Module rustc_infer::traits
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Trait Resolution. See the rustc-dev-guide for more information on how this works.
Re-exports
pub use self::FulfillmentErrorCode::*;pub use self::ImplSource::*;pub use self::ObligationCauseCode::*;pub use self::SelectionError::*;Modules
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Code for projecting associated types out of trait references.
Experimental types for the trait query interface. The methods
defined in this module are all based on canonicalization,
which makes a canonical query by replacing unbound inference
variables and regions, so that results can be reused more broadly.
The providers for the queries defined here can be found in
rustc_traits.Candidate selection. See the rustc dev guide for more information on how this works.
Structs
A chalk environment and goal.
Identifies a particular impl in the source, along with a set of
substitutions from the impl’s type/lifetime parameters. The
nested vector corresponds to the nested obligations attached to
the impl’s type parameters.An
Obligation represents some trait reference (e.g., i32: Eq) for
which the “impl_source” must be found. The process of finding an “impl_source” is
called “resolving” the Obligation. This process consists of
either identifying an impl (e.g., impl Eq for i32) that
satisfies the obligation, or else finding a bound that is in
scope. The eventual result is usually a Selection (defined below).The reason why we incurred this obligation; used for error reporting.
The projection cache. Unlike the standard caches, this can include
infcx-dependent type variables, therefore we have to roll the
cache back each time we roll a snapshot back, to avoid assumptions
on yet-unresolved inference variables. Types with placeholder
regions also have to be removed when the respective snapshot ends.
Enums
These are the error cases for
codegen_select_candidate.The result of trait evaluation. The order is important
here as the evaluation of a list is the maximum of the
evaluations.
Given the successful resolution of an obligation, the
ImplSource
indicates where the impl comes from.Reasons a method might not be object-safe.
Indicates that trait evaluation caused overflow and in which pass.
Depending on the stage of compilation, we want projection to be
more or less conservative.
The ‘location’ at which we try to perform HIR-based wf checking.
This information is used to obtain an
hir::Ty, which
we can walk in order to obtain precise spans for any
‘nested’ types (e.g. Foo in Option<Foo>).Traits
Type Definitions
When performing resolution, it is typically the case that there
can be one of three outcomes: