pub enum VarianceDiagInfo<'tcx> {
    None,
    Invariant {
        ty: Ty<'tcx>,
        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

Fields

§ty: Ty<'tcx>

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>)

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

Implementations§

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impl<'tcx> VarianceDiagInfo<'tcx>

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

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

Trait Implementations§

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impl<'tcx> Clone for VarianceDiagInfo<'tcx>

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fn clone(&self) -> VarianceDiagInfo<'tcx>

Returns a copy of the value. Read more
1.0.0 · source§

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

Performs copy-assignment from source. Read more
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impl<'tcx> Debug for VarianceDiagInfo<'tcx>

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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<'tcx> Default for VarianceDiagInfo<'tcx>

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fn default() -> VarianceDiagInfo<'tcx>

Returns the “default value” for a type. Read more
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impl<'tcx> Ord for VarianceDiagInfo<'tcx>

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fn cmp(&self, other: &VarianceDiagInfo<'tcx>) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval. Read more
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impl<'tcx> PartialEq<VarianceDiagInfo<'tcx>> for VarianceDiagInfo<'tcx>

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fn eq(&self, other: &VarianceDiagInfo<'tcx>) -> 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<'tcx> PartialOrd<VarianceDiagInfo<'tcx>> for VarianceDiagInfo<'tcx>

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fn partial_cmp(&self, other: &VarianceDiagInfo<'tcx>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<'tcx> Copy for VarianceDiagInfo<'tcx>

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impl<'tcx> Eq for VarianceDiagInfo<'tcx>

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impl<'tcx> StructuralEq for VarianceDiagInfo<'tcx>

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impl<'tcx> StructuralPartialEq for VarianceDiagInfo<'tcx>

Auto Trait Implementations§

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impl<'tcx> !RefUnwindSafe for VarianceDiagInfo<'tcx>

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impl<'tcx> !Send for VarianceDiagInfo<'tcx>

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impl<'tcx> !Sync for VarianceDiagInfo<'tcx>

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impl<'tcx> Unpin for VarianceDiagInfo<'tcx>

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impl<'tcx> !UnwindSafe for VarianceDiagInfo<'tcx>

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<'tcx, T> ArenaAllocatable<'tcx, IsCopy> for Twhere
    T: Copy,

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

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

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impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere
    T: ?Sized,

const: unstable · source§

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

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, R> InternIteratorElement<T, R> for T

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type Output = R

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fn intern_with<I, F>(iter: I, f: F) -> <T as InternIteratorElement<T, R>>::Outputwhere
    I: Iterator<Item = T>,
    F: FnOnce(&[T]) -> R,

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impl<T, U> Into<U> for Twhere
    U: From<T>,

const: unstable · source§

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> 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> 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<'tcx, T> ToPredicate<'tcx, T> for T

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fn to_predicate(self, _tcx: TyCtxt<'tcx>) -> T

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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.
const: unstable · source§

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.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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impl<Tcx, T, D> Value<Tcx, D> for Twhere
    Tcx: DepContext,
    D: DepKind,

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default fn from_cycle_error(tcx: Tcx, _: &[QueryInfo<D>]) -> T

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: 16 bytes

Size for each variant:

  • None: 0 bytes
  • Invariant: 12 bytes