Enum rustc_type_ir::solve::CandidateSource

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pub enum CandidateSource<I: Interner> {
    Impl(I::DefId),
    BuiltinImpl(BuiltinImplSource),
    ParamEnv(usize),
    AliasBound,
    CoherenceUnknowable,
}
Expand description

Possible ways the given goal can be proven.

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Impl(I::DefId)

A user written impl.

§Examples
fn main() {
    let x: Vec<u32> = Vec::new();
    // This uses the impl from the standard library to prove `Vec<T>: Clone`.
    let y = x.clone();
}
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BuiltinImpl(BuiltinImplSource)

A builtin impl generated by the compiler. When adding a new special trait, try to use actual impls whenever possible. Builtin impls should only be used in cases where the impl cannot be manually be written.

Notable examples are auto traits, Sized, and DiscriminantKind. For a list of all traits with builtin impls, check out the EvalCtxt::assemble_builtin_impl_candidates method.

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ParamEnv(usize)

An assumption from the environment.

More precisely we’ve used the n-th assumption in the param_env.

§Examples
fn is_clone<T: Clone>(x: T) -> (T, T) {
    // This uses the assumption `T: Clone` from the `where`-bounds
    // to prove `T: Clone`.
    (x.clone(), x)
}
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AliasBound

If the self type is an alias type, e.g. an opaque type or a projection, we know the bounds on that alias to hold even without knowing its concrete underlying type.

More precisely this candidate is using the n-th bound in the item_bounds of the self type.

§Examples
trait Trait {
    type Assoc: Clone;
}

fn foo<T: Trait>(x: <T as Trait>::Assoc) {
    // We prove `<T as Trait>::Assoc` by looking at the bounds on `Assoc` in
    // in the trait definition.
    let _y = x.clone();
}
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CoherenceUnknowable

A candidate that is registered only during coherence to represent some yet-unknown impl that could be produced downstream without violating orphan rules.

Trait Implementations§

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impl<I: Interner> Clone for CandidateSource<I>

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fn clone(&self) -> Self

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<I: Interner> Debug for CandidateSource<I>

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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<I: Interner> Hash for CandidateSource<I>

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fn hash<__HI>(&self, __state: &mut __HI)
where __HI: Hasher,

Feeds this value into the given Hasher. Read more
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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<I: Interner> PartialEq for CandidateSource<I>

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

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> 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<I: Interner> Copy for CandidateSource<I>

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impl<I: Interner> Eq for CandidateSource<I>

Auto Trait Implementations§

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impl<I> DynSend for CandidateSource<I>
where <I as Interner>::DefId: DynSend,

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impl<I> DynSync for CandidateSource<I>
where <I as Interner>::DefId: DynSync,

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impl<I> Freeze for CandidateSource<I>
where <I as Interner>::DefId: Freeze,

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impl<I> RefUnwindSafe for CandidateSource<I>
where <I as Interner>::DefId: RefUnwindSafe,

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impl<I> Send for CandidateSource<I>
where <I as Interner>::DefId: Send,

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impl<I> Sync for CandidateSource<I>
where <I as Interner>::DefId: Sync,

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impl<I> Unpin for CandidateSource<I>
where <I as Interner>::DefId: Unpin,

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impl<I> UnwindSafe for CandidateSource<I>
where <I as Interner>::DefId: UnwindSafe,

Blanket Implementations§

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impl<T> Aligned for T

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const ALIGN: Alignment = _

Alignment of Self.
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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, R> CollectAndApply<T, R> for T

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fn collect_and_apply<I, F>(iter: I, f: F) -> R
where I: Iterator<Item = T>, F: FnOnce(&[T]) -> R,

Equivalent to f(&iter.collect::<Vec<_>>()).

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type Output = R

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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Checks if this value is equivalent to the given key. Read more
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impl<Q, K> Equivalent<K> for Q
where Q: Eq + ?Sized, K: Borrow<Q> + ?Sized,

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fn equivalent(&self, key: &K) -> bool

Compare self to key and return true if they are equal.
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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> Instrument for T

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fn instrument(self, span: Span) -> Instrumented<Self>

Instruments this type with the provided Span, returning an Instrumented wrapper. Read more
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fn in_current_span(self) -> Instrumented<Self>

Instruments this type with the current Span, returning an Instrumented wrapper. Read more
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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> IntoEither for T

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fn into_either(self, into_left: bool) -> Either<Self, Self>

Converts self into a Left variant of Either<Self, Self> if into_left is true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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fn into_either_with<F>(self, into_left: F) -> Either<Self, Self>
where F: FnOnce(&Self) -> bool,

Converts self into a Left variant of Either<Self, Self> if into_left(&self) returns true. Converts self into a Right variant of Either<Self, Self> otherwise. Read more
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impl<T> Pointable for T

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const ALIGN: usize = _

The alignment of pointer.
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type Init = T

The type for initializers.
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unsafe fn init(init: <T as Pointable>::Init) -> usize

Initializes a with the given initializer. Read more
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unsafe fn deref<'a>(ptr: usize) -> &'a T

Dereferences the given pointer. Read more
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unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T

Mutably dereferences the given pointer. Read more
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unsafe fn drop(ptr: usize)

Drops the object pointed to by the given pointer. Read more
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impl<T> Same for T

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type Output = T

Should always be Self
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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.
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impl<I, T, U> Upcast<I, U> for T
where U: UpcastFrom<I, T>,

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fn upcast(self, interner: I) -> U

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impl<I, T> UpcastFrom<I, T> for T

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fn upcast_from(from: T, _tcx: I) -> T

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impl<T> WithSubscriber for T

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fn with_subscriber<S>(self, subscriber: S) -> WithDispatch<Self>
where S: Into<Dispatch>,

Attaches the provided Subscriber to this type, returning a WithDispatch wrapper. Read more
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fn with_current_subscriber(self) -> WithDispatch<Self>

Attaches the current default Subscriber to this type, returning a WithDispatch wrapper. Read more
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impl<'a, T> Captures<'a> for T
where T: ?Sized,

Layout§

Note: Unable to compute type layout, possibly due to this type having generic parameters. Layout can only be computed for concrete, fully-instantiated types.