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Auto merge of #92805 - BoxyUwU:revert-lazy-anon-const-substs, r=lcnr

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partially revertish `lazily "compute" anon const default substs`

reverts #87280 except for some of the changes around `ty::Unevaluated` having a visitor and a generic for promoted
why revert: <https://github.com/rust-lang/rust/pull/92805#issuecomment-1010736049>

r? `@lcnr`
This commit is contained in:
bors 2022-01-16 11:19:21 +00:00
commit 7be8693984
123 changed files with 405 additions and 886 deletions
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4
compiler/rustc_ty_utils/src/instance.rs
View file

@ -54,10 +54,6 @@ impl<'tcx> BoundVarsCollector<'tcx> {
impl<'tcx> TypeVisitor<'tcx> for BoundVarsCollector<'tcx> {
type BreakTy = ();
fn tcx_for_anon_const_substs(&self) -> Option<TyCtxt<'tcx>> {
// Anon const substs do not contain bound vars by default.
None
}
fn visit_binder<T: TypeFoldable<'tcx>>(
&mut self,
t: &Binder<'tcx, T>,

14
compiler/rustc_ty_utils/src/ty.rs
View file

@ -157,16 +157,6 @@ fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
predicates.extend(environment);
}
// It's important that we include the default substs in unevaluated
// constants, since `Unevaluated` instances in predicates whose substs are None
// can lead to "duplicate" caller bounds candidates during trait selection,
// duplicate in the sense that both have their default substs, but the
// candidate that resulted from a superpredicate still uses `None` in its
// `substs_` field of `Unevaluated` to indicate that it has its default substs,
// whereas the other candidate has `substs_: Some(default_substs)`, see
// issue #89334
predicates = tcx.expose_default_const_substs(predicates);
let local_did = def_id.as_local();
let hir_id = local_did.map(|def_id| tcx.hir().local_def_id_to_hir_id(def_id));
@ -333,7 +323,7 @@ fn well_formed_types_in_env<'tcx>(
// constituents are well-formed.
NodeKind::InherentImpl => {
let self_ty = tcx.type_of(def_id);
inputs.extend(self_ty.walk(tcx));
inputs.extend(self_ty.walk());
}
// In an fn, we assume that the arguments and all their constituents are
@ -342,7 +332,7 @@ fn well_formed_types_in_env<'tcx>(
let fn_sig = tcx.fn_sig(def_id);
let fn_sig = tcx.liberate_late_bound_regions(def_id, fn_sig);
inputs.extend(fn_sig.inputs().iter().flat_map(|ty| ty.walk(tcx)));
inputs.extend(fn_sig.inputs().iter().flat_map(|ty| ty.walk()));
}
NodeKind::Other => (),