# Primitive Type tuple

1.0.0 ·
Expand description

A finite heterogeneous sequence, `(T, U, ..)`.

Let’s cover each of those in turn:

Tuples are finite. In other words, a tuple has a length. Here’s a tuple of length `3`:

``("hello", 5, 'c');``
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‘Length’ is also sometimes called ‘arity’ here; each tuple of a different length is a different, distinct type.

Tuples are heterogeneous. This means that each element of the tuple can have a different type. In that tuple above, it has the type:

``(&'static str, i32, char)``
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Tuples are a sequence. This means that they can be accessed by position; this is called ‘tuple indexing’, and it looks like this:

``````let tuple = ("hello", 5, 'c');

assert_eq!(tuple.0, "hello");
assert_eq!(tuple.1, 5);
assert_eq!(tuple.2, 'c');``````
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The sequential nature of the tuple applies to its implementations of various traits. For example, in `PartialOrd` and `Ord`, the elements are compared sequentially until the first non-equal set is found.

For more about tuples, see the book.

## §Trait implementations

In this documentation the shorthand `(T₁, T₂, …, Tₙ)` is used to represent tuples of varying length. When that is used, any trait bound expressed on `T` applies to each element of the tuple independently. Note that this is a convenience notation to avoid repetitive documentation, not valid Rust syntax.

Due to a temporary restriction in Rust’s type system, the following traits are only implemented on tuples of arity 12 or less. In the future, this may change:

The following traits are implemented for tuples of any length. These traits have implementations that are automatically generated by the compiler, so are not limited by missing language features.

## §Examples

Basic usage:

``````let tuple = ("hello", 5, 'c');

assert_eq!(tuple.0, "hello");``````
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Tuples are often used as a return type when you want to return more than one value:

``````fn calculate_point() -> (i32, i32) {
// Don't do a calculation, that's not the point of the example
(4, 5)
}

let point = calculate_point();

assert_eq!(point.0, 4);
assert_eq!(point.1, 5);

// Combining this with patterns can be nicer.

let (x, y) = calculate_point();

assert_eq!(x, 4);
assert_eq!(y, 5);``````
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Homogeneous tuples can be created from arrays of appropriate length:

``````let array: [u32; 3] = [1, 2, 3];
let tuple: (u32, u32, u32) = array.into();``````
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## Trait Implementations§

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### impl<T> Debug for (T₁, T₂, …, Tₙ)where T: ?Sized + Debug,

This trait is implemented for tuples up to twelve items long.

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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### impl<T: Default> Default for (T₁, T₂, …, Tₙ)

This trait is implemented for tuples up to twelve items long.

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#### fn default() -> (T,)

Returns the “default value” for a type. Read more
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### impl<A, B, ExtendA, ExtendB> Extend<(A, B)> for (ExtendA, ExtendB)where ExtendA: Extend<A>, ExtendB: Extend<B>,

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#### fn extend<T: IntoIterator<Item = (A, B)>>(&mut self, into_iter: T)

Allows to `extend` a tuple of collections that also implement `Extend`.

See also: `Iterator::unzip`

##### §Examples
``````let mut tuple = (vec![0], vec![1]);
tuple.extend([(2, 3), (4, 5), (6, 7)]);
assert_eq!(tuple.0, [0, 2, 4, 6]);
assert_eq!(tuple.1, [1, 3, 5, 7]);

// also allows for arbitrarily nested tuples as elements
let mut nested_tuple = (vec![1], (vec![2], vec![3]));
nested_tuple.extend([(4, (5, 6)), (7, (8, 9))]);

let (a, (b, c)) = nested_tuple;
assert_eq!(a, [1, 4, 7]);
assert_eq!(b, [2, 5, 8]);
assert_eq!(c, [3, 6, 9]);``````
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#### fn extend_one(&mut self, item: (A, B))

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Extends a collection with exactly one element.
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#### fn extend_reserve(&mut self, additional: usize)

🔬This is a nightly-only experimental API. (`extend_one` #72631)
Reserves capacity in a collection for the given number of additional elements. Read more
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### impl<T> From<[T; 1]> for (T,)

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#### fn from(array: [T; 1]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 10]> for (T, T, T, T, T, T, T, T, T, T)

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#### fn from(array: [T; 10]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 11]> for (T, T, T, T, T, T, T, T, T, T, T)

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#### fn from(array: [T; 11]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 12]> for (T, T, T, T, T, T, T, T, T, T, T, T)

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#### fn from(array: [T; 12]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 2]> for (T, T)

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#### fn from(array: [T; 2]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 3]> for (T, T, T)

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#### fn from(array: [T; 3]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 4]> for (T, T, T, T)

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#### fn from(array: [T; 4]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 5]> for (T, T, T, T, T)

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#### fn from(array: [T; 5]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 6]> for (T, T, T, T, T, T)

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#### fn from(array: [T; 6]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 7]> for (T, T, T, T, T, T, T)

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#### fn from(array: [T; 7]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 8]> for (T, T, T, T, T, T, T, T)

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#### fn from(array: [T; 8]) -> Self

Converts to this type from the input type.
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### impl<T> From<[T; 9]> for (T, T, T, T, T, T, T, T, T)

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#### fn from(array: [T; 9]) -> Self

Converts to this type from the input type.
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#### fn from(pieces: (I, u16)) -> SocketAddr

Converts a tuple struct (Into<`IpAddr`>, `u16`) into a `SocketAddr`.

This conversion creates a `SocketAddr::V4` for an `IpAddr::V4` and creates a `SocketAddr::V6` for an `IpAddr::V6`.

`u16` is treated as port of the newly created `SocketAddr`.

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### impl<T> From<(T,)> for [T; 1]

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#### fn from(tuple: (T,)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T)> for [T; 2]

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#### fn from(tuple: (T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T)> for [T; 3]

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#### fn from(tuple: (T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T)> for [T; 4]

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#### fn from(tuple: (T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T, T)> for [T; 5]

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#### fn from(tuple: (T, T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T, T, T)> for [T; 6]

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#### fn from(tuple: (T, T, T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T, T, T, T)> for [T; 7]

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#### fn from(tuple: (T, T, T, T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T, T, T, T, T)> for [T; 8]

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#### fn from(tuple: (T, T, T, T, T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T, T, T, T, T, T)> for [T; 9]

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#### fn from(tuple: (T, T, T, T, T, T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T, T, T, T, T, T, T)> for [T; 10]

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#### fn from(tuple: (T, T, T, T, T, T, T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T, T, T, T, T, T, T, T)> for [T; 11]

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#### fn from(tuple: (T, T, T, T, T, T, T, T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<T> From<(T, T, T, T, T, T, T, T, T, T, T, T)> for [T; 12]

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#### fn from(tuple: (T, T, T, T, T, T, T, T, T, T, T, T)) -> Self

Converts to this type from the input type.
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### impl<A, B, AE, BE> FromIterator<(AE, BE)> for (A, B)where A: Default + Extend<AE>, B: Default + Extend<BE>,

This implementation turns an iterator of tuples into a tuple of types which implement `Default` and `Extend`.

This is similar to `Iterator::unzip`, but is also composable with other `FromIterator` implementations:

``````let string = "1,2,123,4";

let (numbers, lengths): (Vec<_>, Vec<_>) = string
.split(',')
.map(|s| s.parse().map(|n: u32| (n, s.len())))
.collect::<Result<_, _>>()?;

assert_eq!(numbers, [1, 2, 123, 4]);
assert_eq!(lengths, [1, 1, 3, 1]);``````
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#### fn from_iter<I: IntoIterator<Item = (AE, BE)>>(iter: I) -> Self

Creates a value from an iterator. Read more
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### impl<T> Hash for (T₁, T₂, …, Tₙ)where T: ?Sized + Hash,

This trait is implemented for tuples up to twelve items long.

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#### fn hash<S: Hasher>(&self, state: &mut S)

Feeds this value into the given `Hasher`. Read more
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### impl<T> Ord for (T₁, T₂, …, Tₙ)where T: ?Sized + Ord,

This trait is implemented for tuples up to twelve items long.

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#### fn cmp(&self, other: &(T,)) -> Ordering

This method returns an `Ordering` between `self` and `other`. Read more
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### impl<T> PartialEq for (T₁, T₂, …, Tₙ)where T: ?Sized + PartialEq,

This trait is implemented for tuples up to twelve items long.

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#### fn eq(&self, other: &(T,)) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`.
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#### fn ne(&self, other: &(T,)) -> bool

This method tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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### impl<T> PartialOrd for (T₁, T₂, …, Tₙ)where T: ?Sized + PartialOrd,

This trait is implemented for tuples up to twelve items long.

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#### fn partial_cmp(&self, other: &(T,)) -> Option<Ordering>

This method returns an ordering between `self` and `other` values if one exists. Read more
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#### fn lt(&self, other: &(T,)) -> bool

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more
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#### fn le(&self, other: &(T,)) -> bool

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more
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#### fn ge(&self, other: &(T,)) -> bool

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more
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#### fn gt(&self, other: &(T,)) -> bool

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more
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### impl<'a, T: ?Sized + 'a> RangeBounds<T> for (Bound<&'a T>, Bound<&'a T>)

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#### fn contains<U>(&self, item: &U) -> boolwhere T: PartialOrd<U>, U: ?Sized + PartialOrd<T>,

Returns `true` if `item` is contained in the range. Read more
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### impl<T> RangeBounds<T> for (Bound<T>, Bound<T>)

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#### fn contains<U>(&self, item: &U) -> boolwhere T: PartialOrd<U>, U: ?Sized + PartialOrd<T>,

Returns `true` if `item` is contained in the range. Read more
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### impl<T> SliceIndex<[T]> for (Bound<usize>, Bound<usize>)

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#### type Output = [T]

The output type returned by methods.
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#### fn get(self, slice: &[T]) -> Option<&Self::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
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#### fn get_mut(self, slice: &mut [T]) -> Option<&mut Self::Output>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
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#### unsafe fn get_unchecked(self, slice: *const [T]) -> *const Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting pointer is not used.
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#### unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting pointer is not used.
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#### fn index(self, slice: &[T]) -> &Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
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#### fn index_mut(self, slice: &mut [T]) -> &mut Self::Output

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
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### impl SliceIndex<str> for (Bound<usize>, Bound<usize>)

Implements substring slicing for arbitrary bounds.

Returns a slice of the given string bounded by the byte indices provided by each bound.

This operation is O(1).

#### §Panics

Panics if `begin` or `end` (if it exists and once adjusted for inclusion/exclusion) does not point to the starting byte offset of a character (as defined by `is_char_boundary`), if `begin > end`, or if `end > len`.

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#### type Output = str

The output type returned by methods.
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#### fn get(self, slice: &str) -> Option<&str>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, if in bounds.
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#### fn get_mut(self, slice: &mut str) -> Option<&mut str>

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, if in bounds.
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#### unsafe fn get_unchecked(self, slice: *const str) -> *const str

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a pointer to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting pointer is not used.
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#### unsafe fn get_unchecked_mut(self, slice: *mut str) -> *mut str

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Calling this method with an out-of-bounds index or a dangling `slice` pointer is undefined behavior even if the resulting pointer is not used.
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#### fn index(self, slice: &str) -> &str

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a shared reference to the output at this location, panicking if out of bounds.
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#### fn index_mut(self, slice: &mut str) -> &mut str

🔬This is a nightly-only experimental API. (`slice_index_methods`)
Returns a mutable reference to the output at this location, panicking if out of bounds.
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### impl<T: ConstParamTy> ConstParamTy for (T₁, T₂, …, Tₙ)

This trait is implemented for tuples up to twelve items long.

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### impl<T> Eq for (T₁, T₂, …, Tₙ)where T: ?Sized + Eq,

This trait is implemented for tuples up to twelve items long.

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### impl<T> StructuralPartialEq for (T₁, T₂, …, Tₙ)

This trait is implemented for tuples up to twelve items long.

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## Blanket Implementations§

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### impl<T> Any for Twhere T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for Twhere T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for Twhere T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for Twhere T: Clone,

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#### default unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dst`. Read more
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### impl<T> CloneToUninit for Twhere T: Copy,

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#### unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dst`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for Twhere U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.