bjoernager/rust
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combine: stop eagerly evaluating consts

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This commit is contained in:
Bastian Kauschke 2021-01-24 20:08:12 +01:00 • committed by lcnr
parent aef11409b4
commit 42150fb8a1
14 changed files with 106 additions and 27 deletions
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28
compiler/rustc_infer/src/infer/combine.rs
View file

@ -543,10 +543,6 @@ impl TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
true
}
fn visit_ct_substs(&self) -> bool {
true
}
fn binders<T>(
&mut self,
a: ty::Binder<T>,
@ -737,6 +733,16 @@ impl TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
}
}
}
ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
if self.tcx().lazy_normalization() =>
{
assert_eq!(promoted, None);
let substs = self.relate_with_variance(ty::Variance::Invariant, substs, substs)?;
Ok(self.tcx().mk_const(ty::Const {
ty: c.ty,
val: ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }),
}))
}
_ => relate::super_relate_consts(self, c, c),
}
}
@ -822,10 +828,6 @@ impl TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
true
}
fn visit_ct_substs(&self) -> bool {
true
}
fn relate_with_variance<T: Relate<'tcx>>(
&mut self,
_variance: ty::Variance,
@ -959,6 +961,16 @@ impl TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
}
}
}
ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
if self.tcx().lazy_normalization() =>
{
assert_eq!(promoted, None);
let substs = self.relate_with_variance(ty::Variance::Invariant, substs, substs)?;
Ok(self.tcx().mk_const(ty::Const {
ty: c.ty,
val: ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }),
}))
}
_ => relate::super_relate_consts(self, c, c),
}
}

11
compiler/rustc_middle/src/ty/relate.rs
View file

@ -33,15 +33,6 @@ pub trait TypeRelation<'tcx>: Sized {
/// relation. Just affects error messages.
fn a_is_expected(&self) -> bool;
/// Whether we should look into the substs of unevaluated constants
/// even if `feature(const_evaluatable_checked)` is active.
///
/// This is needed in `combine` to prevent accidentially creating
/// infinite types as we abuse `TypeRelation` to walk a type there.
fn visit_ct_substs(&self) -> bool {
false
}
fn with_cause<F, R>(&mut self, _cause: Cause, f: F) -> R
where
F: FnOnce(&mut Self) -> R,
@ -532,7 +523,7 @@ pub fn super_relate_consts<R: TypeRelation<'tcx>>(
}
(ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
if tcx.features().const_evaluatable_checked && !relation.visit_ct_substs() =>
if tcx.features().const_evaluatable_checked =>
{
tcx.try_unify_abstract_consts(((au.def, au.substs), (bu.def, bu.substs)))
}