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inspect: strongly typed CandidateKind

This commit is contained in:
lcnr 2023-09-11 11:34:57 +02:00
parent 006d599435
commit 8225a2e9ec
11 changed files with 155 additions and 121 deletions

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@ -5,8 +5,10 @@ use crate::traits::coherence;
use rustc_hir::def_id::DefId;
use rustc_infer::traits::query::NoSolution;
use rustc_infer::traits::Reveal;
use rustc_middle::traits::solve::inspect::CandidateKind;
use rustc_middle::traits::solve::{CanonicalResponse, Certainty, Goal, QueryResult};
use rustc_middle::traits::solve::inspect::ProbeKind;
use rustc_middle::traits::solve::{
CandidateSource, CanonicalResponse, Certainty, Goal, QueryResult,
};
use rustc_middle::traits::BuiltinImplSource;
use rustc_middle::ty::fast_reject::{SimplifiedType, TreatParams};
use rustc_middle::ty::{self, Ty, TyCtxt};
@ -27,66 +29,6 @@ pub(super) struct Candidate<'tcx> {
pub(super) result: CanonicalResponse<'tcx>,
}
/// Possible ways the given goal can be proven.
#[derive(Debug, Clone, Copy)]
pub(super) enum CandidateSource {
/// A user written impl.
///
/// ## Examples
///
/// ```rust
/// fn main() {
/// let x: Vec<u32> = Vec::new();
/// // This uses the impl from the standard library to prove `Vec<T>: Clone`.
/// let y = x.clone();
/// }
/// ```
Impl(DefId),
/// A builtin impl generated by the compiler. When adding a new special
/// trait, try to use actual impls whenever possible. Builtin impls should
/// only be used in cases where the impl cannot be manually be written.
///
/// Notable examples are auto traits, `Sized`, and `DiscriminantKind`.
/// For a list of all traits with builtin impls, check out the
/// [`EvalCtxt::assemble_builtin_impl_candidates`] method. Not
BuiltinImpl(BuiltinImplSource),
/// An assumption from the environment.
///
/// More precisely we've used the `n-th` assumption in the `param_env`.
///
/// ## Examples
///
/// ```rust
/// fn is_clone<T: Clone>(x: T) -> (T, T) {
/// // This uses the assumption `T: Clone` from the `where`-bounds
/// // to prove `T: Clone`.
/// (x.clone(), x)
/// }
/// ```
ParamEnv(usize),
/// If the self type is an alias type, e.g. an opaque type or a projection,
/// we know the bounds on that alias to hold even without knowing its concrete
/// underlying type.
///
/// More precisely this candidate is using the `n-th` bound in the `item_bounds` of
/// the self type.
///
/// ## Examples
///
/// ```rust
/// trait Trait {
/// type Assoc: Clone;
/// }
///
/// fn foo<T: Trait>(x: <T as Trait>::Assoc) {
/// // We prove `<T as Trait>::Assoc` by looking at the bounds on `Assoc` in
/// // in the trait definition.
/// let _y = x.clone();
/// }
/// ```
AliasBound,
}
/// Methods used to assemble candidates for either trait or projection goals.
pub(super) trait GoalKind<'tcx>:
TypeFoldable<TyCtxt<'tcx>> + Copy + Eq + std::fmt::Display
@ -399,7 +341,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
let tcx = self.tcx();
let &ty::Alias(_, projection_ty) = goal.predicate.self_ty().kind() else { return };
candidates.extend(self.probe(|_| CandidateKind::NormalizedSelfTyAssembly).enter(|ecx| {
candidates.extend(self.probe(|_| ProbeKind::NormalizedSelfTyAssembly).enter(|ecx| {
if num_steps < ecx.local_overflow_limit() {
let normalized_ty = ecx.next_ty_infer();
let normalizes_to_goal = goal.with(
@ -910,7 +852,7 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
SolverMode::Coherence => {}
};
let result = self.probe_candidate("coherence unknowable").enter(|ecx| {
let result = self.probe_misc_candidate("coherence unknowable").enter(|ecx| {
let trait_ref = goal.predicate.trait_ref(tcx);
#[derive(Debug)]