bjoernager/rust
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implement ConstEvaluatable goals in new solver

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we don't yet handle `generic_const_exprs`, someone else
can do that :3
This commit is contained in:
lcnr 2023-07-04 15:40:15 +02:00
parent cd68ead9ec
commit abcaf30f9b
8 changed files with 75 additions and 9 deletions
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37
compiler/rustc_trait_selection/src/solve/mod.rs
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@ -159,6 +159,43 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
}
}
#[instrument(level = "debug", skip(self))]
fn compute_const_evaluatable_goal(
&mut self,
Goal { param_env, predicate: ct }: Goal<'tcx, ty::Const<'tcx>>,
) -> QueryResult<'tcx> {
match ct.kind() {
ty::ConstKind::Unevaluated(uv) => {
// We never return `NoSolution` here as `try_const_eval_resolve` emits an
// error itself when failing to evaluate, so emitting an additional fulfillment
// error in that case is unnecessary noise. This may change in the future once
// evaluation failures are allowed to impact selection, e.g. generic const
// expressions in impl headers or `where`-clauses.
// FIXME(generic_const_exprs): Implement handling for generic
// const expressions here.
if let Some(_normalized) = self.try_const_eval_resolve(param_env, uv, ct.ty()) {
self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
} else {
self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
}
}
ty::ConstKind::Infer(_) => {
self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
}
ty::ConstKind::Placeholder(_) | ty::ConstKind::Value(_) | ty::ConstKind::Error(_) => {
self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
}
// We can freely ICE here as:
// - `Param` gets replaced with a placeholder during canonicalization
// - `Bound` cannot exist as we don't have a binder around the self Type
// - `Expr` is part of `feature(generic_const_exprs)` and is not implemented yet
ty::ConstKind::Param(_) | ty::ConstKind::Bound(_, _) | ty::ConstKind::Expr(_) => {
bug!("unexpect const kind: {:?}", ct)
}
}
}
#[instrument(level = "debug", skip(self), ret)]
fn compute_const_arg_has_type_goal(
&mut self,