pub enum ImplSource<'tcx, N> {
    UserDefined(ImplSourceUserDefinedData<'tcx, N>),
    Param(Vec<N, Global>),
    Builtin(BuiltinImplSource, Vec<N, Global>),
}
Expand description

Given the successful resolution of an obligation, the ImplSource indicates where the impl comes from.

For example, the obligation may be satisfied by a specific impl (case A), or it may be relative to some bound that is in scope (case B).

impl<T:Clone> Clone<T> for Option<T> { ... } // Impl_1
impl<T:Clone> Clone<T> for Box<T> { ... }    // Impl_2
impl Clone for i32 { ... }                   // Impl_3

fn foo<T: Clone>(concrete: Option<Box<i32>>, param: T, mixed: Option<T>) {
    // Case A: ImplSource points at a specific impl. Only possible when
    // type is concretely known. If the impl itself has bounded
    // type parameters, ImplSource will carry resolutions for those as well:
    concrete.clone(); // ImplSource(Impl_1, [ImplSource(Impl_2, [ImplSource(Impl_3)])])

    // Case B: ImplSource must be provided by caller. This applies when
    // type is a type parameter.
    param.clone();    // ImplSource::Param

    // Case C: A mix of cases A and B.
    mixed.clone();    // ImplSource(Impl_1, [ImplSource::Param])
}

The type parameter N

See explanation on ImplSourceUserDefinedData.

Variants§

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UserDefined(ImplSourceUserDefinedData<'tcx, N>)

ImplSource identifying a particular impl.

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Param(Vec<N, Global>)

Successful resolution to an obligation provided by the caller for some type parameter. The Vec<N> represents the obligations incurred from normalizing the where-clause (if any).

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Builtin(BuiltinImplSource, Vec<N, Global>)

Successful resolution for a builtin impl.

Auto Trait Implementations§

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impl<'tcx, N> !RefUnwindSafe for ImplSource<'tcx, N>

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impl<'tcx, N> Send for ImplSource<'tcx, N>where N: Send,

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impl<'tcx, N> Sync for ImplSource<'tcx, N>where N: Sync,

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impl<'tcx, N> Unpin for ImplSource<'tcx, N>where N: Unpin,

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impl<'tcx, N> !UnwindSafe for ImplSource<'tcx, N>

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> 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> ToOwned for Twhere 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 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.

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: 48 bytes

Size for each variant:

  • UserDefined: 40 bytes
  • Param: 24 bytes
  • Builtin: 40 bytes