reorder files in solve
This commit is contained in:
lcnr
@@ -1,636 +0,0 @@
|
||||
use crate::traits::{check_args_compatible, specialization_graph};
|
||||
|
||||
use super::assembly::{self, structural_traits};
|
||||
use super::EvalCtxt;
|
||||
use rustc_hir::def::DefKind;
|
||||
use rustc_hir::def_id::DefId;
|
||||
use rustc_hir::LangItem;
|
||||
use rustc_infer::traits::query::NoSolution;
|
||||
use rustc_infer::traits::specialization_graph::LeafDef;
|
||||
use rustc_infer::traits::Reveal;
|
||||
use rustc_middle::traits::solve::{
|
||||
CandidateSource, CanonicalResponse, Certainty, Goal, QueryResult,
|
||||
};
|
||||
use rustc_middle::traits::BuiltinImplSource;
|
||||
use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
|
||||
use rustc_middle::ty::ProjectionPredicate;
|
||||
use rustc_middle::ty::{self, Ty, TyCtxt};
|
||||
use rustc_middle::ty::{ToPredicate, TypeVisitableExt};
|
||||
use rustc_span::{sym, ErrorGuaranteed, DUMMY_SP};
|
||||
|
||||
impl<'tcx> EvalCtxt<'_, 'tcx> {
|
||||
#[instrument(level = "debug", skip(self), ret)]
|
||||
pub(super) fn compute_projection_goal(
|
||||
&mut self,
|
||||
goal: Goal<'tcx, ProjectionPredicate<'tcx>>,
|
||||
) -> QueryResult<'tcx> {
|
||||
let def_id = goal.predicate.def_id();
|
||||
match self.tcx().def_kind(def_id) {
|
||||
DefKind::AssocTy | DefKind::AssocConst => {
|
||||
// To only compute normalization once for each projection we only
|
||||
// assemble normalization candidates if the expected term is an
|
||||
// unconstrained inference variable.
|
||||
//
|
||||
// Why: For better cache hits, since if we have an unconstrained RHS then
|
||||
// there are only as many cache keys as there are (canonicalized) alias
|
||||
// types in each normalizes-to goal. This also weakens inference in a
|
||||
// forwards-compatible way so we don't use the value of the RHS term to
|
||||
// affect candidate assembly for projections.
|
||||
//
|
||||
// E.g. for `<T as Trait>::Assoc == u32` we recursively compute the goal
|
||||
// `exists<U> <T as Trait>::Assoc == U` and then take the resulting type for
|
||||
// `U` and equate it with `u32`. This means that we don't need a separate
|
||||
// projection cache in the solver, since we're piggybacking off of regular
|
||||
// goal caching.
|
||||
if self.term_is_fully_unconstrained(goal) {
|
||||
match self.tcx().associated_item(def_id).container {
|
||||
ty::AssocItemContainer::TraitContainer => {
|
||||
let candidates = self.assemble_and_evaluate_candidates(goal);
|
||||
self.merge_candidates(candidates)
|
||||
}
|
||||
ty::AssocItemContainer::ImplContainer => {
|
||||
self.normalize_inherent_associated_type(goal)
|
||||
}
|
||||
}
|
||||
} else {
|
||||
self.set_normalizes_to_hack_goal(goal);
|
||||
self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
|
||||
}
|
||||
}
|
||||
DefKind::AnonConst => self.normalize_anon_const(goal),
|
||||
DefKind::OpaqueTy => self.normalize_opaque_type(goal),
|
||||
DefKind::TyAlias => self.normalize_weak_type(goal),
|
||||
kind => bug!("unknown DefKind {} in projection goal: {goal:#?}", kind.descr(def_id)),
|
||||
}
|
||||
}
|
||||
|
||||
#[instrument(level = "debug", skip(self), ret)]
|
||||
fn normalize_anon_const(
|
||||
&mut self,
|
||||
goal: Goal<'tcx, ty::ProjectionPredicate<'tcx>>,
|
||||
) -> QueryResult<'tcx> {
|
||||
if let Some(normalized_const) = self.try_const_eval_resolve(
|
||||
goal.param_env,
|
||||
ty::UnevaluatedConst::new(
|
||||
goal.predicate.projection_ty.def_id,
|
||||
goal.predicate.projection_ty.args,
|
||||
),
|
||||
self.tcx()
|
||||
.type_of(goal.predicate.projection_ty.def_id)
|
||||
.no_bound_vars()
|
||||
.expect("const ty should not rely on other generics"),
|
||||
) {
|
||||
self.eq(goal.param_env, normalized_const, goal.predicate.term.ct().unwrap())?;
|
||||
self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
|
||||
} else {
|
||||
self.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
|
||||
fn self_ty(self) -> Ty<'tcx> {
|
||||
self.self_ty()
|
||||
}
|
||||
|
||||
fn trait_ref(self, tcx: TyCtxt<'tcx>) -> ty::TraitRef<'tcx> {
|
||||
self.projection_ty.trait_ref(tcx)
|
||||
}
|
||||
|
||||
fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self {
|
||||
self.with_self_ty(tcx, self_ty)
|
||||
}
|
||||
|
||||
fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId {
|
||||
self.trait_def_id(tcx)
|
||||
}
|
||||
|
||||
fn probe_and_match_goal_against_assumption(
|
||||
ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
assumption: ty::Clause<'tcx>,
|
||||
then: impl FnOnce(&mut EvalCtxt<'_, 'tcx>) -> QueryResult<'tcx>,
|
||||
) -> QueryResult<'tcx> {
|
||||
if let Some(projection_pred) = assumption.as_projection_clause() {
|
||||
if projection_pred.projection_def_id() == goal.predicate.def_id() {
|
||||
let tcx = ecx.tcx();
|
||||
ecx.probe_misc_candidate("assumption").enter(|ecx| {
|
||||
let assumption_projection_pred =
|
||||
ecx.instantiate_binder_with_infer(projection_pred);
|
||||
ecx.eq(
|
||||
goal.param_env,
|
||||
goal.predicate.projection_ty,
|
||||
assumption_projection_pred.projection_ty,
|
||||
)?;
|
||||
ecx.eq(goal.param_env, goal.predicate.term, assumption_projection_pred.term)
|
||||
.expect("expected goal term to be fully unconstrained");
|
||||
|
||||
// Add GAT where clauses from the trait's definition
|
||||
ecx.add_goals(
|
||||
tcx.predicates_of(goal.predicate.def_id())
|
||||
.instantiate_own(tcx, goal.predicate.projection_ty.args)
|
||||
.map(|(pred, _)| goal.with(tcx, pred)),
|
||||
);
|
||||
|
||||
then(ecx)
|
||||
})
|
||||
} else {
|
||||
Err(NoSolution)
|
||||
}
|
||||
} else {
|
||||
Err(NoSolution)
|
||||
}
|
||||
}
|
||||
|
||||
fn consider_impl_candidate(
|
||||
ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, ProjectionPredicate<'tcx>>,
|
||||
impl_def_id: DefId,
|
||||
) -> QueryResult<'tcx> {
|
||||
let tcx = ecx.tcx();
|
||||
|
||||
let goal_trait_ref = goal.predicate.projection_ty.trait_ref(tcx);
|
||||
let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
|
||||
let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::ForLookup };
|
||||
if !drcx.args_refs_may_unify(goal_trait_ref.args, impl_trait_ref.skip_binder().args) {
|
||||
return Err(NoSolution);
|
||||
}
|
||||
|
||||
ecx.probe_trait_candidate(CandidateSource::Impl(impl_def_id)).enter(|ecx| {
|
||||
let impl_args = ecx.fresh_args_for_item(impl_def_id);
|
||||
let impl_trait_ref = impl_trait_ref.instantiate(tcx, impl_args);
|
||||
|
||||
ecx.eq(goal.param_env, goal_trait_ref, impl_trait_ref)?;
|
||||
|
||||
let where_clause_bounds = tcx
|
||||
.predicates_of(impl_def_id)
|
||||
.instantiate(tcx, impl_args)
|
||||
.predicates
|
||||
.into_iter()
|
||||
.map(|pred| goal.with(tcx, pred));
|
||||
ecx.add_goals(where_clause_bounds);
|
||||
|
||||
// Add GAT where clauses from the trait's definition
|
||||
ecx.add_goals(
|
||||
tcx.predicates_of(goal.predicate.def_id())
|
||||
.instantiate_own(tcx, goal.predicate.projection_ty.args)
|
||||
.map(|(pred, _)| goal.with(tcx, pred)),
|
||||
);
|
||||
|
||||
// In case the associated item is hidden due to specialization, we have to
|
||||
// return ambiguity this would otherwise be incomplete, resulting in
|
||||
// unsoundness during coherence (#105782).
|
||||
let Some(assoc_def) = fetch_eligible_assoc_item_def(
|
||||
ecx,
|
||||
goal.param_env,
|
||||
goal_trait_ref,
|
||||
goal.predicate.def_id(),
|
||||
impl_def_id,
|
||||
)?
|
||||
else {
|
||||
return ecx.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS);
|
||||
};
|
||||
|
||||
let error_response = |ecx: &mut EvalCtxt<'_, 'tcx>, reason| {
|
||||
let guar = tcx.sess.delay_span_bug(tcx.def_span(assoc_def.item.def_id), reason);
|
||||
let error_term = match assoc_def.item.kind {
|
||||
ty::AssocKind::Const => ty::Const::new_error(
|
||||
tcx,
|
||||
guar,
|
||||
tcx.type_of(goal.predicate.def_id())
|
||||
.instantiate(tcx, goal.predicate.projection_ty.args),
|
||||
)
|
||||
.into(),
|
||||
ty::AssocKind::Type => Ty::new_error(tcx, guar).into(),
|
||||
ty::AssocKind::Fn => unreachable!(),
|
||||
};
|
||||
ecx.eq(goal.param_env, goal.predicate.term, error_term)
|
||||
.expect("expected goal term to be fully unconstrained");
|
||||
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
|
||||
};
|
||||
|
||||
if !assoc_def.item.defaultness(tcx).has_value() {
|
||||
return error_response(ecx, "missing value for assoc item in impl");
|
||||
}
|
||||
|
||||
// Getting the right args here is complex, e.g. given:
|
||||
// - a goal `<Vec<u32> as Trait<i32>>::Assoc<u64>`
|
||||
// - the applicable impl `impl<T> Trait<i32> for Vec<T>`
|
||||
// - and the impl which defines `Assoc` being `impl<T, U> Trait<U> for Vec<T>`
|
||||
//
|
||||
// We first rebase the goal args onto the impl, going from `[Vec<u32>, i32, u64]`
|
||||
// to `[u32, u64]`.
|
||||
//
|
||||
// And then map these args to the args of the defining impl of `Assoc`, going
|
||||
// from `[u32, u64]` to `[u32, i32, u64]`.
|
||||
let impl_args_with_gat = goal.predicate.projection_ty.args.rebase_onto(
|
||||
tcx,
|
||||
goal_trait_ref.def_id,
|
||||
impl_args,
|
||||
);
|
||||
let args = ecx.translate_args(
|
||||
goal.param_env,
|
||||
impl_def_id,
|
||||
impl_args_with_gat,
|
||||
assoc_def.defining_node,
|
||||
);
|
||||
|
||||
if !check_args_compatible(tcx, assoc_def.item, args) {
|
||||
return error_response(
|
||||
ecx,
|
||||
"associated item has mismatched generic item arguments",
|
||||
);
|
||||
}
|
||||
|
||||
// Finally we construct the actual value of the associated type.
|
||||
let term = match assoc_def.item.kind {
|
||||
ty::AssocKind::Type => tcx.type_of(assoc_def.item.def_id).map_bound(|ty| ty.into()),
|
||||
ty::AssocKind::Const => {
|
||||
if tcx.features().associated_const_equality {
|
||||
bug!("associated const projection is not supported yet")
|
||||
} else {
|
||||
ty::EarlyBinder::bind(
|
||||
ty::Const::new_error_with_message(
|
||||
tcx,
|
||||
tcx.type_of(assoc_def.item.def_id).instantiate_identity(),
|
||||
DUMMY_SP,
|
||||
"associated const projection is not supported yet",
|
||||
)
|
||||
.into(),
|
||||
)
|
||||
}
|
||||
}
|
||||
ty::AssocKind::Fn => unreachable!("we should never project to a fn"),
|
||||
};
|
||||
|
||||
ecx.eq(goal.param_env, goal.predicate.term, term.instantiate(tcx, args))
|
||||
.expect("expected goal term to be fully unconstrained");
|
||||
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
|
||||
})
|
||||
}
|
||||
|
||||
/// Fail to normalize if the predicate contains an error, alternatively, we could normalize to `ty::Error`
|
||||
/// and succeed. Can experiment with this to figure out what results in better error messages.
|
||||
fn consider_error_guaranteed_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
_guar: ErrorGuaranteed,
|
||||
) -> QueryResult<'tcx> {
|
||||
Err(NoSolution)
|
||||
}
|
||||
|
||||
fn consider_auto_trait_candidate(
|
||||
ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
ecx.tcx().sess.delay_span_bug(
|
||||
ecx.tcx().def_span(goal.predicate.def_id()),
|
||||
"associated types not allowed on auto traits",
|
||||
);
|
||||
Err(NoSolution)
|
||||
}
|
||||
|
||||
fn consider_trait_alias_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("trait aliases do not have associated types: {:?}", goal);
|
||||
}
|
||||
|
||||
fn consider_builtin_sized_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("`Sized` does not have an associated type: {:?}", goal);
|
||||
}
|
||||
|
||||
fn consider_builtin_copy_clone_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("`Copy`/`Clone` does not have an associated type: {:?}", goal);
|
||||
}
|
||||
|
||||
fn consider_builtin_pointer_like_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("`PointerLike` does not have an associated type: {:?}", goal);
|
||||
}
|
||||
|
||||
fn consider_builtin_fn_ptr_trait_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("`FnPtr` does not have an associated type: {:?}", goal);
|
||||
}
|
||||
|
||||
fn consider_builtin_fn_trait_candidates(
|
||||
ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
goal_kind: ty::ClosureKind,
|
||||
) -> QueryResult<'tcx> {
|
||||
let tcx = ecx.tcx();
|
||||
let tupled_inputs_and_output =
|
||||
match structural_traits::extract_tupled_inputs_and_output_from_callable(
|
||||
tcx,
|
||||
goal.predicate.self_ty(),
|
||||
goal_kind,
|
||||
)? {
|
||||
Some(tupled_inputs_and_output) => tupled_inputs_and_output,
|
||||
None => {
|
||||
return ecx
|
||||
.evaluate_added_goals_and_make_canonical_response(Certainty::AMBIGUOUS);
|
||||
}
|
||||
};
|
||||
let output_is_sized_pred = tupled_inputs_and_output.map_bound(|(_, output)| {
|
||||
ty::TraitRef::from_lang_item(tcx, LangItem::Sized, DUMMY_SP, [output])
|
||||
});
|
||||
|
||||
let pred = tupled_inputs_and_output
|
||||
.map_bound(|(inputs, output)| ty::ProjectionPredicate {
|
||||
projection_ty: tcx
|
||||
.mk_alias_ty(goal.predicate.def_id(), [goal.predicate.self_ty(), inputs]),
|
||||
term: output.into(),
|
||||
})
|
||||
.to_predicate(tcx);
|
||||
|
||||
// A built-in `Fn` impl only holds if the output is sized.
|
||||
// (FIXME: technically we only need to check this if the type is a fn ptr...)
|
||||
Self::consider_implied_clause(ecx, goal, pred, [goal.with(tcx, output_is_sized_pred)])
|
||||
}
|
||||
|
||||
fn consider_builtin_tuple_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("`Tuple` does not have an associated type: {:?}", goal);
|
||||
}
|
||||
|
||||
fn consider_builtin_pointee_candidate(
|
||||
ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
let tcx = ecx.tcx();
|
||||
ecx.probe_misc_candidate("builtin pointee").enter(|ecx| {
|
||||
let metadata_ty = match goal.predicate.self_ty().kind() {
|
||||
ty::Bool
|
||||
| ty::Char
|
||||
| ty::Int(..)
|
||||
| ty::Uint(..)
|
||||
| ty::Float(..)
|
||||
| ty::Array(..)
|
||||
| ty::RawPtr(..)
|
||||
| ty::Ref(..)
|
||||
| ty::FnDef(..)
|
||||
| ty::FnPtr(..)
|
||||
| ty::Closure(..)
|
||||
| ty::Infer(ty::IntVar(..) | ty::FloatVar(..))
|
||||
| ty::Generator(..)
|
||||
| ty::GeneratorWitness(..)
|
||||
| ty::Never
|
||||
| ty::Foreign(..) => tcx.types.unit,
|
||||
|
||||
ty::Error(e) => Ty::new_error(tcx, *e),
|
||||
|
||||
ty::Str | ty::Slice(_) => tcx.types.usize,
|
||||
|
||||
ty::Dynamic(_, _, _) => {
|
||||
let dyn_metadata = tcx.require_lang_item(LangItem::DynMetadata, None);
|
||||
tcx.type_of(dyn_metadata)
|
||||
.instantiate(tcx, &[ty::GenericArg::from(goal.predicate.self_ty())])
|
||||
}
|
||||
|
||||
ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => {
|
||||
// FIXME(ptr_metadata): It would also be possible to return a `Ok(Ambig)` with no constraints.
|
||||
let sized_predicate = ty::TraitRef::from_lang_item(
|
||||
tcx,
|
||||
LangItem::Sized,
|
||||
DUMMY_SP,
|
||||
[ty::GenericArg::from(goal.predicate.self_ty())],
|
||||
);
|
||||
ecx.add_goal(goal.with(tcx, sized_predicate));
|
||||
tcx.types.unit
|
||||
}
|
||||
|
||||
ty::Adt(def, args) if def.is_struct() => match def.non_enum_variant().tail_opt() {
|
||||
None => tcx.types.unit,
|
||||
Some(field_def) => {
|
||||
let self_ty = field_def.ty(tcx, args);
|
||||
ecx.add_goal(goal.with(tcx, goal.predicate.with_self_ty(tcx, self_ty)));
|
||||
return ecx
|
||||
.evaluate_added_goals_and_make_canonical_response(Certainty::Yes);
|
||||
}
|
||||
},
|
||||
ty::Adt(_, _) => tcx.types.unit,
|
||||
|
||||
ty::Tuple(elements) => match elements.last() {
|
||||
None => tcx.types.unit,
|
||||
Some(&self_ty) => {
|
||||
ecx.add_goal(goal.with(tcx, goal.predicate.with_self_ty(tcx, self_ty)));
|
||||
return ecx
|
||||
.evaluate_added_goals_and_make_canonical_response(Certainty::Yes);
|
||||
}
|
||||
},
|
||||
|
||||
ty::Infer(
|
||||
ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_),
|
||||
)
|
||||
| ty::Bound(..) => bug!(
|
||||
"unexpected self ty `{:?}` when normalizing `<T as Pointee>::Metadata`",
|
||||
goal.predicate.self_ty()
|
||||
),
|
||||
};
|
||||
|
||||
ecx.eq(goal.param_env, goal.predicate.term, metadata_ty.into())
|
||||
.expect("expected goal term to be fully unconstrained");
|
||||
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
|
||||
})
|
||||
}
|
||||
|
||||
fn consider_builtin_future_candidate(
|
||||
ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
let self_ty = goal.predicate.self_ty();
|
||||
let ty::Generator(def_id, args, _) = *self_ty.kind() else {
|
||||
return Err(NoSolution);
|
||||
};
|
||||
|
||||
// Generators are not futures unless they come from `async` desugaring
|
||||
let tcx = ecx.tcx();
|
||||
if !tcx.generator_is_async(def_id) {
|
||||
return Err(NoSolution);
|
||||
}
|
||||
|
||||
let term = args.as_generator().return_ty().into();
|
||||
|
||||
Self::consider_implied_clause(
|
||||
ecx,
|
||||
goal,
|
||||
ty::ProjectionPredicate {
|
||||
projection_ty: ecx.tcx().mk_alias_ty(goal.predicate.def_id(), [self_ty]),
|
||||
term,
|
||||
}
|
||||
.to_predicate(tcx),
|
||||
// Technically, we need to check that the future type is Sized,
|
||||
// but that's already proven by the generator being WF.
|
||||
[],
|
||||
)
|
||||
}
|
||||
|
||||
fn consider_builtin_generator_candidate(
|
||||
ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
let self_ty = goal.predicate.self_ty();
|
||||
let ty::Generator(def_id, args, _) = *self_ty.kind() else {
|
||||
return Err(NoSolution);
|
||||
};
|
||||
|
||||
// `async`-desugared generators do not implement the generator trait
|
||||
let tcx = ecx.tcx();
|
||||
if tcx.generator_is_async(def_id) {
|
||||
return Err(NoSolution);
|
||||
}
|
||||
|
||||
let generator = args.as_generator();
|
||||
|
||||
let name = tcx.associated_item(goal.predicate.def_id()).name;
|
||||
let term = if name == sym::Return {
|
||||
generator.return_ty().into()
|
||||
} else if name == sym::Yield {
|
||||
generator.yield_ty().into()
|
||||
} else {
|
||||
bug!("unexpected associated item `<{self_ty} as Generator>::{name}`")
|
||||
};
|
||||
|
||||
Self::consider_implied_clause(
|
||||
ecx,
|
||||
goal,
|
||||
ty::ProjectionPredicate {
|
||||
projection_ty: ecx
|
||||
.tcx()
|
||||
.mk_alias_ty(goal.predicate.def_id(), [self_ty, generator.resume_ty()]),
|
||||
term,
|
||||
}
|
||||
.to_predicate(tcx),
|
||||
// Technically, we need to check that the future type is Sized,
|
||||
// but that's already proven by the generator being WF.
|
||||
[],
|
||||
)
|
||||
}
|
||||
|
||||
fn consider_unsize_to_dyn_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("`Unsize` does not have an associated type: {:?}", goal)
|
||||
}
|
||||
|
||||
fn consider_structural_builtin_unsize_candidates(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> Vec<(CanonicalResponse<'tcx>, BuiltinImplSource)> {
|
||||
bug!("`Unsize` does not have an associated type: {:?}", goal);
|
||||
}
|
||||
|
||||
fn consider_builtin_discriminant_kind_candidate(
|
||||
ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
let self_ty = goal.predicate.self_ty();
|
||||
let discriminant_ty = match *self_ty.kind() {
|
||||
ty::Bool
|
||||
| ty::Char
|
||||
| ty::Int(..)
|
||||
| ty::Uint(..)
|
||||
| ty::Float(..)
|
||||
| ty::Array(..)
|
||||
| ty::RawPtr(..)
|
||||
| ty::Ref(..)
|
||||
| ty::FnDef(..)
|
||||
| ty::FnPtr(..)
|
||||
| ty::Closure(..)
|
||||
| ty::Infer(ty::IntVar(..) | ty::FloatVar(..))
|
||||
| ty::Generator(..)
|
||||
| ty::GeneratorWitness(..)
|
||||
| ty::Never
|
||||
| ty::Foreign(..)
|
||||
| ty::Adt(_, _)
|
||||
| ty::Str
|
||||
| ty::Slice(_)
|
||||
| ty::Dynamic(_, _, _)
|
||||
| ty::Tuple(_)
|
||||
| ty::Error(_) => self_ty.discriminant_ty(ecx.tcx()),
|
||||
|
||||
// We do not call `Ty::discriminant_ty` on alias, param, or placeholder
|
||||
// types, which return `<self_ty as DiscriminantKind>::Discriminant`
|
||||
// (or ICE in the case of placeholders). Projecting a type to itself
|
||||
// is never really productive.
|
||||
ty::Alias(_, _) | ty::Param(_) | ty::Placeholder(..) => {
|
||||
return Err(NoSolution);
|
||||
}
|
||||
|
||||
ty::Infer(ty::TyVar(_) | ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_))
|
||||
| ty::Bound(..) => bug!(
|
||||
"unexpected self ty `{:?}` when normalizing `<T as DiscriminantKind>::Discriminant`",
|
||||
goal.predicate.self_ty()
|
||||
),
|
||||
};
|
||||
|
||||
ecx.probe_misc_candidate("builtin discriminant kind").enter(|ecx| {
|
||||
ecx.eq(goal.param_env, goal.predicate.term, discriminant_ty.into())
|
||||
.expect("expected goal term to be fully unconstrained");
|
||||
ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes)
|
||||
})
|
||||
}
|
||||
|
||||
fn consider_builtin_destruct_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("`Destruct` does not have an associated type: {:?}", goal);
|
||||
}
|
||||
|
||||
fn consider_builtin_transmute_candidate(
|
||||
_ecx: &mut EvalCtxt<'_, 'tcx>,
|
||||
goal: Goal<'tcx, Self>,
|
||||
) -> QueryResult<'tcx> {
|
||||
bug!("`BikeshedIntrinsicFrom` does not have an associated type: {:?}", goal)
|
||||
}
|
||||
}
|
||||
|
||||
/// This behavior is also implemented in `rustc_ty_utils` and in the old `project` code.
|
||||
///
|
||||
/// FIXME: We should merge these 3 implementations as it's likely that they otherwise
|
||||
/// diverge.
|
||||
#[instrument(level = "debug", skip(ecx, param_env), ret)]
|
||||
fn fetch_eligible_assoc_item_def<'tcx>(
|
||||
ecx: &EvalCtxt<'_, 'tcx>,
|
||||
param_env: ty::ParamEnv<'tcx>,
|
||||
goal_trait_ref: ty::TraitRef<'tcx>,
|
||||
trait_assoc_def_id: DefId,
|
||||
impl_def_id: DefId,
|
||||
) -> Result<Option<LeafDef>, NoSolution> {
|
||||
let node_item = specialization_graph::assoc_def(ecx.tcx(), impl_def_id, trait_assoc_def_id)
|
||||
.map_err(|ErrorGuaranteed { .. }| NoSolution)?;
|
||||
|
||||
let eligible = if node_item.is_final() {
|
||||
// Non-specializable items are always projectable.
|
||||
true
|
||||
} else {
|
||||
// Only reveal a specializable default if we're past type-checking
|
||||
// and the obligation is monomorphic, otherwise passes such as
|
||||
// transmute checking and polymorphic MIR optimizations could
|
||||
// get a result which isn't correct for all monomorphizations.
|
||||
if param_env.reveal() == Reveal::All {
|
||||
let poly_trait_ref = ecx.resolve_vars_if_possible(goal_trait_ref);
|
||||
!poly_trait_ref.still_further_specializable()
|
||||
} else {
|
||||
debug!(?node_item.item.def_id, "not eligible due to default");
|
||||
false
|
||||
}
|
||||
};
|
||||
|
||||
if eligible { Ok(Some(node_item)) } else { Ok(None) }
|
||||
}
|
||||
Reference in New Issue
Block a user