3 [![Actions build status][actions-badge]][actions-url]
5 [actions-badge]: https://github.com/rust-lang/miri/workflows/CI/badge.svg?branch=master
6 [actions-url]: https://github.com/rust-lang/miri/actions
8 An experimental interpreter for [Rust][rust]'s
9 [mid-level intermediate representation][mir] (MIR). It can run binaries and
10 test suites of cargo projects and detect certain classes of
11 [undefined behavior](https://doc.rust-lang.org/reference/behavior-considered-undefined.html),
14 * Out-of-bounds memory accesses and use-after-free
15 * Invalid use of uninitialized data
16 * Violation of intrinsic preconditions (an [`unreachable_unchecked`] being
17 reached, calling [`copy_nonoverlapping`] with overlapping ranges, ...)
18 * Not sufficiently aligned memory accesses and references
19 * Violation of *some* basic type invariants (a `bool` that is not 0 or 1, for example,
20 or an invalid enum discriminant)
21 * **Experimental**: Violations of the [Stacked Borrows] rules governing aliasing
23 * **Experimental**: Data races (but no weak memory effects)
25 On top of that, Miri will also tell you about memory leaks: when there is memory
26 still allocated at the end of the execution, and that memory is not reachable
27 from a global `static`, Miri will raise an error.
29 You can use Miri to emulate programs on other targets, e.g. to ensure that
30 byte-level data manipulation works correctly both on little-endian and
31 big-endian systems. See
32 [cross-interpretation](#cross-interpretation-running-for-different-targets)
35 Miri has already discovered some [real-world bugs](#bugs-found-by-miri). If you
36 found a bug with Miri, we'd appreciate if you tell us and we'll add it to the
39 However, be aware that Miri will **not catch all cases of undefined behavior**
40 in your program, and cannot run all programs:
42 * There are still plenty of open questions around the basic invariants for some
43 types and when these invariants even have to hold. Miri tries to avoid false
44 positives here, so if your program runs fine in Miri right now that is by no
45 means a guarantee that it is UB-free when these questions get answered.
47 In particular, Miri does currently not check that integers/floats are
48 initialized or that references point to valid data.
49 * If the program relies on unspecified details of how data is laid out, it will
50 still run fine in Miri -- but might break (including causing UB) on different
51 compiler versions or different platforms.
52 * Program execution is non-deterministic when it depends, for example, on where
53 exactly in memory allocations end up, or on the exact interleaving of
54 concurrent threads. Miri tests one of many possible executions of your
55 program. You can alleviate this to some extent by running Miri with different
56 values for `-Zmiri-seed`, but that will still by far not explore all possible
58 * Miri runs the program as a platform-independent interpreter, so the program
59 has no access to most platform-specific APIs or FFI. A few APIs have been
60 implemented (such as printing to stdout) but most have not: for example, Miri
61 currently does not support SIMD or networking.
62 * Threading support is not finished yet. E.g., weak memory effects are not
63 emulated and spin loops (without syscalls) just loop forever. There is no
64 threading support on Windows.
66 [rust]: https://www.rust-lang.org/
67 [mir]: https://github.com/rust-lang/rfcs/blob/master/text/1211-mir.md
68 [`unreachable_unchecked`]: https://doc.rust-lang.org/stable/std/hint/fn.unreachable_unchecked.html
69 [`copy_nonoverlapping`]: https://doc.rust-lang.org/stable/std/ptr/fn.copy_nonoverlapping.html
70 [Stacked Borrows]: https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md
75 Install Miri on Rust nightly via `rustup`:
78 rustup +nightly component add miri
81 If `rustup` says the `miri` component is unavailable, that's because not all
82 nightly releases come with all tools. Check out
83 [this website](https://rust-lang.github.io/rustup-components-history) to
84 determine a nightly version that comes with Miri and install that using `rustup
85 toolchain install nightly-YYYY-MM-DD`. Either way, all of the following commands
86 assume the right toolchain is pinned via `rustup override set nightly` or
87 `rustup override set nightly-YYYY-MM-DD`. (Alternatively, use `cargo
88 +nightly`/`cargo +nightly-YYYY-MM-DD` for each of the following commands.)
90 Now you can run your project in Miri:
92 1. Run `cargo clean` to eliminate any cached dependencies. Miri needs your
93 dependencies to be compiled the right way, that would not happen if they have
94 previously already been compiled.
95 2. To run all tests in your project through Miri, use `cargo miri test`.
96 3. If you have a binary project, you can run it through Miri using `cargo miri run`.
98 The first time you run Miri, it will perform some extra setup and install some
99 dependencies. It will ask you for confirmation before installing anything.
101 `cargo miri run/test` supports the exact same flags as `cargo run/test`. For
102 example, `cargo miri test filter` only runs the tests containing `filter` in
105 You can pass arguments to Miri via `MIRIFLAGS`. For example,
106 `MIRIFLAGS="-Zmiri-disable-stacked-borrows" cargo miri run` runs the program
107 without checking the aliasing of references.
109 When compiling code via `cargo miri`, the `cfg(miri)` config flag is set for code
110 that will be interpret under Miri. You can use this to ignore test cases that fail
111 under Miri because they do things Miri does not support:
115 #[cfg_attr(miri, ignore)]
116 fn does_not_work_on_miri() {
117 tokio::run(futures::future::ok::<_, ()>(()));
121 There is no way to list all the infinite things Miri cannot do, but the
122 interpreter will explicitly tell you when it finds something unsupported:
125 error: unsupported operation: can't call foreign function: bind
127 = help: this is likely not a bug in the program; it indicates that the program \
128 performed an operation that the interpreter does not support
131 ### Cross-interpretation: running for different targets
133 Miri can not only run a binary or test suite for your host target, it can also
134 perform cross-interpretation for arbitrary foreign targets: `cargo miri run
135 --target x86_64-unknown-linux-gnu` will run your program as if it was a Linux
136 program, no matter your host OS. This is particularly useful if you are using
137 Windows, as the Linux target is much better supported than Windows targets.
139 You can also use this to test platforms with different properties than your host
140 platform. For example `cargo miri test --target mips64-unknown-linux-gnuabi64`
141 will run your test suite on a big-endian target, which is useful for testing
142 endian-sensitive code.
144 ### Running Miri on CI
146 To run Miri on CI, make sure that you handle the case where the latest nightly
147 does not ship the Miri component because it currently does not build. `rustup
148 toolchain install --component` knows how to handle this situation, so the
149 following snippet should always work:
152 rustup toolchain install nightly --component miri
153 rustup override set nightly
158 Here is an example job for GitHub Actions:
163 runs-on: ubuntu-latest
165 - uses: actions/checkout@v2
168 rustup toolchain install nightly --component miri
169 rustup override set nightly
171 - name: Test with Miri
175 The explicit `cargo miri setup` helps to keep the output of the actual test step
180 When using the above instructions, you may encounter a number of confusing compiler
183 ### "note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace"
185 You may see this when trying to get Miri to display a backtrace. By default, Miri
186 doesn't expose any environment to the program, so running
187 `RUST_BACKTRACE=1 cargo miri test` will not do what you expect.
189 To get a backtrace, you need to disable isolation
190 [using `-Zmiri-disable-isolation`][miri-flags]:
193 RUST_BACKTRACE=1 MIRIFLAGS="-Zmiri-disable-isolation" cargo miri test
196 #### "found possibly newer version of crate `std` which `<dependency>` depends on"
198 Your build directory may contain artifacts from an earlier build that have/have
199 not been built for Miri. Run `cargo clean` before switching from non-Miri to
200 Miri builds and vice-versa.
202 #### "found crate `std` compiled by an incompatible version of rustc"
204 You may be running `cargo miri` with a different compiler version than the one
205 used to build the custom libstd that Miri uses, and Miri failed to detect that.
206 Try deleting `~/.cache/miri`.
208 #### "no mir for `std::rt::lang_start_internal`"
210 This means the sysroot you are using was not compiled with Miri in mind. This
211 should never happen when you use `cargo miri` because that takes care of setting
212 up the sysroot. If you are using `miri` (the Miri driver) directly, see the
213 [contributors' guide](CONTRIBUTING.md) for how to use `./miri` to best do that.
216 ## Miri `-Z` flags and environment variables
217 [miri-flags]: #miri--z-flags-and-environment-variables
219 Miri adds its own set of `-Z` flags, which are usually set via the `MIRIFLAGS`
220 environment variable:
222 * `-Zmiri-check-number-validity` enables checking of integer and float validity
223 (e.g., they must be initialized and not carry pointer provenance) as part of
224 enforcing validity invariants. This has no effect when
225 `-Zmiri-disable-validation` is present.
226 * `-Zmiri-compare-exchange-weak-failure-rate=<rate>` changes the failure rate of
227 `compare_exchange_weak` operations. The default is `0.8` (so 4 out of 5 weak ops will fail).
228 You can change it to any value between `0.0` and `1.0`, where `1.0` means it
229 will always fail and `0.0` means it will never fail.
230 * `-Zmiri-disable-abi-check` disables checking [function ABI]. Using this flag
232 * `-Zmiri-disable-alignment-check` disables checking pointer alignment, so you
233 can focus on other failures, but it means Miri can miss bugs in your program.
234 Using this flag is **unsound**.
235 * `-Zmiri-disable-data-race-detector` disables checking for data races. Using
236 this flag is **unsound**.
237 * `-Zmiri-disable-stacked-borrows` disables checking the experimental
238 [Stacked Borrows] aliasing rules. This can make Miri run faster, but it also
239 means no aliasing violations will be detected. Using this flag is **unsound**
240 (but the affected soundness rules are experimental).
241 * `-Zmiri-disable-validation` disables enforcing validity invariants, which are
242 enforced by default. This is mostly useful to focus on other failures (such
243 as out-of-bounds accesses) first. Setting this flag means Miri can miss bugs
244 in your program. However, this can also help to make Miri run faster. Using
245 this flag is **unsound**.
246 * `-Zmiri-disable-isolation` disables host isolation. As a consequence,
247 the program has access to host resources such as environment variables, file
248 systems, and randomness.
249 * `-Zmiri-isolation-error=<action>` configures Miri's response to operations
250 requiring host access while isolation is enabled. `abort`, `hide`, `warn`,
251 and `warn-nobacktrace` are the supported actions. The default is to `abort`,
252 which halts the machine. Some (but not all) operations also support continuing
253 execution with a "permission denied" error being returned to the program.
254 `warn` prints a full backtrace when that happen; `warn-nobacktrace` is less
255 verbose. `hide` hides the warning entirely.
256 * `-Zmiri-env-exclude=<var>` keeps the `var` environment variable isolated from the host so that it
257 cannot be accessed by the program. Can be used multiple times to exclude several variables. On
258 Windows, the `TERM` environment variable is excluded by default. This has no effect unless
259 `-Zmiri-disable-validation` is also set.
260 * `-Zmiri-env-forward=<var>` forwards the `var` environment variable to the interpreted program. Can
261 be used multiple times to forward several variables. This has no effect if
262 `-Zmiri-disable-validation` is set.
263 * `-Zmiri-ignore-leaks` disables the memory leak checker, and also allows some
264 remaining threads to exist when the main thread exits.
265 * `-Zmiri-measureme=<name>` enables `measureme` profiling for the interpreted program.
266 This can be used to find which parts of your program are executing slowly under Miri.
267 The profile is written out to a file with the prefix `<name>`, and can be processed
268 using the tools in the repository https://github.com/rust-lang/measureme.
269 * `-Zmiri-panic-on-unsupported` will makes some forms of unsupported functionality,
270 such as FFI and unsupported syscalls, panic within the context of the emulated
271 application instead of raising an error within the context of Miri (and halting
272 execution). Note that code might not expect these operations to ever panic, so
273 this flag can lead to strange (mis)behavior.
274 * `-Zmiri-seed=<hex>` configures the seed of the RNG that Miri uses to resolve
275 non-determinism. This RNG is used to pick base addresses for allocations.
276 When isolation is enabled (the default), this is also used to emulate system
277 entropy. The default seed is 0. **NOTE**: This entropy is not good enough
278 for cryptographic use! Do not generate secret keys in Miri or perform other
279 kinds of cryptographic operations that rely on proper random numbers.
280 * `-Zmiri-symbolic-alignment-check` makes the alignment check more strict. By
281 default, alignment is checked by casting the pointer to an integer, and making
282 sure that is a multiple of the alignment. This can lead to cases where a
283 program passes the alignment check by pure chance, because things "happened to
284 be" sufficiently aligned -- there is no UB in this execution but there would
285 be UB in others. To avoid such cases, the symbolic alignment check only takes
286 into account the requested alignment of the relevant allocation, and the
287 offset into that allocation. This avoids missing such bugs, but it also
288 incurs some false positives when the code does manual integer arithmetic to
289 ensure alignment. (The standard library `align_to` method works fine in both
290 modes; under symbolic alignment it only fills the middle slice when the
291 allocation guarantees sufficient alignment.)
292 * `-Zmiri-track-alloc-id=<id>` shows a backtrace when the given allocation is
293 being allocated or freed. This helps in debugging memory leaks and
295 * `-Zmiri-track-call-id=<id>` shows a backtrace when the given call id is
296 assigned to a stack frame. This helps in debugging UB related to Stacked
297 Borrows "protectors".
298 * `-Zmiri-track-pointer-tag=<tag>` shows a backtrace when the given pointer tag
299 is popped from a borrow stack (which is where the tag becomes invalid and any
300 future use of it will error). This helps you in finding out why UB is
301 happening and where in your code would be a good place to look for it.
302 * `-Zmiri-tag-raw-pointers` makes Stacked Borrows assign proper tags even for raw pointers. This can
303 make valid code using int-to-ptr casts fail to pass the checks, but also can help identify latent
304 aliasing issues in code that Miri accepts by default. You can recognize false positives by
305 `<untagged>` occurring in the message -- this indicates a pointer that was cast from an integer,
306 so Miri was unable to track this pointer. Note that it is not currently guaranteed that code that
307 works with `-Zmiri-tag-raw-pointers` also works without `-Zmiri-tag-raw-pointers`, but for the
308 vast majority of code, this will be the case.
310 [function ABI]: https://doc.rust-lang.org/reference/items/functions.html#extern-function-qualifier
312 Some native rustc `-Z` flags are also very relevant for Miri:
314 * `-Zmir-opt-level` controls how many MIR optimizations are performed. Miri
315 overrides the default to be `0`; be advised that using any higher level can
316 make Miri miss bugs in your program because they got optimized away.
317 * `-Zalways-encode-mir` makes rustc dump MIR even for completely monomorphic
318 functions. This is needed so that Miri can execute such functions, so Miri
319 sets this flag per default.
320 * `-Zmir-emit-retag` controls whether `Retag` statements are emitted. Miri
321 enables this per default because it is needed for [Stacked Borrows].
323 Moreover, Miri recognizes some environment variables:
325 * `MIRI_LOG`, `MIRI_BACKTRACE` control logging and backtrace printing during
326 Miri executions, also [see "Testing the Miri driver" in `CONTRIBUTING.md`][testing-miri].
327 * `MIRIFLAGS` (recognized by `cargo miri` and the test suite) defines extra
328 flags to be passed to Miri.
329 * `MIRI_LIB_SRC` defines the directory where Miri expects the sources of the
330 standard library that it will build and use for interpretation. This directory
331 must point to the `library` subdirectory of a `rust-lang/rust` repository
332 checkout. Note that changing files in that directory does not automatically
333 trigger a re-build of the standard library; you have to clear the Miri build
334 cache manually (on Linux, `rm -rf ~/.cache/miri`).
335 * `MIRI_SYSROOT` (recognized by `cargo miri` and the test suite)
336 indicates the sysroot to use. To do the same thing with `miri`
337 directly, use the `--sysroot` flag.
338 * `MIRI_TEST_TARGET` (recognized by the test suite) indicates which target
339 architecture to test against. `miri` and `cargo miri` accept the `--target`
340 flag for the same purpose.
342 The following environment variables are *internal* and must not be used by
343 anyone but Miri itself. They are used to communicate between different Miri
344 binaries, and as such worth documenting:
346 * `MIRI_BE_RUSTC` can be set to `host` or `target`. It tells the Miri driver to
347 actually not interpret the code but compile it like rustc would. With `target`, Miri sets
348 some compiler flags to prepare the code for interpretation; with `host`, this is not done.
349 This environment variable is useful to be sure that the compiled `rlib`s are compatible
351 * `MIRI_CALLED_FROM_XARGO` is set during the Miri-induced `xargo` sysroot build,
352 which will re-invoke `cargo-miri` as the `rustc` to use for this build.
353 * `MIRI_CALLED_FROM_RUSTDOC` when set to any value tells `cargo-miri` that it is
354 running as a child process of `rustdoc`, which invokes it twice for each doc-test
355 and requires special treatment, most notably a check-only build before interpretation.
356 This is set by `cargo-miri` itself when running as a `rustdoc`-wrapper.
357 * `MIRI_CWD` when set to any value tells the Miri driver to change to the given
358 directory after loading all the source files, but before commencing
359 interpretation. This is useful if the interpreted program wants a different
360 working directory at run-time than at build-time.
361 * `MIRI_VERBOSE` when set to any value tells the various `cargo-miri` phases to
362 perform verbose logging.
364 [testing-miri]: CONTRIBUTING.md#testing-the-miri-driver
366 ## Miri `extern` functions
368 Miri provides some `extern` functions that programs can import to access
369 Miri-specific functionality:
374 /// Miri-provided extern function to mark the block `ptr` points to as a "root"
375 /// for some static memory. This memory and everything reachable by it is not
376 /// considered leaking even if it still exists when the program terminates.
378 /// `ptr` has to point to the beginning of an allocated block.
379 fn miri_static_root(ptr: *const u8);
381 /// Miri-provided extern function to obtain a backtrace of the current call stack.
382 /// This returns a boxed slice of pointers - each pointer is an opaque value
383 /// that is only useful when passed to `miri_resolve_frame`
384 /// The `flags` argument must be `0`.
385 fn miri_get_backtrace(flags: u64) -> Box<[*mut ()]>;
387 /// Miri-provided extern function to resolve a frame pointer obtained
388 /// from `miri_get_backtrace`. The `flags` argument must be `0`,
389 /// and `MiriFrame` should be declared as follows:
393 /// struct MiriFrame {
394 /// // The name of the function being executed, encoded in UTF-8
396 /// // The filename of the function being executed, encoded in UTF-8
397 /// filename: Box<[u8]>,
398 /// // The line number currently being executed in `filename`, starting from '1'.
400 /// // The column number currently being executed in `filename`, starting from '1'.
402 /// // The function pointer to the function currently being executed.
403 /// // This can be compared against function pointers obtained by
404 /// // casting a function (e.g. `my_fn as *mut ()`)
409 /// The fields must be declared in exactly the same order as they appear in `MiriFrame` above.
410 /// This function can be called on any thread (not just the one which obtained `frame`).
411 fn miri_resolve_frame(frame: *mut (), flags: u64) -> MiriFrame;
413 /// Miri-provided extern function to begin unwinding with the given payload.
415 /// This is internal and unstable and should not be used; we give it here
416 /// just to be complete.
417 fn miri_start_panic(payload: *mut u8) -> !;
421 ## Contributing and getting help
423 If you want to contribute to Miri, great! Please check out our
424 [contribution guide](CONTRIBUTING.md).
426 For help with running Miri, you can open an issue here on
427 GitHub or use the [Miri stream on the Rust Zulip][zulip].
429 [zulip]: https://rust-lang.zulipchat.com/#narrow/stream/269128-miri
433 This project began as part of an undergraduate research course in 2015 by
434 @solson at the [University of Saskatchewan][usask]. There are [slides] and a
435 [report] available from that project. In 2016, @oli-obk joined to prepare miri
436 for eventually being used as const evaluator in the Rust compiler itself
437 (basically, for `const` and `static` stuff), replacing the old evaluator that
438 worked directly on the AST. In 2017, @RalfJung did an internship with Mozilla
439 and began developing miri towards a tool for detecting undefined behavior, and
440 also using miri as a way to explore the consequences of various possible
441 definitions for undefined behavior in Rust. @oli-obk's move of the miri engine
442 into the compiler finally came to completion in early 2018. Meanwhile, later
443 that year, @RalfJung did a second internship, developing miri further with
444 support for checking basic type invariants and verifying that references are
445 used according to their aliasing restrictions.
447 [usask]: https://www.usask.ca/
448 [slides]: https://solson.me/miri-slides.pdf
449 [report]: https://solson.me/miri-report.pdf
451 ## Bugs found by Miri
453 Miri has already found a number of bugs in the Rust standard library and beyond, which we collect here.
457 * [`Debug for vec_deque::Iter` accessing uninitialized memory](https://github.com/rust-lang/rust/issues/53566)
458 * [`Vec::into_iter` doing an unaligned ZST read](https://github.com/rust-lang/rust/pull/53804)
459 * [`From<&[T]> for Rc` creating a not sufficiently aligned reference](https://github.com/rust-lang/rust/issues/54908)
460 * [`BTreeMap` creating a shared reference pointing to a too small allocation](https://github.com/rust-lang/rust/issues/54957)
461 * [`Vec::append` creating a dangling reference](https://github.com/rust-lang/rust/pull/61082)
462 * [Futures turning a shared reference into a mutable one](https://github.com/rust-lang/rust/pull/56319)
463 * [`str` turning a shared reference into a mutable one](https://github.com/rust-lang/rust/pull/58200)
464 * [`rand` performing unaligned reads](https://github.com/rust-random/rand/issues/779)
465 * [The Unix allocator calling `posix_memalign` in an invalid way](https://github.com/rust-lang/rust/issues/62251)
466 * [`getrandom` calling the `getrandom` syscall in an invalid way](https://github.com/rust-random/getrandom/pull/73)
467 * [`Vec`](https://github.com/rust-lang/rust/issues/69770) and [`BTreeMap`](https://github.com/rust-lang/rust/issues/69769) leaking memory under some (panicky) conditions
468 * [`beef` leaking memory](https://github.com/maciejhirsz/beef/issues/12)
469 * [`EbrCell` using uninitialized memory incorrectly](https://github.com/Firstyear/concread/commit/b15be53b6ec076acb295a5c0483cdb4bf9be838f#diff-6282b2fc8e98bd089a1f0c86f648157cR229)
470 * [TiKV performing an unaligned pointer access](https://github.com/tikv/tikv/issues/7613)
471 * [`servo_arc` creating a dangling shared reference](https://github.com/servo/servo/issues/26357)
472 * [TiKV constructing out-of-bounds pointers (and overlapping mutable references)](https://github.com/tikv/tikv/pull/7751)
473 * [`encoding_rs` doing out-of-bounds pointer arithmetic](https://github.com/hsivonen/encoding_rs/pull/53)
474 * [TiKV using `Vec::from_raw_parts` incorrectly](https://github.com/tikv/agatedb/pull/24)
475 * Incorrect doctests for [`AtomicPtr`](https://github.com/rust-lang/rust/pull/84052) and [`Box::from_raw_in`](https://github.com/rust-lang/rust/pull/84053)
476 * [Insufficient alignment in `ThinVec`](https://github.com/Gankra/thin-vec/pull/27)
477 * [`crossbeam-epoch` calling `assume_init` on a partly-initialized `MaybeUninit`](https://github.com/crossbeam-rs/crossbeam/pull/779)
478 * [`integer-encoding` dereferencing a misaligned pointer](https://github.com/dermesser/integer-encoding-rs/pull/23)
479 * [`rkyv` constructing a `Box<[u8]>` from an overaligned allocation](https://github.com/rkyv/rkyv/commit/a9417193a34757e12e24263178be8b2eebb72456)
481 Violations of [Stacked Borrows] found that are likely bugs (but Stacked Borrows is currently just an experiment):
483 * [`VecDeque::drain` creating overlapping mutable references](https://github.com/rust-lang/rust/pull/56161)
484 * Various `BTreeMap` problems
485 * [`BTreeMap` iterators creating mutable references that overlap with shared references](https://github.com/rust-lang/rust/pull/58431)
486 * [`BTreeMap::iter_mut` creating overlapping mutable references](https://github.com/rust-lang/rust/issues/73915)
487 * [`BTreeMap` node insertion using raw pointers outside their valid memory area](https://github.com/rust-lang/rust/issues/78477)
488 * [`LinkedList` cursor insertion creating overlapping mutable references](https://github.com/rust-lang/rust/pull/60072)
489 * [`Vec::push` invalidating existing references into the vector](https://github.com/rust-lang/rust/issues/60847)
490 * [`align_to_mut` violating uniqueness of mutable references](https://github.com/rust-lang/rust/issues/68549)
491 * [`sized-chunks` creating aliasing mutable references](https://github.com/bodil/sized-chunks/issues/8)
492 * [`String::push_str` invalidating existing references into the string](https://github.com/rust-lang/rust/issues/70301)
493 * [`ryu` using raw pointers outside their valid memory area](https://github.com/dtolnay/ryu/issues/24)
494 * [ink! creating overlapping mutable references](https://github.com/rust-lang/miri/issues/1364)
495 * [TiKV creating overlapping mutable reference and raw pointer](https://github.com/tikv/tikv/pull/7709)
496 * [Windows `Env` iterator using a raw pointer outside its valid memory area](https://github.com/rust-lang/rust/pull/70479)
497 * [`VecDeque::iter_mut` creating overlapping mutable references](https://github.com/rust-lang/rust/issues/74029)
498 * [Various standard library aliasing issues involving raw pointers](https://github.com/rust-lang/rust/pull/78602)
499 * [`<[T]>::copy_within` using a loan after invalidating it](https://github.com/rust-lang/rust/pull/85610)
503 Licensed under either of
505 * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
506 http://www.apache.org/licenses/LICENSE-2.0)
507 * MIT license ([LICENSE-MIT](LICENSE-MIT) or
508 http://opensource.org/licenses/MIT)
514 Unless you explicitly state otherwise, any contribution intentionally submitted
515 for inclusion in the work by you shall be dual licensed as above, without any
516 additional terms or conditions.