Module traits

Trait Resolution. See the rustc-dev-guide for more information on how this works.

Re-exports

• pub use self::ImplSource::*;
• pub use self::SelectionError::*;

Modules

• engine 🔒
• project 🔒
  Code for projecting associated types out of trait references.
• query
  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.
• select
  Candidate selection. See the rustc dev guide for more information on how this works.
• solve
• specialization_graph
• structural_impls 🔒
• util

Structs

• DerivedCause
• IfExpressionCause
• ImplDerivedCause
• ImplSourceUserDefinedData
  Identifies a particular impl in the source, along with a set of generic parameters from the impl’s type/lifetime parameters. The nested vector corresponds to the nested obligations attached to the impl’s type parameters.
• InternedObligationCauseCode
• MatchExpressionArmCause
• MismatchedProjectionTypes
• Normalized
• Obligation
  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).
• ObligationCause
  The reason why we incurred this obligation; used for error reporting.
• ProjectionCache
  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.
• ProjectionCacheKey
• ProjectionCacheStorage
• SignatureMismatchData
• UnifyReceiverContext

Enums

• BuiltinImplSource
• CodegenObligationError
  These are the error cases for codegen_select_candidate.
• DynCompatibilityViolation
• DynCompatibilityViolationSolution
• EvaluationResult
  The result of trait evaluation. The order is important here as the evaluation of a list is the maximum of the evaluations.
• ImplSource
  Given the successful resolution of an obligation, the ImplSource indicates where the impl comes from.
• IsConstable
  Whether a value can be extracted into a const. Used for diagnostics around array repeat expressions.
• MethodViolationCode
  Reasons a method might not be dyn-compatible.
• ObligationCauseCode
• OverflowError
  Indicates that trait evaluation caused overflow and in which pass.
• ProjectionCacheEntry
• Reveal
  Depending on the stage of compilation, we want projection to be more or less conservative.
• ScrubbedTraitError
  A trait error with most of its information removed. This is the error returned by an ObligationCtxt by default, and suitable if you just want to see if a predicate holds, and don’t particularly care about the error itself (except for if it’s an ambiguity or true error).
• SelectionError
• StatementAsExpression
• WellFormedLoc
  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

• FromSolverError
• TraitEngine

Type Aliases

• EvaluationCache
• NormalizedTerm
• ObligationInspector
  A callback that can be provided to inspect_typeck. Invoked on evaluation of root obligations.
• PolyTraitObligation
• PredicateObligation
• Selection
• SelectionCache
• SelectionResult
  When performing resolution, it is typically the case that there can be one of three outcomes:
• TraitObligation