enum NodeState {
    Pending,
    Success,
    Waiting,
    Done,
    Error,
}
Expand description

The state of one node in some tree within the forest. This represents the current state of processing for the obligation (of type O) associated with this node.

The non-Error state transitions are as follows.

(Pre-creation)
 |
 |     register_obligation_at() (called by process_obligations() and
 v                               from outside the crate)
Pending
 |
 |     process_obligations()
 v
Success
 |  ^
 |  |  mark_successes()
 |  v
 |  Waiting
 |
 |     process_cycles()
 v
Done
 |
 |     compress()
 v
(Removed)

The Error state can be introduced in several places, via error_at().

Outside of ObligationForest methods, nodes should be either Pending or Waiting.

Variants

Pending

This obligation has not yet been selected successfully. Cannot have subobligations.

Success

This obligation was selected successfully, but may or may not have subobligations.

Waiting

This obligation was selected successfully, but it has a pending subobligation.

Done

This obligation, along with its subobligations, are complete, and will be removed in the next collection.

Error

This obligation was resolved to an error. It will be removed by the next compression step.

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
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. 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: 1 byte

Size for each variant:

  • Pending: 0 bytes
  • Success: 0 bytes
  • Waiting: 0 bytes
  • Done: 0 bytes
  • Error: 0 bytes