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Get rid of check_opaque_type_well_formed

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This commit is contained in:
Michael Goulet 2024-11-08 03:46:23 +00:00
parent b91a3a0560
commit e4c1a0016c
25 changed files with 247 additions and 412 deletions
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90
compiler/rustc_borrowck/src/region_infer/opaque_types.rs
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@ -1,10 +1,7 @@
use rustc_data_structures::fx::FxIndexMap;
use rustc_errors::ErrorGuaranteed;
use rustc_hir::OpaqueTyOrigin;
use rustc_hir::def::DefKind;
use rustc_hir::def_id::LocalDefId;
use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin, TyCtxtInferExt as _};
use rustc_infer::traits::{Obligation, ObligationCause};
use rustc_macros::extension;
use rustc_middle::ty::visit::TypeVisitableExt;
use rustc_middle::ty::{
@ -12,7 +9,6 @@ use rustc_middle::ty::{
TypingMode,
};
use rustc_span::Span;
use rustc_trait_selection::error_reporting::InferCtxtErrorExt;
use rustc_trait_selection::traits::ObligationCtxt;
use tracing::{debug, instrument};
@ -303,91 +299,7 @@ impl<'tcx> InferCtxt<'tcx> {
return Ty::new_error(self.tcx, e);
}
// `definition_ty` does not live in of the current inference context,
// so lets make sure that we don't accidentally misuse our current `infcx`.
match check_opaque_type_well_formed(
self.tcx,
self.next_trait_solver(),
opaque_type_key.def_id,
instantiated_ty.span,
definition_ty,
) {
Ok(hidden_ty) => hidden_ty,
Err(guar) => Ty::new_error(self.tcx, guar),
}
}
}
/// This logic duplicates most of `check_opaque_meets_bounds`.
/// FIXME(oli-obk): Also do region checks here and then consider removing
/// `check_opaque_meets_bounds` entirely.
fn check_opaque_type_well_formed<'tcx>(
tcx: TyCtxt<'tcx>,
next_trait_solver: bool,
def_id: LocalDefId,
definition_span: Span,
definition_ty: Ty<'tcx>,
) -> Result<Ty<'tcx>, ErrorGuaranteed> {
// Only check this for TAIT. RPIT already supports `tests/ui/impl-trait/nested-return-type2.rs`
// on stable and we'd break that.
let opaque_ty_hir = tcx.hir().expect_opaque_ty(def_id);
let OpaqueTyOrigin::TyAlias { .. } = opaque_ty_hir.origin else {
return Ok(definition_ty);
};
let param_env = tcx.param_env(def_id);
let mut parent_def_id = def_id;
while tcx.def_kind(parent_def_id) == DefKind::OpaqueTy {
parent_def_id = tcx.local_parent(parent_def_id);
}
// FIXME(#132279): This should eventually use the already defined hidden types
// instead. Alternatively we'll entirely remove this function given we also check
// the opaque in `check_opaque_meets_bounds` later.
let infcx = tcx
.infer_ctxt()
.with_next_trait_solver(next_trait_solver)
.build(TypingMode::analysis_in_body(tcx, parent_def_id));
let ocx = ObligationCtxt::new_with_diagnostics(&infcx);
let identity_args = GenericArgs::identity_for_item(tcx, def_id);
// Require that the hidden type actually fulfills all the bounds of the opaque type, even without
// the bounds that the function supplies.
let opaque_ty = Ty::new_opaque(tcx, def_id.to_def_id(), identity_args);
ocx.eq(&ObligationCause::misc(definition_span, def_id), param_env, opaque_ty, definition_ty)
.map_err(|err| {
infcx
.err_ctxt()
.report_mismatched_types(
&ObligationCause::misc(definition_span, def_id),
param_env,
opaque_ty,
definition_ty,
err,
)
.emit()
})?;
// Require the hidden type to be well-formed with only the generics of the opaque type.
// Defining use functions may have more bounds than the opaque type, which is ok, as long as the
// hidden type is well formed even without those bounds.
let predicate = ty::Binder::dummy(ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(
definition_ty.into(),
)));
ocx.register_obligation(Obligation::misc(tcx, definition_span, def_id, param_env, predicate));
// Check that all obligations are satisfied by the implementation's
// version.
let errors = ocx.select_all_or_error();
// This is fishy, but we check it again in `check_opaque_meets_bounds`.
// Remove once we can prepopulate with known hidden types.
let _ = infcx.take_opaque_types();
if errors.is_empty() {
Ok(definition_ty)
} else {
Err(infcx.err_ctxt().report_fulfillment_errors(errors))
definition_ty
}
}