enum Elaborate {
    All,
    None,
}
Expand description

Controls whether we “elaborate” supertraits and so forth on the WF predicates. This is a kind of hack to address #43784. The underlying problem in that issue was a trait structure like:

trait Foo: Copy { }
trait Bar: Foo { }
impl<T: Bar> Foo for T { }
impl<T> Bar for T { }

Here, in the Foo impl, we will check that T: Copy holds – but we decide that this is true because T: Bar is in the where-clauses (and we can elaborate that to include T: Copy). This wouldn’t be a problem, except that when we check the Bar impl, we decide that T: Foo must hold because of the Foo impl. And so nowhere did we check that T: Copy holds!

To resolve this, we elaborate the WF requirements that must be proven when checking impls. This means that (e.g.) the impl Bar for T will be forced to prove not only that T: Foo but also T: Copy (which it won’t be able to do, because there is no Copy impl for T).

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All

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None

Trait Implementations§

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impl Clone for Elaborate

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fn clone(&self) -> Elaborate

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 Debug for Elaborate

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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 PartialEq<Elaborate> for Elaborate

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fn eq(&self, other: &Elaborate) -> 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 Copy for Elaborate

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impl Eq for Elaborate

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impl StructuralEq for Elaborate

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impl StructuralPartialEq for Elaborate

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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: 1 byte

Size for each variant:

  • All: 0 bytes
  • None: 0 bytes