLocal<rustc_hir::Arena>, rustc_driver_impl::run_compiler::{closure#0}::{closure#2})>>::call_once
- at RUSTLIB/alloc/src/boxed.rs:LL:CC
-  32: rustc_interface::passes::create_and_enter_global_ctxt
- at /home/gh-bjorn3/rust/compiler/rustc_interface/src/passes.rs:LL:CC
-  33: rustc_driver_impl::run_compiler::{closure#0}
- at /home/gh-bjorn3/rust/compiler/rustc_driver_impl/src/lib.rs:LL:CC
-  34: rustc_interface::interface::run_compiler::{closure#1}::{closure#0}
- at /home/gh-bjorn3/rust/compiler/rustc_interface/src/interface.rs:LL:CC
-  35: <core::panic::unwind_safe::AssertUnwindSafe<rustc_interface::interface::run_compiler<(), rustc_driver_impl::run_compiler::{closure#0}>::{closure#1}::{closure#0}> as core::ops::function::FnOnce<()>>::call_once
- at RUSTLIB/core/src/panic/unwind_safe.rs:LL:CC
-  36: std::panicking::try::do_call
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  37: std::panicking::try
- at RUSTLIB/std/src/panicking.rs:LL:CC
-  38: std::panic::catch_unwind
- at RUSTLIB/std/src/panic.rs:LL:CC
-  39: rustc_interface::interface::run_compiler::{closure#1}
- at /home/gh-bjorn3/rust/compiler/rustc_interface/src/interface.rs:LL:CC
-  40: rustc_interface::util::run_in_thread_pool_with_globals::{closure#0}
- at /home/gh-bjorn3/rust/compiler/rustc_interface/src/util.rs:LL:CC
-  41: rustc_interface::util::run_in_thread_with_globals::{closure#0}::{closure#0}::{closure#0}
- at /home/gh-bjorn3/rust/compiler/rustc_interface/src/util.rs:LL:CC
-  42: <scoped_tls::ScopedKey<rustc_span::SessionGlobals>>::set
- at CARGO_REGISTRY/.../lib.rs:LL:CC
-  43: rustc_span::create_session_globals_then
- at /home/gh-bjorn3/rust/compiler/rustc_span/src/lib.rs:LL:CC
-  44: rustc_interface::util::run_in_thread_with_globals::{closure#0}::{closure#0}
- at /home/gh-bjorn3/rust/compiler/rustc_interface/src/util.rs:LL:CC
-note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
-
-error: the compiler unexpectedly panicked. this is a bug.
-
-note: we would appreciate a bug report: https://github.com/rust-lang/miri/issues/new
-
-note: please make sure that you have updated to the latest nightly
-
-note: please attach the file at `/home/gh-bjorn3/rust/src/tools/miri/rustc-ice-2024-12-20T10_31_46-710436.txt` to your bug report
-
-note: compiler flags: -Z ui-testing
-
-query stack during panic:
-end of query stack
-
-Miri caused an ICE during evaluation. Here's the interpreter backtrace at the time of the panic:
-note: the place in the program where the ICE was triggered
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   |
-LL |             let ret = unsafe { libc::posix_memalign(&mut out, align, layout.size()) };
-   |                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: BACKTRACE:
-   = note: inside `std::sys::alloc::unix::aligned_malloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::alloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_alloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `main`
+error: unsupported operation: creating allocation with alignment ALIGN exceeding rustc's maximum supported value
   --> tests/fail/alloc/unsupported_big_alignment.rs:LL:CC
    |
 LL |         __rust_alloc(1, 1 << 30);
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: inside `<fn() as std::ops::FnOnce<()>>::call_once - shim(fn())` at RUSTLIB/core/src/ops/function.rs:LL:CC
-   = note: inside `std::sys::backtrace::__rust_begin_short_backtrace::<fn(), ()>` at RUSTLIB/std/src/sys/backtrace.rs:LL:CC
-   = note: inside closure at RUSTLIB/std/src/rt.rs:LL:CC
-   = note: inside `std::ops::function::impls::<impl std::ops::FnOnce<()> for &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>::call_once` at RUSTLIB/core/src/ops/function.rs:LL:CC
-   = note: inside `std::panicking::r#try::do_call::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `std::panicking::r#try::<i32, &dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe>` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `std::panic::catch_unwind::<&dyn std::ops::Fn() -> i32 + std::marker::Sync + std::panic::RefUnwindSafe, i32>` at RUSTLIB/std/src/panic.rs:LL:CC
-   = note: inside closure at RUSTLIB/std/src/rt.rs:LL:CC
-   = note: inside `std::panicking::r#try::do_call::<{closure@std::rt::lang_start_internal::{closure#1}}, isize>` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `std::panicking::r#try::<isize, {closure@std::rt::lang_start_internal::{closure#1}}>` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `std::panic::catch_unwind::<{closure@std::rt::lang_start_internal::{closure#1}}, isize>` at RUSTLIB/std/src/panic.rs:LL:CC
-   = note: inside `std::rt::lang_start_internal` at RUSTLIB/std/src/rt.rs:LL:CC
-   = note: inside `std::rt::lang_start::<()>` at RUSTLIB/std/src/rt.rs:LL:CC
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^ creating allocation with alignment ALIGN exceeding rustc's maximum supported value
+   |
+   = help: this is likely not a bug in the program; it indicates that the program performed an operation that Miri does not support
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/alloc/unsupported_big_alignment.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
 
diff --git a/src/tools/miri/tests/fail/alloc/unsupported_non_power_two_alignment.stderr b/src/tools/miri/tests/fail/alloc/unsupported_non_power_two_alignment.stderr
index b7cc9f1a64904..0a36d3d58b616 100644
--- a/src/tools/miri/tests/fail/alloc/unsupported_non_power_two_alignment.stderr
+++ b/src/tools/miri/tests/fail/alloc/unsupported_non_power_two_alignment.stderr
@@ -1,29 +1,13 @@
-thread 'main' panicked at RUSTLIB/core/src/panicking.rs:LL:CC:
-unsafe precondition(s) violated: Layout::from_size_align_unchecked requires that align is a power of 2 and the rounded-up allocation size does not exceed isize::MAX
-note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
-note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
-thread caused non-unwinding panic. aborting.
-error: abnormal termination: the program aborted execution
-  --> RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
-   |
-LL |     unsafe { libc::abort() }
-   |              ^^^^^^^^^^^^^ the program aborted execution
-   |
-   = note: BACKTRACE:
-   = note: inside `std::sys::pal::PLATFORM::abort_internal` at RUSTLIB/std/src/sys/pal/PLATFORM/mod.rs:LL:CC
-   = note: inside `std::panicking::rust_panic_with_hook` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside closure at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `std::sys::backtrace::__rust_end_short_backtrace::<{closure@std::panicking::begin_panic_handler::{closure#0}}, !>` at RUSTLIB/std/src/sys/backtrace.rs:LL:CC
-   = note: inside `std::panicking::begin_panic_handler` at RUSTLIB/std/src/panicking.rs:LL:CC
-   = note: inside `core::panicking::panic_nounwind` at RUSTLIB/core/src/panicking.rs:LL:CC
-   = note: inside `std::alloc::Layout::from_size_align_unchecked::precondition_check` at RUSTLIB/core/src/ub_checks.rs:LL:CC
-   = note: inside `std::alloc::Layout::from_size_align_unchecked` at RUSTLIB/core/src/ub_checks.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_alloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `main`
+error: Undefined Behavior: creating allocation with non-power-of-two alignment ALIGN
   --> tests/fail/alloc/unsupported_non_power_two_alignment.rs:LL:CC
    |
 LL |         __rust_alloc(1, 3);
-   |         ^^^^^^^^^^^^^^^^^^
+   |         ^^^^^^^^^^^^^^^^^^ creating allocation with non-power-of-two alignment ALIGN
+   |
+   = 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
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/alloc/unsupported_non_power_two_alignment.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.tree.stderr b/src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.tree.stderr
index 5e49ef214095a..ef1aa74ddf4ba 100644
--- a/src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/newtype_pair_retagging.tree.stderr
@@ -1,8 +1,8 @@
 error: Undefined Behavior: deallocation through <TAG> at ALLOC[0x0] is forbidden
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> RUSTLIB/alloc/src/boxed.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocation through <TAG> at ALLOC[0x0] is forbidden
+LL |                 self.1.deallocate(From::from(ptr.cast()), layout);
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocation through <TAG> at ALLOC[0x0] is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
    = help: the accessed tag <TAG> is foreign to the protected tag <TAG> (i.e., it is not a child)
@@ -25,8 +25,6 @@ LL |             || drop(Box::from_raw(ptr)),
    |                     ^^^^^^^^^^^^^^^^^^
    = help: this transition corresponds to a temporary loss of write permissions until function exit
    = note: BACKTRACE (of the first span):
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
    = note: inside `<std::boxed::Box<i32> as std::ops::Drop>::drop` at RUSTLIB/alloc/src/boxed.rs:LL:CC
    = note: inside `std::ptr::drop_in_place::<std::boxed::Box<i32>> - shim(Some(std::boxed::Box<i32>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
    = note: inside `std::mem::drop::<std::boxed::Box<i32>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
diff --git a/src/tools/miri/tests/fail/both_borrows/newtype_retagging.tree.stderr b/src/tools/miri/tests/fail/both_borrows/newtype_retagging.tree.stderr
index 4b264a73dff6b..28fcd1411f962 100644
--- a/src/tools/miri/tests/fail/both_borrows/newtype_retagging.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/newtype_retagging.tree.stderr
@@ -1,8 +1,8 @@
 error: Undefined Behavior: deallocation through <TAG> at ALLOC[0x0] is forbidden
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> RUSTLIB/alloc/src/boxed.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocation through <TAG> at ALLOC[0x0] is forbidden
+LL |                 self.1.deallocate(From::from(ptr.cast()), layout);
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocation through <TAG> at ALLOC[0x0] is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
    = help: the accessed tag <TAG> is foreign to the protected tag <TAG> (i.e., it is not a child)
@@ -25,8 +25,6 @@ LL |             || drop(Box::from_raw(ptr)),
    |                     ^^^^^^^^^^^^^^^^^^
    = help: this transition corresponds to a temporary loss of write permissions until function exit
    = note: BACKTRACE (of the first span):
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
    = note: inside `<std::boxed::Box<i32> as std::ops::Drop>::drop` at RUSTLIB/alloc/src/boxed.rs:LL:CC
    = note: inside `std::ptr::drop_in_place::<std::boxed::Box<i32>> - shim(Some(std::boxed::Box<i32>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
    = note: inside `std::mem::drop::<std::boxed::Box<i32>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
diff --git a/src/tools/miri/tests/fail/both_borrows/zero-sized-protected.tree.stderr b/src/tools/miri/tests/fail/both_borrows/zero-sized-protected.tree.stderr
index 48e84a8b04900..18d1fb6939540 100644
--- a/src/tools/miri/tests/fail/both_borrows/zero-sized-protected.tree.stderr
+++ b/src/tools/miri/tests/fail/both_borrows/zero-sized-protected.tree.stderr
@@ -1,8 +1,8 @@
 error: Undefined Behavior: deallocation through <TAG> (root of the allocation) at ALLOC[0x0] is forbidden
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> tests/fail/both_borrows/zero-sized-protected.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocation through <TAG> (root of the allocation) at ALLOC[0x0] is forbidden
+LL |     unsafe { dealloc(ptr, l) };
+   |              ^^^^^^^^^^^^^^^ deallocation through <TAG> (root of the allocation) at ALLOC[0x0] is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
    = help: the allocation of the accessed tag <TAG> (root of the allocation) also contains the strongly protected tag <TAG>
@@ -18,13 +18,7 @@ help: the strongly protected tag <TAG> was created here, in the initial state Re
 LL | fn test(_x: &mut (), ptr: *mut u8, l: Layout) {
    |         ^^
    = note: BACKTRACE (of the first span):
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `test`
-  --> tests/fail/both_borrows/zero-sized-protected.rs:LL:CC
-   |
-LL |     unsafe { dealloc(ptr, l) };
-   |              ^^^^^^^^^^^^^^^
+   = note: inside `test` at tests/fail/both_borrows/zero-sized-protected.rs:LL:CC
 note: inside `main`
   --> tests/fail/both_borrows/zero-sized-protected.rs:LL:CC
    |
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr
index 767a08e48de0f..8eb4ebbcf729d 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr
+++ b/src/tools/miri/tests/fail/data_race/dealloc_read_race1.stderr
@@ -1,8 +1,13 @@
 error: Undefined Behavior: Data race detected between (1) non-atomic read on thread `unnamed-ID` and (2) deallocation on thread `unnamed-ID` at ALLOC. (2) just happened here
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> tests/fail/data_race/dealloc_read_race1.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) non-atomic read on thread `unnamed-ID` and (2) deallocation on thread `unnamed-ID` at ALLOC. (2) just happened here
+LL | /             __rust_dealloc(
+LL | |
+LL | |                 ptr.0 as *mut _,
+LL | |                 std::mem::size_of::<usize>(),
+LL | |                 std::mem::align_of::<usize>(),
+LL | |             );
+   | |_____________^ Data race detected between (1) non-atomic read on thread `unnamed-ID` and (2) deallocation on thread `unnamed-ID` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> tests/fail/data_race/dealloc_read_race1.rs:LL:CC
@@ -12,18 +17,7 @@ LL |             let _val = *ptr.0;
    = 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
    = note: BACKTRACE (of the first span) on thread `unnamed-ID`:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside closure
-  --> tests/fail/data_race/dealloc_read_race1.rs:LL:CC
-   |
-LL | /             __rust_dealloc(
-LL | |
-LL | |                 ptr.0 as *mut _,
-LL | |                 std::mem::size_of::<usize>(),
-LL | |                 std::mem::align_of::<usize>(),
-LL | |             );
-   | |_____________^
+   = note: inside closure at tests/fail/data_race/dealloc_read_race1.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr
index 9b9e3e40fe5a4..48d974241aada 100644
--- a/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr
+++ b/src/tools/miri/tests/fail/data_race/dealloc_write_race1.stderr
@@ -1,8 +1,13 @@
 error: Undefined Behavior: Data race detected between (1) non-atomic write on thread `unnamed-ID` and (2) deallocation on thread `unnamed-ID` at ALLOC. (2) just happened here
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> tests/fail/data_race/dealloc_write_race1.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Data race detected between (1) non-atomic write on thread `unnamed-ID` and (2) deallocation on thread `unnamed-ID` at ALLOC. (2) just happened here
+LL | /             __rust_dealloc(
+LL | |
+LL | |                 ptr.0 as *mut _,
+LL | |                 std::mem::size_of::<usize>(),
+LL | |                 std::mem::align_of::<usize>(),
+LL | |             );
+   | |_____________^ Data race detected between (1) non-atomic write on thread `unnamed-ID` and (2) deallocation on thread `unnamed-ID` at ALLOC. (2) just happened here
    |
 help: and (1) occurred earlier here
   --> tests/fail/data_race/dealloc_write_race1.rs:LL:CC
@@ -12,18 +17,7 @@ LL |             *ptr.0 = 2;
    = 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
    = note: BACKTRACE (of the first span) on thread `unnamed-ID`:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside closure
-  --> tests/fail/data_race/dealloc_write_race1.rs:LL:CC
-   |
-LL | /             __rust_dealloc(
-LL | |
-LL | |                 ptr.0 as *mut _,
-LL | |                 std::mem::size_of::<usize>(),
-LL | |                 std::mem::align_of::<usize>(),
-LL | |             );
-   | |_____________^
+   = note: inside closure at tests/fail/data_race/dealloc_write_race1.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/memleak.stderr b/src/tools/miri/tests/fail/memleak.stderr
index b73b79cba1bb7..89db0f1eb1628 100644
--- a/src/tools/miri/tests/fail/memleak.stderr
+++ b/src/tools/miri/tests/fail/memleak.stderr
@@ -1,17 +1,11 @@
-error: memory leaked: ALLOC (C heap, size: 4, align: 4), allocated here:
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   |
-LL |             unsafe { libc::malloc(layout.size()) as *mut u8 }
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: BACKTRACE:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::alloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_alloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `main`
+error: memory leaked: ALLOC (Rust heap, size: 4, align: 4), allocated here:
   --> tests/fail/memleak.rs:LL:CC
    |
 LL |     std::mem::forget(Box::new(42));
    |                      ^^^^^^^^^^^^
+   |
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/memleak.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/memleak_no_backtrace.stderr b/src/tools/miri/tests/fail/memleak_no_backtrace.stderr
index 5b9f73f5c61e7..6850928e1503c 100644
--- a/src/tools/miri/tests/fail/memleak_no_backtrace.stderr
+++ b/src/tools/miri/tests/fail/memleak_no_backtrace.stderr
@@ -1,4 +1,4 @@
-error: memory leaked: ALLOC (C heap, size: 4, align: 4)
+error: memory leaked: ALLOC (Rust heap, size: 4, align: 4)
 
 note: set `MIRIFLAGS=-Zmiri-ignore-leaks` to disable this check
 
diff --git a/src/tools/miri/tests/fail/memleak_rc.stderr b/src/tools/miri/tests/fail/memleak_rc.stderr
index 07e4cf2bd5eb1..df12eeed6ac64 100644
--- a/src/tools/miri/tests/fail/memleak_rc.stderr
+++ b/src/tools/miri/tests/fail/memleak_rc.stderr
@@ -1,12 +1,10 @@
-error: memory leaked: ALLOC (C heap, size: 32, align: 16), allocated here:
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+error: memory leaked: ALLOC (Rust heap, SIZE, ALIGN), allocated here:
+  --> RUSTLIB/alloc/src/rc.rs:LL:CC
    |
-LL |             unsafe { libc::malloc(layout.size()) as *mut u8 }
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+LL |                 Box::leak(Box::new(RcInner { strong: Cell::new(1), weak: Cell::new(1), value }))
+   |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: BACKTRACE:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::alloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_alloc` at RUSTLIB/std/src/alloc.rs:LL:CC
    = note: inside `std::rc::Rc::<std::cell::RefCell<std::option::Option<Dummy>>>::new` at RUSTLIB/alloc/src/rc.rs:LL:CC
 note: inside `main`
   --> tests/fail/memleak_rc.rs:LL:CC
diff --git a/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.stderr b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.stderr
index 5dd163ca5facf..f4cfa49c1564e 100644
--- a/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.stderr
+++ b/src/tools/miri/tests/fail/stacked_borrows/deallocate_against_protector1.stderr
@@ -1,14 +1,12 @@
 error: Undefined Behavior: deallocating while item [Unique for <TAG>] is strongly protected
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> RUSTLIB/alloc/src/boxed.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating while item [Unique for <TAG>] is strongly protected
+LL |                 self.1.deallocate(From::from(ptr.cast()), layout);
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocating while item [Unique for <TAG>] is strongly protected
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
    = note: BACKTRACE:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
    = note: inside `<std::boxed::Box<i32> as std::ops::Drop>::drop` at RUSTLIB/alloc/src/boxed.rs:LL:CC
    = note: inside `std::ptr::drop_in_place::<std::boxed::Box<i32>> - shim(Some(std::boxed::Box<i32>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
    = note: inside `std::mem::drop::<std::boxed::Box<i32>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
diff --git a/src/tools/miri/tests/fail/stacked_borrows/illegal_dealloc1.stderr b/src/tools/miri/tests/fail/stacked_borrows/illegal_dealloc1.stderr
index 7459ffc9fba47..ddf8dbea31f59 100644
--- a/src/tools/miri/tests/fail/stacked_borrows/illegal_dealloc1.stderr
+++ b/src/tools/miri/tests/fail/stacked_borrows/illegal_dealloc1.stderr
@@ -1,8 +1,8 @@
 error: Undefined Behavior: attempting deallocation using <TAG> at ALLOC, but that tag does not exist in the borrow stack for this location
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> tests/fail/stacked_borrows/illegal_deALLOC.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ attempting deallocation using <TAG> at ALLOC, but that tag does not exist in the borrow stack for this location
+LL |         dealloc(ptr2, Layout::from_size_align_unchecked(1, 1));
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ attempting deallocation using <TAG> at ALLOC, but that tag does not exist in the borrow stack for this location
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Stacked Borrows rules it violated are still experimental
    = help: see https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information
@@ -17,13 +17,7 @@ help: <TAG> was later invalidated at offsets [0x0..0x1] by a write access
 LL |         ptr1.write(0);
    |         ^^^^^^^^^^^^^
    = note: BACKTRACE (of the first span):
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside `main`
-  --> tests/fail/stacked_borrows/illegal_deALLOC.rs:LL:CC
-   |
-LL |         dealloc(ptr2, Layout::from_size_align_unchecked(1, 1));
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: inside `main` at tests/fail/stacked_borrows/illegal_deALLOC.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/tls_macro_leak.stderr b/src/tools/miri/tests/fail/tls_macro_leak.stderr
index caac06ff4e4e9..512932b3cb8a6 100644
--- a/src/tools/miri/tests/fail/tls_macro_leak.stderr
+++ b/src/tools/miri/tests/fail/tls_macro_leak.stderr
@@ -1,17 +1,11 @@
-error: memory leaked: ALLOC (C heap, size: 4, align: 4), allocated here:
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   |
-LL |             unsafe { libc::malloc(layout.size()) as *mut u8 }
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: BACKTRACE:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::alloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_alloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside closure
+error: memory leaked: ALLOC (Rust heap, size: 4, align: 4), allocated here:
   --> tests/fail/tls_macro_leak.rs:LL:CC
    |
 LL |             cell.set(Some(Box::leak(Box::new(123))));
    |                                     ^^^^^^^^^^^^^
+   |
+   = note: BACKTRACE:
+   = note: inside closure at tests/fail/tls_macro_leak.rs:LL:CC
    = note: inside `std::thread::LocalKey::<std::cell::Cell<std::option::Option<&i32>>>::try_with::<{closure@tests/fail/tls_macro_leak.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/local.rs:LL:CC
    = note: inside `std::thread::LocalKey::<std::cell::Cell<std::option::Option<&i32>>>::with::<{closure@tests/fail/tls_macro_leak.rs:LL:CC}, ()>` at RUSTLIB/std/src/thread/local.rs:LL:CC
 note: inside closure
diff --git a/src/tools/miri/tests/fail/tls_static_leak.stderr b/src/tools/miri/tests/fail/tls_static_leak.stderr
index 946a2927f67a8..24306cca7ffdd 100644
--- a/src/tools/miri/tests/fail/tls_static_leak.stderr
+++ b/src/tools/miri/tests/fail/tls_static_leak.stderr
@@ -1,17 +1,11 @@
-error: memory leaked: ALLOC (C heap, size: 4, align: 4), allocated here:
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   |
-LL |             unsafe { libc::malloc(layout.size()) as *mut u8 }
-   |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: BACKTRACE:
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::alloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_alloc` at RUSTLIB/std/src/alloc.rs:LL:CC
-note: inside closure
+error: memory leaked: ALLOC (Rust heap, size: 4, align: 4), allocated here:
   --> tests/fail/tls_static_leak.rs:LL:CC
    |
 LL |         TLS.set(Some(Box::leak(Box::new(123))));
    |                                ^^^^^^^^^^^^^
+   |
+   = note: BACKTRACE:
+   = note: inside closure at tests/fail/tls_static_leak.rs:LL:CC
 
 note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
 
diff --git a/src/tools/miri/tests/fail/tree_borrows/strongly-protected.stderr b/src/tools/miri/tests/fail/tree_borrows/strongly-protected.stderr
index f7066853827e8..f6197a2acb391 100644
--- a/src/tools/miri/tests/fail/tree_borrows/strongly-protected.stderr
+++ b/src/tools/miri/tests/fail/tree_borrows/strongly-protected.stderr
@@ -1,8 +1,8 @@
 error: Undefined Behavior: deallocation through <TAG> at ALLOC[0x0] is forbidden
-  --> RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
+  --> RUSTLIB/alloc/src/boxed.rs:LL:CC
    |
-LL |         unsafe { libc::free(ptr as *mut libc::c_void) }
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocation through <TAG> at ALLOC[0x0] is forbidden
+LL |                 self.1.deallocate(From::from(ptr.cast()), layout);
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ deallocation through <TAG> at ALLOC[0x0] is forbidden
    |
    = help: this indicates a potential bug in the program: it performed an invalid operation, but the Tree Borrows rules it violated are still experimental
    = help: the allocation of the accessed tag <TAG> also contains the strongly protected tag <TAG>
@@ -18,8 +18,6 @@ help: the strongly protected tag <TAG> was created here, in the initial state Re
 LL | fn inner(x: &mut i32, f: fn(*mut i32)) {
    |          ^
    = note: BACKTRACE (of the first span):
-   = note: inside `std::sys::alloc::unix::<impl std::alloc::GlobalAlloc for std::alloc::System>::dealloc` at RUSTLIB/std/src/sys/alloc/unix.rs:LL:CC
-   = note: inside `std::alloc::__default_lib_allocator::__rust_dealloc` at RUSTLIB/std/src/alloc.rs:LL:CC
    = note: inside `<std::boxed::Box<i32> as std::ops::Drop>::drop` at RUSTLIB/alloc/src/boxed.rs:LL:CC
    = note: inside `std::ptr::drop_in_place::<std::boxed::Box<i32>> - shim(Some(std::boxed::Box<i32>))` at RUSTLIB/core/src/ptr/mod.rs:LL:CC
    = note: inside `std::mem::drop::<std::boxed::Box<i32>>` at RUSTLIB/core/src/mem/mod.rs:LL:CC
diff --git a/src/tools/miri/tests/fail/uninit/uninit_alloc_diagnostic.stderr b/src/tools/miri/tests/fail/uninit/uninit_alloc_diagnostic.stderr
index 420b4e051affd..0996e5d11eff6 100644
--- a/src/tools/miri/tests/fail/uninit/uninit_alloc_diagnostic.stderr
+++ b/src/tools/miri/tests/fail/uninit/uninit_alloc_diagnostic.stderr
@@ -16,7 +16,7 @@ LL |         drop(slice1.cmp(slice2));
    |              ^^^^^^^^^^^^^^^^^^
 
 Uninitialized memory occurred at ALLOC[0x4..0x10], in this allocation:
-ALLOC (C heap, size: 32, align: 16) {
+ALLOC (Rust heap, size: 32, align: 8) {
     0x00 │ 41 42 43 44 __ __ __ __ __ __ __ __ __ __ __ __ │ ABCD░░░░░░░░░░░░
     0x10 │ 00 __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ │ .░░░░░░░░░░░░░░░
 }
diff --git a/src/tools/miri/tests/fail/uninit/uninit_alloc_diagnostic_with_provenance.stderr b/src/tools/miri/tests/fail/uninit/uninit_alloc_diagnostic_with_provenance.stderr
index 59aae23a66c21..bcde9377c5400 100644
--- a/src/tools/miri/tests/fail/uninit/uninit_alloc_diagnostic_with_provenance.stderr
+++ b/src/tools/miri/tests/fail/uninit/uninit_alloc_diagnostic_with_provenance.stderr
@@ -16,7 +16,7 @@ LL |         drop(slice1.cmp(slice2));
    |              ^^^^^^^^^^^^^^^^^^
 
 Uninitialized memory occurred at ALLOC[0x4..0x8], in this allocation:
-ALLOC (C heap, size: 16, align: 16) {
+ALLOC (Rust heap, size: 16, align: 8) {
     ╾42[ALLOC]<TAG> (1 ptr byte)╼ 12 13 ╾43[ALLOC]<TAG> (1 ptr byte)╼ __ __ __ __ __ __ __ __ __ __ __ __ │ ━..━░░░░░░░░░░░░
 }
 ALLOC (global (static or const), size: 1, align: 1) {