pub struct VerifyIfEq<'tcx> {
    pub ty: Ty<'tcx>,
    pub bound: Region<'tcx>,
}
Expand description

This is a “conditional bound” that checks the result of inference and supplies a bound if it ended up being relevant. It’s used in situations like this:

fn foo<'a, 'b, T: SomeTrait<'a>>
where
   <T as SomeTrait<'a>>::Item: 'b

If we have an obligation like <T as SomeTrait<'?x>>::Item: 'c, then we don’t know yet whether it suffices to show that 'b: 'c. If '?x winds up being equal to 'a, then the where-clauses on function applies, and in that case we can show 'b: 'c. But if '?x winds up being something else, the bound isn’t relevant.

In the VerifyBound, this struct is enclosed in Binder to account for cases like

where for<'a> <T as SomeTrait<'a>::Item: 'a

The idea is that we have to find some instantiation of 'a that can make <T as SomeTrait<'a>>::Item equal to the final value of G, the generic we are checking.

fn(min) -> bool {
    exists<'a> {
        if G == K {
            B(min)
        } else {
            false
        }
    }
}

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§ty: Ty<'tcx>

Type which must match the generic G

§bound: Region<'tcx>

Bound that applies if ty is equal.

Trait Implementations§

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impl<'tcx> Clone for VerifyIfEq<'tcx>

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

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<'tcx> Debug for VerifyIfEq<'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> TypeFoldable<TyCtxt<'tcx>> for VerifyIfEq<'tcx>

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fn try_fold_with<__F: FallibleTypeFolder<TyCtxt<'tcx>>>( self, __folder: &mut __F ) -> Result<Self, __F::Error>

The entry point for folding. To fold a value t with a folder f call: t.try_fold_with(f). Read more
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fn fold_with<F>(self, folder: &mut F) -> Selfwhere F: TypeFolder<I>,

A convenient alternative to try_fold_with for use with infallible folders. Do not override this method, to ensure coherence with try_fold_with.
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impl<'tcx> TypeVisitable<TyCtxt<'tcx>> for VerifyIfEq<'tcx>

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fn visit_with<__V: TypeVisitor<TyCtxt<'tcx>>>( &self, __visitor: &mut __V ) -> ControlFlow<__V::BreakTy>

The entry point for visiting. To visit a value t with a visitor v call: t.visit_with(v). Read more
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impl<'tcx> Copy for VerifyIfEq<'tcx>

Auto Trait Implementations§

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

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impl<'tcx> Send for VerifyIfEq<'tcx>

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impl<'tcx> Sync for VerifyIfEq<'tcx>

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impl<'tcx> Unpin for VerifyIfEq<'tcx>

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impl<'tcx> !UnwindSafe for VerifyIfEq<'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<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: 16 bytes