GenericParamDefKind in rustdoc_json_types - Rust
Description: The kind of a `GenericParamDef`.

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## GenericParamDefKind

# Enum GenericParamDefKind

Source

    pub enum GenericParamDefKind {
        Lifetime {
            outlives: Vec<String>,
        },
        Type {
            bounds: Vec<GenericBound>,
            default: Option<Type>,
            is_synthetic: bool,
        },
        Const {
            type_: Type,
            default: Option<String>,
        },
    }

Expand description

The kind of a `GenericParamDef`.

## Variants§

§

### Lifetime

Denotes a lifetime parameter.

#### Fields

§`outlives: Vec<String>`

Lifetimes that this lifetime parameter is required to outlive.

    fn f<'a, 'b, 'resource: 'a + 'b>(a: &'a str, b: &'b str, res: &'resource str) {}
    //                      ^^^^^^^

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### Type

Denotes a type parameter.

#### Fields

§`bounds: Vec<GenericBound>`

Bounds applied directly to the type. Note that the bounds from `where` clauses that constrain this parameter won’t appear here.

    fn default2<T: Default>() -> [T; 2] where T: Clone { todo!() }
    //             ^^^^^^^

§`default: Option<Type>`

The default type for this parameter, if provided, e.g.

    trait PartialEq<Rhs = Self> {}
    //                    ^^^^

§`is_synthetic: bool`

This is normally `false`, which means that this generic parameter is declared in the Rust source text.

If it is `true`, this generic parameter has been introduced by the compiler behind the scenes.

##### §Example

Consider

ⓘ

    pub fn f(_: impl Trait) {}

The compiler will transform this behind the scenes to

ⓘ

    pub fn f<impl Trait: Trait>(_: impl Trait) {}

In this example, the generic parameter named `impl Trait` (and which is bound by `Trait`) is synthetic, because it was not originally in the Rust source text.

§

### Const

Denotes a constant parameter.

#### Fields

§`type_: Type`

The type of the constant as declared.

§`default: Option<String>`

The stringified expression for the default value, if provided. It’s not guaranteed that it’ll match the actual source code for the default value.

## Trait Implementations§

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### impl Clone for GenericParamDefKind

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#### fn clone(&self) -> GenericParamDefKind

Returns a duplicate of the value. Read more
1.0.0 (const: unstable) · Source§

#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for GenericParamDefKind

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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<'de> Deserialize<'de> for GenericParamDefKind

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#### fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>
where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer. Read more
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### impl Eq for GenericParamDefKind

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### impl Hash for GenericParamDefKind

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

Feeds this value into the given `Hasher`. Read more
1.3.0 · Source§

#### fn hash_slice<H>(data: &[Self], state: &mut H)
where H: Hasher, Self: Sized,

Feeds a slice of this type into the given `Hasher`. Read more
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### impl PartialEq for GenericParamDefKind

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

Tests for `self` and `other` values to be equal, and is used by `==`.
1.0.0 (const: unstable) · Source§

#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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### impl Serialize for GenericParamDefKind

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#### fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>
where __S: Serializer,

Serialize this value into the given Serde serializer. Read more
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### impl StructuralPartialEq for GenericParamDefKind

## Auto Trait Implementations§

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### impl Freeze for GenericParamDefKind

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### impl RefUnwindSafe for GenericParamDefKind

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### impl Send for GenericParamDefKind

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### impl Sync for GenericParamDefKind

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### impl Unpin for GenericParamDefKind

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### impl UnsafeUnpin for GenericParamDefKind

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### impl UnwindSafe for GenericParamDefKind

## Blanket Implementations§

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### impl<T> Any for T
where 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 T
where 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 T
where 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 T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> DeserializeOwned for T
where T: for<'de> Deserialize<'de>,

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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 T
where 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> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T, U> TryFrom<U> for T
where 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 T
where 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.

## Layout§

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain `repr(...)` attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 112 bytes

Size for each variant:

- `Lifetime`: 32 bytes
- `Type`: 112 bytes
- `Const`: 112 bytes