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Rollup merge of #124623 - lcnr:coherence-uwu, r=compiler-errors

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shallow resolve in orphan check

r? ``@compiler-errors`` cc https://github.com/rust-lang/rust/pull/124588#pullrequestreview-2036012292
This commit is contained in:
Matthias Krüger 2024-05-02 19:42:49 +02:00 committed by GitHub
commit fe62bc5ea5
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5 changed files with 44 additions and 36 deletions
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1
compiler/rustc_hir_analysis/src/coherence/orphan.rs
View File

@ -330,6 +330,7 @@ fn orphan_check<'tcx>(
};
let Ok(result) = traits::orphan_check_trait_ref::<!>(
&infcx,
trait_ref,
traits::InCrate::Local { mode },
lazily_normalize_ty,

12
compiler/rustc_trait_selection/src/solve/assembly/mod.rs
View File

@ -2,7 +2,6 @@
use crate::solve::GoalSource;
use crate::solve::{inspect, EvalCtxt, SolverMode};
use crate::traits::coherence;
use rustc_hir::def_id::DefId;
use rustc_infer::traits::query::NoSolution;
use rustc_middle::traits::solve::inspect::ProbeKind;
@ -769,13 +768,10 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
candidates.extend(self.probe_trait_candidate(CandidateSource::CoherenceUnknowable).enter(
|ecx| {
let trait_ref = goal.predicate.trait_ref(tcx);
let lazily_normalize_ty = |ty| ecx.structurally_normalize_ty(goal.param_env, ty);
match coherence::trait_ref_is_knowable(tcx, trait_ref, lazily_normalize_ty)? {
Ok(()) => Err(NoSolution),
Err(_) => {
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
}
if ecx.trait_ref_is_knowable(goal.param_env, trait_ref)? {
Err(NoSolution)
} else {
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
}
},
))

12
compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs
View File

@ -27,6 +27,7 @@ use rustc_span::DUMMY_SP;
use std::io::Write;
use std::ops::ControlFlow;
use crate::traits::coherence;
use crate::traits::vtable::{count_own_vtable_entries, prepare_vtable_segments, VtblSegment};
use super::inspect::ProofTreeBuilder;
@ -942,6 +943,17 @@ impl<'tcx> EvalCtxt<'_, 'tcx> {
}
}
pub(super) fn trait_ref_is_knowable(
&mut self,
param_env: ty::ParamEnv<'tcx>,
trait_ref: ty::TraitRef<'tcx>,
) -> Result<bool, NoSolution> {
let infcx = self.infcx;
let lazily_normalize_ty = |ty| self.structurally_normalize_ty(param_env, ty);
coherence::trait_ref_is_knowable(infcx, trait_ref, lazily_normalize_ty)
.map(|is_knowable| is_knowable.is_ok())
}
pub(super) fn can_define_opaque_ty(&self, def_id: impl Into<DefId>) -> bool {
self.infcx.can_define_opaque_ty(def_id)
}

53
compiler/rustc_trait_selection/src/traits/coherence.rs
View File

@ -618,19 +618,20 @@ fn try_prove_negated_where_clause<'tcx>(
/// This both checks whether any downstream or sibling crates could
/// implement it and whether an upstream crate can add this impl
/// without breaking backwards compatibility.
#[instrument(level = "debug", skip(tcx, lazily_normalize_ty), ret)]
#[instrument(level = "debug", skip(infcx, lazily_normalize_ty), ret)]
pub fn trait_ref_is_knowable<'tcx, E: Debug>(
tcx: TyCtxt<'tcx>,
infcx: &InferCtxt<'tcx>,
trait_ref: ty::TraitRef<'tcx>,
mut lazily_normalize_ty: impl FnMut(Ty<'tcx>) -> Result<Ty<'tcx>, E>,
) -> Result<Result<(), Conflict>, E> {
if orphan_check_trait_ref(trait_ref, InCrate::Remote, &mut lazily_normalize_ty)?.is_ok() {
if orphan_check_trait_ref(infcx, trait_ref, InCrate::Remote, &mut lazily_normalize_ty)?.is_ok()
{
// A downstream or cousin crate is allowed to implement some
// generic parameters of this trait-ref.
return Ok(Err(Conflict::Downstream));
}
if trait_ref_is_local_or_fundamental(tcx, trait_ref) {
if trait_ref_is_local_or_fundamental(infcx.tcx, trait_ref) {
// This is a local or fundamental trait, so future-compatibility
// is no concern. We know that downstream/cousin crates are not
// allowed to implement a generic parameter of this trait ref,
@ -648,6 +649,7 @@ pub fn trait_ref_is_knowable<'tcx, E: Debug>(
// about future-compatibility, which means that we're OK if
// we are an owner.
if orphan_check_trait_ref(
infcx,
trait_ref,
InCrate::Local { mode: OrphanCheckMode::Proper },
&mut lazily_normalize_ty,
@ -786,38 +788,32 @@ pub struct UncoveredTyParams<'tcx, T> {
///
/// Note that this function is never called for types that have both type
/// parameters and inference variables.
#[instrument(level = "trace", skip(lazily_normalize_ty), ret)]
#[instrument(level = "trace", skip(infcx, lazily_normalize_ty), ret)]
pub fn orphan_check_trait_ref<'tcx, E: Debug>(
infcx: &InferCtxt<'tcx>,
trait_ref: ty::TraitRef<'tcx>,
in_crate: InCrate,
lazily_normalize_ty: impl FnMut(Ty<'tcx>) -> Result<Ty<'tcx>, E>,
) -> Result<Result<(), OrphanCheckErr<'tcx, Ty<'tcx>>>, E> {
if trait_ref.has_infer() && trait_ref.has_param() {
bug!(
"can't orphan check a trait ref with both params and inference variables {:?}",
trait_ref
);
if trait_ref.has_param() {
bug!("orphan check only expects inference variables: {trait_ref:?}");
}
let mut checker = OrphanChecker::new(in_crate, lazily_normalize_ty);
// Does there exist some local type after the `ParamTy`.
let search_first_local_ty = |checker: &mut OrphanChecker<'tcx, _>| {
checker.search_first_local_ty = true;
match trait_ref.visit_with(checker).break_value() {
Some(OrphanCheckEarlyExit::LocalTy(local_ty)) => Some(local_ty),
_ => None,
}
};
let mut checker = OrphanChecker::new(infcx, in_crate, lazily_normalize_ty);
Ok(match trait_ref.visit_with(&mut checker) {
ControlFlow::Continue(()) => Err(OrphanCheckErr::NonLocalInputType(checker.non_local_tys)),
ControlFlow::Break(residual) => match residual {
OrphanCheckEarlyExit::NormalizationFailure(err) => return Err(err),
OrphanCheckEarlyExit::UncoveredTyParam(ty) => {
// Does there exist some local type after the `ParamTy`.
checker.search_first_local_ty = true;
let local_ty = match trait_ref.visit_with(&mut checker).break_value() {
Some(OrphanCheckEarlyExit::LocalTy(local_ty)) => Some(local_ty),
_ => None,
};
Err(OrphanCheckErr::UncoveredTyParams(UncoveredTyParams {
uncovered: ty,
local_ty: search_first_local_ty(&mut checker),
local_ty,
}))
}
OrphanCheckEarlyExit::LocalTy(_) => Ok(()),
@ -825,7 +821,8 @@ pub fn orphan_check_trait_ref<'tcx, E: Debug>(
})
}
struct OrphanChecker<'tcx, F> {
struct OrphanChecker<'a, 'tcx, F> {
infcx: &'a InferCtxt<'tcx>,
in_crate: InCrate,
in_self_ty: bool,
lazily_normalize_ty: F,
@ -834,12 +831,13 @@ struct OrphanChecker<'tcx, F> {
non_local_tys: Vec<(Ty<'tcx>, IsFirstInputType)>,
}
impl<'tcx, F, E> OrphanChecker<'tcx, F>
impl<'a, 'tcx, F, E> OrphanChecker<'a, 'tcx, F>
where
F: FnOnce(Ty<'tcx>) -> Result<Ty<'tcx>, E>,
{
fn new(in_crate: InCrate, lazily_normalize_ty: F) -> Self {
fn new(infcx: &'a InferCtxt<'tcx>, in_crate: InCrate, lazily_normalize_ty: F) -> Self {
OrphanChecker {
infcx,
in_crate,
in_self_ty: true,
lazily_normalize_ty,
@ -878,7 +876,7 @@ enum OrphanCheckEarlyExit<'tcx, E> {
LocalTy(Ty<'tcx>),
}
impl<'tcx, F, E> TypeVisitor<TyCtxt<'tcx>> for OrphanChecker<'tcx, F>
impl<'a, 'tcx, F, E> TypeVisitor<TyCtxt<'tcx>> for OrphanChecker<'a, 'tcx, F>
where
F: FnMut(Ty<'tcx>) -> Result<Ty<'tcx>, E>,
{
@ -889,6 +887,7 @@ where
}
fn visit_ty(&mut self, ty: Ty<'tcx>) -> Self::Result {
let ty = self.infcx.shallow_resolve(ty);
let ty = match (self.lazily_normalize_ty)(ty) {
Ok(norm_ty) if norm_ty.is_ty_var() => ty,
Ok(norm_ty) => norm_ty,
@ -1149,7 +1148,7 @@ impl<'a, 'tcx> ProofTreeVisitor<'tcx> for AmbiguityCausesVisitor<'a, 'tcx> {
};
infcx.probe(|_| {
match trait_ref_is_knowable(infcx.tcx, trait_ref, lazily_normalize_ty) {
match trait_ref_is_knowable(infcx, trait_ref, lazily_normalize_ty) {
Err(()) => {}
Ok(Ok(())) => warn!("expected an unknowable trait ref: {trait_ref:?}"),
Ok(Err(conflict)) => {

2
compiler/rustc_trait_selection/src/traits/select/mod.rs
View File

@ -1497,7 +1497,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// bound regions.
let trait_ref = predicate.skip_binder().trait_ref;
coherence::trait_ref_is_knowable::<!>(self.tcx(), trait_ref, |ty| Ok(ty)).unwrap()
coherence::trait_ref_is_knowable::<!>(self.infcx, trait_ref, |ty| Ok(ty)).unwrap()
}
/// Returns `true` if the global caches can be used.