bjoernager/rust
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Use structurally_normalize instead of manual normalizes-to goals

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This commit is contained in:
Boxy 2025-01-21 11:10:02 +00:00
parent b2728d5426
commit 513bfaa8bc
21 changed files with 254 additions and 108 deletions
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21
compiler/rustc_trait_selection/src/error_reporting/traits/fulfillment_errors.rs
View file

@ -1338,20 +1338,15 @@ impl<'a, 'tcx> TypeErrCtxt<'a, 'tcx> {
let derive_better_type_error =
|alias_term: ty::AliasTerm<'tcx>, expected_term: ty::Term<'tcx>| {
let ocx = ObligationCtxt::new(self);
let normalized_term = match expected_term.unpack() {
ty::TermKind::Ty(_) => self.next_ty_var(DUMMY_SP).into(),
ty::TermKind::Const(_) => self.next_const_var(DUMMY_SP).into(),
};
ocx.register_obligation(Obligation::new(
self.tcx,
ObligationCause::dummy(),
let Ok(normalized_term) = ocx.structurally_normalize_term(
&ObligationCause::dummy(),
obligation.param_env,
ty::PredicateKind::NormalizesTo(ty::NormalizesTo {
alias: alias_term,
term: normalized_term,
}),
));
let _ = ocx.select_where_possible();
alias_term.to_term(self.tcx),
) else {
return None;
};
if let Err(terr) = ocx.eq(
&ObligationCause::dummy(),
obligation.param_env,

11
compiler/rustc_trait_selection/src/traits/engine.rs
View file

@ -340,4 +340,15 @@ where
.at(cause, param_env)
.structurally_normalize_const(value, &mut **self.engine.borrow_mut())
}
pub fn structurally_normalize_term(
&self,
cause: &ObligationCause<'tcx>,
param_env: ty::ParamEnv<'tcx>,
value: ty::Term<'tcx>,
) -> Result<ty::Term<'tcx>, Vec<E>> {
self.infcx
.at(cause, param_env)
.structurally_normalize_term(value, &mut **self.engine.borrow_mut())
}
}

71
compiler/rustc_trait_selection/src/traits/structural_normalize.rs
View file

@ -12,39 +12,7 @@ impl<'tcx> At<'_, 'tcx> {
ty: Ty<'tcx>,
fulfill_cx: &mut dyn TraitEngine<'tcx, E>,
) -> Result<Ty<'tcx>, Vec<E>> {
assert!(!ty.is_ty_var(), "should have resolved vars before calling");
if self.infcx.next_trait_solver() {
let ty::Alias(..) = *ty.kind() else {
return Ok(ty);
};
let new_infer_ty = self.infcx.next_ty_var(self.cause.span);
// We simply emit an `alias-eq` goal here, since that will take care of
// normalizing the LHS of the projection until it is a rigid projection
// (or a not-yet-defined opaque in scope).
let obligation = Obligation::new(
self.infcx.tcx,
self.cause.clone(),
self.param_env,
ty::PredicateKind::AliasRelate(
ty.into(),
new_infer_ty.into(),
ty::AliasRelationDirection::Equate,
),
);
fulfill_cx.register_predicate_obligation(self.infcx, obligation);
let errors = fulfill_cx.select_where_possible(self.infcx);
if !errors.is_empty() {
return Err(errors);
}
Ok(self.infcx.resolve_vars_if_possible(new_infer_ty))
} else {
Ok(self.normalize(ty).into_value_registering_obligations(self.infcx, fulfill_cx))
}
self.structurally_normalize_term(ty.into(), fulfill_cx).map(|term| term.expect_type())
}
fn structurally_normalize_const<E: 'tcx>(
@ -52,14 +20,29 @@ impl<'tcx> At<'_, 'tcx> {
ct: ty::Const<'tcx>,
fulfill_cx: &mut dyn TraitEngine<'tcx, E>,
) -> Result<ty::Const<'tcx>, Vec<E>> {
assert!(!ct.is_ct_infer(), "should have resolved vars before calling");
if self.infcx.tcx.features().generic_const_exprs() {
return Ok(super::evaluate_const(&self.infcx, ct, self.param_env));
}
self.structurally_normalize_term(ct.into(), fulfill_cx).map(|term| term.expect_const())
}
fn structurally_normalize_term<E: 'tcx>(
&self,
term: ty::Term<'tcx>,
fulfill_cx: &mut dyn TraitEngine<'tcx, E>,
) -> Result<ty::Term<'tcx>, Vec<E>> {
assert!(!term.is_infer(), "should have resolved vars before calling");
if self.infcx.next_trait_solver() {
let ty::ConstKind::Unevaluated(..) = ct.kind() else {
return Ok(ct);
};
if let None = term.to_alias_term() {
return Ok(term);
}
let new_infer_ct = self.infcx.next_const_var(self.cause.span);
let new_infer = match term.unpack() {
ty::TermKind::Ty(_) => self.infcx.next_ty_var(self.cause.span).into(),
ty::TermKind::Const(_) => self.infcx.next_const_var(self.cause.span).into(),
};
// We simply emit an `alias-eq` goal here, since that will take care of
// normalizing the LHS of the projection until it is a rigid projection
@ -68,11 +51,7 @@ impl<'tcx> At<'_, 'tcx> {
self.infcx.tcx,
self.cause.clone(),
self.param_env,
ty::PredicateKind::AliasRelate(
ct.into(),
new_infer_ct.into(),
ty::AliasRelationDirection::Equate,
),
ty::PredicateKind::AliasRelate(term, new_infer, ty::AliasRelationDirection::Equate),
);
fulfill_cx.register_predicate_obligation(self.infcx, obligation);
@ -81,11 +60,9 @@ impl<'tcx> At<'_, 'tcx> {
return Err(errors);
}
Ok(self.infcx.resolve_vars_if_possible(new_infer_ct))
} else if self.infcx.tcx.features().generic_const_exprs() {
Ok(super::evaluate_const(&self.infcx, ct, self.param_env))
Ok(self.infcx.resolve_vars_if_possible(new_infer))
} else {
Ok(self.normalize(ct).into_value_registering_obligations(self.infcx, fulfill_cx))
Ok(self.normalize(term).into_value_registering_obligations(self.infcx, fulfill_cx))
}
}
}