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

AdtDestructorKind

Indicates that a impl Drop for Adt is const or not.

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.

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.