rustc_trait_selection::infer::relate

Enum VarianceDiagInfo

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pub enum VarianceDiagInfo<I>
where
    I: Interner,
{
    None,
    Invariant {
        ty: <I as Interner>::Ty,
        param_index: u32,
    },
}
Expand description

Extra information about why we ended up with a particular variance. This is only used to add more information to error messages, and has no effect on soundness. While choosing the ‘wrong’ VarianceDiagInfo may lead to confusing notes in error messages, it will never cause a miscompilation or unsoundness.

When in doubt, use VarianceDiagInfo::default()

Variants§

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None

No additional information - this is the default. We will not add any additional information to error messages.

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Invariant

We switched our variance because a generic argument occurs inside the invariant generic argument of another type.

Fields

§ty: <I as Interner>::Ty

The generic type containing the generic parameter that changes the variance (e.g. *mut T, MyStruct<T>)

§param_index: u32

The index of the generic parameter being used (e.g. 0 for *mut T, 1 for MyStruct<'CovariantParam, 'InvariantParam>)

Implementations§

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impl<I> VarianceDiagInfo<I>
where I: Interner,

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pub fn xform(self, other: VarianceDiagInfo<I>) -> VarianceDiagInfo<I>

Mirrors Variance::xform - used to ‘combine’ the existing and new VarianceDiagInfos when our variance changes.

Trait Implementations§

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impl<I> Clone for VarianceDiagInfo<I>
where I: Interner,

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fn clone(&self) -> VarianceDiagInfo<I>

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> Debug for VarianceDiagInfo<I>
where I: Interner,

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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<I> Default for VarianceDiagInfo<I>
where I: Interner,

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fn default() -> VarianceDiagInfo<I>

Returns the “default value” for a type. Read more
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impl<I> PartialEq for VarianceDiagInfo<I>
where I: Interner,

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fn eq(&self, __other: &VarianceDiagInfo<I>) -> 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<I> Copy for VarianceDiagInfo<I>
where I: Interner,

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impl<I> Eq for VarianceDiagInfo<I>
where I: Interner,

Auto Trait Implementations§

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impl<I> Freeze for VarianceDiagInfo<I>
where <I as Interner>::Ty: Freeze,

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impl<I> RefUnwindSafe for VarianceDiagInfo<I>
where <I as Interner>::Ty: RefUnwindSafe,

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impl<I> Send for VarianceDiagInfo<I>
where <I as Interner>::Ty: Send,

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impl<I> Sync for VarianceDiagInfo<I>
where <I as Interner>::Ty: Sync,

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impl<I> Unpin for VarianceDiagInfo<I>
where <I as Interner>::Ty: Unpin,

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impl<I> UnwindSafe for VarianceDiagInfo<I>
where <I as Interner>::Ty: 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> AnyEq for T
where T: Any + PartialEq,

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fn equals(&self, other: &(dyn Any + 'static)) -> bool

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fn as_any(&self) -> &(dyn Any + 'static)

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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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fn allocate_on(self, arena: &'tcx Arena<'tcx>) -> &'tcx mut T

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fn allocate_from_iter( arena: &'tcx Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'tcx mut [T]

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impl<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for T
where T: Copy,

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fn allocate_on(self, arena: &'tcx Arena<'tcx>) -> &'tcx mut T

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fn allocate_from_iter( arena: &'tcx Arena<'tcx>, iter: impl IntoIterator<Item = T>, ) -> &'tcx mut [T]

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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, 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> Filterable for T

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fn filterable( self, filter_name: &'static str, ) -> RequestFilterDataProvider<T, fn(_: DataRequest<'_>) -> bool>

Creates a filterable data provider with the given name for debugging. 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> 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<P> IntoQueryParam<P> for P

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fn into_query_param(self) -> P

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impl<T> MaybeResult<T> for T

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type Error = !

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fn from(_: Result<T, <T as MaybeResult<T>>::Error>) -> T

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fn to_result(self) -> Result<T, <T as MaybeResult<T>>::Error>

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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<V, T> VZip<V> for T
where V: MultiLane<T>,

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fn vzip(self) -> V

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impl<Tcx, T> Value<Tcx> for T
where Tcx: DepContext,

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default fn from_cycle_error( tcx: Tcx, cycle_error: &CycleError, _guar: ErrorGuaranteed, ) -> 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,

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impl<T> ErasedDestructor for T
where T: 'static,

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impl<T> MaybeSendSync for T

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.