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Change InferCtxtBuilder from enter to build

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This commit is contained in:
Cameron Steffen 2022-09-19 22:03:59 -05:00
parent 91269fa5b8
commit 283abbf0e7
53 changed files with 1966 additions and 2182 deletions
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144
compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs
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@ -62,85 +62,81 @@ impl<'tcx> LateLintPass<'tcx> for OpaqueHiddenInferredBound {
fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) {
let hir::ItemKind::OpaqueTy(_) = &item.kind else { return; };
let def_id = item.def_id.def_id.to_def_id();
cx.tcx.infer_ctxt().enter(|ref infcx| {
// For every projection predicate in the opaque type's explicit bounds,
// check that the type that we're assigning actually satisfies the bounds
// of the associated type.
for &(pred, pred_span) in cx.tcx.explicit_item_bounds(def_id) {
// Liberate bound regions in the predicate since we
// don't actually care about lifetimes in this check.
let predicate = cx.tcx.liberate_late_bound_regions(
def_id,
pred.kind(),
);
let ty::PredicateKind::Projection(proj) = predicate else {
let infcx = &cx.tcx.infer_ctxt().build();
// For every projection predicate in the opaque type's explicit bounds,
// check that the type that we're assigning actually satisfies the bounds
// of the associated type.
for &(pred, pred_span) in cx.tcx.explicit_item_bounds(def_id) {
// Liberate bound regions in the predicate since we
// don't actually care about lifetimes in this check.
let predicate = cx.tcx.liberate_late_bound_regions(def_id, pred.kind());
let ty::PredicateKind::Projection(proj) = predicate else {
continue;
};
// Only check types, since those are the only things that may
// have opaques in them anyways.
let Some(proj_term) = proj.term.ty() else { continue };
let proj_ty =
cx.tcx.mk_projection(proj.projection_ty.item_def_id, proj.projection_ty.substs);
// For every instance of the projection type in the bounds,
// replace them with the term we're assigning to the associated
// type in our opaque type.
let proj_replacer = &mut BottomUpFolder {
tcx: cx.tcx,
ty_op: |ty| if ty == proj_ty { proj_term } else { ty },
lt_op: |lt| lt,
ct_op: |ct| ct,
};
// For example, in `impl Trait<Assoc = impl Send>`, for all of the bounds on `Assoc`,
// e.g. `type Assoc: OtherTrait`, replace `<impl Trait as Trait>::Assoc: OtherTrait`
// with `impl Send: OtherTrait`.
for assoc_pred_and_span in
cx.tcx.bound_explicit_item_bounds(proj.projection_ty.item_def_id).transpose_iter()
{
let assoc_pred_span = assoc_pred_and_span.0.1;
let assoc_pred = assoc_pred_and_span
.map_bound(|(pred, _)| *pred)
.subst(cx.tcx, &proj.projection_ty.substs)
.fold_with(proj_replacer);
let Ok(assoc_pred) = traits::fully_normalize(infcx, traits::ObligationCause::dummy(), cx.param_env, assoc_pred) else {
continue;
};
// Only check types, since those are the only things that may
// have opaques in them anyways.
let Some(proj_term) = proj.term.ty() else { continue };
let proj_ty =
cx
.tcx
.mk_projection(proj.projection_ty.item_def_id, proj.projection_ty.substs);
// For every instance of the projection type in the bounds,
// replace them with the term we're assigning to the associated
// type in our opaque type.
let proj_replacer = &mut BottomUpFolder {
tcx: cx.tcx,
ty_op: |ty| if ty == proj_ty { proj_term } else { ty },
lt_op: |lt| lt,
ct_op: |ct| ct,
};
// For example, in `impl Trait<Assoc = impl Send>`, for all of the bounds on `Assoc`,
// e.g. `type Assoc: OtherTrait`, replace `<impl Trait as Trait>::Assoc: OtherTrait`
// with `impl Send: OtherTrait`.
for assoc_pred_and_span in cx
.tcx
.bound_explicit_item_bounds(proj.projection_ty.item_def_id)
.transpose_iter()
{
let assoc_pred_span = assoc_pred_and_span.0.1;
let assoc_pred = assoc_pred_and_span
.map_bound(|(pred, _)| *pred)
.subst(cx.tcx, &proj.projection_ty.substs)
.fold_with(proj_replacer);
let Ok(assoc_pred) = traits::fully_normalize(infcx, traits::ObligationCause::dummy(), cx.param_env, assoc_pred) else {
continue;
// If that predicate doesn't hold modulo regions (but passed during type-check),
// then we must've taken advantage of the hack in `project_and_unify_types` where
// we replace opaques with inference vars. Emit a warning!
if !infcx.predicate_must_hold_modulo_regions(&traits::Obligation::new(
traits::ObligationCause::dummy(),
cx.param_env,
assoc_pred,
)) {
// If it's a trait bound and an opaque that doesn't satisfy it,
// then we can emit a suggestion to add the bound.
let add_bound = match (proj_term.kind(), assoc_pred.kind().skip_binder()) {
(ty::Opaque(def_id, _), ty::PredicateKind::Trait(trait_pred)) => {
Some(AddBound {
suggest_span: cx.tcx.def_span(*def_id).shrink_to_hi(),
trait_ref: trait_pred.print_modifiers_and_trait_path(),
})
}
_ => None,
};
// If that predicate doesn't hold modulo regions (but passed during type-check),
// then we must've taken advantage of the hack in `project_and_unify_types` where
// we replace opaques with inference vars. Emit a warning!
if !infcx.predicate_must_hold_modulo_regions(&traits::Obligation::new(
traits::ObligationCause::dummy(),
cx.param_env,
assoc_pred,
)) {
// If it's a trait bound and an opaque that doesn't satisfy it,
// then we can emit a suggestion to add the bound.
let add_bound =
match (proj_term.kind(), assoc_pred.kind().skip_binder()) {
(ty::Opaque(def_id, _), ty::PredicateKind::Trait(trait_pred)) => Some(AddBound {
suggest_span: cx.tcx.def_span(*def_id).shrink_to_hi(),
trait_ref: trait_pred.print_modifiers_and_trait_path(),
}),
_ => None,
};
cx.emit_spanned_lint(
OPAQUE_HIDDEN_INFERRED_BOUND,
pred_span,
OpaqueHiddenInferredBoundLint {
ty: cx.tcx.mk_opaque(def_id, ty::InternalSubsts::identity_for_item(cx.tcx, def_id)),
proj_ty: proj_term,
assoc_pred_span,
add_bound,
},
);
}
cx.emit_spanned_lint(
OPAQUE_HIDDEN_INFERRED_BOUND,
pred_span,
OpaqueHiddenInferredBoundLint {
ty: cx.tcx.mk_opaque(
def_id,
ty::InternalSubsts::identity_for_item(cx.tcx, def_id),
),
proj_ty: proj_term,
assoc_pred_span,
add_bound,
},
);
}
}
});
}
}
}