[−][src]Struct nimiq_collections::limit_hash_set::LimitHashSet
A hash set implemented as UniqueLinkedList
that has a limit on the number of elements.
As with the UniqueLinkedList
type, a LimitHashSet
requires that the elements
implement the Eq
and Hash
traits. This can frequently be achieved by
using #[derive(PartialEq, Eq, Hash)]
. If you implement these yourself,
it is important that the following property holds:
k1 == k2 -> hash(k1) == hash(k2)
In other words, if two keys are equal, their hashes must be equal.
It is a logic error for an item to be modified in such a way that the
item's hash, as determined by the Hash
trait, or its equality, as
determined by the Eq
trait, changes while it is in the set. This is
normally only possible through Cell
, RefCell
, global state, I/O, or
unsafe code.
Examples
use nimiq_collections::LimitHashSet; // Type inference lets us omit an explicit type signature (which // would be `LimitHashSet<String>` in this example). let mut books = LimitHashSet::new(3); // Add some books. books.insert("A Dance With Dragons".to_string()); books.insert("To Kill a Mockingbird".to_string()); books.insert("The Odyssey".to_string()); books.insert("The Great Gatsby".to_string()); // Check for a specific one. if !books.contains(&"The Winds of Winter".to_string()) { println!("We have {} books, but The Winds of Winter ain't one.", books.len()); } // Remove a book. books.remove(&"The Odyssey".to_string()); // Iterate over everything. for book in &books { println!("{}", book); }
The easiest way to use LimitHashSet
with a custom type is to derive
Eq
and Hash
. We must also derive PartialEq
, this will in the
future be implied by Eq
.
use nimiq_collections::LimitHashSet; #[derive(Hash, Eq, PartialEq, Debug)] struct Viking { name: String, power: usize, } let mut vikings = LimitHashSet::new(3); vikings.insert(Viking { name: "Einar".to_string(), power: 9 }); vikings.insert(Viking { name: "Einar".to_string(), power: 9 }); vikings.insert(Viking { name: "Olaf".to_string(), power: 4 }); vikings.insert(Viking { name: "Harald".to_string(), power: 8 }); // Use derived implementation to print the vikings. for x in &vikings { println!("{:?}", x); }
Methods
impl<T> LimitHashSet<T> where
T: Hash + Eq,
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T: Hash + Eq,
pub fn new(limit: usize) -> Self
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Creates an empty LimitHashSet
with a limit of limit
elements.
limit
must be greater than zero or this function will panic.
Examples
use nimiq_collections::LimitHashSet; let set: LimitHashSet<i32> = LimitHashSet::new(10);
ⓘImportant traits for Iter<'a, T>pub fn iter(&self) -> Iter<T>
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An iterator visiting all elements in insertion order.
The iterator element type is &'a T
.
Examples
use nimiq_collections::LimitHashSet; let mut set = LimitHashSet::new(10); set.insert("a"); set.insert("b"); // Will print in an arbitrary order. for x in set.iter() { println!("{}", x); }
pub fn len(&self) -> usize
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Returns the number of elements in the set.
Examples
use nimiq_collections::LimitHashSet; let mut v = LimitHashSet::new(10); assert_eq!(v.len(), 0); v.insert(1); assert_eq!(v.len(), 1);
pub fn is_empty(&self) -> bool
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Returns true if the set contains no elements.
Examples
use nimiq_collections::LimitHashSet; let mut v = LimitHashSet::new(10); assert!(v.is_empty()); v.insert(1); assert!(!v.is_empty());
pub fn clear(&mut self)
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Clears the set, removing all values.
Examples
use nimiq_collections::LimitHashSet; let mut v = LimitHashSet::new(10); v.insert(1); v.clear(); assert!(v.is_empty());
ⓘImportant traits for Difference<'a, T>pub fn difference<'a>(&'a self, other: &'a LimitHashSet<T>) -> Difference<'a, T>
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Visits the values representing the difference,
i.e. the values that are in self
but not in other
.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); let b: LimitHashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); // Can be seen as `a - b`. for x in a.difference(&b) { println!("{}", x); // Print 1 } let diff: LimitHashSet<_> = a.difference(&b).collect(); assert_eq!(diff, [1].iter().collect()); // Note that difference is not symmetric, // and `b - a` means something else: let diff: LimitHashSet<_> = b.difference(&a).collect(); assert_eq!(diff, [4].iter().collect());
ⓘImportant traits for SymmetricDifference<'a, T>pub fn symmetric_difference<'a>(
&'a self,
other: &'a LimitHashSet<T>
) -> SymmetricDifference<'a, T>
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&'a self,
other: &'a LimitHashSet<T>
) -> SymmetricDifference<'a, T>
Visits the values representing the symmetric difference,
i.e. the values that are in self
or in other
but not in both.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); let b: LimitHashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); // Print 1, 4 in arbitrary order. for x in a.symmetric_difference(&b) { println!("{}", x); } let diff1: LimitHashSet<_> = a.symmetric_difference(&b).collect(); let diff2: LimitHashSet<_> = b.symmetric_difference(&a).collect(); assert_eq!(diff1, diff2); assert_eq!(diff1, [1, 4].iter().collect());
ⓘImportant traits for Intersection<'a, T>pub fn intersection<'a>(
&'a self,
other: &'a LimitHashSet<T>
) -> Intersection<'a, T>
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&'a self,
other: &'a LimitHashSet<T>
) -> Intersection<'a, T>
Visits the values representing the intersection,
i.e. the values that are both in self
and other
.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); let b: LimitHashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); // Print 2, 3 in arbitrary order. for x in a.intersection(&b) { println!("{}", x); } let intersection: LimitHashSet<_> = a.intersection(&b).collect(); assert_eq!(intersection, [2, 3].iter().collect());
ⓘImportant traits for Union<'a, T>pub fn union<'a>(&'a self, other: &'a LimitHashSet<T>) -> Union<'a, T>
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Visits the values representing the union,
i.e. all the values in self
or other
, without duplicates.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); let b: LimitHashSet<_> = [4, 2, 3, 4].iter().cloned().collect(); // Print 1, 2, 3, 4 in arbitrary order. for x in a.union(&b) { println!("{}", x); } let union: LimitHashSet<_> = a.union(&b).collect(); assert_eq!(union, [1, 2, 3, 4].iter().collect());
pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool where
Rc<T>: Borrow<Q>,
Q: Hash + Eq,
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Rc<T>: Borrow<Q>,
Q: Hash + Eq,
Returns true
if the set contains a value.
The value may be any borrowed form of the set's value type, but
Hash
and Eq
on the borrowed form must match those for
the value type.
Examples
use nimiq_collections::LimitHashSet; let set: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); assert_eq!(set.contains(&1), true); assert_eq!(set.contains(&4), false);
pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T> where
Rc<T>: Borrow<Q>,
Q: Hash + Eq,
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Rc<T>: Borrow<Q>,
Q: Hash + Eq,
Returns a reference to the value in the set, if any, that is equal to the given value.
The value may be any borrowed form of the set's value type, but
Hash
and Eq
on the borrowed form must match those for
the value type.
Examples
use nimiq_collections::LimitHashSet; let set: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); assert_eq!(set.get(&2), Some(&2)); assert_eq!(set.get(&4), None);
pub fn is_disjoint(&self, other: &LimitHashSet<T>) -> bool
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Returns true
if self
has no elements in common with other
.
This is equivalent to checking for an empty intersection.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); let mut b = LimitHashSet::new(10); assert_eq!(a.is_disjoint(&b), true); b.insert(4); assert_eq!(a.is_disjoint(&b), true); b.insert(1); assert_eq!(a.is_disjoint(&b), false);
pub fn is_subset(&self, other: &LimitHashSet<T>) -> bool
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Returns true
if the set is a subset of another,
i.e. other
contains at least all the values in self
.
Examples
use nimiq_collections::LimitHashSet; let sup: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); let mut set = LimitHashSet::new(10); assert_eq!(set.is_subset(&sup), true); set.insert(2); assert_eq!(set.is_subset(&sup), true); set.insert(4); assert_eq!(set.is_subset(&sup), false);
pub fn is_superset(&self, other: &LimitHashSet<T>) -> bool
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Returns true
if the set is a superset of another,
i.e. self
contains at least all the values in other
.
Examples
use nimiq_collections::LimitHashSet; let sub: LimitHashSet<_> = [1, 2].iter().cloned().collect(); let mut set = LimitHashSet::new(10); assert_eq!(set.is_superset(&sub), false); set.insert(0); set.insert(1); assert_eq!(set.is_superset(&sub), false); set.insert(2); assert_eq!(set.is_superset(&sub), true);
pub fn insert(&mut self, value: T) -> bool
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Adds a value to the set and removes the oldest value if the limit is reached.
If the set did not have this value present, true
is returned.
If the set did have this value present, false
is returned.
Examples
use nimiq_collections::LimitHashSet; let mut set = LimitHashSet::new(10); assert_eq!(set.insert(2), true); assert_eq!(set.insert(2), false); assert_eq!(set.len(), 1);
pub fn replace(&mut self, value: T) -> Option<T>
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Adds a value to the set, replacing the existing value, if any, that is equal to the given one. Returns the replaced value. Removes the oldest value if the limit is reached.
Examples
use nimiq_collections::LimitHashSet; let mut set = LimitHashSet::new(10); set.insert(Vec::<i32>::new()); assert_eq!(set.get(&Vec::<i32>::new()).unwrap().capacity(), 0); set.replace(Vec::with_capacity(10)); assert_eq!(set.get(&Vec::<i32>::new()).unwrap().capacity(), 10);
pub fn insert_and_get_removed(&mut self, value: T) -> Option<T>
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Adds a value to the set, replacing the existing value, if any, that is equal to the given one. Removes and returns the oldest value if the limit is reached.
Examples
use nimiq_collections::LimitHashSet; let mut set = LimitHashSet::new(2); assert_eq!(set.insert_and_get_removed(4), None); assert_eq!(set.insert_and_get_removed(3), None); assert_eq!(set.insert_and_get_removed(5), Some(4));
pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool where
Rc<T>: Borrow<Q>,
Q: Hash + Eq,
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Rc<T>: Borrow<Q>,
Q: Hash + Eq,
Removes a value from the set. Returns true
if the value was
present in the set.
The value may be any borrowed form of the set's value type, but
Hash
and Eq
on the borrowed form must match those for
the value type.
Examples
use nimiq_collections::LimitHashSet; let mut set = LimitHashSet::new(10); set.insert(2); assert_eq!(set.remove(&2), true); assert_eq!(set.remove(&2), false);
pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T> where
Rc<T>: Borrow<Q>,
Q: Hash + Eq,
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Rc<T>: Borrow<Q>,
Q: Hash + Eq,
Removes and returns the value in the set, if any, that is equal to the given one.
The value may be any borrowed form of the set's value type, but
Hash
and Eq
on the borrowed form must match those for
the value type.
Examples
use nimiq_collections::LimitHashSet; let mut set: LimitHashSet<_> = [1, 2, 3].iter().cloned().collect(); assert_eq!(set.take(&2), Some(2)); assert_eq!(set.take(&2), None);
Trait Implementations
impl<T> Extend<T> for LimitHashSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I)
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impl<'a, T> Extend<&'a T> for LimitHashSet<T> where
T: 'a + Eq + Hash + Copy,
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T: 'a + Eq + Hash + Copy,
fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iter: I)
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impl<'a, T> IntoIterator for &'a LimitHashSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
type Item = &'a T
The type of the elements being iterated over.
type IntoIter = Iter<'a, T>
Which kind of iterator are we turning this into?
ⓘImportant traits for Iter<'a, T>fn into_iter(self) -> Iter<'a, T>
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impl<T> IntoIterator for LimitHashSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
type Item = T
The type of the elements being iterated over.
type IntoIter = IntoIter<T>
Which kind of iterator are we turning this into?
ⓘImportant traits for IntoIter<T>fn into_iter(self) -> IntoIter<T>
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Creates a consuming iterator, that is, one that moves each value out of the set in insertion order. The set cannot be used after calling this.
Examples
use nimiq_collections::LimitHashSet; let mut set = LimitHashSet::new(10); set.insert("a".to_string()); set.insert("b".to_string()); // Not possible to collect to a Vec<String> with a regular `.iter()`. let v: Vec<String> = set.into_iter().collect(); // Will print in an arbitrary order. for x in &v { println!("{}", x); }
impl<T: Clone> Clone for LimitHashSet<T> where
T: Hash + Eq,
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T: Hash + Eq,
fn clone(&self) -> LimitHashSet<T>
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fn clone_from(&mut self, source: &Self)
1.0.0[src]
impl<T> Eq for LimitHashSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
impl<T> PartialEq<LimitHashSet<T>> for LimitHashSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
fn eq(&self, other: &LimitHashSet<T>) -> bool
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#[must_use]
fn ne(&self, other: &Rhs) -> bool
1.0.0[src]
impl<T> Debug for LimitHashSet<T> where
T: Eq + Hash + Debug,
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T: Eq + Hash + Debug,
impl<'a, 'b, T> Sub<&'b LimitHashSet<T>> for &'a LimitHashSet<T> where
T: Eq + Hash + Clone,
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T: Eq + Hash + Clone,
type Output = LimitHashSet<T>
The resulting type after applying the -
operator.
fn sub(self, rhs: &LimitHashSet<T>) -> LimitHashSet<T>
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Returns the difference of self
and rhs
as a new LimitHashSet<T>
.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = vec![1, 2, 3].into_iter().collect(); let b: LimitHashSet<_> = vec![3, 4, 5].into_iter().collect(); let set = &a - &b; let mut i = 0; let expected = [1, 2]; for x in &set { assert!(expected.contains(x)); i += 1; } assert_eq!(i, expected.len());
impl<'a, 'b, T> BitAnd<&'b LimitHashSet<T>> for &'a LimitHashSet<T> where
T: Eq + Hash + Clone,
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T: Eq + Hash + Clone,
type Output = LimitHashSet<T>
The resulting type after applying the &
operator.
fn bitand(self, rhs: &LimitHashSet<T>) -> LimitHashSet<T>
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Returns the intersection of self
and rhs
as a new LimitHashSet<T>
.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = vec![1, 2, 3].into_iter().collect(); let b: LimitHashSet<_> = vec![2, 3, 4].into_iter().collect(); let set = &a & &b; let mut i = 0; let expected = [2, 3]; for x in &set { assert!(expected.contains(x)); i += 1; } assert_eq!(i, expected.len());
impl<'a, 'b, T> BitOr<&'b LimitHashSet<T>> for &'a LimitHashSet<T> where
T: Eq + Hash + Clone,
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T: Eq + Hash + Clone,
type Output = LimitHashSet<T>
The resulting type after applying the |
operator.
fn bitor(self, rhs: &LimitHashSet<T>) -> LimitHashSet<T>
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Returns the union of self
and rhs
as a new LimitHashSet<T>
.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = vec![1, 2, 3].into_iter().collect(); let b: LimitHashSet<_> = vec![3, 4, 5].into_iter().collect(); let set = &a | &b; let mut i = 0; let expected = [1, 2, 3, 4, 5]; for x in &set { assert!(expected.contains(x)); i += 1; } assert_eq!(i, expected.len());
impl<'a, 'b, T> BitXor<&'b LimitHashSet<T>> for &'a LimitHashSet<T> where
T: Eq + Hash + Clone,
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T: Eq + Hash + Clone,
type Output = LimitHashSet<T>
The resulting type after applying the ^
operator.
fn bitxor(self, rhs: &LimitHashSet<T>) -> LimitHashSet<T>
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Returns the symmetric difference of self
and rhs
as a new LimitHashSet<T>
.
Examples
use nimiq_collections::LimitHashSet; let a: LimitHashSet<_> = vec![1, 2, 3].into_iter().collect(); let b: LimitHashSet<_> = vec![3, 4, 5].into_iter().collect(); let set = &a ^ &b; let mut i = 0; let expected = [1, 2, 4, 5]; for x in &set { assert!(expected.contains(x)); i += 1; } assert_eq!(i, expected.len());
impl<T> FromIterator<T> for LimitHashSet<T> where
T: Eq + Hash,
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T: Eq + Hash,
fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> LimitHashSet<T>
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Auto Trait Implementations
impl<T> Send for LimitHashSet<T> where
T: Send,
T: Send,
impl<T> Sync for LimitHashSet<T> where
T: Sync,
T: Sync,
impl<T> Unpin for LimitHashSet<T>
impl<T> !UnwindSafe for LimitHashSet<T>
impl<T> !RefUnwindSafe for LimitHashSet<T>
Blanket Implementations
impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> From<T> for T
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impl<I> IntoIterator for I where
I: Iterator,
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I: Iterator,
type Item = <I as Iterator>::Item
The type of the elements being iterated over.
type IntoIter = I
Which kind of iterator are we turning this into?
fn into_iter(self) -> I
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impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
fn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,