pub enum VerifyBound<'tcx> {
    IfEq(Binder<'tcx, VerifyIfEq<'tcx>>),
    OutlivedBy(Region<'tcx>),
    IsEmpty,
    AnyBound(Vec<VerifyBound<'tcx>>),
    AllBounds(Vec<VerifyBound<'tcx>>),
}
Expand description

Describes the things that some GenericKind value G is known to outlive. Each variant of VerifyBound can be thought of as a function:

fn(min: Region) -> bool { .. }

where true means that the region min meets that G: min. (False means nothing.)

So, for example, if we have the type T and we have in scope that T: 'a and T: 'b, then the verify bound might be:

fn(min: Region) -> bool {
   ('a: min) || ('b: min)
}

This is described with an AnyRegion('a, 'b) node.

Variants

IfEq(Binder<'tcx, VerifyIfEq<'tcx>>)

See VerifyIfEq docs

OutlivedBy(Region<'tcx>)

Given a region R, expands to the function:

fn(min) -> bool {
    R: min
}

This is used when we can establish that G: R – therefore, if R: min, then by transitivity G: min.

IsEmpty

Given a region R, true if it is 'empty.

AnyBound(Vec<VerifyBound<'tcx>>)

Given a set of bounds B, expands to the function:

fn(min) -> bool {
    exists (b in B) { b(min) }
}

In other words, if we meet some bound in B, that suffices. This is used when all the bounds in B are known to apply to G.

AllBounds(Vec<VerifyBound<'tcx>>)

Given a set of bounds B, expands to the function:

fn(min) -> bool {
    forall (b in B) { b(min) }
}

In other words, if we meet all bounds in B, that suffices. This is used when some bound in B is known to suffice, but we don’t know which.

Implementations

Trait Implementations

Returns a copy of the value. Read more

Performs copy-assignment from source. Read more

Formats the value using the given formatter. Read more

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.

Creates owned data from borrowed data, usually by cloning. Read more

Uses borrowed data to replace owned data, usually by cloning. Read more

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion 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: 32 bytes

Size for each variant:

  • IfEq: 24 bytes
  • OutlivedBy: 8 bytes
  • IsEmpty: 0 bytes
  • AnyBound: 24 bytes
  • AllBounds: 24 bytes