Adding upstream version 115.7.0esr.upstream/115.7.0esr

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

2 files changed, 1743 insertions, 0 deletions

diff --git a/third_party/rust/bitflags/src/example_generated.rs b/third_party/rust/bitflags/src/example_generated.rs
new file mode 100644
index 0000000000..cf188d99cb
--- /dev/null
+++ b/third_party/rust/bitflags/src/example_generated.rs
@@ -0,0 +1,14 @@
+//! This module shows an example of code generated by the macro. **IT MUST NOT BE USED OUTSIDE THIS
+//! CRATE**.
+
+bitflags! {
+    /// This is the same `Flags` struct defined in the [crate level example](../index.html#example).
+    /// Note that this struct is just for documentation purposes only, it must not be used outside
+    /// this crate.
+    pub struct Flags: u32 {
+        const A = 0b00000001;
+        const B = 0b00000010;
+        const C = 0b00000100;
+        const ABC = Self::A.bits | Self::B.bits | Self::C.bits;
+    }
+}
diff --git a/third_party/rust/bitflags/src/lib.rs b/third_party/rust/bitflags/src/lib.rs
new file mode 100644
index 0000000000..935e432f17
--- /dev/null
+++ b/third_party/rust/bitflags/src/lib.rs
@@ -0,0 +1,1729 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! A typesafe bitmask flag generator useful for sets of C-style bitmask flags.
+//! It can be used for creating typesafe wrappers around C APIs.
+//!
+//! The `bitflags!` macro generates `struct`s that manage a set of flags. The
+//! flags should only be defined for integer types, otherwise unexpected type
+//! errors may occur at compile time.
+//!
+//! # Example
+//!
+//! ```
+//! use bitflags::bitflags;
+//!
+//! bitflags! {
+//!     struct Flags: u32 {
+//!         const A = 0b00000001;
+//!         const B = 0b00000010;
+//!         const C = 0b00000100;
+//!         const ABC = Self::A.bits | Self::B.bits | Self::C.bits;
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let e1 = Flags::A | Flags::C;
+//!     let e2 = Flags::B | Flags::C;
+//!     assert_eq!((e1 | e2), Flags::ABC);   // union
+//!     assert_eq!((e1 & e2), Flags::C);     // intersection
+//!     assert_eq!((e1 - e2), Flags::A);     // set difference
+//!     assert_eq!(!e2, Flags::A);           // set complement
+//! }
+//! ```
+//!
+//! See [`example_generated::Flags`](./example_generated/struct.Flags.html) for documentation of code
+//! generated by the above `bitflags!` expansion.
+//!
+//! The generated `struct`s can also be extended with type and trait
+//! implementations:
+//!
+//! ```
+//! use std::fmt;
+//!
+//! use bitflags::bitflags;
+//!
+//! bitflags! {
+//!     struct Flags: u32 {
+//!         const A = 0b00000001;
+//!         const B = 0b00000010;
+//!     }
+//! }
+//!
+//! impl Flags {
+//!     pub fn clear(&mut self) {
+//!         self.bits = 0;  // The `bits` field can be accessed from within the
+//!                         // same module where the `bitflags!` macro was invoked.
+//!     }
+//! }
+//!
+//! impl fmt::Display for Flags {
+//!     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+//!         write!(f, "hi!")
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let mut flags = Flags::A | Flags::B;
+//!     flags.clear();
+//!     assert!(flags.is_empty());
+//!     assert_eq!(format!("{}", flags), "hi!");
+//!     assert_eq!(format!("{:?}", Flags::A | Flags::B), "A | B");
+//!     assert_eq!(format!("{:?}", Flags::B), "B");
+//! }
+//! ```
+//!
+//! # Visibility
+//!
+//! The generated structs and their associated flag constants are not exported
+//! out of the current module by default. A definition can be exported out of
+//! the current module by adding `pub` before `struct`:
+//!
+//! ```
+//! mod example {
+//!     use bitflags::bitflags;
+//!
+//!     bitflags! {
+//!         pub struct Flags1: u32 {
+//!             const A = 0b00000001;
+//!         }
+//!
+//! #       pub
+//!         struct Flags2: u32 {
+//!             const B = 0b00000010;
+//!         }
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let flag1 = example::Flags1::A;
+//!     let flag2 = example::Flags2::B; // error: const `B` is private
+//! }
+//! ```
+//!
+//! # Attributes
+//!
+//! Attributes can be attached to the generated `struct`s by placing them
+//! before the `struct` keyword.
+//!
+//! ## Representations
+//!
+//! It's valid to add a `#[repr(C)]` or `#[repr(transparent)]` attribute to a type
+//! generated by `bitflags!`. In these cases, the type is guaranteed to be a newtype.
+//!
+//! ```
+//! use bitflags::bitflags;
+//!
+//! bitflags! {
+//!     #[repr(transparent)]
+//!     struct Flags: u32 {
+//!         const A = 0b00000001;
+//!         const B = 0b00000010;
+//!         const C = 0b00000100;
+//!     }
+//! }
+//! ```
+//!
+//! # Trait implementations
+//!
+//! The `Copy`, `Clone`, `PartialEq`, `Eq`, `PartialOrd`, `Ord` and `Hash`
+//! traits are automatically derived for the `struct`s using the `derive` attribute.
+//! Additional traits can be derived by providing an explicit `derive`
+//! attribute on `struct`.
+//!
+//! The `Extend` and `FromIterator` traits are implemented for the `struct`s,
+//! too: `Extend` adds the union of the instances of the `struct` iterated over,
+//! while `FromIterator` calculates the union.
+//!
+//! The `Binary`, `Debug`, `LowerHex`, `Octal` and `UpperHex` traits are also
+//! implemented by displaying the bits value of the internal struct.
+//!
+//! ## Operators
+//!
+//! The following operator traits are implemented for the generated `struct`s:
+//!
+//! - `BitOr` and `BitOrAssign`: union
+//! - `BitAnd` and `BitAndAssign`: intersection
+//! - `BitXor` and `BitXorAssign`: toggle
+//! - `Sub` and `SubAssign`: set difference
+//! - `Not`: set complement
+//!
+//! # Methods
+//!
+//! The following methods are defined for the generated `struct`s:
+//!
+//! - `empty`: an empty set of flags
+//! - `all`: the set of all defined flags
+//! - `bits`: the raw value of the flags currently stored
+//! - `from_bits`: convert from underlying bit representation, unless that
+//!                representation contains bits that do not correspond to a
+//!                defined flag
+//! - `from_bits_truncate`: convert from underlying bit representation, dropping
+//!                         any bits that do not correspond to defined flags
+//! - `from_bits_unchecked`: convert from underlying bit representation, keeping
+//!                          all bits (even those not corresponding to defined
+//!                          flags)
+//! - `is_empty`: `true` if no flags are currently stored
+//! - `is_all`: `true` if currently set flags exactly equal all defined flags
+//! - `intersects`: `true` if there are flags common to both `self` and `other`
+//! - `contains`: `true` if all of the flags in `other` are contained within `self`
+//! - `insert`: inserts the specified flags in-place
+//! - `remove`: removes the specified flags in-place
+//! - `toggle`: the specified flags will be inserted if not present, and removed
+//!             if they are.
+//! - `set`: inserts or removes the specified flags depending on the passed value
+//! - `intersection`: returns a new set of flags, containing only the flags present
+//!                   in both `self` and `other` (the argument to the function).
+//! - `union`: returns a new set of flags, containing any flags present in
+//!            either `self` or `other` (the argument to the function).
+//! - `difference`: returns a new set of flags, containing all flags present in
+//!                 `self` without any of the flags present in `other` (the
+//!                 argument to the function).
+//! - `symmetric_difference`: returns a new set of flags, containing all flags
+//!                           present in either `self` or `other` (the argument
+//!                           to the function), but not both.
+//! - `complement`: returns a new set of flags, containing all flags which are
+//!                 not set in `self`, but which are allowed for this type.
+//!
+//! ## Default
+//!
+//! The `Default` trait is not automatically implemented for the generated structs.
+//!
+//! If your default value is equal to `0` (which is the same value as calling `empty()`
+//! on the generated struct), you can simply derive `Default`:
+//!
+//! ```
+//! use bitflags::bitflags;
+//!
+//! bitflags! {
+//!     // Results in default value with bits: 0
+//!     #[derive(Default)]
+//!     struct Flags: u32 {
+//!         const A = 0b00000001;
+//!         const B = 0b00000010;
+//!         const C = 0b00000100;
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let derived_default: Flags = Default::default();
+//!     assert_eq!(derived_default.bits(), 0);
+//! }
+//! ```
+//!
+//! If your default value is not equal to `0` you need to implement `Default` yourself:
+//!
+//! ```
+//! use bitflags::bitflags;
+//!
+//! bitflags! {
+//!     struct Flags: u32 {
+//!         const A = 0b00000001;
+//!         const B = 0b00000010;
+//!         const C = 0b00000100;
+//!     }
+//! }
+//!
+//! // explicit `Default` implementation
+//! impl Default for Flags {
+//!     fn default() -> Flags {
+//!         Flags::A | Flags::C
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let implemented_default: Flags = Default::default();
+//!     assert_eq!(implemented_default, (Flags::A | Flags::C));
+//! }
+//! ```
+//!
+//! # Zero Flags
+//!
+//! Flags with a value equal to zero will have some strange behavior that one should be aware of.
+//!
+//! ```
+//! use bitflags::bitflags;
+//!
+//! bitflags! {
+//!     struct Flags: u32 {
+//!         const NONE = 0b00000000;
+//!         const SOME = 0b00000001;
+//!     }
+//! }
+//!
+//! fn main() {
+//!     let empty = Flags::empty();
+//!     let none = Flags::NONE;
+//!     let some = Flags::SOME;
+//!
+//!     // Zero flags are treated as always present
+//!     assert!(empty.contains(Flags::NONE));
+//!     assert!(none.contains(Flags::NONE));
+//!     assert!(some.contains(Flags::NONE));
+//!
+//!     // Zero flags will be ignored when testing for emptiness
+//!     assert!(none.is_empty());
+//! }
+//! ```
+//!
+//! Users should generally avoid defining a flag with a value of zero.
+
+#![cfg_attr(not(test), no_std)]
+#![doc(html_root_url = "https://docs.rs/bitflags/1.3.2")]
+
+#[doc(hidden)]
+pub extern crate core as _core;
+
+/// The macro used to generate the flag structures.
+///
+/// See the [crate level docs](../bitflags/index.html) for complete documentation.
+///
+/// # Example
+///
+/// ```
+/// use bitflags::bitflags;
+///
+/// bitflags! {
+///     struct Flags: u32 {
+///         const A = 0b00000001;
+///         const B = 0b00000010;
+///         const C = 0b00000100;
+///         const ABC = Self::A.bits | Self::B.bits | Self::C.bits;
+///     }
+/// }
+///
+/// fn main() {
+///     let e1 = Flags::A | Flags::C;
+///     let e2 = Flags::B | Flags::C;
+///     assert_eq!((e1 | e2), Flags::ABC);   // union
+///     assert_eq!((e1 & e2), Flags::C);     // intersection
+///     assert_eq!((e1 - e2), Flags::A);     // set difference
+///     assert_eq!(!e2, Flags::A);           // set complement
+/// }
+/// ```
+///
+/// The generated `struct`s can also be extended with type and trait
+/// implementations:
+///
+/// ```
+/// use std::fmt;
+///
+/// use bitflags::bitflags;
+///
+/// bitflags! {
+///     struct Flags: u32 {
+///         const A = 0b00000001;
+///         const B = 0b00000010;
+///     }
+/// }
+///
+/// impl Flags {
+///     pub fn clear(&mut self) {
+///         self.bits = 0;  // The `bits` field can be accessed from within the
+///                         // same module where the `bitflags!` macro was invoked.
+///     }
+/// }
+///
+/// impl fmt::Display for Flags {
+///     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+///         write!(f, "hi!")
+///     }
+/// }
+///
+/// fn main() {
+///     let mut flags = Flags::A | Flags::B;
+///     flags.clear();
+///     assert!(flags.is_empty());
+///     assert_eq!(format!("{}", flags), "hi!");
+///     assert_eq!(format!("{:?}", Flags::A | Flags::B), "A | B");
+///     assert_eq!(format!("{:?}", Flags::B), "B");
+/// }
+/// ```
+#[macro_export(local_inner_macros)]
+macro_rules! bitflags {
+    (
+        $(#[$outer:meta])*
+        $vis:vis struct $BitFlags:ident: $T:ty {
+            $(
+                $(#[$inner:ident $($args:tt)*])*
+                const $Flag:ident = $value:expr;
+            )*
+        }
+
+        $($t:tt)*
+    ) => {
+        $(#[$outer])*
+        #[derive(Copy, PartialEq, Eq, Clone, PartialOrd, Ord, Hash)]
+        $vis struct $BitFlags {
+            bits: $T,
+        }
+
+        __impl_bitflags! {
+            $BitFlags: $T {
+                $(
+                    $(#[$inner $($args)*])*
+                    $Flag = $value;
+                )*
+            }
+        }
+
+        bitflags! {
+            $($t)*
+        }
+    };
+    () => {};
+}
+
+// A helper macro to implement the `all` function.
+#[macro_export(local_inner_macros)]
+#[doc(hidden)]
+macro_rules! __impl_all_bitflags {
+    (
+        $BitFlags:ident: $T:ty {
+            $(
+                $(#[$attr:ident $($args:tt)*])*
+                $Flag:ident = $value:expr;
+            )+
+        }
+    ) => {
+        // See `Debug::fmt` for why this approach is taken.
+        #[allow(non_snake_case)]
+        trait __BitFlags {
+            $(
+                const $Flag: $T = 0;
+            )+
+        }
+        #[allow(non_snake_case)]
+        impl __BitFlags for $BitFlags {
+            $(
+                __impl_bitflags! {
+                    #[allow(deprecated)]
+                    $(? #[$attr $($args)*])*
+                    const $Flag: $T = Self::$Flag.bits;
+                }
+            )+
+        }
+        Self { bits: $(<Self as __BitFlags>::$Flag)|+ }
+    };
+    (
+        $BitFlags:ident: $T:ty { }
+    ) => {
+        Self { bits: 0 }
+    };
+}
+
+#[macro_export(local_inner_macros)]
+#[doc(hidden)]
+macro_rules! __impl_bitflags {
+    (
+        $BitFlags:ident: $T:ty {
+            $(
+                $(#[$attr:ident $($args:tt)*])*
+                $Flag:ident = $value:expr;
+            )*
+        }
+    ) => {
+        impl $crate::_core::fmt::Debug for $BitFlags {
+            fn fmt(&self, f: &mut $crate::_core::fmt::Formatter) -> $crate::_core::fmt::Result {
+                // This convoluted approach is to handle #[cfg]-based flag
+                // omission correctly. For example it needs to support:
+                //
+                //    #[cfg(unix)] const A: Flag = /* ... */;
+                //    #[cfg(windows)] const B: Flag = /* ... */;
+
+                // Unconditionally define a check for every flag, even disabled
+                // ones.
+                #[allow(non_snake_case)]
+                trait __BitFlags {
+                    $(
+                        #[inline]
+                        fn $Flag(&self) -> bool { false }
+                    )*
+                }
+
+                // Conditionally override the check for just those flags that
+                // are not #[cfg]ed away.
+                #[allow(non_snake_case)]
+                impl __BitFlags for $BitFlags {
+                    $(
+                        __impl_bitflags! {
+                            #[allow(deprecated)]
+                            #[inline]
+                            $(? #[$attr $($args)*])*
+                            fn $Flag(&self) -> bool {
+                                if Self::$Flag.bits == 0 && self.bits != 0 {
+                                    false
+                                } else {
+                                    self.bits & Self::$Flag.bits == Self::$Flag.bits
+                                }
+                            }
+                        }
+                    )*
+                }
+
+                let mut first = true;
+                $(
+                    if <Self as __BitFlags>::$Flag(self) {
+                        if !first {
+                            f.write_str(" | ")?;
+                        }
+                        first = false;
+                        f.write_str($crate::_core::stringify!($Flag))?;
+                    }
+                )*
+                let extra_bits = self.bits & !Self::all().bits();
+                if extra_bits != 0 {
+                    if !first {
+                        f.write_str(" | ")?;
+                    }
+                    first = false;
+                    f.write_str("0x")?;
+                    $crate::_core::fmt::LowerHex::fmt(&extra_bits, f)?;
+                }
+                if first {
+                    f.write_str("(empty)")?;
+                }
+                Ok(())
+            }
+        }
+        impl $crate::_core::fmt::Binary for $BitFlags {
+            fn fmt(&self, f: &mut $crate::_core::fmt::Formatter) -> $crate::_core::fmt::Result {
+                $crate::_core::fmt::Binary::fmt(&self.bits, f)
+            }
+        }
+        impl $crate::_core::fmt::Octal for $BitFlags {
+            fn fmt(&self, f: &mut $crate::_core::fmt::Formatter) -> $crate::_core::fmt::Result {
+                $crate::_core::fmt::Octal::fmt(&self.bits, f)
+            }
+        }
+        impl $crate::_core::fmt::LowerHex for $BitFlags {
+            fn fmt(&self, f: &mut $crate::_core::fmt::Formatter) -> $crate::_core::fmt::Result {
+                $crate::_core::fmt::LowerHex::fmt(&self.bits, f)
+            }
+        }
+        impl $crate::_core::fmt::UpperHex for $BitFlags {
+            fn fmt(&self, f: &mut $crate::_core::fmt::Formatter) -> $crate::_core::fmt::Result {
+                $crate::_core::fmt::UpperHex::fmt(&self.bits, f)
+            }
+        }
+
+        #[allow(dead_code)]
+        impl $BitFlags {
+            $(
+                $(#[$attr $($args)*])*
+                pub const $Flag: Self = Self { bits: $value };
+            )*
+
+            /// Returns an empty set of flags.
+            #[inline]
+            pub const fn empty() -> Self {
+                Self { bits: 0 }
+            }
+
+            /// Returns the set containing all flags.
+            #[inline]
+            pub const fn all() -> Self {
+                __impl_all_bitflags! {
+                    $BitFlags: $T {
+                        $(
+                            $(#[$attr $($args)*])*
+                            $Flag = $value;
+                        )*
+                    }
+                }
+            }
+
+            /// Returns the raw value of the flags currently stored.
+            #[inline]
+            pub const fn bits(&self) -> $T {
+                self.bits
+            }
+
+            /// Convert from underlying bit representation, unless that
+            /// representation contains bits that do not correspond to a flag.
+            #[inline]
+            pub const fn from_bits(bits: $T) -> $crate::_core::option::Option<Self> {
+                if (bits & !Self::all().bits()) == 0 {
+                    $crate::_core::option::Option::Some(Self { bits })
+                } else {
+                    $crate::_core::option::Option::None
+                }
+            }
+
+            /// Convert from underlying bit representation, dropping any bits
+            /// that do not correspond to flags.
+            #[inline]
+            pub const fn from_bits_truncate(bits: $T) -> Self {
+                Self { bits: bits & Self::all().bits }
+            }
+
+            /// Convert from underlying bit representation, preserving all
+            /// bits (even those not corresponding to a defined flag).
+            ///
+            /// # Safety
+            ///
+            /// The caller of the `bitflags!` macro can chose to allow or
+            /// disallow extra bits for their bitflags type.
+            ///
+            /// The caller of `from_bits_unchecked()` has to ensure that
+            /// all bits correspond to a defined flag or that extra bits
+            /// are valid for this bitflags type.
+            #[inline]
+            pub const unsafe fn from_bits_unchecked(bits: $T) -> Self {
+                Self { bits }
+            }
+
+            /// Returns `true` if no flags are currently stored.
+            #[inline]
+            pub const fn is_empty(&self) -> bool {
+                self.bits() == Self::empty().bits()
+            }
+
+            /// Returns `true` if all flags are currently set.
+            #[inline]
+            pub const fn is_all(&self) -> bool {
+                Self::all().bits | self.bits == self.bits
+            }
+
+            /// Returns `true` if there are flags common to both `self` and `other`.
+            #[inline]
+            pub const fn intersects(&self, other: Self) -> bool {
+                !(Self { bits: self.bits & other.bits}).is_empty()
+            }
+
+            /// Returns `true` if all of the flags in `other` are contained within `self`.
+            #[inline]
+            pub const fn contains(&self, other: Self) -> bool {
+                (self.bits & other.bits) == other.bits
+            }
+
+            /// Inserts the specified flags in-place.
+            #[inline]
+            pub fn insert(&mut self, other: Self) {
+                self.bits |= other.bits;
+            }
+
+            /// Removes the specified flags in-place.
+            #[inline]
+            pub fn remove(&mut self, other: Self) {
+                self.bits &= !other.bits;
+            }
+
+            /// Toggles the specified flags in-place.
+            #[inline]
+            pub fn toggle(&mut self, other: Self) {
+                self.bits ^= other.bits;
+            }
+
+            /// Inserts or removes the specified flags depending on the passed value.
+            #[inline]
+            pub fn set(&mut self, other: Self, value: bool) {
+                if value {
+                    self.insert(other);
+                } else {
+                    self.remove(other);
+                }
+            }
+
+            /// Returns the intersection between the flags in `self` and
+            /// `other`.
+            ///
+            /// Specifically, the returned set contains only the flags which are
+            /// present in *both* `self` *and* `other`.
+            ///
+            /// This is equivalent to using the `&` operator (e.g.
+            /// [`ops::BitAnd`]), as in `flags & other`.
+            ///
+            /// [`ops::BitAnd`]: https://doc.rust-lang.org/std/ops/trait.BitAnd.html
+            #[inline]
+            #[must_use]
+            pub const fn intersection(self, other: Self) -> Self {
+                Self { bits: self.bits & other.bits }
+            }
+
+            /// Returns the union of between the flags in `self` and `other`.
+            ///
+            /// Specifically, the returned set contains all flags which are
+            /// present in *either* `self` *or* `other`, including any which are
+            /// present in both (see [`Self::symmetric_difference`] if that
+            /// is undesirable).
+            ///
+            /// This is equivalent to using the `|` operator (e.g.
+            /// [`ops::BitOr`]), as in `flags | other`.
+            ///
+            /// [`ops::BitOr`]: https://doc.rust-lang.org/std/ops/trait.BitOr.html
+            #[inline]
+            #[must_use]
+            pub const fn union(self, other: Self) -> Self {
+                Self { bits: self.bits | other.bits }
+            }
+
+            /// Returns the difference between the flags in `self` and `other`.
+            ///
+            /// Specifically, the returned set contains all flags present in
+            /// `self`, except for the ones present in `other`.
+            ///
+            /// It is also conceptually equivalent to the "bit-clear" operation:
+            /// `flags & !other` (and this syntax is also supported).
+            ///
+            /// This is equivalent to using the `-` operator (e.g.
+            /// [`ops::Sub`]), as in `flags - other`.
+            ///
+            /// [`ops::Sub`]: https://doc.rust-lang.org/std/ops/trait.Sub.html
+            #[inline]
+            #[must_use]
+            pub const fn difference(self, other: Self) -> Self {
+                Self { bits: self.bits & !other.bits }
+            }
+
+            /// Returns the [symmetric difference][sym-diff] between the flags
+            /// in `self` and `other`.
+            ///
+            /// Specifically, the returned set contains the flags present which
+            /// are present in `self` or `other`, but that are not present in
+            /// both. Equivalently, it contains the flags present in *exactly
+            /// one* of the sets `self` and `other`.
+            ///
+            /// This is equivalent to using the `^` operator (e.g.
+            /// [`ops::BitXor`]), as in `flags ^ other`.
+            ///
+            /// [sym-diff]: https://en.wikipedia.org/wiki/Symmetric_difference
+            /// [`ops::BitXor`]: https://doc.rust-lang.org/std/ops/trait.BitXor.html
+            #[inline]
+            #[must_use]
+            pub const fn symmetric_difference(self, other: Self) -> Self {
+                Self { bits: self.bits ^ other.bits }
+            }
+
+            /// Returns the complement of this set of flags.
+            ///
+            /// Specifically, the returned set contains all the flags which are
+            /// not set in `self`, but which are allowed for this type.
+            ///
+            /// Alternatively, it can be thought of as the set difference
+            /// between [`Self::all()`] and `self` (e.g. `Self::all() - self`)
+            ///
+            /// This is equivalent to using the `!` operator (e.g.
+            /// [`ops::Not`]), as in `!flags`.
+            ///
+            /// [`Self::all()`]: Self::all
+            /// [`ops::Not`]: https://doc.rust-lang.org/std/ops/trait.Not.html
+            #[inline]
+            #[must_use]
+            pub const fn complement(self) -> Self {
+                Self::from_bits_truncate(!self.bits)
+            }
+
+        }
+
+        impl $crate::_core::ops::BitOr for $BitFlags {
+            type Output = Self;
+
+            /// Returns the union of the two sets of flags.
+            #[inline]
+            fn bitor(self, other: $BitFlags) -> Self {
+                Self { bits: self.bits | other.bits }
+            }
+        }
+
+        impl $crate::_core::ops::BitOrAssign for $BitFlags {
+            /// Adds the set of flags.
+            #[inline]
+            fn bitor_assign(&mut self, other: Self) {
+                self.bits |= other.bits;
+            }
+        }
+
+        impl $crate::_core::ops::BitXor for $BitFlags {
+            type Output = Self;
+
+            /// Returns the left flags, but with all the right flags toggled.
+            #[inline]
+            fn bitxor(self, other: Self) -> Self {
+                Self { bits: self.bits ^ other.bits }
+            }
+        }
+
+        impl $crate::_core::ops::BitXorAssign for $BitFlags {
+            /// Toggles the set of flags.
+            #[inline]
+            fn bitxor_assign(&mut self, other: Self) {
+                self.bits ^= other.bits;
+            }
+        }
+
+        impl $crate::_core::ops::BitAnd for $BitFlags {
+            type Output = Self;
+
+            /// Returns the intersection between the two sets of flags.
+            #[inline]
+            fn bitand(self, other: Self) -> Self {
+                Self { bits: self.bits & other.bits }
+            }
+        }
+
+        impl $crate::_core::ops::BitAndAssign for $BitFlags {
+            /// Disables all flags disabled in the set.
+            #[inline]
+            fn bitand_assign(&mut self, other: Self) {
+                self.bits &= other.bits;
+            }
+        }
+
+        impl $crate::_core::ops::Sub for $BitFlags {
+            type Output = Self;
+
+            /// Returns the set difference of the two sets of flags.
+            #[inline]
+            fn sub(self, other: Self) -> Self {
+                Self { bits: self.bits & !other.bits }
+            }
+        }
+
+        impl $crate::_core::ops::SubAssign for $BitFlags {
+            /// Disables all flags enabled in the set.
+            #[inline]
+            fn sub_assign(&mut self, other: Self) {
+                self.bits &= !other.bits;
+            }
+        }
+
+        impl $crate::_core::ops::Not for $BitFlags {
+            type Output = Self;
+
+            /// Returns the complement of this set of flags.
+            #[inline]
+            fn not(self) -> Self {
+                Self { bits: !self.bits } & Self::all()
+            }
+        }
+
+        impl $crate::_core::iter::Extend<$BitFlags> for $BitFlags {
+            fn extend<T: $crate::_core::iter::IntoIterator<Item=Self>>(&mut self, iterator: T) {
+                for item in iterator {
+                    self.insert(item)
+                }
+            }
+        }
+
+        impl $crate::_core::iter::FromIterator<$BitFlags> for $BitFlags {
+            fn from_iter<T: $crate::_core::iter::IntoIterator<Item=Self>>(iterator: T) -> Self {
+                let mut result = Self::empty();
+                result.extend(iterator);
+                result
+            }
+        }
+    };
+
+    // Every attribute that the user writes on a const is applied to the
+    // corresponding const that we generate, but within the implementation of
+    // Debug and all() we want to ignore everything but #[cfg] attributes. In
+    // particular, including a #[deprecated] attribute on those items would fail
+    // to compile.
+    // https://github.com/bitflags/bitflags/issues/109
+    //
+    // Input:
+    //
+    //     ? #[cfg(feature = "advanced")]
+    //     ? #[deprecated(note = "Use something else.")]
+    //     ? #[doc = r"High quality documentation."]
+    //     fn f() -> i32 { /* ... */ }
+    //
+    // Output:
+    //
+    //     #[cfg(feature = "advanced")]
+    //     fn f() -> i32 { /* ... */ }
+    (
+        $(#[$filtered:meta])*
+        ? #[cfg $($cfgargs:tt)*]
+        $(? #[$rest:ident $($restargs:tt)*])*
+        fn $($item:tt)*
+    ) => {
+        __impl_bitflags! {
+            $(#[$filtered])*
+            #[cfg $($cfgargs)*]
+            $(? #[$rest $($restargs)*])*
+            fn $($item)*
+        }
+    };
+    (
+        $(#[$filtered:meta])*
+        // $next != `cfg`
+        ? #[$next:ident $($nextargs:tt)*]
+        $(? #[$rest:ident $($restargs:tt)*])*
+        fn $($item:tt)*
+    ) => {
+        __impl_bitflags! {
+            $(#[$filtered])*
+            // $next filtered out
+            $(? #[$rest $($restargs)*])*
+            fn $($item)*
+        }
+    };
+    (
+        $(#[$filtered:meta])*
+        fn $($item:tt)*
+    ) => {
+        $(#[$filtered])*
+        fn $($item)*
+    };
+
+    // Every attribute that the user writes on a const is applied to the
+    // corresponding const that we generate, but within the implementation of
+    // Debug and all() we want to ignore everything but #[cfg] attributes. In
+    // particular, including a #[deprecated] attribute on those items would fail
+    // to compile.
+    // https://github.com/bitflags/bitflags/issues/109
+    //
+    // const version
+    //
+    // Input:
+    //
+    //     ? #[cfg(feature = "advanced")]
+    //     ? #[deprecated(note = "Use something else.")]
+    //     ? #[doc = r"High quality documentation."]
+    //     const f: i32 { /* ... */ }
+    //
+    // Output:
+    //
+    //     #[cfg(feature = "advanced")]
+    //     const f: i32 { /* ... */ }
+    (
+        $(#[$filtered:meta])*
+        ? #[cfg $($cfgargs:tt)*]
+        $(? #[$rest:ident $($restargs:tt)*])*
+        const $($item:tt)*
+    ) => {
+        __impl_bitflags! {
+            $(#[$filtered])*
+            #[cfg $($cfgargs)*]
+            $(? #[$rest $($restargs)*])*
+            const $($item)*
+        }
+    };
+    (
+        $(#[$filtered:meta])*
+        // $next != `cfg`
+        ? #[$next:ident $($nextargs:tt)*]
+        $(? #[$rest:ident $($restargs:tt)*])*
+        const $($item:tt)*
+    ) => {
+        __impl_bitflags! {
+            $(#[$filtered])*
+            // $next filtered out
+            $(? #[$rest $($restargs)*])*
+            const $($item)*
+        }
+    };
+    (
+        $(#[$filtered:meta])*
+        const $($item:tt)*
+    ) => {
+        $(#[$filtered])*
+        const $($item)*
+    };
+}
+
+#[cfg(feature = "example_generated")]
+pub mod example_generated;
+
+#[cfg(test)]
+mod tests {
+    use std::collections::hash_map::DefaultHasher;
+    use std::hash::{Hash, Hasher};
+
+    bitflags! {
+        #[doc = "> The first principle is that you must not fool yourself — and"]
+        #[doc = "> you are the easiest person to fool."]
+        #[doc = "> "]
+        #[doc = "> - Richard Feynman"]
+        #[derive(Default)]
+        struct Flags: u32 {
+            const A = 0b00000001;
+            #[doc = "<pcwalton> macros are way better at generating code than trans is"]
+            const B = 0b00000010;
+            const C = 0b00000100;
+            #[doc = "* cmr bed"]
+            #[doc = "* strcat table"]
+            #[doc = "<strcat> wait what?"]
+            const ABC = Self::A.bits | Self::B.bits | Self::C.bits;
+        }
+
+        struct _CfgFlags: u32 {
+            #[cfg(unix)]
+            const _CFG_A = 0b01;
+            #[cfg(windows)]
+            const _CFG_B = 0b01;
+            #[cfg(unix)]
+            const _CFG_C = Self::_CFG_A.bits | 0b10;
+        }
+
+        struct AnotherSetOfFlags: i8 {
+            const ANOTHER_FLAG = -1_i8;
+        }
+
+        struct LongFlags: u32 {
+            const LONG_A = 0b1111111111111111;
+        }
+    }
+
+    bitflags! {
+        struct EmptyFlags: u32 {
+        }
+    }
+
+    #[test]
+    fn test_bits() {
+        assert_eq!(Flags::empty().bits(), 0b00000000);
+        assert_eq!(Flags::A.bits(), 0b00000001);
+        assert_eq!(Flags::ABC.bits(), 0b00000111);
+
+        assert_eq!(AnotherSetOfFlags::empty().bits(), 0b00);
+        assert_eq!(AnotherSetOfFlags::ANOTHER_FLAG.bits(), !0_i8);
+
+        assert_eq!(EmptyFlags::empty().bits(), 0b00000000);
+    }
+
+    #[test]
+    fn test_from_bits() {
+        assert_eq!(Flags::from_bits(0), Some(Flags::empty()));
+        assert_eq!(Flags::from_bits(0b1), Some(Flags::A));
+        assert_eq!(Flags::from_bits(0b10), Some(Flags::B));
+        assert_eq!(Flags::from_bits(0b11), Some(Flags::A | Flags::B));
+        assert_eq!(Flags::from_bits(0b1000), None);
+
+        assert_eq!(
+            AnotherSetOfFlags::from_bits(!0_i8),
+            Some(AnotherSetOfFlags::ANOTHER_FLAG)
+        );
+
+        assert_eq!(EmptyFlags::from_bits(0), Some(EmptyFlags::empty()));
+        assert_eq!(EmptyFlags::from_bits(0b1), None);
+    }
+
+    #[test]
+    fn test_from_bits_truncate() {
+        assert_eq!(Flags::from_bits_truncate(0), Flags::empty());
+        assert_eq!(Flags::from_bits_truncate(0b1), Flags::A);
+        assert_eq!(Flags::from_bits_truncate(0b10), Flags::B);
+        assert_eq!(Flags::from_bits_truncate(0b11), (Flags::A | Flags::B));
+        assert_eq!(Flags::from_bits_truncate(0b1000), Flags::empty());
+        assert_eq!(Flags::from_bits_truncate(0b1001), Flags::A);
+
+        assert_eq!(
+            AnotherSetOfFlags::from_bits_truncate(0_i8),
+            AnotherSetOfFlags::empty()
+        );
+
+        assert_eq!(EmptyFlags::from_bits_truncate(0), EmptyFlags::empty());
+        assert_eq!(EmptyFlags::from_bits_truncate(0b1), EmptyFlags::empty());
+    }
+
+    #[test]
+    fn test_from_bits_unchecked() {
+        let extra = unsafe { Flags::from_bits_unchecked(0b1000) };
+        assert_eq!(unsafe { Flags::from_bits_unchecked(0) }, Flags::empty());
+        assert_eq!(unsafe { Flags::from_bits_unchecked(0b1) }, Flags::A);
+        assert_eq!(unsafe { Flags::from_bits_unchecked(0b10) }, Flags::B);
+
+        assert_eq!(
+            unsafe { Flags::from_bits_unchecked(0b11) },
+            (Flags::A | Flags::B)
+        );
+        assert_eq!(
+            unsafe { Flags::from_bits_unchecked(0b1000) },
+            (extra | Flags::empty())
+        );
+        assert_eq!(
+            unsafe { Flags::from_bits_unchecked(0b1001) },
+            (extra | Flags::A)
+        );
+
+        let extra = unsafe { EmptyFlags::from_bits_unchecked(0b1000) };
+        assert_eq!(
+            unsafe { EmptyFlags::from_bits_unchecked(0b1000) },
+            (extra | EmptyFlags::empty())
+        );
+    }
+
+    #[test]
+    fn test_is_empty() {
+        assert!(Flags::empty().is_empty());
+        assert!(!Flags::A.is_empty());
+        assert!(!Flags::ABC.is_empty());
+
+        assert!(!AnotherSetOfFlags::ANOTHER_FLAG.is_empty());
+
+        assert!(EmptyFlags::empty().is_empty());
+        assert!(EmptyFlags::all().is_empty());
+    }
+
+    #[test]
+    fn test_is_all() {
+        assert!(Flags::all().is_all());
+        assert!(!Flags::A.is_all());
+        assert!(Flags::ABC.is_all());
+
+        let extra = unsafe { Flags::from_bits_unchecked(0b1000) };
+        assert!(!extra.is_all());
+        assert!(!(Flags::A | extra).is_all());
+        assert!((Flags::ABC | extra).is_all());
+
+        assert!(AnotherSetOfFlags::ANOTHER_FLAG.is_all());
+
+        assert!(EmptyFlags::all().is_all());
+        assert!(EmptyFlags::empty().is_all());
+    }
+
+    #[test]
+    fn test_two_empties_do_not_intersect() {
+        let e1 = Flags::empty();
+        let e2 = Flags::empty();
+        assert!(!e1.intersects(e2));
+
+        assert!(AnotherSetOfFlags::ANOTHER_FLAG.intersects(AnotherSetOfFlags::ANOTHER_FLAG));
+    }
+
+    #[test]
+    fn test_empty_does_not_intersect_with_full() {
+        let e1 = Flags::empty();
+        let e2 = Flags::ABC;
+        assert!(!e1.intersects(e2));
+    }
+
+    #[test]
+    fn test_disjoint_intersects() {
+        let e1 = Flags::A;
+        let e2 = Flags::B;
+        assert!(!e1.intersects(e2));
+    }
+
+    #[test]
+    fn test_overlapping_intersects() {
+        let e1 = Flags::A;
+        let e2 = Flags::A | Flags::B;
+        assert!(e1.intersects(e2));
+    }
+
+    #[test]
+    fn test_contains() {
+        let e1 = Flags::A;
+        let e2 = Flags::A | Flags::B;
+        assert!(!e1.contains(e2));
+        assert!(e2.contains(e1));
+        assert!(Flags::ABC.contains(e2));
+
+        assert!(AnotherSetOfFlags::ANOTHER_FLAG.contains(AnotherSetOfFlags::ANOTHER_FLAG));
+
+        assert!(EmptyFlags::empty().contains(EmptyFlags::empty()));
+    }
+
+    #[test]
+    fn test_insert() {
+        let mut e1 = Flags::A;
+        let e2 = Flags::A | Flags::B;
+        e1.insert(e2);
+        assert_eq!(e1, e2);
+
+        let mut e3 = AnotherSetOfFlags::empty();
+        e3.insert(AnotherSetOfFlags::ANOTHER_FLAG);
+        assert_eq!(e3, AnotherSetOfFlags::ANOTHER_FLAG);
+    }
+
+    #[test]
+    fn test_remove() {
+        let mut e1 = Flags::A | Flags::B;
+        let e2 = Flags::A | Flags::C;
+        e1.remove(e2);
+        assert_eq!(e1, Flags::B);
+
+        let mut e3 = AnotherSetOfFlags::ANOTHER_FLAG;
+        e3.remove(AnotherSetOfFlags::ANOTHER_FLAG);
+        assert_eq!(e3, AnotherSetOfFlags::empty());
+    }
+
+    #[test]
+    fn test_operators() {
+        let e1 = Flags::A | Flags::C;
+        let e2 = Flags::B | Flags::C;
+        assert_eq!((e1 | e2), Flags::ABC); // union
+        assert_eq!((e1 & e2), Flags::C); // intersection
+        assert_eq!((e1 - e2), Flags::A); // set difference
+        assert_eq!(!e2, Flags::A); // set complement
+        assert_eq!(e1 ^ e2, Flags::A | Flags::B); // toggle
+        let mut e3 = e1;
+        e3.toggle(e2);
+        assert_eq!(e3, Flags::A | Flags::B);
+
+        let mut m4 = AnotherSetOfFlags::empty();
+        m4.toggle(AnotherSetOfFlags::empty());
+        assert_eq!(m4, AnotherSetOfFlags::empty());
+    }
+
+    #[test]
+    fn test_operators_unchecked() {
+        let extra = unsafe { Flags::from_bits_unchecked(0b1000) };
+        let e1 = Flags::A | Flags::C | extra;
+        let e2 = Flags::B | Flags::C;
+        assert_eq!((e1 | e2), (Flags::ABC | extra)); // union
+        assert_eq!((e1 & e2), Flags::C); // intersection
+        assert_eq!((e1 - e2), (Flags::A | extra)); // set difference
+        assert_eq!(!e2, Flags::A); // set complement
+        assert_eq!(!e1, Flags::B); // set complement
+        assert_eq!(e1 ^ e2, Flags::A | Flags::B | extra); // toggle
+        let mut e3 = e1;
+        e3.toggle(e2);
+        assert_eq!(e3, Flags::A | Flags::B | extra);
+    }
+
+    #[test]
+    fn test_set_ops_basic() {
+        let ab = Flags::A.union(Flags::B);
+        let ac = Flags::A.union(Flags::C);
+        let bc = Flags::B.union(Flags::C);
+        assert_eq!(ab.bits, 0b011);
+        assert_eq!(bc.bits, 0b110);
+        assert_eq!(ac.bits, 0b101);
+
+        assert_eq!(ab, Flags::B.union(Flags::A));
+        assert_eq!(ac, Flags::C.union(Flags::A));
+        assert_eq!(bc, Flags::C.union(Flags::B));
+
+        assert_eq!(ac, Flags::A | Flags::C);
+        assert_eq!(bc, Flags::B | Flags::C);
+        assert_eq!(ab.union(bc), Flags::ABC);
+
+        assert_eq!(ac, Flags::A | Flags::C);
+        assert_eq!(bc, Flags::B | Flags::C);
+
+        assert_eq!(ac.union(bc), ac | bc);
+        assert_eq!(ac.union(bc), Flags::ABC);
+        assert_eq!(bc.union(ac), Flags::ABC);
+
+        assert_eq!(ac.intersection(bc), ac & bc);
+        assert_eq!(ac.intersection(bc), Flags::C);
+        assert_eq!(bc.intersection(ac), Flags::C);
+
+        assert_eq!(ac.difference(bc), ac - bc);
+        assert_eq!(bc.difference(ac), bc - ac);
+        assert_eq!(ac.difference(bc), Flags::A);
+        assert_eq!(bc.difference(ac), Flags::B);
+
+        assert_eq!(bc.complement(), !bc);
+        assert_eq!(bc.complement(), Flags::A);
+        assert_eq!(ac.symmetric_difference(bc), Flags::A.union(Flags::B));
+        assert_eq!(bc.symmetric_difference(ac), Flags::A.union(Flags::B));
+    }
+
+    #[test]
+    fn test_set_ops_const() {
+        // These just test that these compile and don't cause use-site panics
+        // (would be possible if we had some sort of UB)
+        const INTERSECT: Flags = Flags::all().intersection(Flags::C);
+        const UNION: Flags = Flags::A.union(Flags::C);
+        const DIFFERENCE: Flags = Flags::all().difference(Flags::A);
+        const COMPLEMENT: Flags = Flags::C.complement();
+        const SYM_DIFFERENCE: Flags = UNION.symmetric_difference(DIFFERENCE);
+        assert_eq!(INTERSECT, Flags::C);
+        assert_eq!(UNION, Flags::A | Flags::C);
+        assert_eq!(DIFFERENCE, Flags::all() - Flags::A);
+        assert_eq!(COMPLEMENT, !Flags::C);
+        assert_eq!(SYM_DIFFERENCE, (Flags::A | Flags::C) ^ (Flags::all() - Flags::A));
+    }
+
+    #[test]
+    fn test_set_ops_unchecked() {
+        let extra = unsafe { Flags::from_bits_unchecked(0b1000) };
+        let e1 = Flags::A.union(Flags::C).union(extra);
+        let e2 = Flags::B.union(Flags::C);
+        assert_eq!(e1.bits, 0b1101);
+        assert_eq!(e1.union(e2), (Flags::ABC | extra));
+        assert_eq!(e1.intersection(e2), Flags::C);
+        assert_eq!(e1.difference(e2), Flags::A | extra);
+        assert_eq!(e2.difference(e1), Flags::B);
+        assert_eq!(e2.complement(), Flags::A);
+        assert_eq!(e1.complement(), Flags::B);
+        assert_eq!(e1.symmetric_difference(e2), Flags::A | Flags::B | extra); // toggle
+    }
+
+    #[test]
+    fn test_set_ops_exhaustive() {
+        // Define a flag that contains gaps to help exercise edge-cases,
+        // especially around "unknown" flags (e.g. ones outside of `all()`
+        // `from_bits_unchecked`).
+        // - when lhs and rhs both have different sets of unknown flags.
+        // - unknown flags at both ends, and in the middle
+        // - cases with "gaps".
+        bitflags! {
+            struct Test: u16 {
+                // Intentionally no `A`
+                const B = 0b000000010;
+                // Intentionally no `C`
+                const D = 0b000001000;
+                const E = 0b000010000;
+                const F = 0b000100000;
+                const G = 0b001000000;
+                // Intentionally no `H`
+                const I = 0b100000000;
+            }
+        }
+        let iter_test_flags =
+            || (0..=0b111_1111_1111).map(|bits| unsafe { Test::from_bits_unchecked(bits) });
+
+        for a in iter_test_flags() {
+            assert_eq!(
+                a.complement(),
+                Test::from_bits_truncate(!a.bits),
+                "wrong result: !({:?})",
+                a,
+            );
+            assert_eq!(a.complement(), !a, "named != op: !({:?})", a);
+            for b in iter_test_flags() {
+                // Check that the named operations produce the expected bitwise
+                // values.
+                assert_eq!(
+                    a.union(b).bits,
+                    a.bits | b.bits,
+                    "wrong result: `{:?}` | `{:?}`",
+                    a,
+                    b,
+                );
+                assert_eq!(
+                    a.intersection(b).bits,
+                    a.bits & b.bits,
+                    "wrong result: `{:?}` & `{:?}`",
+                    a,
+                    b,
+                );
+                assert_eq!(
+                    a.symmetric_difference(b).bits,
+                    a.bits ^ b.bits,
+                    "wrong result: `{:?}` ^ `{:?}`",
+                    a,
+                    b,
+                );
+                assert_eq!(
+                    a.difference(b).bits,
+                    a.bits & !b.bits,
+                    "wrong result: `{:?}` - `{:?}`",
+                    a,
+                    b,
+                );
+                // Note: Difference is checked as both `a - b` and `b - a`
+                assert_eq!(
+                    b.difference(a).bits,
+                    b.bits & !a.bits,
+                    "wrong result: `{:?}` - `{:?}`",
+                    b,
+                    a,
+                );
+                // Check that the named set operations are equivalent to the
+                // bitwise equivalents
+                assert_eq!(a.union(b), a | b, "named != op: `{:?}` | `{:?}`", a, b,);
+                assert_eq!(
+                    a.intersection(b),
+                    a & b,
+                    "named != op: `{:?}` & `{:?}`",
+                    a,
+                    b,
+                );
+                assert_eq!(
+                    a.symmetric_difference(b),
+                    a ^ b,
+                    "named != op: `{:?}` ^ `{:?}`",
+                    a,
+                    b,
+                );
+                assert_eq!(a.difference(b), a - b, "named != op: `{:?}` - `{:?}`", a, b,);
+                // Note: Difference is checked as both `a - b` and `b - a`
+                assert_eq!(b.difference(a), b - a, "named != op: `{:?}` - `{:?}`", b, a,);
+                // Verify that the operations which should be symmetric are
+                // actually symmetric.
+                assert_eq!(a.union(b), b.union(a), "asymmetry: `{:?}` | `{:?}`", a, b,);
+                assert_eq!(
+                    a.intersection(b),
+                    b.intersection(a),
+                    "asymmetry: `{:?}` & `{:?}`",
+                    a,
+                    b,
+                );
+                assert_eq!(
+                    a.symmetric_difference(b),
+                    b.symmetric_difference(a),
+                    "asymmetry: `{:?}` ^ `{:?}`",
+                    a,
+                    b,
+                );
+            }
+        }
+    }
+
+    #[test]
+    fn test_set() {
+        let mut e1 = Flags::A | Flags::C;
+        e1.set(Flags::B, true);
+        e1.set(Flags::C, false);
+
+        assert_eq!(e1, Flags::A | Flags::B);
+    }
+
+    #[test]
+    fn test_assignment_operators() {
+        let mut m1 = Flags::empty();
+        let e1 = Flags::A | Flags::C;
+        // union
+        m1 |= Flags::A;
+        assert_eq!(m1, Flags::A);
+        // intersection
+        m1 &= e1;
+        assert_eq!(m1, Flags::A);
+        // set difference
+        m1 -= m1;
+        assert_eq!(m1, Flags::empty());
+        // toggle
+        m1 ^= e1;
+        assert_eq!(m1, e1);
+    }
+
+    #[test]
+    fn test_const_fn() {
+        const _M1: Flags = Flags::empty();
+
+        const M2: Flags = Flags::A;
+        assert_eq!(M2, Flags::A);
+
+        const M3: Flags = Flags::C;
+        assert_eq!(M3, Flags::C);
+    }
+
+    #[test]
+    fn test_extend() {
+        let mut flags;
+
+        flags = Flags::empty();
+        flags.extend([].iter().cloned());
+        assert_eq!(flags, Flags::empty());
+
+        flags = Flags::empty();
+        flags.extend([Flags::A, Flags::B].iter().cloned());
+        assert_eq!(flags, Flags::A | Flags::B);
+
+        flags = Flags::A;
+        flags.extend([Flags::A, Flags::B].iter().cloned());
+        assert_eq!(flags, Flags::A | Flags::B);
+
+        flags = Flags::B;
+        flags.extend([Flags::A, Flags::ABC].iter().cloned());
+        assert_eq!(flags, Flags::ABC);
+    }
+
+    #[test]
+    fn test_from_iterator() {
+        assert_eq!([].iter().cloned().collect::<Flags>(), Flags::empty());
+        assert_eq!(
+            [Flags::A, Flags::B].iter().cloned().collect::<Flags>(),
+            Flags::A | Flags::B
+        );
+        assert_eq!(
+            [Flags::A, Flags::ABC].iter().cloned().collect::<Flags>(),
+            Flags::ABC
+        );
+    }
+
+    #[test]
+    fn test_lt() {
+        let mut a = Flags::empty();
+        let mut b = Flags::empty();
+
+        assert!(!(a < b) && !(b < a));
+        b = Flags::B;
+        assert!(a < b);
+        a = Flags::C;
+        assert!(!(a < b) && b < a);
+        b = Flags::C | Flags::B;
+        assert!(a < b);
+    }
+
+    #[test]
+    fn test_ord() {
+        let mut a = Flags::empty();
+        let mut b = Flags::empty();
+
+        assert!(a <= b && a >= b);
+        a = Flags::A;
+        assert!(a > b && a >= b);
+        assert!(b < a && b <= a);
+        b = Flags::B;
+        assert!(b > a && b >= a);
+        assert!(a < b && a <= b);
+    }
+
+    fn hash<T: Hash>(t: &T) -> u64 {
+        let mut s = DefaultHasher::new();
+        t.hash(&mut s);
+        s.finish()
+    }
+
+    #[test]
+    fn test_hash() {
+        let mut x = Flags::empty();
+        let mut y = Flags::empty();
+        assert_eq!(hash(&x), hash(&y));
+        x = Flags::all();
+        y = Flags::ABC;
+        assert_eq!(hash(&x), hash(&y));
+    }
+
+    #[test]
+    fn test_default() {
+        assert_eq!(Flags::empty(), Flags::default());
+    }
+
+    #[test]
+    fn test_debug() {
+        assert_eq!(format!("{:?}", Flags::A | Flags::B), "A | B");
+        assert_eq!(format!("{:?}", Flags::empty()), "(empty)");
+        assert_eq!(format!("{:?}", Flags::ABC), "A | B | C | ABC");
+        let extra = unsafe { Flags::from_bits_unchecked(0xb8) };
+        assert_eq!(format!("{:?}", extra), "0xb8");
+        assert_eq!(format!("{:?}", Flags::A | extra), "A | 0xb8");
+
+        assert_eq!(
+            format!("{:?}", Flags::ABC | extra),
+            "A | B | C | ABC | 0xb8"
+        );
+
+        assert_eq!(format!("{:?}", EmptyFlags::empty()), "(empty)");
+    }
+
+    #[test]
+    fn test_binary() {
+        assert_eq!(format!("{:b}", Flags::ABC), "111");
+        assert_eq!(format!("{:#b}", Flags::ABC), "0b111");
+        let extra = unsafe { Flags::from_bits_unchecked(0b1010000) };
+        assert_eq!(format!("{:b}", Flags::ABC | extra), "1010111");
+        assert_eq!(format!("{:#b}", Flags::ABC | extra), "0b1010111");
+    }
+
+    #[test]
+    fn test_octal() {
+        assert_eq!(format!("{:o}", LongFlags::LONG_A), "177777");
+        assert_eq!(format!("{:#o}", LongFlags::LONG_A), "0o177777");
+        let extra = unsafe { LongFlags::from_bits_unchecked(0o5000000) };
+        assert_eq!(format!("{:o}", LongFlags::LONG_A | extra), "5177777");
+        assert_eq!(format!("{:#o}", LongFlags::LONG_A | extra), "0o5177777");
+    }
+
+    #[test]
+    fn test_lowerhex() {
+        assert_eq!(format!("{:x}", LongFlags::LONG_A), "ffff");
+        assert_eq!(format!("{:#x}", LongFlags::LONG_A), "0xffff");
+        let extra = unsafe { LongFlags::from_bits_unchecked(0xe00000) };
+        assert_eq!(format!("{:x}", LongFlags::LONG_A | extra), "e0ffff");
+        assert_eq!(format!("{:#x}", LongFlags::LONG_A | extra), "0xe0ffff");
+    }
+
+    #[test]
+    fn test_upperhex() {
+        assert_eq!(format!("{:X}", LongFlags::LONG_A), "FFFF");
+        assert_eq!(format!("{:#X}", LongFlags::LONG_A), "0xFFFF");
+        let extra = unsafe { LongFlags::from_bits_unchecked(0xe00000) };
+        assert_eq!(format!("{:X}", LongFlags::LONG_A | extra), "E0FFFF");
+        assert_eq!(format!("{:#X}", LongFlags::LONG_A | extra), "0xE0FFFF");
+    }
+
+    mod submodule {
+        bitflags! {
+            pub struct PublicFlags: i8 {
+                const X = 0;
+            }
+
+            struct PrivateFlags: i8 {
+                const Y = 0;
+            }
+        }
+
+        #[test]
+        fn test_private() {
+            let _ = PrivateFlags::Y;
+        }
+    }
+
+    #[test]
+    fn test_public() {
+        let _ = submodule::PublicFlags::X;
+    }
+
+    mod t1 {
+        mod foo {
+            pub type Bar = i32;
+        }
+
+        bitflags! {
+            /// baz
+            struct Flags: foo::Bar {
+                const A = 0b00000001;
+                #[cfg(foo)]
+                const B = 0b00000010;
+                #[cfg(foo)]
+                const C = 0b00000010;
+            }
+        }
+    }
+
+    #[test]
+    fn test_in_function() {
+        bitflags! {
+           struct Flags: u8 {
+                const A = 1;
+                #[cfg(any())] // false
+                const B = 2;
+            }
+        }
+        assert_eq!(Flags::all(), Flags::A);
+        assert_eq!(format!("{:?}", Flags::A), "A");
+    }
+
+    #[test]
+    fn test_deprecated() {
+        bitflags! {
+            pub struct TestFlags: u32 {
+                #[deprecated(note = "Use something else.")]
+                const ONE = 1;
+            }
+        }
+    }
+
+    #[test]
+    fn test_pub_crate() {
+        mod module {
+            bitflags! {
+                pub (crate) struct Test: u8 {
+                    const FOO = 1;
+                }
+            }
+        }
+
+        assert_eq!(module::Test::FOO.bits(), 1);
+    }
+
+    #[test]
+    fn test_pub_in_module() {
+        mod module {
+            mod submodule {
+                bitflags! {
+                    // `pub (in super)` means only the module `module` will
+                    // be able to access this.
+                    pub (in super) struct Test: u8 {
+                        const FOO = 1;
+                    }
+                }
+            }
+
+            mod test {
+                // Note: due to `pub (in super)`,
+                // this cannot be accessed directly by the testing code.
+                pub(super) fn value() -> u8 {
+                    super::submodule::Test::FOO.bits()
+                }
+            }
+
+            pub fn value() -> u8 {
+                test::value()
+            }
+        }
+
+        assert_eq!(module::value(), 1)
+    }
+
+    #[test]
+    fn test_zero_value_flags() {
+        bitflags! {
+            struct Flags: u32 {
+                const NONE = 0b0;
+                const SOME = 0b1;
+            }
+        }
+
+        assert!(Flags::empty().contains(Flags::NONE));
+        assert!(Flags::SOME.contains(Flags::NONE));
+        assert!(Flags::NONE.is_empty());
+
+        assert_eq!(format!("{:?}", Flags::empty()), "NONE");
+        assert_eq!(format!("{:?}", Flags::SOME), "SOME");
+    }
+
+    #[test]
+    fn test_empty_bitflags() {
+        bitflags! {}
+    }
+
+    #[test]
+    fn test_u128_bitflags() {
+        bitflags! {
+            struct Flags128: u128 {
+                const A = 0x0000_0000_0000_0000_0000_0000_0000_0001;
+                const B = 0x0000_0000_0000_1000_0000_0000_0000_0000;
+                const C = 0x8000_0000_0000_0000_0000_0000_0000_0000;
+                const ABC = Self::A.bits | Self::B.bits | Self::C.bits;
+            }
+        }
+
+        assert_eq!(Flags128::ABC, Flags128::A | Flags128::B | Flags128::C);
+        assert_eq!(Flags128::A.bits, 0x0000_0000_0000_0000_0000_0000_0000_0001);
+        assert_eq!(Flags128::B.bits, 0x0000_0000_0000_1000_0000_0000_0000_0000);
+        assert_eq!(Flags128::C.bits, 0x8000_0000_0000_0000_0000_0000_0000_0000);
+        assert_eq!(
+            Flags128::ABC.bits,
+            0x8000_0000_0000_1000_0000_0000_0000_0001
+        );
+        assert_eq!(format!("{:?}", Flags128::A), "A");
+        assert_eq!(format!("{:?}", Flags128::B), "B");
+        assert_eq!(format!("{:?}", Flags128::C), "C");
+        assert_eq!(format!("{:?}", Flags128::ABC), "A | B | C | ABC");
+    }
+
+    #[test]
+    fn test_serde_bitflags_serialize() {
+        let flags = SerdeFlags::A | SerdeFlags::B;
+
+        let serialized = serde_json::to_string(&flags).unwrap();
+
+        assert_eq!(serialized, r#"{"bits":3}"#);
+    }
+
+    #[test]
+    fn test_serde_bitflags_deserialize() {
+        let deserialized: SerdeFlags = serde_json::from_str(r#"{"bits":12}"#).unwrap();
+
+        let expected = SerdeFlags::C | SerdeFlags::D;
+
+        assert_eq!(deserialized.bits, expected.bits);
+    }
+
+    #[test]
+    fn test_serde_bitflags_roundtrip() {
+        let flags = SerdeFlags::A | SerdeFlags::B;
+
+        let deserialized: SerdeFlags = serde_json::from_str(&serde_json::to_string(&flags).unwrap()).unwrap();
+
+        assert_eq!(deserialized.bits, flags.bits);
+    }
+
+    bitflags! {
+        #[derive(serde::Serialize, serde::Deserialize)]
+        struct SerdeFlags: u32 {
+            const A = 1;
+            const B = 2;
+            const C = 4;
+            const D = 8;
+        }
+    }
+}