bjoernager/rust
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deal with const_evaluatable_checked in ConstEquate

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This commit is contained in:
lcnr 2021-05-19 21:23:32 +02:00
parent 1773f14a24
commit 412e0404c0
7 changed files with 80 additions and 6 deletions
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13
compiler/rustc_trait_selection/src/traits/fulfill.rs
View file

@ -6,7 +6,7 @@ use rustc_errors::ErrorReported;
use rustc_infer::traits::{SelectionError, TraitEngine, TraitEngineExt as _, TraitObligation};
use rustc_middle::mir::abstract_const::NotConstEvaluatable;
use rustc_middle::mir::interpret::ErrorHandled;
use rustc_middle::ty::error::ExpectedFound;
use rustc_middle::ty::error::{ExpectedFound, TypeError};
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::ToPredicate;
use rustc_middle::ty::{self, Binder, Const, Ty, TypeFoldable};
@ -591,7 +591,16 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
)
}
(Err(ErrorHandled::TooGeneric), _) | (_, Err(ErrorHandled::TooGeneric)) => {
ProcessResult::Unchanged
if c1.has_infer_types_or_consts() || c2.has_infer_types_or_consts() {
ProcessResult::Unchanged
} else {
// Two different constants using generic parameters ~> error.
let expected_found = ExpectedFound::new(true, c1, c2);
ProcessResult::Error(FulfillmentErrorCode::CodeConstEquateError(
expected_found,
TypeError::ConstMismatch(expected_found),
))
}
}
}
}

24
compiler/rustc_trait_selection/src/traits/select/mod.rs
View file

@ -557,6 +557,23 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
ty::PredicateKind::ConstEquate(c1, c2) => {
debug!(?c1, ?c2, "evaluate_predicate_recursively: equating consts");
if self.tcx().features().const_evaluatable_checked {
// FIXME: we probably should only try to unify abstract constants
// if the constants depend on generic parameters.
//
// Let's just see where this breaks :shrug:
if let (ty::ConstKind::Unevaluated(a), ty::ConstKind::Unevaluated(b)) =
(c1.val, c2.val)
{
if self
.tcx()
.try_unify_abstract_consts(((a.def, a.substs), (b.def, b.substs)))
{
return Ok(EvaluatedToOk);
}
}
}
let evaluate = |c: &'tcx ty::Const<'tcx>| {
if let ty::ConstKind::Unevaluated(unevaluated) = c.val {
self.infcx
@ -591,7 +608,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
)
}
(Err(ErrorHandled::TooGeneric), _) | (_, Err(ErrorHandled::TooGeneric)) => {
Ok(EvaluatedToAmbig)
if c1.has_infer_types_or_consts() || c2.has_infer_types_or_consts() {
Ok(EvaluatedToAmbig)
} else {
// Two different constants using generic parameters ~> error.
Ok(EvaluatedToErr)
}
}
}
}