pub struct ObligationForest<O: ForestObligation> {
    nodes: Vec<Node<O>>,
    done_cache: FxHashSet<O::CacheKey>,
    active_cache: FxHashMap<O::CacheKey, usize>,
    reused_node_vec: Vec<usize>,
    obligation_tree_id_generator: Map<RangeFrom<usize>, fn(_: usize) -> ObligationTreeId>,
    error_cache: FxHashMap<ObligationTreeId, FxHashSet<O::CacheKey>>,
}

Fields§

§nodes: Vec<Node<O>>

The list of obligations. In between calls to Self::process_obligations, this list only contains nodes in the Pending or Waiting state.

usize indices are used here and throughout this module, rather than rustc_index::newtype_index! indices, because this code is hot enough that the u32-to-usize conversions that would be required are significant, and space considerations are not important.

§done_cache: FxHashSet<O::CacheKey>

A cache of predicates that have been successfully completed.

§active_cache: FxHashMap<O::CacheKey, usize>

A cache of the nodes in nodes, indexed by predicate. Unfortunately, its contents are not guaranteed to match those of nodes. See the comments in Self::process_obligation for details.

§reused_node_vec: Vec<usize>

A vector reused in Self::compress() and Self::find_cycles_from_node(), to avoid allocating new vectors.

§obligation_tree_id_generator: Map<RangeFrom<usize>, fn(_: usize) -> ObligationTreeId>§error_cache: FxHashMap<ObligationTreeId, FxHashSet<O::CacheKey>>

Per tree error cache. This is used to deduplicate errors, which is necessary to avoid trait resolution overflow in some cases.

See this for details.

Implementations§

Creates a graphviz representation of the obligation forest. Given a directory this will create files with name of the format <counter>_<description>.gv. The counter is global and is maintained internally.

Calling this will do nothing unless the environment variable DUMP_OBLIGATION_FOREST_GRAPHVIZ is defined.

A few post-processing that you might want to do make the forest easier to visualize:

  • sed 's,std::[a-z]*::,,g' — Deletes the std::<package>:: prefix of paths.
  • sed 's,"Binder(TraitPredicate(<\(.*\)>)) (\([^)]*\))","\1 (\2)",' — Transforms Binder(TraitPredicate(<predicate>)) into just <predicate>.

Returns the total number of nodes in the forest that have not yet been fully resolved.

Registers an obligation.

Converts all remaining obligations to the given error.

Returns the set of obligations that are in a pending state.

Performs a fixpoint computation over the obligation list.

Returns a vector of obligations for p and all of its ancestors, putting them into the error state in the process.

Mark all Waiting nodes as Success, except those that depend on a pending node.

Report cycles between all Success nodes, and convert all Success nodes to Done. This must be called after mark_successes.

Compresses the vector, removing all popped nodes. This adjusts the indices and hence invalidates any outstanding indices. process_cycles must be run beforehand to remove any cycles on Success nodes.

Trait Implementations§

Returns all the nodes in this graph.
Returns all of the edges in this graph.
The source node for edge.
The target node for edge.
Must return a DOT compatible identifier naming the graph.
Maps n to a unique identifier with respect to self. The implementor is responsible for ensuring that the returned name is a valid DOT identifier. Read more
Maps n to a label that will be used in the rendered output. The label need not be unique, and may be the empty string; the default is just the output from node_id. Read more
Maps e to a label that will be used in the rendered output. The label need not be unique, and may be the empty string; the default is in fact the empty string. Read more
Maps n to one of the graphviz shape names. If None is returned, no shape attribute is specified. Read more
Maps n to a style that will be used in the rendered output.
Maps e to a style that will be used in the rendered output.

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 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: 160 bytes