Module rustc_trait_selection::traits::util[−][src]

Structs

“Elaboration” is the process of identifying all the predicates that are implied by a source predicate. Currently, this basically means walking the “supertraits” and other similar assumptions. For example, if we know that T: Ord, the elaborator would deduce that T: PartialOrd holds as well. Similarly, if we have trait Foo: 'static, and we know that T: Foo, then we know that T: 'static.

FilterToTraits

A filter around an iterator of predicates that makes it yield up just trait references.

PredicateSet

SupertraitDefIds

TraitAliasExpander

“Trait alias expansion” is the process of expanding a sequence of trait references into another sequence by transitively following all trait aliases. e.g. If you have bounds like Foo + Send, a trait alias trait Foo = Bar + Sync;, and another trait alias trait Bar = Read + Write, then the bounds would expand to Read + Write + Sync + Send. Expansion is done via a DFS (depth-first search), and the visited field is used to avoid cycles.

TraitAliasExpansionInfo

Stores information about the expansion of a trait via a path of zero or more trait aliases.

Enums

TupleArgumentsFlag

Functions

anonymize_predicate

closure_trait_ref_and_return_type

count_own_vtable_entries

Given a trait trait_ref, returns the number of vtable entries that come from trait_ref, excluding its supertraits. Used in computing the vtable base for an upcast trait of a trait object.

elaborate_obligations

generator_trait_ref_and_outputs

get_vtable_index_of_object_method

Given an upcast trait object described by object, returns the index of the method method_def_id (which should be part of object.upcast_trait_ref) within the vtable for object.

impl_item_is_final

impl_trait_ref_and_oblig

Instantiate all bound parameters of the impl with the given substs, returning the resulting trait ref and all obligations that arise. The obligations are closed under normalization.

predicate_for_trait_def

predicate_for_trait_ref

predicates_for_generics

supertrait_def_ids

supertraits

transitive_bounds

transitive_bounds_that_define_assoc_type

A specialized variant of elaborate_trait_refs that only elaborates trait references that may define the given associated type assoc_name. It uses the super_predicates_that_define_assoc_type query to avoid enumerating super-predicates that aren’t related to assoc_item. This is used when resolving types like Self::Item or T::Item and helps to avoid cycle errors (see e.g. #35237).

upcast_choices

Casts a trait reference into a reference to one of its super traits; returns None if target_trait_def_id is not a supertrait.

Type Definitions

Supertraits