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Rollup merge of #112867 - compiler-errors:more-impl-source-nits, r=lcnr
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More `ImplSource` nits

Even more clean-ups, I'll put this up in parallel with the `select_in_new_trait_solver` PR.

r? ``@lcnr``
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@Dylan-DPC
Dylan-DPC authored Jun 28, 2023
2 parents dabcbae + 7d0a5c3 commit fc2c587
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Showing 8 changed files with 47 additions and 106 deletions.
23 changes: 0 additions & 23 deletions compiler/rustc_middle/src/traits/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -660,9 +660,6 @@ pub enum ImplSource<'tcx, N> {

/// ImplSource for trait upcasting coercion
TraitUpcasting(ImplSourceTraitUpcastingData<N>),

/// ImplSource for a trait alias.
TraitAlias(ImplSourceTraitAliasData<'tcx, N>),
}

impl<'tcx, N> ImplSource<'tcx, N> {
Expand All @@ -671,7 +668,6 @@ impl<'tcx, N> ImplSource<'tcx, N> {
ImplSource::UserDefined(i) => i.nested,
ImplSource::Param(n, _) | ImplSource::Builtin(n) => n,
ImplSource::Object(d) => d.nested,
ImplSource::TraitAlias(d) => d.nested,
ImplSource::TraitUpcasting(d) => d.nested,
}
}
Expand All @@ -681,7 +677,6 @@ impl<'tcx, N> ImplSource<'tcx, N> {
ImplSource::UserDefined(i) => &i.nested,
ImplSource::Param(n, _) | ImplSource::Builtin(n) => &n,
ImplSource::Object(d) => &d.nested,
ImplSource::TraitAlias(d) => &d.nested,
ImplSource::TraitUpcasting(d) => &d.nested,
}
}
Expand All @@ -691,7 +686,6 @@ impl<'tcx, N> ImplSource<'tcx, N> {
ImplSource::UserDefined(i) => &mut i.nested,
ImplSource::Param(n, _) | ImplSource::Builtin(n) => n,
ImplSource::Object(d) => &mut d.nested,
ImplSource::TraitAlias(d) => &mut d.nested,
ImplSource::TraitUpcasting(d) => &mut d.nested,
}
}
Expand All @@ -709,15 +703,9 @@ impl<'tcx, N> ImplSource<'tcx, N> {
ImplSource::Param(n, ct) => ImplSource::Param(n.into_iter().map(f).collect(), ct),
ImplSource::Builtin(n) => ImplSource::Builtin(n.into_iter().map(f).collect()),
ImplSource::Object(o) => ImplSource::Object(ImplSourceObjectData {
upcast_trait_def_id: o.upcast_trait_def_id,
vtable_base: o.vtable_base,
nested: o.nested.into_iter().map(f).collect(),
}),
ImplSource::TraitAlias(d) => ImplSource::TraitAlias(ImplSourceTraitAliasData {
alias_def_id: d.alias_def_id,
substs: d.substs,
nested: d.nested.into_iter().map(f).collect(),
}),
ImplSource::TraitUpcasting(d) => {
ImplSource::TraitUpcasting(ImplSourceTraitUpcastingData {
vtable_vptr_slot: d.vtable_vptr_slot,
Expand Down Expand Up @@ -761,9 +749,6 @@ pub struct ImplSourceTraitUpcastingData<N> {
#[derive(PartialEq, Eq, Clone, TyEncodable, TyDecodable, HashStable, Lift)]
#[derive(TypeFoldable, TypeVisitable)]
pub struct ImplSourceObjectData<N> {
/// `Foo` upcast to the obligation trait. This will be some supertrait of `Foo`.
pub upcast_trait_def_id: DefId,

/// The vtable is formed by concatenating together the method lists of
/// the base object trait and all supertraits, pointers to supertrait vtable will
/// be provided when necessary; this is the start of `upcast_trait_ref`'s methods
Expand All @@ -773,14 +758,6 @@ pub struct ImplSourceObjectData<N> {
pub nested: Vec<N>,
}

#[derive(Clone, PartialEq, Eq, TyEncodable, TyDecodable, HashStable, Lift)]
#[derive(TypeFoldable, TypeVisitable)]
pub struct ImplSourceTraitAliasData<'tcx, N> {
pub alias_def_id: DefId,
pub substs: SubstsRef<'tcx>,
pub nested: Vec<N>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash, HashStable, PartialOrd, Ord)]
pub enum ObjectSafetyViolation {
/// `Self: Sized` declared on the trait.
Expand Down
16 changes: 2 additions & 14 deletions compiler/rustc_middle/src/traits/structural_impls.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -17,8 +17,6 @@ impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSource<'tcx, N> {
write!(f, "ImplSourceParamData({:?}, {:?})", n, ct)
}

super::ImplSource::TraitAlias(ref d) => write!(f, "{:?}", d),

super::ImplSource::TraitUpcasting(ref d) => write!(f, "{:?}", d),
}
}
Expand Down Expand Up @@ -48,18 +46,8 @@ impl<N: fmt::Debug> fmt::Debug for traits::ImplSourceObjectData<N> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"ImplSourceObjectData(upcast={:?}, vtable_base={}, nested={:?})",
self.upcast_trait_def_id, self.vtable_base, self.nested
)
}
}

impl<'tcx, N: fmt::Debug> fmt::Debug for traits::ImplSourceTraitAliasData<'tcx, N> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
write!(
f,
"ImplSourceTraitAliasData(alias_def_id={:?}, substs={:?}, nested={:?})",
self.alias_def_id, self.substs, self.nested
"ImplSourceObjectData(vtable_base={}, nested={:?})",
self.vtable_base, self.nested
)
}
}
83 changes: 34 additions & 49 deletions compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -5,7 +5,7 @@ pub mod suggestions;
use super::{
FulfillmentError, FulfillmentErrorCode, MismatchedProjectionTypes, Obligation, ObligationCause,
ObligationCauseCode, ObligationCtxt, OutputTypeParameterMismatch, Overflow,
PredicateObligation, SelectionContext, SelectionError, TraitNotObjectSafe,
PredicateObligation, SelectionError, TraitNotObjectSafe,
};
use crate::infer::error_reporting::{TyCategory, TypeAnnotationNeeded as ErrorCode};
use crate::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
Expand Down Expand Up @@ -2272,55 +2272,40 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
)
};

let obligation = obligation.with(self.tcx, trait_ref);
let mut selcx = SelectionContext::new(&self);
match selcx.select_from_obligation(&obligation) {
Ok(None) => {
let ambiguities =
ambiguity::recompute_applicable_impls(self.infcx, &obligation);
let has_non_region_infer = trait_ref
.skip_binder()
.substs
.types()
.any(|t| !t.is_ty_or_numeric_infer());
// It doesn't make sense to talk about applicable impls if there are more
// than a handful of them.
if ambiguities.len() > 1 && ambiguities.len() < 10 && has_non_region_infer {
if self.tainted_by_errors().is_some() && subst.is_none() {
// If `subst.is_none()`, then this is probably two param-env
// candidates or impl candidates that are equal modulo lifetimes.
// Therefore, if we've already emitted an error, just skip this
// one, since it's not particularly actionable.
err.cancel();
return;
}
self.annotate_source_of_ambiguity(&mut err, &ambiguities, predicate);
} else {
if self.tainted_by_errors().is_some() {
err.cancel();
return;
}
err.note(format!("cannot satisfy `{}`", predicate));
let impl_candidates = self.find_similar_impl_candidates(
predicate.to_opt_poly_trait_pred().unwrap(),
);
if impl_candidates.len() < 10 {
self.report_similar_impl_candidates(
impl_candidates.as_slice(),
trait_ref,
obligation.cause.body_id,
&mut err,
false,
);
}
}
let ambiguities = ambiguity::recompute_applicable_impls(
self.infcx,
&obligation.with(self.tcx, trait_ref),
);
let has_non_region_infer =
trait_ref.skip_binder().substs.types().any(|t| !t.is_ty_or_numeric_infer());
// It doesn't make sense to talk about applicable impls if there are more
// than a handful of them.
if ambiguities.len() > 1 && ambiguities.len() < 10 && has_non_region_infer {
if self.tainted_by_errors().is_some() && subst.is_none() {
// If `subst.is_none()`, then this is probably two param-env
// candidates or impl candidates that are equal modulo lifetimes.
// Therefore, if we've already emitted an error, just skip this
// one, since it's not particularly actionable.
err.cancel();
return;
}
_ => {
if self.tainted_by_errors().is_some() {
err.cancel();
return;
}
err.note(format!("cannot satisfy `{}`", predicate));
self.annotate_source_of_ambiguity(&mut err, &ambiguities, predicate);
} else {
if self.tainted_by_errors().is_some() {
err.cancel();
return;
}
err.note(format!("cannot satisfy `{}`", predicate));
let impl_candidates = self
.find_similar_impl_candidates(predicate.to_opt_poly_trait_pred().unwrap());
if impl_candidates.len() < 10 {
self.report_similar_impl_candidates(
impl_candidates.as_slice(),
trait_ref,
obligation.cause.body_id,
&mut err,
false,
);
}
}

Expand Down
4 changes: 1 addition & 3 deletions compiler/rustc_trait_selection/src/traits/project.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1720,7 +1720,6 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
};

let eligible = match &impl_source {
super::ImplSource::TraitAlias(_) => true,
super::ImplSource::UserDefined(impl_data) => {
// We have to be careful when projecting out of an
// impl because of specialization. If we are not in
Expand Down Expand Up @@ -2012,8 +2011,7 @@ fn confirm_select_candidate<'cx, 'tcx>(
}
super::ImplSource::Object(_)
| super::ImplSource::Param(..)
| super::ImplSource::TraitUpcasting(_)
| super::ImplSource::TraitAlias(..) => {
| super::ImplSource::TraitUpcasting(_) => {
// we don't create Select candidates with this kind of resolution
span_bug!(
obligation.cause.span,
Expand Down
20 changes: 7 additions & 13 deletions compiler/rustc_trait_selection/src/traits/select/confirmation.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -27,10 +27,9 @@ use crate::traits::vtable::{
};
use crate::traits::{
BuiltinDerivedObligation, ImplDerivedObligation, ImplDerivedObligationCause, ImplSource,
ImplSourceObjectData, ImplSourceTraitAliasData, ImplSourceTraitUpcastingData,
ImplSourceUserDefinedData, Normalized, Obligation, ObligationCause,
OutputTypeParameterMismatch, PredicateObligation, Selection, SelectionError,
TraitNotObjectSafe, TraitObligation, Unimplemented,
ImplSourceObjectData, ImplSourceTraitUpcastingData, ImplSourceUserDefinedData, Normalized,
Obligation, ObligationCause, OutputTypeParameterMismatch, PredicateObligation, Selection,
SelectionError, TraitNotObjectSafe, TraitObligation, Unimplemented,
};

use super::BuiltinImplConditions;
Expand Down Expand Up @@ -105,7 +104,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {

TraitAliasCandidate => {
let data = self.confirm_trait_alias_candidate(obligation);
ImplSource::TraitAlias(data)
ImplSource::Builtin(data)
}

BuiltinObjectCandidate => {
Expand Down Expand Up @@ -652,11 +651,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
(unnormalized_upcast_trait_ref, ty::Binder::dummy(object_trait_ref)),
);

Ok(ImplSourceObjectData {
upcast_trait_def_id: upcast_trait_ref.def_id(),
vtable_base,
nested,
})
Ok(ImplSourceObjectData { vtable_base, nested })
}

fn confirm_fn_pointer_candidate(
Expand Down Expand Up @@ -721,10 +716,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
fn confirm_trait_alias_candidate(
&mut self,
obligation: &TraitObligation<'tcx>,
) -> ImplSourceTraitAliasData<'tcx, PredicateObligation<'tcx>> {
) -> Vec<PredicateObligation<'tcx>> {
debug!(?obligation, "confirm_trait_alias_candidate");

let alias_def_id = obligation.predicate.def_id();
let predicate = self.infcx.instantiate_binder_with_placeholders(obligation.predicate);
let trait_ref = predicate.trait_ref;
let trait_def_id = trait_ref.def_id;
Expand All @@ -741,7 +735,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {

debug!(?trait_def_id, ?trait_obligations, "trait alias obligations");

ImplSourceTraitAliasData { alias_def_id, substs, nested: trait_obligations }
trait_obligations
}

fn confirm_generator_candidate(
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_trait_selection/src/traits/util.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -248,7 +248,7 @@ pub fn get_vtable_index_of_object_method<'tcx, N>(
) -> Option<usize> {
// Count number of methods preceding the one we are selecting and
// add them to the total offset.
tcx.own_existential_vtable_entries(object.upcast_trait_def_id)
tcx.own_existential_vtable_entries(tcx.parent(method_def_id))
.iter()
.copied()
.position(|def_id| def_id == method_def_id)
Expand Down
4 changes: 1 addition & 3 deletions compiler/rustc_ty_utils/src/instance.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -293,9 +293,7 @@ fn resolve_associated_item<'tcx>(
None
}
}
traits::ImplSource::Param(..)
| traits::ImplSource::TraitAlias(..)
| traits::ImplSource::TraitUpcasting(_) => None,
traits::ImplSource::Param(..) | traits::ImplSource::TraitUpcasting(_) => None,
})
}

Expand Down
1 change: 1 addition & 0 deletions tests/ui/traits/new-solver/two-projection-param-candidates-are-ambiguous.stderr
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ LL | needs_bar::<T>();
| ^^^^^^^^^^^^^^
|
= note: cannot satisfy `T: Bar`
= help: the trait `Bar` is implemented for `T`
note: required by a bound in `needs_bar`
--> $DIR/two-projection-param-candidates-are-ambiguous.rs:23:17
|
Expand Down

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