Initial vendor packages

Signed-off-by: Valentin Popov <valentin@popov.link>

8 files changed, 1003 insertions, 0 deletions

diff --git a/vendor/scopeguard/.cargo-checksum.json b/vendor/scopeguard/.cargo-checksum.json
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+{"files":{"Cargo.lock":"684e99cc5938e7e51e1c5808214f9125ccfe66efa6ca5392303a7ee5337e1294","Cargo.toml":"68899251551903e2e1ba03c927f12e4c19fc8a15e8bd3756610f53f5ec075b48","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"fb77f0a9c53e473abe5103c8632ef9f0f2874d4fb3f17cb2d8c661aab9cee9d7","README.md":"68d5a7beebf814cffaaf6fe5758984fd06554b3bb5a49b2e13fc101522909b91","examples/readme.rs":"c6b1b458a130e091b1465040184759f1cc7d4e8de8d9cb893def0107238c2964","src/lib.rs":"3fb8bba1227724954c01cf98ec984bcf49ee74624faa74eb1bcea9018682751c"},"package":"94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"}
\ No newline at end of file
diff --git a/vendor/scopeguard/Cargo.lock b/vendor/scopeguard/Cargo.lock
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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "scopeguard"
+version = "1.2.0"
diff --git a/vendor/scopeguard/Cargo.toml b/vendor/scopeguard/Cargo.toml
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+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+name = "scopeguard"
+version = "1.2.0"
+authors = ["bluss"]
+description = """
+A RAII scope guard that will run a given closure when it goes out of scope,
+even if the code between panics (assuming unwinding panic).
+
+Defines the macros `defer!`, `defer_on_unwind!`, `defer_on_success!` as
+shorthands for guards with one of the implemented strategies.
+"""
+documentation = "https://docs.rs/scopeguard/"
+readme = "README.md"
+keywords = [
+    "scope-guard",
+    "defer",
+    "panic",
+    "unwind",
+]
+categories = [
+    "rust-patterns",
+    "no-std",
+]
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/bluss/scopeguard"
+
+[package.metadata.release]
+no-dev-version = true
+
+[features]
+default = ["use_std"]
+use_std = []
diff --git a/vendor/scopeguard/LICENSE-APACHE b/vendor/scopeguard/LICENSE-APACHE
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index 0000000..16fe87b
--- /dev/null
+++ b/vendor/scopeguard/LICENSE-APACHE
@@ -0,0 +1,201 @@
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diff --git a/vendor/scopeguard/LICENSE-MIT b/vendor/scopeguard/LICENSE-MIT
new file mode 100644
index 0000000..8514471
--- /dev/null
+++ b/vendor/scopeguard/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2016-2019 Ulrik Sverdrup "bluss" and scopeguard developers
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/vendor/scopeguard/README.md b/vendor/scopeguard/README.md
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+++ b/vendor/scopeguard/README.md
@@ -0,0 +1,102 @@
+# scopeguard
+
+Rust crate for a convenient RAII scope guard that will run a given closure when
+it goes out of scope, even if the code between panics (assuming unwinding panic).
+
+The `defer!` macro and `guard` are `no_std` compatible (require only `core`),
+but the on unwinding / not on unwinding strategies require linking to `std`.
+By default, the `use_std` crate feature is enabled. Disable the default features
+for `no_std` support.
+
+Please read the [API documentation here](https://docs.rs/scopeguard/).
+
+Minimum supported Rust version: 1.20
+
+[![build_status](https://github.com/bluss/scopeguard/actions/workflows/ci.yaml/badge.svg)](https://github.com/bluss/scopeguard/actions/workflows/ci.yaml)
+[![crates](https://img.shields.io/crates/v/scopeguard.svg)](https://crates.io/crates/scopeguard)
+
+## How to use
+
+```rs
+#[macro_use(defer)]
+extern crate scopeguard;
+
+use scopeguard::guard;
+
+fn f() {
+    defer! {
+        println!("Called at return or panic");
+    }
+    panic!();
+}
+
+use std::fs::File;
+use std::io::Write;
+
+fn g() {
+    let f = File::create("newfile.txt").unwrap();
+    let mut file = guard(f, |f| {
+        // write file at return or panic
+        let _ = f.sync_all();
+    });
+    // access the file through the scope guard itself
+    file.write_all(b"test me\n").unwrap();
+}
+```
+
+## Recent Changes
+
+- 1.2.0
+
+  - Use ManuallyDrop instead of mem::forget in into_inner. (by @willtunnels)
+  - Warn if the guard is not assigned to a variable and is dropped immediately
+    instead of at the scope's end. (by @sergey-v-galtsev)
+
+- 1.1.0
+
+  - Change macros (`defer!`, `defer_on_success!` and `defer_on_unwind!`)
+    to accept statements. (by @konsumlamm)
+
+- 1.0.0
+
+  - Change the closure type from `FnMut(&mut T)` to `FnOnce(T)`:
+    Passing the inner value by value instead of a mutable reference is a
+    breaking change, but allows the guard closure to consume it. (by @tormol)
+
+  - Add `defer_on_success!`, `guard_on_success()` and `OnSuccess`
+    strategy, which triggers when scope is exited *without* panic. It's the
+    opposite to `defer_on_unwind!` / `guard_on_unwind()` / `OnUnwind`.
+
+  - Add `ScopeGuard::into_inner()`, which "defuses" the guard and returns the
+    guarded value. (by @tormol)
+
+  - Implement `Sync` for guards with non-`Sync` closures.
+
+  - Require Rust 1.20
+
+- 0.3.3
+
+  - Use `#[inline]` on a few more functions by @stjepang (#14)
+  - Add examples to crate documentation
+
+- 0.3.2
+
+  - Add crate categories
+
+- 0.3.1
+
+  - Add `defer_on_unwind!`, `Strategy` trait
+  - Rename `Guard` → `ScopeGuard`
+  - Add `ScopeGuard::with_strategy`.
+  - `ScopeGuard` now implements `Debug`.
+  - Require Rust 1.11
+
+- 0.2.0
+
+  - Require Rust 1.6
+  - Use `no_std` unconditionally
+  - No other changes
+
+- 0.1.2
+
+  - Add macro `defer!`
diff --git a/vendor/scopeguard/examples/readme.rs b/vendor/scopeguard/examples/readme.rs
new file mode 100644
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--- /dev/null
+++ b/vendor/scopeguard/examples/readme.rs
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+#[macro_use(defer)]
+extern crate scopeguard;
+
+use scopeguard::guard;
+
+fn f() {
+    defer! {
+        println!("Called at return or panic");
+    }
+    panic!();
+}
+
+use std::fs::File;
+use std::io::Write;
+
+fn g() {
+    let f = File::create("newfile.txt").unwrap();
+    let mut file = guard(f, |f| {
+        // write file at return or panic
+        let _ = f.sync_all();
+    });
+    // access the file through the scope guard itself
+    file.write_all(b"test me\n").unwrap();
+}
+
+fn main() {
+    f();
+    g();
+}
diff --git a/vendor/scopeguard/src/lib.rs b/vendor/scopeguard/src/lib.rs
new file mode 100644
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--- /dev/null
+++ b/vendor/scopeguard/src/lib.rs
@@ -0,0 +1,595 @@
+#![cfg_attr(not(any(test, feature = "use_std")), no_std)]
+#![doc(html_root_url = "https://docs.rs/scopeguard/1/")]
+
+//! A scope guard will run a given closure when it goes out of scope,
+//! even if the code between panics.
+//! (as long as panic doesn't abort)
+//!
+//! # Examples
+//!
+//! ## Hello World
+//!
+//! This example creates a scope guard with an example function:
+//!
+//! ```
+//! extern crate scopeguard;
+//!
+//! fn f() {
+//!     let _guard = scopeguard::guard((), |_| {
+//!         println!("Hello Scope Exit!");
+//!     });
+//!
+//!     // rest of the code here.
+//!
+//!     // Here, at the end of `_guard`'s scope, the guard's closure is called.
+//!     // It is also called if we exit this scope through unwinding instead.
+//! }
+//! # fn main() {
+//! #    f();
+//! # }
+//! ```
+//!
+//! ## `defer!`
+//!
+//! Use the `defer` macro to run an operation at scope exit,
+//! either regular scope exit or during unwinding from a panic.
+//!
+//! ```
+//! #[macro_use(defer)] extern crate scopeguard;
+//!
+//! use std::cell::Cell;
+//!
+//! fn main() {
+//!     // use a cell to observe drops during and after the scope guard is active
+//!     let drop_counter = Cell::new(0);
+//!     {
+//!         // Create a scope guard using `defer!` for the current scope
+//!         defer! {
+//!             drop_counter.set(1 + drop_counter.get());
+//!         }
+//!
+//!         // Do regular operations here in the meantime.
+//!
+//!         // Just before scope exit: it hasn't run yet.
+//!         assert_eq!(drop_counter.get(), 0);
+//!
+//!         // The following scope end is where the defer closure is called
+//!     }
+//!     assert_eq!(drop_counter.get(), 1);
+//! }
+//! ```
+//!
+//! ## Scope Guard with Value
+//!
+//! If the scope guard closure needs to access an outer value that is also
+//! mutated outside of the scope guard, then you may want to use the scope guard
+//! with a value. The guard works like a smart pointer, so the inner value can
+//! be accessed by reference or by mutable reference.
+//!
+//! ### 1. The guard owns a file
+//!
+//! In this example, the scope guard owns a file and ensures pending writes are
+//! synced at scope exit.
+//!
+//! ```
+//! extern crate scopeguard;
+//!
+//! use std::fs::*;
+//! use std::io::{self, Write};
+//! # // Mock file so that we don't actually write a file
+//! # struct MockFile;
+//! # impl MockFile {
+//! #     fn create(_s: &str) -> io::Result<Self> { Ok(MockFile) }
+//! #     fn write_all(&self, _b: &[u8]) -> io::Result<()> { Ok(()) }
+//! #     fn sync_all(&self) -> io::Result<()> { Ok(()) }
+//! # }
+//! # use self::MockFile as File;
+//!
+//! fn try_main() -> io::Result<()> {
+//!     let f = File::create("newfile.txt")?;
+//!     let mut file = scopeguard::guard(f, |f| {
+//!         // ensure we flush file at return or panic
+//!         let _ = f.sync_all();
+//!     });
+//!     // Access the file through the scope guard itself
+//!     file.write_all(b"test me\n").map(|_| ())
+//! }
+//!
+//! fn main() {
+//!     try_main().unwrap();
+//! }
+//!
+//! ```
+//!
+//! ### 2. The guard restores an invariant on scope exit
+//!
+//! ```
+//! extern crate scopeguard;
+//!
+//! use std::mem::ManuallyDrop;
+//! use std::ptr;
+//!
+//! // This function, just for this example, takes the first element
+//! // and inserts it into the assumed sorted tail of the vector.
+//! //
+//! // For optimization purposes we temporarily violate an invariant of the
+//! // Vec, that it owns all of its elements.
+//! //
+//! // The safe approach is to use swap, which means two writes to memory,
+//! // the optimization is to use a “hole” which uses only one write of memory
+//! // for each position it moves.
+//! //
+//! // We *must* use a scope guard to run this code safely. We
+//! // are running arbitrary user code (comparison operators) that may panic.
+//! // The scope guard ensures we restore the invariant after successful
+//! // exit or during unwinding from panic.
+//! fn insertion_sort_first<T>(v: &mut Vec<T>)
+//!     where T: PartialOrd
+//! {
+//!     struct Hole<'a, T: 'a> {
+//!         v: &'a mut Vec<T>,
+//!         index: usize,
+//!         value: ManuallyDrop<T>,
+//!     }
+//!
+//!     unsafe {
+//!         // Create a moved-from location in the vector, a “hole”.
+//!         let value = ptr::read(&v[0]);
+//!         let mut hole = Hole { v: v, index: 0, value: ManuallyDrop::new(value) };
+//!
+//!         // Use a scope guard with a value.
+//!         // At scope exit, plug the hole so that the vector is fully
+//!         // initialized again.
+//!         // The scope guard owns the hole, but we can access it through the guard.
+//!         let mut hole_guard = scopeguard::guard(hole, |hole| {
+//!             // plug the hole in the vector with the value that was // taken out
+//!             let index = hole.index;
+//!             ptr::copy_nonoverlapping(&*hole.value, &mut hole.v[index], 1);
+//!         });
+//!
+//!         // run algorithm that moves the hole in the vector here
+//!         // move the hole until it's in a sorted position
+//!         for i in 1..hole_guard.v.len() {
+//!             if *hole_guard.value >= hole_guard.v[i] {
+//!                 // move the element back and the hole forward
+//!                 let index = hole_guard.index;
+//!                 hole_guard.v.swap(index, index + 1);
+//!                 hole_guard.index += 1;
+//!             } else {
+//!                 break;
+//!             }
+//!         }
+//!
+//!         // When the scope exits here, the Vec becomes whole again!
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let string = String::from;
+//!     let mut data = vec![string("c"), string("a"), string("b"), string("d")];
+//!     insertion_sort_first(&mut data);
+//!     assert_eq!(data, vec!["a", "b", "c", "d"]);
+//! }
+//!
+//! ```
+//!
+//!
+//! # Crate Features
+//!
+//! - `use_std`
+//!   + Enabled by default. Enables the `OnUnwind` and `OnSuccess` strategies.
+//!   + Disable to use `no_std`.
+//!
+//! # Rust Version
+//!
+//! This version of the crate requires Rust 1.20 or later.
+//!
+//! The scopeguard 1.x release series will use a carefully considered version
+//! upgrade policy, where in a later 1.x version, we will raise the minimum
+//! required Rust version.
+
+#[cfg(not(any(test, feature = "use_std")))]
+extern crate core as std;
+
+use std::fmt;
+use std::marker::PhantomData;
+use std::mem::ManuallyDrop;
+use std::ops::{Deref, DerefMut};
+use std::ptr;
+
+/// Controls in which cases the associated code should be run
+pub trait Strategy {
+    /// Return `true` if the guard’s associated code should run
+    /// (in the context where this method is called).
+    fn should_run() -> bool;
+}
+
+/// Always run on scope exit.
+///
+/// “Always” run: on regular exit from a scope or on unwinding from a panic.
+/// Can not run on abort, process exit, and other catastrophic events where
+/// destructors don’t run.
+#[derive(Debug)]
+pub enum Always {}
+
+/// Run on scope exit through unwinding.
+///
+/// Requires crate feature `use_std`.
+#[cfg(feature = "use_std")]
+#[derive(Debug)]
+pub enum OnUnwind {}
+
+/// Run on regular scope exit, when not unwinding.
+///
+/// Requires crate feature `use_std`.
+#[cfg(feature = "use_std")]
+#[derive(Debug)]
+pub enum OnSuccess {}
+
+impl Strategy for Always {
+    #[inline(always)]
+    fn should_run() -> bool {
+        true
+    }
+}
+
+#[cfg(feature = "use_std")]
+impl Strategy for OnUnwind {
+    #[inline]
+    fn should_run() -> bool {
+        std::thread::panicking()
+    }
+}
+
+#[cfg(feature = "use_std")]
+impl Strategy for OnSuccess {
+    #[inline]
+    fn should_run() -> bool {
+        !std::thread::panicking()
+    }
+}
+
+/// Macro to create a `ScopeGuard` (always run).
+///
+/// The macro takes statements, which are the body of a closure
+/// that will run when the scope is exited.
+#[macro_export]
+macro_rules! defer {
+    ($($t:tt)*) => {
+        let _guard = $crate::guard((), |()| { $($t)* });
+    };
+}
+
+/// Macro to create a `ScopeGuard` (run on successful scope exit).
+///
+/// The macro takes statements, which are the body of a closure
+/// that will run when the scope is exited.
+///
+/// Requires crate feature `use_std`.
+#[cfg(feature = "use_std")]
+#[macro_export]
+macro_rules! defer_on_success {
+    ($($t:tt)*) => {
+        let _guard = $crate::guard_on_success((), |()| { $($t)* });
+    };
+}
+
+/// Macro to create a `ScopeGuard` (run on unwinding from panic).
+///
+/// The macro takes statements, which are the body of a closure
+/// that will run when the scope is exited.
+///
+/// Requires crate feature `use_std`.
+#[cfg(feature = "use_std")]
+#[macro_export]
+macro_rules! defer_on_unwind {
+    ($($t:tt)*) => {
+        let _guard = $crate::guard_on_unwind((), |()| { $($t)* });
+    };
+}
+
+/// `ScopeGuard` is a scope guard that may own a protected value.
+///
+/// If you place a guard in a local variable, the closure can
+/// run regardless how you leave the scope — through regular return or panic
+/// (except if panic or other code aborts; so as long as destructors run).
+/// It is run only once.
+///
+/// The `S` parameter for [`Strategy`](trait.Strategy.html) determines if
+/// the closure actually runs.
+///
+/// The guard's closure will be called with the held value in the destructor.
+///
+/// The `ScopeGuard` implements `Deref` so that you can access the inner value.
+pub struct ScopeGuard<T, F, S = Always>
+where
+    F: FnOnce(T),
+    S: Strategy,
+{
+    value: ManuallyDrop<T>,
+    dropfn: ManuallyDrop<F>,
+    // fn(S) -> S is used, so that the S is not taken into account for auto traits.
+    strategy: PhantomData<fn(S) -> S>,
+}
+
+impl<T, F, S> ScopeGuard<T, F, S>
+where
+    F: FnOnce(T),
+    S: Strategy,
+{
+    /// Create a `ScopeGuard` that owns `v` (accessible through deref) and calls
+    /// `dropfn` when its destructor runs.
+    ///
+    /// The `Strategy` decides whether the scope guard's closure should run.
+    #[inline]
+    #[must_use]
+    pub fn with_strategy(v: T, dropfn: F) -> ScopeGuard<T, F, S> {
+        ScopeGuard {
+            value: ManuallyDrop::new(v),
+            dropfn: ManuallyDrop::new(dropfn),
+            strategy: PhantomData,
+        }
+    }
+
+    /// “Defuse” the guard and extract the value without calling the closure.
+    ///
+    /// ```
+    /// extern crate scopeguard;
+    ///
+    /// use scopeguard::{guard, ScopeGuard};
+    ///
+    /// fn conditional() -> bool { true }
+    ///
+    /// fn main() {
+    ///     let mut guard = guard(Vec::new(), |mut v| v.clear());
+    ///     guard.push(1);
+    ///
+    ///     if conditional() {
+    ///         // a condition maybe makes us decide to
+    ///         // “defuse” the guard and get back its inner parts
+    ///         let value = ScopeGuard::into_inner(guard);
+    ///     } else {
+    ///         // guard still exists in this branch
+    ///     }
+    /// }
+    /// ```
+    #[inline]
+    pub fn into_inner(guard: Self) -> T {
+        // Cannot move out of `Drop`-implementing types,
+        // so `ptr::read` the value and forget the guard.
+        let mut guard = ManuallyDrop::new(guard);
+        unsafe {
+            let value = ptr::read(&*guard.value);
+            // Drop the closure after `value` has been read, so that if the
+            // closure's `drop` function panics, unwinding still tries to drop
+            // `value`.
+            ManuallyDrop::drop(&mut guard.dropfn);
+            value
+        }
+    }
+}
+
+/// Create a new `ScopeGuard` owning `v` and with deferred closure `dropfn`.
+#[inline]
+#[must_use]
+pub fn guard<T, F>(v: T, dropfn: F) -> ScopeGuard<T, F, Always>
+where
+    F: FnOnce(T),
+{
+    ScopeGuard::with_strategy(v, dropfn)
+}
+
+/// Create a new `ScopeGuard` owning `v` and with deferred closure `dropfn`.
+///
+/// Requires crate feature `use_std`.
+#[cfg(feature = "use_std")]
+#[inline]
+#[must_use]
+pub fn guard_on_success<T, F>(v: T, dropfn: F) -> ScopeGuard<T, F, OnSuccess>
+where
+    F: FnOnce(T),
+{
+    ScopeGuard::with_strategy(v, dropfn)
+}
+
+/// Create a new `ScopeGuard` owning `v` and with deferred closure `dropfn`.
+///
+/// Requires crate feature `use_std`.
+///
+/// ## Examples
+///
+/// For performance reasons, or to emulate “only run guard on unwind” in
+/// no-std environments, we can also use the default guard and simply manually
+/// defuse it at the end of scope like the following example. (The performance
+/// reason would be if the [`OnUnwind`]'s call to [std::thread::panicking()] is
+/// an issue.)
+///
+/// ```
+/// extern crate scopeguard;
+///
+/// use scopeguard::ScopeGuard;
+/// # fn main() {
+/// {
+///     let guard = scopeguard::guard((), |_| {});
+///
+///     // rest of the code here
+///
+///     // we reached the end of scope without unwinding - defuse it
+///     ScopeGuard::into_inner(guard);
+/// }
+/// # }
+/// ```
+#[cfg(feature = "use_std")]
+#[inline]
+#[must_use]
+pub fn guard_on_unwind<T, F>(v: T, dropfn: F) -> ScopeGuard<T, F, OnUnwind>
+where
+    F: FnOnce(T),
+{
+    ScopeGuard::with_strategy(v, dropfn)
+}
+
+// ScopeGuard can be Sync even if F isn't because the closure is
+// not accessible from references.
+// The guard does not store any instance of S, so it is also irrelevant.
+unsafe impl<T, F, S> Sync for ScopeGuard<T, F, S>
+where
+    T: Sync,
+    F: FnOnce(T),
+    S: Strategy,
+{
+}
+
+impl<T, F, S> Deref for ScopeGuard<T, F, S>
+where
+    F: FnOnce(T),
+    S: Strategy,
+{
+    type Target = T;
+
+    fn deref(&self) -> &T {
+        &*self.value
+    }
+}
+
+impl<T, F, S> DerefMut for ScopeGuard<T, F, S>
+where
+    F: FnOnce(T),
+    S: Strategy,
+{
+    fn deref_mut(&mut self) -> &mut T {
+        &mut *self.value
+    }
+}
+
+impl<T, F, S> Drop for ScopeGuard<T, F, S>
+where
+    F: FnOnce(T),
+    S: Strategy,
+{
+    fn drop(&mut self) {
+        // This is OK because the fields are `ManuallyDrop`s
+        // which will not be dropped by the compiler.
+        let (value, dropfn) = unsafe { (ptr::read(&*self.value), ptr::read(&*self.dropfn)) };
+        if S::should_run() {
+            dropfn(value);
+        }
+    }
+}
+
+impl<T, F, S> fmt::Debug for ScopeGuard<T, F, S>
+where
+    T: fmt::Debug,
+    F: FnOnce(T),
+    S: Strategy,
+{
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct(stringify!(ScopeGuard))
+            .field("value", &*self.value)
+            .finish()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::cell::Cell;
+    use std::panic::catch_unwind;
+    use std::panic::AssertUnwindSafe;
+
+    #[test]
+    fn test_defer() {
+        let drops = Cell::new(0);
+        defer!(drops.set(1000));
+        assert_eq!(drops.get(), 0);
+    }
+
+    #[cfg(feature = "use_std")]
+    #[test]
+    fn test_defer_success_1() {
+        let drops = Cell::new(0);
+        {
+            defer_on_success!(drops.set(1));
+            assert_eq!(drops.get(), 0);
+        }
+        assert_eq!(drops.get(), 1);
+    }
+
+    #[cfg(feature = "use_std")]
+    #[test]
+    fn test_defer_success_2() {
+        let drops = Cell::new(0);
+        let _ = catch_unwind(AssertUnwindSafe(|| {
+            defer_on_success!(drops.set(1));
+            panic!("failure")
+        }));
+        assert_eq!(drops.get(), 0);
+    }
+
+    #[cfg(feature = "use_std")]
+    #[test]
+    fn test_defer_unwind_1() {
+        let drops = Cell::new(0);
+        let _ = catch_unwind(AssertUnwindSafe(|| {
+            defer_on_unwind!(drops.set(1));
+            assert_eq!(drops.get(), 0);
+            panic!("failure")
+        }));
+        assert_eq!(drops.get(), 1);
+    }
+
+    #[cfg(feature = "use_std")]
+    #[test]
+    fn test_defer_unwind_2() {
+        let drops = Cell::new(0);
+        {
+            defer_on_unwind!(drops.set(1));
+        }
+        assert_eq!(drops.get(), 0);
+    }
+
+    #[test]
+    fn test_only_dropped_by_closure_when_run() {
+        let value_drops = Cell::new(0);
+        let value = guard((), |()| value_drops.set(1 + value_drops.get()));
+        let closure_drops = Cell::new(0);
+        let guard = guard(value, |_| closure_drops.set(1 + closure_drops.get()));
+        assert_eq!(value_drops.get(), 0);
+        assert_eq!(closure_drops.get(), 0);
+        drop(guard);
+        assert_eq!(value_drops.get(), 1);
+        assert_eq!(closure_drops.get(), 1);
+    }
+
+    #[cfg(feature = "use_std")]
+    #[test]
+    fn test_dropped_once_when_not_run() {
+        let value_drops = Cell::new(0);
+        let value = guard((), |()| value_drops.set(1 + value_drops.get()));
+        let captured_drops = Cell::new(0);
+        let captured = guard((), |()| captured_drops.set(1 + captured_drops.get()));
+        let closure_drops = Cell::new(0);
+        let guard = guard_on_unwind(value, |value| {
+            drop(value);
+            drop(captured);
+            closure_drops.set(1 + closure_drops.get())
+        });
+        assert_eq!(value_drops.get(), 0);
+        assert_eq!(captured_drops.get(), 0);
+        assert_eq!(closure_drops.get(), 0);
+        drop(guard);
+        assert_eq!(value_drops.get(), 1);
+        assert_eq!(captured_drops.get(), 1);
+        assert_eq!(closure_drops.get(), 0);
+    }
+
+    #[test]
+    fn test_into_inner() {
+        let dropped = Cell::new(false);
+        let value = guard(42, |_| dropped.set(true));
+        let guard = guard(value, |_| dropped.set(true));
+        let inner = ScopeGuard::into_inner(guard);
+        assert_eq!(dropped.get(), false);
+        assert_eq!(*inner, 42);
+    }
+}