Struct rustc_infer::traits::specialization_graph::Graph

pub struct Graph {
    pub parent: HashMap<DefId, DefId, BuildHasherDefault<FxHasher>>,
    pub children: HashMap<DefId, Children, BuildHasherDefault<FxHasher>>,
    pub has_errored: bool,
}

A per-trait graph of impls in specialization order. At the moment, this graph forms a tree rooted with the trait itself, with all other nodes representing impls, and parent-child relationships representing specializations.

The graph provides two key services:

• Construction. This implicitly checks for overlapping impls (i.e., impls that overlap but where neither specializes the other -- an artifact of the simple "chain" rule.

• Parent extraction. In particular, the graph can give you the immediate parents of a given specializing impl, which is needed for extracting default items amongst other things. In the simple "chain" rule, every impl has at most one parent.

Fields

parent: HashMap<DefId, DefId, BuildHasherDefault<FxHasher>>

All impls have a parent; the "root" impls have as their parent the def_id of the trait.

children: HashMap<DefId, Children, BuildHasherDefault<FxHasher>>

The "root" impls are found by looking up the trait's def_id.

has_errored: bool

Whether an error was emitted while constructing the graph.