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Rollup merge of #109755 - compiler-errors:new-solver-generator-witness-mir, r=cjgillot

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Implement support for `GeneratorWitnessMIR` in new solver

r? ```@cjgillot```

I mostly want this to cut down the number of failing UI tests when running the UI test suite with `--compare-mode=next-solver`, but there doesn't seem like much reason to block implementing this since it adds minimal complexity to the existing structural traits impl in the new solver.

If others are against adding this for some reason, then maybe we should just make `GeneratorWitnessMIR` return `NoSolution` for these traits. Anything but an ICE please 😸 🧊
This commit is contained in:
Matthias Krüger 2023-04-06 18:42:57 +02:00 • committed by GitHub
commit c86c9339e6
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3 changed files with 90 additions and 3 deletions
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49
compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs
View file

@ -1,7 +1,9 @@
use rustc_data_structures::fx::FxHashMap;
use rustc_hir::{def_id::DefId, Movability, Mutability};
use rustc_infer::traits::query::NoSolution;
use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable};
use rustc_middle::ty::{
self, Ty, TyCtxt, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitableExt,
};
use crate::solve::EvalCtxt;
@ -60,7 +62,16 @@ pub(super) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
ty::GeneratorWitness(types) => Ok(ecx.instantiate_binder_with_placeholders(types).to_vec()),
ty::GeneratorWitnessMIR(..) => todo!(),
ty::GeneratorWitnessMIR(def_id, substs) => Ok(ecx
.tcx()
.generator_hidden_types(def_id)
.map(|bty| {
ecx.instantiate_binder_with_placeholders(replace_erased_lifetimes_with_bound_vars(
tcx,
bty.subst(tcx, substs),
))
})
.collect()),
// For `PhantomData<T>`, we pass `T`.
ty::Adt(def, substs) if def.is_phantom_data() => Ok(vec![substs.type_at(0)]),
@ -76,6 +87,29 @@ pub(super) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
}
}
fn replace_erased_lifetimes_with_bound_vars<'tcx>(
tcx: TyCtxt<'tcx>,
ty: Ty<'tcx>,
) -> ty::Binder<'tcx, Ty<'tcx>> {
debug_assert!(!ty.has_late_bound_regions());
let mut counter = 0;
let ty = tcx.fold_regions(ty, |mut r, current_depth| {
if let ty::ReErased = r.kind() {
let br = ty::BoundRegion {
var: ty::BoundVar::from_u32(counter),
kind: ty::BrAnon(counter, None),
};
counter += 1;
r = tcx.mk_re_late_bound(current_depth, br);
}
r
});
let bound_vars = tcx.mk_bound_variable_kinds_from_iter(
(0..counter).map(|i| ty::BoundVariableKind::Region(ty::BrAnon(i, None))),
);
ty::Binder::bind_with_vars(ty, bound_vars)
}
pub(super) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
ecx: &EvalCtxt<'_, 'tcx>,
ty: Ty<'tcx>,
@ -178,7 +212,16 @@ pub(super) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>(
ty::GeneratorWitness(types) => Ok(ecx.instantiate_binder_with_placeholders(types).to_vec()),
ty::GeneratorWitnessMIR(..) => todo!(),
ty::GeneratorWitnessMIR(def_id, substs) => Ok(ecx
.tcx()
.generator_hidden_types(def_id)
.map(|bty| {
ecx.instantiate_binder_with_placeholders(replace_erased_lifetimes_with_bound_vars(
ecx.tcx(),
bty.subst(ecx.tcx(), substs),
))
})
.collect()),
}
}