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Don't fall back to crate-level opaque type definitions. #92045

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merged 1 commit into from
Jan 14, 2022
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Don't fall back to crate-level opaque type definitions. #92045

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18 changes: 9 additions & 9 deletions compiler/rustc_infer/src/infer/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,6 @@ pub(crate) use self::undo_log::{InferCtxtUndoLogs, Snapshot, UndoLog};

use crate::traits::{self, ObligationCause, PredicateObligations, TraitEngine};

use hir::def_id::CRATE_DEF_ID;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::sync::Lrc;
use rustc_data_structures::undo_log::Rollback;
Expand Down Expand Up @@ -291,7 +290,12 @@ pub struct InferCtxt<'a, 'tcx> {

/// The `DefId` of the item in whose context we are performing inference or typeck.
/// It is used to check whether an opaque type use is a defining use.
pub defining_use_anchor: LocalDefId,
///
/// If it is `None`, we can't resolve opaque types here and need to bubble up
/// the obligation. This frequently happens for
/// short lived InferCtxt within queries. The opaque type obligations are forwarded
/// to the outside until the end up in an `InferCtxt` for typeck or borrowck.
pub defining_use_anchor: Option<LocalDefId>,

/// During type-checking/inference of a body, `in_progress_typeck_results`
/// contains a reference to the typeck results being built up, which are
Expand Down Expand Up @@ -547,7 +551,7 @@ impl<'tcx> fmt::Display for FixupError<'tcx> {
pub struct InferCtxtBuilder<'tcx> {
tcx: TyCtxt<'tcx>,
fresh_typeck_results: Option<RefCell<ty::TypeckResults<'tcx>>>,
defining_use_anchor: LocalDefId,
defining_use_anchor: Option<LocalDefId>,
}

pub trait TyCtxtInferExt<'tcx> {
Expand All @@ -556,11 +560,7 @@ pub trait TyCtxtInferExt<'tcx> {

impl<'tcx> TyCtxtInferExt<'tcx> for TyCtxt<'tcx> {
fn infer_ctxt(self) -> InferCtxtBuilder<'tcx> {
InferCtxtBuilder {
tcx: self,
defining_use_anchor: CRATE_DEF_ID,
fresh_typeck_results: None,
}
InferCtxtBuilder { tcx: self, defining_use_anchor: None, fresh_typeck_results: None }
}
}

Expand All @@ -580,7 +580,7 @@ impl<'tcx> InferCtxtBuilder<'tcx> {
/// (via `with_fresh_in_progress_typeck_results`) and for the inference context used
/// in mir borrowck.
pub fn with_opaque_type_inference(mut self, defining_use_anchor: LocalDefId) -> Self {
self.defining_use_anchor = defining_use_anchor;
self.defining_use_anchor = Some(defining_use_anchor);
self
}

Expand Down
50 changes: 27 additions & 23 deletions compiler/rustc_infer/src/infer/opaque_types.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -328,6 +328,31 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
},
});
}

fn opaque_type_origin(&self, def_id: LocalDefId) -> Option<hir::OpaqueTyOrigin> {
let tcx = self.tcx;
let opaque_hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
let parent_def_id = self.defining_use_anchor?;
let item_kind = &tcx.hir().expect_item(def_id).kind;
let hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) = item_kind else {
span_bug!(
tcx.def_span(def_id),
"weird opaque type: {:#?}",
item_kind
)
};
let in_definition_scope = match *origin {
// Async `impl Trait`
hir::OpaqueTyOrigin::AsyncFn(parent) => parent == parent_def_id,
// Anonymous `impl Trait`
hir::OpaqueTyOrigin::FnReturn(parent) => parent == parent_def_id,
// Named `type Foo = impl Bar;`
hir::OpaqueTyOrigin::TyAlias => {
may_define_opaque_type(tcx, parent_def_id, opaque_hir_id)
}
};
in_definition_scope.then_some(*origin)
}
}

// Visitor that requires that (almost) all regions in the type visited outlive
Expand Down Expand Up @@ -459,31 +484,10 @@ impl<'a, 'tcx> Instantiator<'a, 'tcx> {
// }
// ```
if let Some(def_id) = def_id.as_local() {
let opaque_hir_id = tcx.hir().local_def_id_to_hir_id(def_id);
let parent_def_id = self.infcx.defining_use_anchor;
let item_kind = &tcx.hir().expect_item(def_id).kind;
let hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) = item_kind else {
span_bug!(
self.value_span,
"weird opaque type: {:#?}, {:#?}",
ty.kind(),
item_kind
)
};
let in_definition_scope = match *origin {
// Async `impl Trait`
hir::OpaqueTyOrigin::AsyncFn(parent) => parent == parent_def_id,
// Anonymous `impl Trait`
hir::OpaqueTyOrigin::FnReturn(parent) => parent == parent_def_id,
// Named `type Foo = impl Bar;`
hir::OpaqueTyOrigin::TyAlias => {
may_define_opaque_type(tcx, parent_def_id, opaque_hir_id)
}
};
if in_definition_scope {
if let Some(origin) = self.infcx.opaque_type_origin(def_id) {
let opaque_type_key =
OpaqueTypeKey { def_id: def_id.to_def_id(), substs };
return self.fold_opaque_ty(ty, opaque_type_key, *origin);
return self.fold_opaque_ty(ty, opaque_type_key, origin);
}

debug!(
Expand Down