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introduce enter_forall

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This commit is contained in:
Boxy
2024-01-30 01:27:06 +00:00
parent af88f7db51
commit ac559af98f
15 changed files with 524 additions and 446 deletions
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2
compiler/rustc_trait_selection/src/traits/coherence.rs
View File

@@ -971,7 +971,7 @@ impl<'a, 'tcx> ProofTreeVisitor<'tcx> for AmbiguityCausesVisitor<'a, 'tcx> {
let Goal { param_env, predicate } = goal.goal();
// For bound predicates we simply call `infcx.instantiate_binder_with_placeholders`
// For bound predicates we simply call `infcx.enter_forall`
// and then prove the resulting predicate as a nested goal.
let trait_ref = match predicate.kind().no_bound_vars() {
Some(ty::PredicateKind::Clause(ty::ClauseKind::Trait(tr))) => tr.trait_ref,

79
compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
View File

@@ -21,51 +21,62 @@ pub fn recompute_applicable_impls<'tcx>(
let impl_may_apply = |impl_def_id| {
let ocx = ObligationCtxt::new(infcx);
let placeholder_obligation =
infcx.instantiate_binder_with_placeholders(obligation.predicate);
let obligation_trait_ref =
ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref);
infcx.enter_forall(obligation.predicate, |placeholder_obligation| {
let obligation_trait_ref = ocx.normalize(
&ObligationCause::dummy(),
param_env,
placeholder_obligation.trait_ref,
);
let impl_args = infcx.fresh_args_for_item(DUMMY_SP, impl_def_id);
let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().instantiate(tcx, impl_args);
let impl_trait_ref = ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref);
let impl_args = infcx.fresh_args_for_item(DUMMY_SP, impl_def_id);
let impl_trait_ref =
tcx.impl_trait_ref(impl_def_id).unwrap().instantiate(tcx, impl_args);
let impl_trait_ref =
ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref);
if let Err(_) =
ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, impl_trait_ref)
{
return false;
}
if let Err(_) =
ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, impl_trait_ref)
{
return false;
}
let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_args);
ocx.register_obligations(impl_predicates.predicates.iter().map(|&predicate| {
Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate)
}));
let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_args);
ocx.register_obligations(impl_predicates.predicates.iter().map(|&predicate| {
Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate)
}));
ocx.select_where_possible().is_empty()
ocx.select_where_possible().is_empty()
})
};
let param_env_candidate_may_apply = |poly_trait_predicate: ty::PolyTraitPredicate<'tcx>| {
let ocx = ObligationCtxt::new(infcx);
let placeholder_obligation =
infcx.instantiate_binder_with_placeholders(obligation.predicate);
let obligation_trait_ref =
ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref);
infcx.enter_forall(obligation.predicate, |placeholder_obligation| {
let obligation_trait_ref = ocx.normalize(
&ObligationCause::dummy(),
param_env,
placeholder_obligation.trait_ref,
);
let param_env_predicate = infcx.instantiate_binder_with_fresh_vars(
DUMMY_SP,
BoundRegionConversionTime::HigherRankedType,
poly_trait_predicate,
);
let param_env_trait_ref =
ocx.normalize(&ObligationCause::dummy(), param_env, param_env_predicate.trait_ref);
let param_env_predicate = infcx.instantiate_binder_with_fresh_vars(
DUMMY_SP,
BoundRegionConversionTime::HigherRankedType,
poly_trait_predicate,
);
let param_env_trait_ref =
ocx.normalize(&ObligationCause::dummy(), param_env, param_env_predicate.trait_ref);
if let Err(_) =
ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, param_env_trait_ref)
{
return false;
}
if let Err(_) = ocx.eq(
&ObligationCause::dummy(),
param_env,
obligation_trait_ref,
param_env_trait_ref,
) {
return false;
}
ocx.select_where_possible().is_empty()
ocx.select_where_possible().is_empty()
})
};
let mut ambiguities = Vec::new();

53
compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs
View File

@@ -64,39 +64,44 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
) -> Option<(DefId, GenericArgsRef<'tcx>)> {
let tcx = self.tcx;
let param_env = obligation.param_env;
let trait_ref = self.instantiate_binder_with_placeholders(trait_ref);
let trait_self_ty = trait_ref.self_ty();
self.enter_forall(trait_ref, |trait_ref| {
let trait_self_ty = trait_ref.self_ty();
let mut self_match_impls = vec![];
let mut fuzzy_match_impls = vec![];
let mut self_match_impls = vec![];
let mut fuzzy_match_impls = vec![];
self.tcx.for_each_relevant_impl(trait_ref.def_id, trait_self_ty, |def_id| {
let impl_args = self.fresh_args_for_item(obligation.cause.span, def_id);
let impl_trait_ref = tcx.impl_trait_ref(def_id).unwrap().instantiate(tcx, impl_args);
self.tcx.for_each_relevant_impl(trait_ref.def_id, trait_self_ty, |def_id| {
let impl_args = self.fresh_args_for_item(obligation.cause.span, def_id);
let impl_trait_ref =
tcx.impl_trait_ref(def_id).unwrap().instantiate(tcx, impl_args);
let impl_self_ty = impl_trait_ref.self_ty();
let impl_self_ty = impl_trait_ref.self_ty();
if self.can_eq(param_env, trait_self_ty, impl_self_ty) {
self_match_impls.push((def_id, impl_args));
if self.can_eq(param_env, trait_self_ty, impl_self_ty) {
self_match_impls.push((def_id, impl_args));
if iter::zip(trait_ref.args.types().skip(1), impl_trait_ref.args.types().skip(1))
if iter::zip(
trait_ref.args.types().skip(1),
impl_trait_ref.args.types().skip(1),
)
.all(|(u, v)| self.fuzzy_match_tys(u, v, false).is_some())
{
fuzzy_match_impls.push((def_id, impl_args));
{
fuzzy_match_impls.push((def_id, impl_args));
}
}
}
});
});
let impl_def_id_and_args = if self_match_impls.len() == 1 {
self_match_impls[0]
} else if fuzzy_match_impls.len() == 1 {
fuzzy_match_impls[0]
} else {
return None;
};
let impl_def_id_and_args = if self_match_impls.len() == 1 {
self_match_impls[0]
} else if fuzzy_match_impls.len() == 1 {
fuzzy_match_impls[0]
} else {
return None;
};
tcx.has_attr(impl_def_id_and_args.0, sym::rustc_on_unimplemented)
.then_some(impl_def_id_and_args)
tcx.has_attr(impl_def_id_and_args.0, sym::rustc_on_unimplemented)
.then_some(impl_def_id_and_args)
})
}
/// Used to set on_unimplemented's `ItemContext`

150
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View File

@@ -1248,52 +1248,55 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> bool {
let self_ty = self.resolve_vars_if_possible(trait_pred.self_ty());
let ty = self.instantiate_binder_with_placeholders(self_ty);
let Some(generics) = self.tcx.hir().get_generics(obligation.cause.body_id) else {
return false;
};
let ty::Ref(_, inner_ty, hir::Mutability::Not) = ty.kind() else { return false };
let ty::Param(param) = inner_ty.kind() else { return false };
let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } =
obligation.cause.code()
else {
return false;
};
let arg_node = self.tcx.hir_node(*arg_hir_id);
let Node::Expr(Expr { kind: hir::ExprKind::Path(_), .. }) = arg_node else { return false };
self.enter_forall(self_ty, |ty: Ty<'_>| {
let Some(generics) = self.tcx.hir().get_generics(obligation.cause.body_id) else {
return false;
};
let ty::Ref(_, inner_ty, hir::Mutability::Not) = ty.kind() else { return false };
let ty::Param(param) = inner_ty.kind() else { return false };
let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } =
obligation.cause.code()
else {
return false;
};
let arg_node = self.tcx.hir_node(*arg_hir_id);
let Node::Expr(Expr { kind: hir::ExprKind::Path(_), .. }) = arg_node else {
return false;
};
let clone_trait = self.tcx.require_lang_item(LangItem::Clone, None);
let has_clone = |ty| {
self.type_implements_trait(clone_trait, [ty], obligation.param_env)
.must_apply_modulo_regions()
};
let clone_trait = self.tcx.require_lang_item(LangItem::Clone, None);
let has_clone = |ty| {
self.type_implements_trait(clone_trait, [ty], obligation.param_env)
.must_apply_modulo_regions()
};
let new_obligation = self.mk_trait_obligation_with_new_self_ty(
obligation.param_env,
trait_pred.map_bound(|trait_pred| (trait_pred, *inner_ty)),
);
if self.predicate_may_hold(&new_obligation) && has_clone(ty) {
if !has_clone(param.to_ty(self.tcx)) {
suggest_constraining_type_param(
self.tcx,
generics,
err,
param.name.as_str(),
"Clone",
Some(clone_trait),
None,
);
}
err.span_suggestion_verbose(
obligation.cause.span.shrink_to_hi(),
"consider using clone here",
".clone()",
Applicability::MaybeIncorrect,
let new_obligation = self.mk_trait_obligation_with_new_self_ty(
obligation.param_env,
trait_pred.map_bound(|trait_pred| (trait_pred, *inner_ty)),
);
return true;
}
false
if self.predicate_may_hold(&new_obligation) && has_clone(ty) {
if !has_clone(param.to_ty(self.tcx)) {
suggest_constraining_type_param(
self.tcx,
generics,
err,
param.name.as_str(),
"Clone",
Some(clone_trait),
None,
);
}
err.span_suggestion_verbose(
obligation.cause.span.shrink_to_hi(),
"consider using clone here",
".clone()".to_string(),
Applicability::MaybeIncorrect,
);
return true;
}
false
})
}
/// Extracts information about a callable type for diagnostics. This is a
@@ -4038,26 +4041,27 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
if let Some(where_pred) = where_pred.as_trait_clause()
&& let Some(failed_pred) = failed_pred.to_opt_poly_trait_pred()
{
let where_pred = self.instantiate_binder_with_placeholders(where_pred);
let failed_pred = self.instantiate_binder_with_fresh_vars(
expr.span,
BoundRegionConversionTime::FnCall,
failed_pred,
);
self.enter_forall(where_pred, |where_pred| {
let failed_pred = self.instantiate_binder_with_fresh_vars(
expr.span,
BoundRegionConversionTime::FnCall,
failed_pred,
);
let zipped = iter::zip(where_pred.trait_ref.args, failed_pred.trait_ref.args);
for (expected, actual) in zipped {
self.probe(|_| {
match self.at(&ObligationCause::misc(expr.span, body_id), param_env).eq(
DefineOpaqueTypes::No,
expected,
actual,
) {
Ok(_) => (), // We ignore nested obligations here for now.
Err(err) => type_diffs.push(err),
}
})
}
let zipped =
iter::zip(where_pred.trait_ref.args, failed_pred.trait_ref.args);
for (expected, actual) in zipped {
self.probe(|_| {
match self
.at(&ObligationCause::misc(expr.span, body_id), param_env)
.eq(DefineOpaqueTypes::No, expected, actual)
{
Ok(_) => (), // We ignore nested obligations here for now.
Err(err) => type_diffs.push(err),
}
})
}
})
} else if let Some(where_pred) = where_pred.as_projection_clause()
&& let Some(failed_pred) = failed_pred.to_opt_poly_projection_pred()
&& let Some(found) = failed_pred.skip_binder().term.ty()
@@ -4615,14 +4619,16 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
{
self.probe(|_| {
let ocx = ObligationCtxt::new(self);
let pred = self.instantiate_binder_with_placeholders(pred);
let pred = ocx.normalize(&ObligationCause::dummy(), param_env, pred);
ocx.register_obligation(Obligation::new(
self.tcx,
ObligationCause::dummy(),
param_env,
pred,
));
self.enter_forall(pred, |pred| {
let pred = ocx.normalize(&ObligationCause::dummy(), param_env, pred);
// FIXME(tree_universes): universe leakage
ocx.register_obligation(Obligation::new(
self.tcx,
ObligationCause::dummy(),
param_env,
pred,
));
});
if !ocx.select_where_possible().is_empty() {
// encountered errors.
return;
@@ -4769,13 +4775,13 @@ fn hint_missing_borrow<'tcx>(
}
let found_args = match found.kind() {
ty::FnPtr(f) => infcx.instantiate_binder_with_placeholders(*f).inputs().iter(),
ty::FnPtr(f) => infcx.enter_forall(*f, |f| f.inputs().iter()),
kind => {
span_bug!(span, "found was converted to a FnPtr above but is now {:?}", kind)
}
};
let expected_args = match expected.kind() {
ty::FnPtr(f) => infcx.instantiate_binder_with_placeholders(*f).inputs().iter(),
ty::FnPtr(f) => infcx.enter_forall(*f, |f| f.inputs().iter()),
kind => {
span_bug!(span, "expected was converted to a FnPtr above but is now {:?}", kind)
}

132
compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs
View File

@@ -1307,12 +1307,13 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
let mut pred = obligation.predicate.to_opt_poly_trait_pred();
while let Some((next_code, next_pred)) = code.parent() {
if let Some(pred) = pred {
let pred = self.instantiate_binder_with_placeholders(pred);
diag.note(format!(
"`{}` must implement `{}`, but it does not",
pred.self_ty(),
pred.print_modifiers_and_trait_path()
));
self.enter_forall(pred, |pred| {
diag.note(format!(
"`{}` must implement `{}`, but it does not",
pred.self_ty(),
pred.print_modifiers_and_trait_path()
));
})
}
code = next_code;
pred = next_pred;
@@ -2017,70 +2018,79 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
if let [single] = &impl_candidates {
if self.probe(|_| {
let ocx = ObligationCtxt::new(self);
let obligation_trait_ref = self.instantiate_binder_with_placeholders(trait_ref);
let impl_args = self.fresh_args_for_item(DUMMY_SP, single.impl_def_id);
let impl_trait_ref = ocx.normalize(
&ObligationCause::dummy(),
param_env,
ty::EarlyBinder::bind(single.trait_ref).instantiate(self.tcx, impl_args),
);
ocx.register_obligations(
self.tcx
.predicates_of(single.impl_def_id)
.instantiate(self.tcx, impl_args)
.into_iter()
.map(|(clause, _)| {
Obligation::new(self.tcx, ObligationCause::dummy(), param_env, clause)
}),
);
if !ocx.select_where_possible().is_empty() {
return false;
}
self.enter_forall(trait_ref, |obligation_trait_ref| {
let impl_args = self.fresh_args_for_item(DUMMY_SP, single.impl_def_id);
let impl_trait_ref = ocx.normalize(
&ObligationCause::dummy(),
param_env,
ty::EarlyBinder::bind(single.trait_ref).instantiate(self.tcx, impl_args),
);
let mut terrs = vec![];
for (obligation_arg, impl_arg) in
std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args)
{
if let Err(terr) =
ocx.eq(&ObligationCause::dummy(), param_env, impl_arg, obligation_arg)
{
terrs.push(terr);
}
ocx.register_obligations(
self.tcx
.predicates_of(single.impl_def_id)
.instantiate(self.tcx, impl_args)
.into_iter()
.map(|(clause, _)| {
Obligation::new(
self.tcx,
ObligationCause::dummy(),
param_env,
clause,
)
}),
);
if !ocx.select_where_possible().is_empty() {
return false;
}
}
// Literally nothing unified, just give up.
if terrs.len() == impl_trait_ref.args.len() {
return false;
}
let mut terrs = vec![];
for (obligation_arg, impl_arg) in
std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args)
{
// FIXME(tree_universes): universe leakage
if let Err(terr) =
ocx.eq(&ObligationCause::dummy(), param_env, impl_arg, obligation_arg)
{
terrs.push(terr);
}
if !ocx.select_where_possible().is_empty() {
return false;
}
}
let cand =
self.resolve_vars_if_possible(impl_trait_ref).fold_with(&mut BottomUpFolder {
tcx: self.tcx,
ty_op: |ty| ty,
lt_op: |lt| lt,
ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()),
});
err.highlighted_help(vec![
StringPart::normal(format!("the trait `{}` ", cand.print_trait_sugared())),
StringPart::highlighted("is"),
StringPart::normal(" implemented for `"),
StringPart::highlighted(cand.self_ty().to_string()),
StringPart::normal("`"),
]);
// Literally nothing unified, just give up.
if terrs.len() == impl_trait_ref.args.len() {
return false;
}
if let [TypeError::Sorts(exp_found)] = &terrs[..] {
let exp_found = self.resolve_vars_if_possible(*exp_found);
err.help(format!(
"for that trait implementation, expected `{}`, found `{}`",
exp_found.expected, exp_found.found
));
}
let cand = self.resolve_vars_if_possible(impl_trait_ref).fold_with(
&mut BottomUpFolder {
tcx: self.tcx,
ty_op: |ty| ty,
lt_op: |lt| lt,
ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()),
},
);
err.highlighted_help(vec![
StringPart::normal(format!("the trait `{}` ", cand.print_trait_sugared())),
StringPart::highlighted("is"),
StringPart::normal(" implemented for `"),
StringPart::highlighted(cand.self_ty().to_string()),
StringPart::normal("`"),
]);
true
if let [TypeError::Sorts(exp_found)] = &terrs[..] {
let exp_found = self.resolve_vars_if_possible(*exp_found);
err.help(format!(
"for that trait implementation, expected `{}`, found `{}`",
exp_found.expected, exp_found.found
));
}
true
})
}) {
return true;
}