[][src]Struct rustc_data_structures::obligation_forest::ObligationForest

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


nodes: Vec<Node<O>>

The list of obligations. In between calls to 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 process_obligation for details.

node_rewrites: Vec<usize>

A vector reused in compress(), 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.


impl<O: ForestObligation> ObligationForest<O>[src]

pub fn dump_graphviz<P: AsRef<Path>>(&self, dir: P, description: &str)[src]

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>.

impl<O: ForestObligation> ObligationForest<O>[src]

pub fn new() -> ObligationForest<O>[src]

pub fn len(&self) -> usize[src]

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

pub fn register_obligation(&mut self, obligation: O)[src]

Registers an obligation.

fn register_obligation_at(
    &mut self,
    obligation: O,
    parent: Option<usize>
) -> Result<(), ()>

pub fn to_errors<E: Clone>(&mut self, error: E) -> Vec<Error<O, E>>[src]

Converts all remaining obligations to the given error.

pub fn map_pending_obligations<P, F>(&self, f: F) -> Vec<P> where
    F: Fn(&O) -> P, 

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

fn insert_into_error_cache(&mut self, index: usize)[src]

pub fn process_obligations<P>(
    &mut self,
    processor: &mut P,
    do_completed: DoCompleted
) -> Outcome<O, P::Error> where
    P: ObligationProcessor<Obligation = O>, 

Performs a pass through the obligation list. This must be called in a loop until outcome.stalled is false.

This cannot be unrolled (presently, at least).

fn error_at(&self, index: usize) -> Vec<O>[src]

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

fn mark_successes(&self)[src]

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

fn inlined_mark_dependents_as_waiting(&self, node: &Node<O>)[src]

fn uninlined_mark_dependents_as_waiting(&self, node: &Node<O>)[src]

fn process_cycles<P>(&self, processor: &mut P) where
    P: ObligationProcessor<Obligation = O>, 

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

fn find_cycles_from_node<P>(
    stack: &mut Vec<usize>,
    processor: &mut P,
    index: usize
) where
    P: ObligationProcessor<Obligation = O>, 

fn compress(&mut self, do_completed: DoCompleted) -> Option<Vec<O>>[src]

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.

fn apply_rewrites(&mut self, node_rewrites: &[usize])[src]

Trait Implementations

impl<'a, O: ForestObligation + 'a> GraphWalk<'a> for &'a ObligationForest<O>[src]

type Node = usize

type Edge = (usize, usize)

impl<'a, O: ForestObligation + 'a> Labeller<'a> for &'a ObligationForest<O>[src]

type Node = usize

type Edge = (usize, usize)

Auto Trait Implementations

impl<O> !RefUnwindSafe for ObligationForest<O>

impl<O> Send for ObligationForest<O> where
    O: Send,
    <O as ForestObligation>::CacheKey: Send

impl<O> !Sync for ObligationForest<O>

impl<O> Unpin for ObligationForest<O> where
    O: Unpin,
    <O as ForestObligation>::CacheKey: Unpin

impl<O> UnwindSafe for ObligationForest<O> where
    O: UnwindSafe,
    <O as ForestObligation>::CacheKey: UnwindSafe

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized

impl<T> Borrow<T> for T where
    T: ?Sized

impl<T> BorrowMut<T> for T where
    T: ?Sized

impl<'a, T> Captures<'a> for T where
    T: ?Sized

impl<T> Erased for T[src]

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 

type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.