darling::usage

Enum Purpose

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pub enum Purpose {
    BoundImpl,
    Declare,
}
Expand description

The goal of tracing generic parameter usage.

Not all uses of type parameters imply a need to add bounds to a generated trait impl. For example, a field of type <Vec<T> as a::b::Trait>::Associated does not need a where T: Serialize bound in serde. However, a proc macro that is attempting to generate a helper struct would need to know about this usage, or else the generated code would reference an unknown type T and fail to compile.

Variants§

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BoundImpl

The tracing is being used to generate an impl block.

Uses such as syn::TypePath.qself will not be returned.

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Declare

The tracing is being used to generate a new struct or enum.

All uses will be returned.

Trait Implementations§

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impl Clone for Purpose

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fn clone(&self) -> Purpose

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for Purpose

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

Formats the value using the given formatter. Read more
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impl From<Purpose> for Options

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fn from(purpose: Purpose) -> Options

Converts to this type from the input type.
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impl PartialEq for Purpose

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

Tests for self and other values to be equal, and is used by ==.
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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 Copy for Purpose

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impl Eq for Purpose

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impl StructuralPartialEq for Purpose

Auto Trait Implementations§

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, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit)
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 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.