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Use InternedObligationCauseCode everywhere
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@oli-obk
oli-obk committed May 10, 2022
1 parent 213c174 commit 824e9e4
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Showing 4 changed files with 33 additions and 42 deletions.
48 changes: 20 additions & 28 deletions compiler/rustc_middle/src/traits/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -97,9 +97,7 @@ pub struct ObligationCause<'tcx> {
/// information.
pub body_id: hir::HirId,

/// `None` for `MISC_OBLIGATION_CAUSE_CODE` (a common case, occurs ~60% of
/// the time). `Some` otherwise.
code: Option<Lrc<ObligationCauseCode<'tcx>>>,
code: InternedObligationCauseCode<'tcx>,
}

// This custom hash function speeds up hashing for `Obligation` deduplication
Expand All @@ -123,11 +121,7 @@ impl<'tcx> ObligationCause<'tcx> {
body_id: hir::HirId,
code: ObligationCauseCode<'tcx>,
) -> ObligationCause<'tcx> {
ObligationCause {
span,
body_id,
code: if code == MISC_OBLIGATION_CAUSE_CODE { None } else { Some(Lrc::new(code)) },
}
ObligationCause { span, body_id, code: code.into() }
}

pub fn misc(span: Span, body_id: hir::HirId) -> ObligationCause<'tcx> {
Expand All @@ -136,11 +130,11 @@ impl<'tcx> ObligationCause<'tcx> {

#[inline(always)]
pub fn dummy() -> ObligationCause<'tcx> {
ObligationCause { span: DUMMY_SP, body_id: hir::CRATE_HIR_ID, code: None }
ObligationCause::dummy_with_span(DUMMY_SP)
}

pub fn dummy_with_span(span: Span) -> ObligationCause<'tcx> {
ObligationCause { span, body_id: hir::CRATE_HIR_ID, code: None }
ObligationCause { span, body_id: hir::CRATE_HIR_ID, code: Default::default() }
}

pub fn span(&self, tcx: TyCtxt<'tcx>) -> Span {
Expand All @@ -160,14 +154,14 @@ impl<'tcx> ObligationCause<'tcx> {

#[inline]
pub fn code(&self) -> &ObligationCauseCode<'tcx> {
self.code.as_deref().unwrap_or(&MISC_OBLIGATION_CAUSE_CODE)
&self.code
}

pub fn map_code(
&mut self,
f: impl FnOnce(InternedObligationCauseCode<'tcx>) -> Lrc<ObligationCauseCode<'tcx>>,
f: impl FnOnce(InternedObligationCauseCode<'tcx>) -> ObligationCauseCode<'tcx>,
) {
self.code = Some(f(InternedObligationCauseCode { code: self.code.take() }));
self.code = f(std::mem::take(&mut self.code)).into();
}

pub fn derived_cause(
Expand All @@ -188,10 +182,8 @@ impl<'tcx> ObligationCause<'tcx> {
// NOTE(flaper87): As of now, it keeps track of the whole error
// chain. Ideally, we should have a way to configure this either
// by using -Z verbose or just a CLI argument.
self.code = Some(
variant(DerivedObligationCause { parent_trait_pred, parent_code: self.code.take() })
.into(),
);
self.code =
variant(DerivedObligationCause { parent_trait_pred, parent_code: self.code }).into();
self
}
}
Expand All @@ -203,11 +195,19 @@ pub struct UnifyReceiverContext<'tcx> {
pub substs: SubstsRef<'tcx>,
}

#[derive(Clone, Debug, PartialEq, Eq, Hash, Lift)]
#[derive(Clone, Debug, PartialEq, Eq, Hash, Lift, Default)]
pub struct InternedObligationCauseCode<'tcx> {
/// `None` for `MISC_OBLIGATION_CAUSE_CODE` (a common case, occurs ~60% of
/// the time). `Some` otherwise.
code: Option<Lrc<ObligationCauseCode<'tcx>>>,
}

impl<'tcx> From<ObligationCauseCode<'tcx>> for InternedObligationCauseCode<'tcx> {
fn from(code: ObligationCauseCode<'tcx>) -> Self {
Self { code: if code == MISC_OBLIGATION_CAUSE_CODE { None } else { Some(Lrc::new(code)) } }
}
}

impl<'tcx> std::ops::Deref for InternedObligationCauseCode<'tcx> {
type Target = ObligationCauseCode<'tcx>;

Expand Down Expand Up @@ -454,7 +454,7 @@ impl<'tcx> ObligationCauseCode<'tcx> {
BuiltinDerivedObligation(derived)
| DerivedObligation(derived)
| ImplDerivedObligation(box ImplDerivedObligationCause { derived, .. }) => {
Some((derived.parent_code(), Some(derived.parent_trait_pred)))
Some((&derived.parent_code, Some(derived.parent_trait_pred)))
}
_ => None,
}
Expand Down Expand Up @@ -508,15 +508,7 @@ pub struct DerivedObligationCause<'tcx> {
pub parent_trait_pred: ty::PolyTraitPredicate<'tcx>,

/// The parent trait had this cause.
parent_code: Option<Lrc<ObligationCauseCode<'tcx>>>,
}

impl<'tcx> DerivedObligationCause<'tcx> {
/// Get a reference to the derived obligation cause's parent code.
#[must_use]
pub fn parent_code(&self) -> &ObligationCauseCode<'tcx> {
self.parent_code.as_deref().unwrap_or(&MISC_OBLIGATION_CAUSE_CODE)
}
pub parent_code: InternedObligationCauseCode<'tcx>,
}

#[derive(Clone, Debug, TypeFoldable, Lift)]
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1868,7 +1868,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'a, 'tcx> for InferCtxt<'a, 'tcx> {
match code {
ObligationCauseCode::BuiltinDerivedObligation(data) => {
let parent_trait_ref = self.resolve_vars_if_possible(data.parent_trait_pred);
match self.get_parent_trait_ref(data.parent_code()) {
match self.get_parent_trait_ref(&data.parent_code) {
Some(t) => Some(t),
None => {
let ty = parent_trait_ref.skip_binder().self_ty();
Expand Down
20 changes: 10 additions & 10 deletions compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1683,7 +1683,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
_ => {}
}

next_code = Some(cause.derived.parent_code());
next_code = Some(&cause.derived.parent_code);
}
ObligationCauseCode::DerivedObligation(derived_obligation)
| ObligationCauseCode::BuiltinDerivedObligation(derived_obligation) => {
Expand Down Expand Up @@ -1715,7 +1715,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
_ => {}
}

next_code = Some(derived_obligation.parent_code());
next_code = Some(&derived_obligation.parent_code);
}
_ => break,
}
Expand Down Expand Up @@ -2365,7 +2365,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
let is_upvar_tys_infer_tuple = if !matches!(ty.kind(), ty::Tuple(..)) {
false
} else {
if let ObligationCauseCode::BuiltinDerivedObligation(data) = data.parent_code()
if let ObligationCauseCode::BuiltinDerivedObligation(data) = &*data.parent_code
{
let parent_trait_ref =
self.resolve_vars_if_possible(data.parent_trait_pred);
Expand All @@ -2392,14 +2392,14 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
obligated_types.push(ty);

let parent_predicate = parent_trait_ref.to_predicate(tcx);
if !self.is_recursive_obligation(obligated_types, data.parent_code()) {
if !self.is_recursive_obligation(obligated_types, &data.parent_code) {
// #74711: avoid a stack overflow
ensure_sufficient_stack(|| {
self.note_obligation_cause_code(
err,
&parent_predicate,
param_env,
data.parent_code(),
&data.parent_code,
obligated_types,
seen_requirements,
)
Expand All @@ -2410,7 +2410,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
err,
&parent_predicate,
param_env,
&cause_code.peel_derives(),
cause_code.peel_derives(),
obligated_types,
seen_requirements,
)
Expand Down Expand Up @@ -2461,7 +2461,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
// We don't want to point at the ADT saying "required because it appears within
// the type `X`", like we would otherwise do in test `supertrait-auto-trait.rs`.
while let ObligationCauseCode::BuiltinDerivedObligation(derived) =
data.parent_code()
&*data.parent_code
{
let child_trait_ref =
self.resolve_vars_if_possible(derived.parent_trait_pred);
Expand All @@ -2474,7 +2474,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
parent_trait_pred = child_trait_ref;
}
}
while let ObligationCauseCode::ImplDerivedObligation(child) = data.parent_code() {
while let ObligationCauseCode::ImplDerivedObligation(child) = &*data.parent_code {
// Skip redundant recursive obligation notes. See `ui/issue-20413.rs`.
let child_trait_pred =
self.resolve_vars_if_possible(child.derived.parent_trait_pred);
Expand Down Expand Up @@ -2505,7 +2505,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
err,
&parent_predicate,
param_env,
data.parent_code(),
&data.parent_code,
obligated_types,
seen_requirements,
)
Expand All @@ -2520,7 +2520,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
err,
&parent_predicate,
param_env,
data.parent_code(),
&data.parent_code,
obligated_types,
seen_requirements,
)
Expand Down
5 changes: 2 additions & 3 deletions compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1606,9 +1606,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let mut result_code = code;
loop {
let parent = match code {
ObligationCauseCode::ImplDerivedObligation(c) => c.derived.parent_code(),
ObligationCauseCode::ImplDerivedObligation(c) => &c.derived.parent_code,
ObligationCauseCode::BuiltinDerivedObligation(c)
| ObligationCauseCode::DerivedObligation(c) => c.parent_code(),
| ObligationCauseCode::DerivedObligation(c) => &c.parent_code,
_ => break result_code,
};
(result_code, code) = (code, parent);
Expand Down Expand Up @@ -1670,7 +1670,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
call_hir_id: expr.hir_id,
parent_code,
}
.into()
});
} else if error.obligation.cause.span == call_sp {
// Make function calls point at the callee, not the whole thing.
Expand Down

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