Module rustc_infer::traits::util

source ·


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



  • Describes how to elaborate an obligation into a sub-obligation.


  • A specialized variant of elaborate that only elaborates trait references that may define the given associated item with the name assoc_name. It uses the super_predicates_that_define_assoc_item 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).