Module solve

The next-generation trait solver, currently still WIP.

As a user of rust, you can use -Znext-solver to enable the new trait solver.

As a developer of rustc, you shouldn’t be using the new trait solver without asking the trait-system-refactor-initiative, but it can be enabled with InferCtxtBuilder::with_next_trait_solver. This will ensure that trait solving using that inference context will be routed to the new trait solver.

For a high-level overview of how this solver works, check out the relevant section of the rustc-dev-guide.

Modules

• alias_relate 🔒
  Implements the AliasRelate goal, which is used when unifying aliases. Doing this via a separate goal is called “deferred alias relation” and part of our more general approach to “lazy normalization”.
• assembly 🔒
  Code shared by trait and projection goals for candidate assembly.
• effect_goals 🔒
  Dealing with host effect goals, i.e. enforcing the constness in T: const Trait or T: ~const Trait.
• eval_ctxt 🔒
• inspect
• normalizes_to 🔒
• project_goals 🔒
• search_graph 🔒
• trait_goals 🔒
  Dealing with trait goals, i.e. T: Trait<'a, U>.

Structs

• EvalCtxt
• ExternalConstraintsData
  Additional constraints returned on success.
• Goal
  A goal is a statement, i.e. predicate, we want to prove given some assumptions, i.e. param_env.
• NestedNormalizationGoals
• NoSolution
• PredefinedOpaquesData
  Opaques that are defined in the inference context before a query is called.
• QueryInput
• Response

Enums

• BuiltinImplSource
• CandidateSource
  Possible ways the given goal can be proven.
• Certainty
• GenerateProofTree
• GoalEvaluationKind 🔒
• GoalSource
  Why a specific goal has to be proven.
• HasChanged
  Whether evaluating this goal ended up changing the inference state.
• MaybeCause
  Why we failed to evaluate a goal.
• Reveal
  Depending on the stage of compilation, we want projection to be more or less conservative.

Constants

• FIXPOINT_STEP_LIMIT 🔒
  How many fixpoint iterations we should attempt inside of the solver before bailing with overflow.

Traits

• SolverDelegateEvalExt

Functions

• has_no_inference_or_external_constraints 🔒
• response_no_constraints_raw 🔒

Type Aliases

• CanonicalInput
• CanonicalResponse
• QueryResult
  The result of evaluating a canonical query.