diff --git a/compiler/rustc_infer/src/infer/canonical/query_response.rs b/compiler/rustc_infer/src/infer/canonical/query_response.rs
index 8938ed78a94d7..7120d5ad93455 100644
--- a/compiler/rustc_infer/src/infer/canonical/query_response.rs
+++ b/compiler/rustc_infer/src/infer/canonical/query_response.rs
@@ -128,7 +128,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
let region_constraints = self.with_region_constraints(|region_constraints| {
make_query_region_constraints(
tcx,
- region_obligations.iter().map(|(_, r_o)| (r_o.sup_type, r_o.sub_region)),
+ region_obligations.iter().map(|r_o| (r_o.sup_type, r_o.sub_region)),
region_constraints,
)
});
diff --git a/compiler/rustc_infer/src/infer/free_regions.rs b/compiler/rustc_infer/src/infer/free_regions.rs
index 082eb1bf11101..fad949a3bc6a1 100644
--- a/compiler/rustc_infer/src/infer/free_regions.rs
+++ b/compiler/rustc_infer/src/infer/free_regions.rs
@@ -4,7 +4,6 @@
//! and use that to decide when one free region outlives another, and so forth.
use rustc_data_structures::transitive_relation::TransitiveRelation;
-use rustc_hir::def_id::DefId;
use rustc_middle::ty::{self, Lift, Region, TyCtxt};
/// Combines a `FreeRegionMap` and a `TyCtxt`.
@@ -14,16 +13,13 @@ use rustc_middle::ty::{self, Lift, Region, TyCtxt};
pub(crate) struct RegionRelations<'a, 'tcx> {
pub tcx: TyCtxt<'tcx>,
- /// The context used for debug messages
- pub context: DefId,
-
/// Free-region relationships.
pub free_regions: &'a FreeRegionMap<'tcx>,
}
impl<'a, 'tcx> RegionRelations<'a, 'tcx> {
- pub fn new(tcx: TyCtxt<'tcx>, context: DefId, free_regions: &'a FreeRegionMap<'tcx>) -> Self {
- Self { tcx, context, free_regions }
+ pub fn new(tcx: TyCtxt<'tcx>, free_regions: &'a FreeRegionMap<'tcx>) -> Self {
+ Self { tcx, free_regions }
}
pub fn lub_free_regions(&self, r_a: Region<'tcx>, r_b: Region<'tcx>) -> Region<'tcx> {
diff --git a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
index 68c709a2e24d3..87fa22b3835ef 100644
--- a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
+++ b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
@@ -120,13 +120,9 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
) -> LexicalRegionResolutions<'tcx> {
let mut var_data = self.construct_var_data(self.tcx());
- // Dorky hack to cause `dump_constraints` to only get called
- // if debug mode is enabled:
- debug!(
- "----() End constraint listing (context={:?}) {:?}---",
- self.region_rels.context,
- self.dump_constraints(self.region_rels)
- );
+ if cfg!(debug_assertions) {
+ self.dump_constraints();
+ }
let graph = self.construct_graph();
self.expand_givens(&graph);
@@ -156,8 +152,8 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
}
}
- fn dump_constraints(&self, free_regions: &RegionRelations<'_, 'tcx>) {
- debug!("----() Start constraint listing (context={:?}) ()----", free_regions.context);
+ #[instrument(level = "debug", skip(self))]
+ fn dump_constraints(&self) {
for (idx, (constraint, _)) in self.data.constraints.iter().enumerate() {
debug!("Constraint {} => {:?}", idx, constraint);
}
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index 6f88b83a47321..c73302c7e415a 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -15,7 +15,6 @@ use rustc_data_structures::sync::Lrc;
use rustc_data_structures::undo_log::Rollback;
use rustc_data_structures::unify as ut;
use rustc_errors::{DiagnosticBuilder, ErrorGuaranteed};
-use rustc_hir as hir;
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_middle::infer::canonical::{Canonical, CanonicalVarValues};
use rustc_middle::infer::unify_key::{ConstVarValue, ConstVariableValue};
@@ -147,7 +146,7 @@ pub struct InferCtxtInner<'tcx> {
/// for each body-id in this map, which will process the
/// obligations within. This is expected to be done 'late enough'
/// that all type inference variables have been bound and so forth.
- region_obligations: Vec<(hir::HirId, RegionObligation<'tcx>)>,
+ region_obligations: Vec<RegionObligation<'tcx>>,
undo_log: InferCtxtUndoLogs<'tcx>,
@@ -171,7 +170,7 @@ impl<'tcx> InferCtxtInner<'tcx> {
}
#[inline]
- pub fn region_obligations(&self) -> &[(hir::HirId, RegionObligation<'tcx>)] {
+ pub fn region_obligations(&self) -> &[RegionObligation<'tcx>] {
&self.region_obligations
}
@@ -1267,7 +1266,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
/// `resolve_vars_if_possible` as well as `fully_resolve`.
pub fn resolve_regions(
&self,
- region_context: DefId,
outlives_env: &OutlivesEnvironment<'tcx>,
) -> Vec<RegionResolutionError<'tcx>> {
let (var_infos, data) = {
@@ -1286,8 +1284,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
.into_infos_and_data()
};
- let region_rels =
- &RegionRelations::new(self.tcx, region_context, outlives_env.free_region_map());
+ let region_rels = &RegionRelations::new(self.tcx, outlives_env.free_region_map());
let (lexical_region_resolutions, errors) =
lexical_region_resolve::resolve(outlives_env.param_env, region_rels, var_infos, data);
@@ -1302,12 +1299,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
/// result. After this, no more unification operations should be
/// done -- or the compiler will panic -- but it is legal to use
/// `resolve_vars_if_possible` as well as `fully_resolve`.
- pub fn resolve_regions_and_report_errors(
- &self,
- region_context: DefId,
- outlives_env: &OutlivesEnvironment<'tcx>,
- ) {
- let errors = self.resolve_regions(region_context, outlives_env);
+ pub fn resolve_regions_and_report_errors(&self, outlives_env: &OutlivesEnvironment<'tcx>) {
+ let errors = self.resolve_regions(outlives_env);
if !self.is_tainted_by_errors() {
// As a heuristic, just skip reporting region errors
diff --git a/compiler/rustc_infer/src/infer/outlives/env.rs b/compiler/rustc_infer/src/infer/outlives/env.rs
index 9ddda7b92eb5a..b897de7315a02 100644
--- a/compiler/rustc_infer/src/infer/outlives/env.rs
+++ b/compiler/rustc_infer/src/infer/outlives/env.rs
@@ -1,8 +1,6 @@
use crate::infer::free_regions::FreeRegionMap;
use crate::infer::{GenericKind, InferCtxt};
use crate::traits::query::OutlivesBound;
-use rustc_data_structures::fx::FxHashMap;
-use rustc_hir as hir;
use rustc_middle::ty::{self, ReEarlyBound, ReFree, ReVar, Region};
use super::explicit_outlives_bounds;
@@ -31,9 +29,7 @@ pub struct OutlivesEnvironment<'tcx> {
pub param_env: ty::ParamEnv<'tcx>,
free_region_map: FreeRegionMap<'tcx>,
- // Contains, for each body B that we are checking (that is, the fn
- // item, but also any nested closures), the set of implied region
- // bounds that are in scope in that particular body.
+ // Contains the implied region bounds in scope for our current body.
//
// Example:
//
@@ -43,24 +39,15 @@ pub struct OutlivesEnvironment<'tcx> {
// } // body B0
// ```
//
- // Here, for body B0, the list would be `[T: 'a]`, because we
+ // Here, when checking the body B0, the list would be `[T: 'a]`, because we
// infer that `T` must outlive `'a` from the implied bounds on the
// fn declaration.
//
- // For the body B1, the list would be `[T: 'a, T: 'b]`, because we
+ // For the body B1 however, the list would be `[T: 'a, T: 'b]`, because we
// also can see that -- within the closure body! -- `T` must
// outlive `'b`. This is not necessarily true outside the closure
// body, since the closure may never be called.
- //
- // We collect this map as we descend the tree. We then use the
- // results when proving outlives obligations like `T: 'x` later
- // (e.g., if `T: 'x` must be proven within the body B1, then we
- // know it is true if either `'a: 'x` or `'b: 'x`).
- region_bound_pairs_map: FxHashMap<hir::HirId, RegionBoundPairs<'tcx>>,
-
- // Used to compute `region_bound_pairs_map`: contains the set of
- // in-scope region-bound pairs thus far.
- region_bound_pairs_accum: RegionBoundPairs<'tcx>,
+ region_bound_pairs: RegionBoundPairs<'tcx>,
}
/// "Region-bound pairs" tracks outlives relations that are known to
@@ -73,8 +60,7 @@ impl<'a, 'tcx> OutlivesEnvironment<'tcx> {
let mut env = OutlivesEnvironment {
param_env,
free_region_map: Default::default(),
- region_bound_pairs_map: Default::default(),
- region_bound_pairs_accum: vec![],
+ region_bound_pairs: Default::default(),
};
env.add_outlives_bounds(None, explicit_outlives_bounds(param_env));
@@ -87,62 +73,9 @@ impl<'a, 'tcx> OutlivesEnvironment<'tcx> {
&self.free_region_map
}
- /// Borrows current value of the `region_bound_pairs`.
- pub fn region_bound_pairs_map(&self) -> &FxHashMap<hir::HirId, RegionBoundPairs<'tcx>> {
- &self.region_bound_pairs_map
- }
-
- /// This is a hack to support the old-school regionck, which
- /// processes region constraints from the main function and the
- /// closure together. In that context, when we enter a closure, we
- /// want to be able to "save" the state of the surrounding a
- /// function. We can then add implied bounds and the like from the
- /// closure arguments into the environment -- these should only
- /// apply in the closure body, so once we exit, we invoke
- /// `pop_snapshot_post_typeck_child` to remove them.
- ///
- /// Example:
- ///
- /// ```ignore (pseudo-rust)
- /// fn foo<T>() {
- /// callback(for<'a> |x: &'a T| {
- /// // ^^^^^^^ not legal syntax, but probably should be
- /// // within this closure body, `T: 'a` holds
- /// })
- /// }
- /// ```
- ///
- /// This "containment" of closure's effects only works so well. In
- /// particular, we (intentionally) leak relationships between free
- /// regions that are created by the closure's bounds. The case
- /// where this is useful is when you have (e.g.) a closure with a
- /// signature like `for<'a, 'b> fn(x: &'a &'b u32)` -- in this
- /// case, we want to keep the relationship `'b: 'a` in the
- /// free-region-map, so that later if we have to take `LUB('b,
- /// 'a)` we can get the result `'b`.
- ///
- /// I have opted to keep **all modifications** to the
- /// free-region-map, however, and not just those that concern free
- /// variables bound in the closure. The latter seems more correct,
- /// but it is not the existing behavior, and I could not find a
- /// case where the existing behavior went wrong. In any case, it
- /// seems like it'd be readily fixed if we wanted. There are
- /// similar leaks around givens that seem equally suspicious, to
- /// be honest. --nmatsakis
- pub fn push_snapshot_pre_typeck_child(&self) -> usize {
- self.region_bound_pairs_accum.len()
- }
-
- /// See `push_snapshot_pre_typeck_child`.
- pub fn pop_snapshot_post_typeck_child(&mut self, len: usize) {
- self.region_bound_pairs_accum.truncate(len);
- }
-
- /// Save the current set of region-bound pairs under the given `body_id`.
- pub fn save_implied_bounds(&mut self, body_id: hir::HirId) {
- let old =
- self.region_bound_pairs_map.insert(body_id, self.region_bound_pairs_accum.clone());
- assert!(old.is_none());
+ /// Borrows current `region_bound_pairs`.
+ pub fn region_bound_pairs(&self) -> &RegionBoundPairs<'tcx> {
+ &self.region_bound_pairs
}
/// Processes outlives bounds that are known to hold, whether from implied or other sources.
@@ -164,11 +97,10 @@ impl<'a, 'tcx> OutlivesEnvironment<'tcx> {
debug!("add_outlives_bounds: outlives_bound={:?}", outlives_bound);
match outlives_bound {
OutlivesBound::RegionSubParam(r_a, param_b) => {
- self.region_bound_pairs_accum.push((r_a, GenericKind::Param(param_b)));
+ self.region_bound_pairs.push((r_a, GenericKind::Param(param_b)));
}
OutlivesBound::RegionSubProjection(r_a, projection_b) => {
- self.region_bound_pairs_accum
- .push((r_a, GenericKind::Projection(projection_b)));
+ self.region_bound_pairs.push((r_a, GenericKind::Projection(projection_b)));
}
OutlivesBound::RegionSubRegion(r_a, r_b) => {
if let (ReEarlyBound(_) | ReFree(_), ReVar(vid_b)) = (r_a.kind(), r_b.kind()) {
diff --git a/compiler/rustc_infer/src/infer/outlives/obligations.rs b/compiler/rustc_infer/src/infer/outlives/obligations.rs
index 1c1906f3375af..b839566bec99f 100644
--- a/compiler/rustc_infer/src/infer/outlives/obligations.rs
+++ b/compiler/rustc_infer/src/infer/outlives/obligations.rs
@@ -60,18 +60,16 @@
//! imply that `'b: 'a`.
use crate::infer::outlives::components::{push_outlives_components, Component};
+use crate::infer::outlives::env::OutlivesEnvironment;
use crate::infer::outlives::env::RegionBoundPairs;
use crate::infer::outlives::verify::VerifyBoundCx;
use crate::infer::{
self, GenericKind, InferCtxt, RegionObligation, SubregionOrigin, UndoLog, VerifyBound,
};
use crate::traits::{ObligationCause, ObligationCauseCode};
+use rustc_data_structures::undo_log::UndoLogs;
use rustc_middle::ty::subst::GenericArgKind;
use rustc_middle::ty::{self, Region, Ty, TyCtxt, TypeFoldable};
-
-use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::undo_log::UndoLogs;
-use rustc_hir as hir;
use smallvec::smallvec;
impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
@@ -80,16 +78,11 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
/// and later processed by regionck, when full type information is
/// available (see `region_obligations` field for more
/// information).
- pub fn register_region_obligation(
- &self,
- body_id: hir::HirId,
- obligation: RegionObligation<'tcx>,
- ) {
- debug!("register_region_obligation(body_id={:?}, obligation={:?})", body_id, obligation);
-
+ #[instrument(level = "debug", skip(self))]
+ pub fn register_region_obligation(&self, obligation: RegionObligation<'tcx>) {
let mut inner = self.inner.borrow_mut();
inner.undo_log.push(UndoLog::PushRegionObligation);
- inner.region_obligations.push((body_id, obligation));
+ inner.region_obligations.push(obligation);
}
pub fn register_region_obligation_with_cause(
@@ -109,14 +102,11 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
)
});
- self.register_region_obligation(
- cause.body_id,
- RegionObligation { sup_type, sub_region, origin },
- );
+ self.register_region_obligation(RegionObligation { sup_type, sub_region, origin });
}
/// Trait queries just want to pass back type obligations "as is"
- pub fn take_registered_region_obligations(&self) -> Vec<(hir::HirId, RegionObligation<'tcx>)> {
+ pub fn take_registered_region_obligations(&self) -> Vec<RegionObligation<'tcx>> {
std::mem::take(&mut self.inner.borrow_mut().region_obligations)
}
@@ -144,10 +134,10 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
/// - `param_env` is the parameter environment for the enclosing function.
/// - `body_id` is the body-id whose region obligations are being
/// processed.
- #[instrument(level = "debug", skip(self, region_bound_pairs_map))]
+ #[instrument(level = "debug", skip(self, region_bound_pairs))]
pub fn process_registered_region_obligations(
&self,
- region_bound_pairs_map: &FxHashMap<hir::HirId, RegionBoundPairs<'tcx>>,
+ region_bound_pairs: &RegionBoundPairs<'tcx>,
param_env: ty::ParamEnv<'tcx>,
) {
assert!(
@@ -157,7 +147,7 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
let my_region_obligations = self.take_registered_region_obligations();
- for (body_id, RegionObligation { sup_type, sub_region, origin }) in my_region_obligations {
+ for RegionObligation { sup_type, sub_region, origin } in my_region_obligations {
debug!(
"process_registered_region_obligations: sup_type={:?} sub_region={:?} origin={:?}",
sup_type, sub_region, origin
@@ -165,18 +155,23 @@ impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
let sup_type = self.resolve_vars_if_possible(sup_type);
- if let Some(region_bound_pairs) = region_bound_pairs_map.get(&body_id) {
- let outlives =
- &mut TypeOutlives::new(self, self.tcx, ®ion_bound_pairs, None, param_env);
- outlives.type_must_outlive(origin, sup_type, sub_region);
- } else {
- self.tcx.sess.delay_span_bug(
- origin.span(),
- &format!("no region-bound-pairs for {:?}", body_id),
- );
- }
+ let outlives =
+ &mut TypeOutlives::new(self, self.tcx, ®ion_bound_pairs, None, param_env);
+ outlives.type_must_outlive(origin, sup_type, sub_region);
}
}
+
+ pub fn check_region_obligations_and_report_errors(
+ &self,
+ outlives_env: &OutlivesEnvironment<'tcx>,
+ ) {
+ self.process_registered_region_obligations(
+ outlives_env.region_bound_pairs(),
+ outlives_env.param_env,
+ );
+
+ self.resolve_regions_and_report_errors(outlives_env)
+ }
}
/// The `TypeOutlives` struct has the job of "lowering" a `T: 'a`
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
index 90ff07cba026a..49434ec142828 100644
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -212,15 +212,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
panic!("Unable to fulfill trait {:?} for '{:?}': {:?}", trait_did, ty, errors);
}
- let body_id_map: FxHashMap<_, _> = infcx
- .inner
- .borrow()
- .region_obligations()
- .iter()
- .map(|&(id, _)| (id, vec![]))
- .collect();
-
- infcx.process_registered_region_obligations(&body_id_map, full_env);
+ infcx.process_registered_region_obligations(&Default::default(), full_env);
let region_data = infcx
.inner
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index 2b26b916d3289..ae69f2f7eb324 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -16,7 +16,6 @@ use crate::traits::{
//use rustc_data_structures::fx::FxHashMap;
use rustc_errors::Diagnostic;
use rustc_hir::def_id::{DefId, LOCAL_CRATE};
-use rustc_hir::CRATE_HIR_ID;
use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
use rustc_infer::traits::{util, TraitEngine};
use rustc_middle::traits::specialization_graph::OverlapMode;
@@ -317,14 +316,13 @@ fn negative_impl<'cx, 'tcx>(
let (subject2, obligations) =
impl_subject_and_oblig(selcx, impl_env, impl2_def_id, impl2_substs);
- !equate(&infcx, impl_env, impl1_def_id, subject1, subject2, obligations)
+ !equate(&infcx, impl_env, subject1, subject2, obligations)
})
}
fn equate<'cx, 'tcx>(
infcx: &InferCtxt<'cx, 'tcx>,
impl_env: ty::ParamEnv<'tcx>,
- impl1_def_id: DefId,
subject1: ImplSubject<'tcx>,
subject2: ImplSubject<'tcx>,
obligations: impl Iterator<Item = PredicateObligation<'tcx>>,
@@ -341,7 +339,7 @@ fn equate<'cx, 'tcx>(
let opt_failing_obligation = obligations
.into_iter()
.chain(more_obligations)
- .find(|o| negative_impl_exists(selcx, impl_env, impl1_def_id, o));
+ .find(|o| negative_impl_exists(selcx, impl_env, o));
if let Some(failing_obligation) = opt_failing_obligation {
debug!("overlap: obligation unsatisfiable {:?}", failing_obligation);
@@ -356,18 +354,17 @@ fn equate<'cx, 'tcx>(
fn negative_impl_exists<'cx, 'tcx>(
selcx: &SelectionContext<'cx, 'tcx>,
param_env: ty::ParamEnv<'tcx>,
- region_context: DefId,
o: &PredicateObligation<'tcx>,
) -> bool {
let infcx = &selcx.infcx().fork();
- if resolve_negative_obligation(infcx, param_env, region_context, o) {
+ if resolve_negative_obligation(infcx, param_env, o) {
return true;
}
// Try to prove a negative obligation exists for super predicates
for o in util::elaborate_predicates(infcx.tcx, iter::once(o.predicate)) {
- if resolve_negative_obligation(infcx, param_env, region_context, &o) {
+ if resolve_negative_obligation(infcx, param_env, &o) {
return true;
}
}
@@ -379,7 +376,6 @@ fn negative_impl_exists<'cx, 'tcx>(
fn resolve_negative_obligation<'cx, 'tcx>(
infcx: &InferCtxt<'cx, 'tcx>,
param_env: ty::ParamEnv<'tcx>,
- region_context: DefId,
o: &PredicateObligation<'tcx>,
) -> bool {
let tcx = infcx.tcx;
@@ -397,19 +393,11 @@ fn resolve_negative_obligation<'cx, 'tcx>(
return false;
}
- let mut outlives_env = OutlivesEnvironment::new(param_env);
- // FIXME -- add "assumed to be well formed" types into the `outlives_env`
-
- // "Save" the accumulated implied bounds into the outlives environment
- // (due to the FIXME above, there aren't any, but this step is still needed).
- // The "body id" is given as `CRATE_HIR_ID`, which is the same body-id used
- // by the "dummy" causes elsewhere (body-id is only relevant when checking
- // function bodies with closures).
- outlives_env.save_implied_bounds(CRATE_HIR_ID);
-
- infcx.process_registered_region_obligations(outlives_env.region_bound_pairs_map(), param_env);
+ // FIXME -- also add "assumed to be well formed" types into the `outlives_env`
+ let outlives_env = OutlivesEnvironment::new(param_env);
+ infcx.process_registered_region_obligations(outlives_env.region_bound_pairs(), param_env);
- let errors = infcx.resolve_regions(region_context, &outlives_env);
+ let errors = infcx.resolve_regions(&outlives_env);
if !errors.is_empty() {
return false;
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index 34b0f431b8e2d..b45f72e8748d6 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -198,17 +198,13 @@ pub fn type_known_to_meet_bound_modulo_regions<'a, 'tcx>(
}
}
+#[instrument(level = "debug", skip(tcx, elaborated_env))]
fn do_normalize_predicates<'tcx>(
tcx: TyCtxt<'tcx>,
- region_context: DefId,
cause: ObligationCause<'tcx>,
elaborated_env: ty::ParamEnv<'tcx>,
predicates: Vec<ty::Predicate<'tcx>>,
) -> Result<Vec<ty::Predicate<'tcx>>, ErrorGuaranteed> {
- debug!(
- "do_normalize_predicates(predicates={:?}, region_context={:?}, cause={:?})",
- predicates, region_context, cause,
- );
let span = cause.span;
tcx.infer_ctxt().enter(|infcx| {
// FIXME. We should really... do something with these region
@@ -240,7 +236,7 @@ fn do_normalize_predicates<'tcx>(
// cares about declarations like `'a: 'b`.
let outlives_env = OutlivesEnvironment::new(elaborated_env);
- infcx.resolve_regions_and_report_errors(region_context, &outlives_env);
+ infcx.resolve_regions_and_report_errors(&outlives_env);
let predicates = match infcx.fully_resolve(predicates) {
Ok(predicates) => predicates,
@@ -269,9 +265,9 @@ fn do_normalize_predicates<'tcx>(
// FIXME: this is gonna need to be removed ...
/// Normalizes the parameter environment, reporting errors if they occur.
+#[instrument(level = "debug", skip(tcx))]
pub fn normalize_param_env_or_error<'tcx>(
tcx: TyCtxt<'tcx>,
- region_context: DefId,
unnormalized_env: ty::ParamEnv<'tcx>,
cause: ObligationCause<'tcx>,
) -> ty::ParamEnv<'tcx> {
@@ -289,12 +285,6 @@ pub fn normalize_param_env_or_error<'tcx>(
// parameter environments once for every fn as it goes,
// and errors will get reported then; so outside of type inference we
// can be sure that no errors should occur.
-
- debug!(
- "normalize_param_env_or_error(region_context={:?}, unnormalized_env={:?}, cause={:?})",
- region_context, unnormalized_env, cause
- );
-
let mut predicates: Vec<_> =
util::elaborate_predicates(tcx, unnormalized_env.caller_bounds().into_iter())
.map(|obligation| obligation.predicate)
@@ -338,7 +328,6 @@ pub fn normalize_param_env_or_error<'tcx>(
);
let Ok(non_outlives_predicates) = do_normalize_predicates(
tcx,
- region_context,
cause.clone(),
elaborated_env,
predicates,
@@ -362,7 +351,6 @@ pub fn normalize_param_env_or_error<'tcx>(
);
let Ok(outlives_predicates) = do_normalize_predicates(
tcx,
- region_context,
cause,
outlives_env,
outlives_predicates,
diff --git a/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs b/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs
index 25cc6e9f9f2f1..aad3c37f84e5a 100644
--- a/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs
@@ -1,73 +1,7 @@
-use crate::infer::at::At;
-use crate::infer::canonical::OriginalQueryValues;
-use crate::infer::InferOk;
-
-use rustc_middle::ty::subst::GenericArg;
use rustc_middle::ty::{self, Ty, TyCtxt};
pub use rustc_middle::traits::query::{DropckConstraint, DropckOutlivesResult};
-pub trait AtExt<'tcx> {
- fn dropck_outlives(&self, ty: Ty<'tcx>) -> InferOk<'tcx, Vec<GenericArg<'tcx>>>;
-}
-
-impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> {
- /// Given a type `ty` of some value being dropped, computes a set
- /// of "kinds" (types, regions) that must be outlive the execution
- /// of the destructor. These basically correspond to data that the
- /// destructor might access. This is used during regionck to
- /// impose "outlives" constraints on any lifetimes referenced
- /// within.
- ///
- /// The rules here are given by the "dropck" RFCs, notably [#1238]
- /// and [#1327]. This is a fixed-point computation, where we
- /// explore all the data that will be dropped (transitively) when
- /// a value of type `ty` is dropped. For each type T that will be
- /// dropped and which has a destructor, we must assume that all
- /// the types/regions of T are live during the destructor, unless
- /// they are marked with a special attribute (`#[may_dangle]`).
- ///
- /// [#1238]: https://github.com/rust-lang/rfcs/blob/master/text/1238-nonparametric-dropck.md
- /// [#1327]: https://github.com/rust-lang/rfcs/blob/master/text/1327-dropck-param-eyepatch.md
- fn dropck_outlives(&self, ty: Ty<'tcx>) -> InferOk<'tcx, Vec<GenericArg<'tcx>>> {
- debug!("dropck_outlives(ty={:?}, param_env={:?})", ty, self.param_env,);
-
- // Quick check: there are a number of cases that we know do not require
- // any destructor.
- let tcx = self.infcx.tcx;
- if trivial_dropck_outlives(tcx, ty) {
- return InferOk { value: vec![], obligations: vec![] };
- }
-
- let mut orig_values = OriginalQueryValues::default();
- let c_ty = self.infcx.canonicalize_query(self.param_env.and(ty), &mut orig_values);
- let span = self.cause.span;
- debug!("c_ty = {:?}", c_ty);
- if let Ok(result) = tcx.dropck_outlives(c_ty)
- && result.is_proven()
- && let Ok(InferOk { value, obligations }) =
- self.infcx.instantiate_query_response_and_region_obligations(
- self.cause,
- self.param_env,
- &orig_values,
- result,
- )
- {
- let ty = self.infcx.resolve_vars_if_possible(ty);
- let kinds = value.into_kinds_reporting_overflows(tcx, span, ty);
- return InferOk { value: kinds, obligations };
- }
-
- // Errors and ambiguity in dropck occur in two cases:
- // - unresolved inference variables at the end of typeck
- // - non well-formed types where projections cannot be resolved
- // Either of these should have created an error before.
- tcx.sess.delay_span_bug(span, "dtorck encountered internal error");
-
- InferOk { value: vec![], obligations: vec![] }
- }
-}
-
/// This returns true if the type `ty` is "trivial" for
/// dropck-outlives -- that is, if it doesn't require any types to
/// outlive. This is similar but not *quite* the same as the
@@ -79,6 +13,8 @@ impl<'cx, 'tcx> AtExt<'tcx> for At<'cx, 'tcx> {
///
/// Note also that `needs_drop` requires a "global" type (i.e., one
/// with erased regions), but this function does not.
+///
+// FIXME(@lcnr): remove this module and move this function somewhere else.
pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
match ty.kind() {
// None of these types have a destructor and hence they do not
@@ -105,7 +41,7 @@ pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
ty::Array(ty, _) | ty::Slice(ty) => trivial_dropck_outlives(tcx, *ty),
// (T1..Tn) and closures have same properties as T1..Tn --
- // check if *any* of those are trivial.
+ // check if *all* of them are trivial.
ty::Tuple(tys) => tys.iter().all(|t| trivial_dropck_outlives(tcx, t)),
ty::Closure(_, ref substs) => {
trivial_dropck_outlives(tcx, substs.as_closure().tupled_upvars_ty())
diff --git a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
index 605c9ace5ed06..c9d46b2810ddb 100644
--- a/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/type_op/custom.rs
@@ -95,7 +95,7 @@ pub fn scrape_region_constraints<'tcx, Op: super::TypeOp<'tcx, Output = R>, R>(
infcx.tcx,
region_obligations
.iter()
- .map(|(_, r_o)| (r_o.sup_type, r_o.sub_region))
+ .map(|r_o| (r_o.sup_type, r_o.sub_region))
.map(|(ty, r)| (infcx.resolve_vars_if_possible(ty), r)),
®ion_constraint_data,
);
diff --git a/compiler/rustc_ty_utils/src/ty.rs b/compiler/rustc_ty_utils/src/ty.rs
index 38ae6a25b1806..1d345caf69971 100644
--- a/compiler/rustc_ty_utils/src/ty.rs
+++ b/compiler/rustc_ty_utils/src/ty.rs
@@ -211,7 +211,7 @@ fn param_env(tcx: TyCtxt<'_>, def_id: DefId) -> ty::ParamEnv<'_> {
tcx.hir().maybe_body_owned_by(id).map_or(id, |body| body.hir_id)
});
let cause = traits::ObligationCause::misc(tcx.def_span(def_id), body_id);
- traits::normalize_param_env_or_error(tcx, def_id, unnormalized_env, cause)
+ traits::normalize_param_env_or_error(tcx, unnormalized_env, cause)
}
/// Elaborate the environment.
diff --git a/compiler/rustc_typeck/src/check/check.rs b/compiler/rustc_typeck/src/check/check.rs
index 6222dbb40741c..ef74214781e5d 100644
--- a/compiler/rustc_typeck/src/check/check.rs
+++ b/compiler/rustc_typeck/src/check/check.rs
@@ -13,6 +13,7 @@ use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit::Visitor;
use rustc_hir::lang_items::LangItem;
use rustc_hir::{ItemKind, Node, PathSegment};
+use rustc_infer::infer::outlives::env::OutlivesEnvironment;
use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
use rustc_infer::traits::Obligation;
@@ -736,10 +737,8 @@ fn check_opaque_meets_bounds<'tcx>(
hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..) => {}
// Can have different predicates to their defining use
hir::OpaqueTyOrigin::TyAlias => {
- // Finally, resolve all regions. This catches wily misuses of
- // lifetime parameters.
- let fcx = FnCtxt::new(&inh, param_env, hir_id);
- fcx.regionck_item(hir_id, span, FxHashSet::default());
+ let outlives_environment = OutlivesEnvironment::new(param_env);
+ infcx.check_region_obligations_and_report_errors(&outlives_environment);
}
}
diff --git a/compiler/rustc_typeck/src/check/compare_method.rs b/compiler/rustc_typeck/src/check/compare_method.rs
index 95c82a7d2c3d8..0a9b6863ef577 100644
--- a/compiler/rustc_typeck/src/check/compare_method.rs
+++ b/compiler/rustc_typeck/src/check/compare_method.rs
@@ -1,3 +1,4 @@
+use crate::check::regionck::OutlivesEnvironmentExt;
use crate::errors::LifetimesOrBoundsMismatchOnTrait;
use rustc_data_structures::stable_set::FxHashSet;
use rustc_errors::{pluralize, struct_span_err, Applicability, DiagnosticId, ErrorGuaranteed};
@@ -5,6 +6,7 @@ use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::intravisit;
use rustc_hir::{GenericParamKind, ImplItemKind, TraitItemKind};
+use rustc_infer::infer::outlives::env::OutlivesEnvironment;
use rustc_infer::infer::{self, InferOk, TyCtxtInferExt};
use rustc_infer::traits::util;
use rustc_middle::ty::error::{ExpectedFound, TypeError};
@@ -78,10 +80,11 @@ fn compare_predicate_entailment<'tcx>(
let trait_to_impl_substs = impl_trait_ref.substs;
// This node-id should be used for the `body_id` field on each
- // `ObligationCause` (and the `FnCtxt`). This is what
- // `regionck_item` expects.
+ // `ObligationCause` (and the `FnCtxt`).
+ //
+ // FIXME(@lcnr): remove that after removing `cause.body_id` from
+ // obligations.
let impl_m_hir_id = tcx.hir().local_def_id_to_hir_id(impl_m.def_id.expect_local());
-
// We sometimes modify the span further down.
let mut cause = ObligationCause::new(
impl_m_span,
@@ -208,8 +211,7 @@ fn compare_predicate_entailment<'tcx>(
Reveal::UserFacing,
hir::Constness::NotConst,
);
- let param_env =
- traits::normalize_param_env_or_error(tcx, impl_m.def_id, param_env, normalize_cause);
+ let param_env = traits::normalize_param_env_or_error(tcx, param_env, normalize_cause);
tcx.infer_ctxt().enter(|infcx| {
let inh = Inherited::new(infcx, impl_m.def_id.expect_local());
@@ -399,8 +401,9 @@ fn compare_predicate_entailment<'tcx>(
// Finally, resolve all regions. This catches wily misuses of
// lifetime parameters.
- let fcx = FnCtxt::new(&inh, param_env, impl_m_hir_id);
- fcx.regionck_item(impl_m_hir_id, impl_m_span, wf_tys);
+ let mut outlives_environment = OutlivesEnvironment::new(param_env);
+ outlives_environment.add_implied_bounds(infcx, wf_tys, impl_m_hir_id);
+ infcx.check_region_obligations_and_report_errors(&outlives_environment);
Ok(())
})
@@ -1155,8 +1158,8 @@ pub(crate) fn compare_const_impl<'tcx>(
return;
}
- let fcx = FnCtxt::new(&inh, param_env, impl_c_hir_id);
- fcx.regionck_item(impl_c_hir_id, impl_c_span, FxHashSet::default());
+ let outlives_environment = OutlivesEnvironment::new(param_env);
+ infcx.resolve_regions_and_report_errors(&outlives_environment);
});
}
@@ -1247,12 +1250,7 @@ fn compare_type_predicate_entailment<'tcx>(
Reveal::UserFacing,
hir::Constness::NotConst,
);
- let param_env = traits::normalize_param_env_or_error(
- tcx,
- impl_ty.def_id,
- param_env,
- normalize_cause.clone(),
- );
+ let param_env = traits::normalize_param_env_or_error(tcx, param_env, normalize_cause.clone());
tcx.infer_ctxt().enter(|infcx| {
let inh = Inherited::new(infcx, impl_ty.def_id.expect_local());
let infcx = &inh.infcx;
@@ -1279,8 +1277,8 @@ fn compare_type_predicate_entailment<'tcx>(
// Finally, resolve all regions. This catches wily misuses of
// lifetime parameters.
- let fcx = FnCtxt::new(&inh, param_env, impl_ty_hir_id);
- fcx.regionck_item(impl_ty_hir_id, impl_ty_span, FxHashSet::default());
+ let outlives_environment = OutlivesEnvironment::new(param_env);
+ infcx.check_region_obligations_and_report_errors(&outlives_environment);
Ok(())
})
@@ -1504,12 +1502,16 @@ pub fn check_type_bounds<'tcx>(
// Finally, resolve all regions. This catches wily misuses of
// lifetime parameters.
+ //
+ // FIXME: Remove that `FnCtxt`.
let fcx = FnCtxt::new(&inh, param_env, impl_ty_hir_id);
let implied_bounds = match impl_ty.container {
ty::TraitContainer(_) => FxHashSet::default(),
ty::ImplContainer(def_id) => fcx.impl_implied_bounds(def_id, impl_ty_span),
};
- fcx.regionck_item(impl_ty_hir_id, impl_ty_span, implied_bounds);
+ let mut outlives_environment = OutlivesEnvironment::new(param_env);
+ outlives_environment.add_implied_bounds(infcx, implied_bounds, impl_ty_hir_id);
+ infcx.check_region_obligations_and_report_errors(&outlives_environment);
Ok(())
})
diff --git a/compiler/rustc_typeck/src/check/dropck.rs b/compiler/rustc_typeck/src/check/dropck.rs
index a4013e10525ee..72095c408075c 100644
--- a/compiler/rustc_typeck/src/check/dropck.rs
+++ b/compiler/rustc_typeck/src/check/dropck.rs
@@ -1,5 +1,6 @@
-use crate::check::regionck::RegionCtxt;
-use crate::hir;
+// FIXME(@lcnr): Move this module out of `rustc_typeck`.
+//
+// We don't do any drop checking during hir typeck.
use crate::hir::def_id::{DefId, LocalDefId};
use rustc_errors::{struct_span_err, ErrorGuaranteed};
use rustc_middle::ty::error::TypeError;
@@ -7,7 +8,6 @@ use rustc_middle::ty::relate::{Relate, RelateResult, TypeRelation};
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::util::IgnoreRegions;
use rustc_middle::ty::{self, Predicate, Ty, TyCtxt};
-use rustc_span::Span;
/// This function confirms that the `Drop` implementation identified by
/// `drop_impl_did` is not any more specialized than the type it is
@@ -229,19 +229,6 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>(
result
}
-/// This function is not only checking that the dropck obligations are met for
-/// the given type, but it's also currently preventing non-regular recursion in
-/// types from causing stack overflows (dropck_no_diverge_on_nonregular_*.rs).
-///
-/// FIXME: Completely rip out dropck and regionck.
-pub(crate) fn check_drop_obligations<'a, 'tcx>(
- _rcx: &mut RegionCtxt<'a, 'tcx>,
- _ty: Ty<'tcx>,
- _span: Span,
- _body_id: hir::HirId,
-) {
-}
-
// This is an implementation of the TypeRelation trait with the
// aim of simply comparing for equality (without side-effects).
// It is not intended to be used anywhere else other than here.
diff --git a/compiler/rustc_typeck/src/check/mod.rs b/compiler/rustc_typeck/src/check/mod.rs
index 0ede9ef775631..dee58791cec18 100644
--- a/compiler/rustc_typeck/src/check/mod.rs
+++ b/compiler/rustc_typeck/src/check/mod.rs
@@ -368,7 +368,7 @@ fn typeck_with_fallback<'tcx>(
let typeck_results = Inherited::build(tcx, def_id).enter(|inh| {
let param_env = tcx.param_env(def_id);
- let (fcx, wf_tys) = if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
+ let fcx = if let Some(hir::FnSig { header, decl, .. }) = fn_sig {
let fn_sig = if crate::collect::get_infer_ret_ty(&decl.output).is_some() {
let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
<dyn AstConv<'_>>::ty_of_fn(&fcx, id, header.unsafety, header.abi, decl, None, None)
@@ -378,13 +378,7 @@ fn typeck_with_fallback<'tcx>(
check_abi(tcx, id, span, fn_sig.abi());
- // When normalizing the function signature, we assume all types are
- // well-formed. So, we don't need to worry about the obligations
- // from normalization. We could just discard these, but to align with
- // compare_method and elsewhere, we just add implied bounds for
- // these types.
- let mut wf_tys = FxHashSet::default();
- // Compute the fty from point of view of inside the fn.
+ // Compute the function signature from point of view of inside the fn.
let fn_sig = tcx.liberate_late_bound_regions(def_id.to_def_id(), fn_sig);
let fn_sig = inh.normalize_associated_types_in(
body.value.span,
@@ -392,10 +386,7 @@ fn typeck_with_fallback<'tcx>(
param_env,
fn_sig,
);
- wf_tys.extend(fn_sig.inputs_and_output.iter());
-
- let fcx = check_fn(&inh, param_env, fn_sig, decl, id, body, None, true).0;
- (fcx, wf_tys)
+ check_fn(&inh, param_env, fn_sig, decl, id, body, None, true).0
} else {
let fcx = FnCtxt::new(&inh, param_env, body.value.hir_id);
let expected_type = body_ty
@@ -458,7 +449,7 @@ fn typeck_with_fallback<'tcx>(
fcx.write_ty(id, expected_type);
- (fcx, FxHashSet::default())
+ fcx
};
let fallback_has_occurred = fcx.type_inference_fallback();
@@ -490,11 +481,7 @@ fn typeck_with_fallback<'tcx>(
fcx.check_asms();
- if fn_sig.is_some() {
- fcx.regionck_fn(id, body, span, wf_tys);
- } else {
- fcx.regionck_expr(body);
- }
+ fcx.infcx.skip_region_resolution();
fcx.resolve_type_vars_in_body(body)
});
diff --git a/compiler/rustc_typeck/src/check/regionck.rs b/compiler/rustc_typeck/src/check/regionck.rs
index 0ce6392209894..1c3c5f999bca8 100644
--- a/compiler/rustc_typeck/src/check/regionck.rs
+++ b/compiler/rustc_typeck/src/check/regionck.rs
@@ -1,106 +1,9 @@
-//! The region check is a final pass that runs over the AST after we have
-//! inferred the type constraints but before we have actually finalized
-//! the types. Its purpose is to embed a variety of region constraints.
-//! Inserting these constraints as a separate pass is good because (1) it
-//! localizes the code that has to do with region inference and (2) often
-//! we cannot know what constraints are needed until the basic types have
-//! been inferred.
-//!
-//! ### Interaction with the borrow checker
-//!
-//! In general, the job of the borrowck module (which runs later) is to
-//! check that all soundness criteria are met, given a particular set of
-//! regions. The job of *this* module is to anticipate the needs of the
-//! borrow checker and infer regions that will satisfy its requirements.
-//! It is generally true that the inference doesn't need to be sound,
-//! meaning that if there is a bug and we inferred bad regions, the borrow
-//! checker should catch it. This is not entirely true though; for
-//! example, the borrow checker doesn't check subtyping, and it doesn't
-//! check that region pointers are always live when they are used. It
-//! might be worthwhile to fix this so that borrowck serves as a kind of
-//! verification step -- that would add confidence in the overall
-//! correctness of the compiler, at the cost of duplicating some type
-//! checks and effort.
-//!
-//! ### Inferring the duration of borrows, automatic and otherwise
-//!
-//! Whenever we introduce a borrowed pointer, for example as the result of
-//! a borrow expression `let x = &data`, the lifetime of the pointer `x`
-//! is always specified as a region inference variable. `regionck` has the
-//! job of adding constraints such that this inference variable is as
-//! narrow as possible while still accommodating all uses (that is, every
-//! dereference of the resulting pointer must be within the lifetime).
-//!
-//! #### Reborrows
-//!
-//! Generally speaking, `regionck` does NOT try to ensure that the data
-//! `data` will outlive the pointer `x`. That is the job of borrowck. The
-//! one exception is when "re-borrowing" the contents of another borrowed
-//! pointer. For example, imagine you have a borrowed pointer `b` with
-//! lifetime `L1` and you have an expression `&*b`. The result of this
-//! expression will be another borrowed pointer with lifetime `L2` (which is
-//! an inference variable). The borrow checker is going to enforce the
-//! constraint that `L2 < L1`, because otherwise you are re-borrowing data
-//! for a lifetime larger than the original loan. However, without the
-//! routines in this module, the region inferencer would not know of this
-//! dependency and thus it might infer the lifetime of `L2` to be greater
-//! than `L1` (issue #3148).
-//!
-//! There are a number of troublesome scenarios in the tests
-//! `region-dependent-*.rs`, but here is one example:
-//!
-//! struct Foo { i: i32 }
-//! struct Bar { foo: Foo }
-//! fn get_i<'a>(x: &'a Bar) -> &'a i32 {
-//! let foo = &x.foo; // Lifetime L1
-//! &foo.i // Lifetime L2
-//! }
-//!
-//! Note that this comes up either with `&` expressions, `ref`
-//! bindings, and `autorefs`, which are the three ways to introduce
-//! a borrow.
-//!
-//! The key point here is that when you are borrowing a value that
-//! is "guaranteed" by a borrowed pointer, you must link the
-//! lifetime of that borrowed pointer (`L1`, here) to the lifetime of
-//! the borrow itself (`L2`). What do I mean by "guaranteed" by a
-//! borrowed pointer? I mean any data that is reached by first
-//! dereferencing a borrowed pointer and then either traversing
-//! interior offsets or boxes. We say that the guarantor
-//! of such data is the region of the borrowed pointer that was
-//! traversed. This is essentially the same as the ownership
-//! relation, except that a borrowed pointer never owns its
-//! contents.
-
-use crate::check::dropck;
-use crate::check::FnCtxt;
-use crate::mem_categorization as mc;
use crate::outlives::outlives_bounds::InferCtxtExt as _;
use rustc_data_structures::stable_set::FxHashSet;
use rustc_hir as hir;
-use rustc_hir::def_id::LocalDefId;
-use rustc_hir::intravisit::{self, Visitor};
-use rustc_hir::PatKind;
use rustc_infer::infer::outlives::env::OutlivesEnvironment;
-use rustc_infer::infer::{self, InferCtxt, RegionObligation};
-use rustc_middle::hir::place::{PlaceBase, PlaceWithHirId};
-use rustc_middle::ty::adjustment;
-use rustc_middle::ty::{self, Ty};
-use rustc_span::Span;
-use std::ops::Deref;
-
-// a variation on try that just returns unit
-macro_rules! ignore_err {
- ($e:expr) => {
- match $e {
- Ok(e) => e,
- Err(_) => {
- debug!("ignoring mem-categorization error!");
- return ();
- }
- }
- };
-}
+use rustc_infer::infer::InferCtxt;
+use rustc_middle::ty::Ty;
pub(crate) trait OutlivesEnvironmentExt<'tcx> {
fn add_implied_bounds(
@@ -108,7 +11,6 @@ pub(crate) trait OutlivesEnvironmentExt<'tcx> {
infcx: &InferCtxt<'_, 'tcx>,
fn_sig_tys: FxHashSet<Ty<'tcx>>,
body_id: hir::HirId,
- span: Span,
);
}
@@ -135,750 +37,11 @@ impl<'tcx> OutlivesEnvironmentExt<'tcx> for OutlivesEnvironment<'tcx> {
infcx: &InferCtxt<'a, 'tcx>,
fn_sig_tys: FxHashSet<Ty<'tcx>>,
body_id: hir::HirId,
- span: Span,
) {
for ty in fn_sig_tys {
let ty = infcx.resolve_vars_if_possible(ty);
- let implied_bounds = infcx.implied_outlives_bounds(self.param_env, body_id, ty, span);
+ let implied_bounds = infcx.implied_outlives_bounds(self.param_env, body_id, ty);
self.add_outlives_bounds(Some(infcx), implied_bounds)
}
}
}
-
-///////////////////////////////////////////////////////////////////////////
-// PUBLIC ENTRY POINTS
-
-impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
- pub fn regionck_expr(&self, body: &'tcx hir::Body<'tcx>) {
- let subject = self.tcx.hir().body_owner_def_id(body.id());
- let id = body.value.hir_id;
- let mut rcx = RegionCtxt::new(self, id, Subject(subject), self.param_env);
-
- // There are no add'l implied bounds when checking a
- // standalone expr (e.g., the `E` in a type like `[u32; E]`).
- rcx.outlives_environment.save_implied_bounds(id);
-
- if !self.errors_reported_since_creation() {
- // regionck assumes typeck succeeded
- rcx.visit_body(body);
- rcx.visit_region_obligations(id);
- }
- // Checked by NLL
- rcx.fcx.skip_region_resolution();
- }
-
- /// Region checking during the WF phase for items. `wf_tys` are the
- /// types from which we should derive implied bounds, if any.
- #[instrument(level = "debug", skip(self))]
- pub fn regionck_item(&self, item_id: hir::HirId, span: Span, wf_tys: FxHashSet<Ty<'tcx>>) {
- let subject = self.tcx.hir().local_def_id(item_id);
- let mut rcx = RegionCtxt::new(self, item_id, Subject(subject), self.param_env);
- rcx.outlives_environment.add_implied_bounds(self, wf_tys, item_id, span);
- rcx.outlives_environment.save_implied_bounds(item_id);
- rcx.visit_region_obligations(item_id);
- rcx.resolve_regions_and_report_errors();
- }
-
- /// Region check a function body. Not invoked on closures, but
- /// only on the "root" fn item (in which closures may be
- /// embedded). Walks the function body and adds various add'l
- /// constraints that are needed for region inference. This is
- /// separated both to isolate "pure" region constraints from the
- /// rest of type check and because sometimes we need type
- /// inference to have completed before we can determine which
- /// constraints to add.
- pub(crate) fn regionck_fn(
- &self,
- fn_id: hir::HirId,
- body: &'tcx hir::Body<'tcx>,
- span: Span,
- wf_tys: FxHashSet<Ty<'tcx>>,
- ) {
- debug!("regionck_fn(id={})", fn_id);
- let subject = self.tcx.hir().body_owner_def_id(body.id());
- let hir_id = body.value.hir_id;
- let mut rcx = RegionCtxt::new(self, hir_id, Subject(subject), self.param_env);
- // We need to add the implied bounds from the function signature
- rcx.outlives_environment.add_implied_bounds(self, wf_tys, fn_id, span);
- rcx.outlives_environment.save_implied_bounds(fn_id);
-
- if !self.errors_reported_since_creation() {
- // regionck assumes typeck succeeded
- rcx.visit_fn_body(fn_id, body, self.tcx.hir().span(fn_id));
- }
-
- // Checked by NLL
- rcx.fcx.skip_region_resolution();
- }
-}
-
-///////////////////////////////////////////////////////////////////////////
-// INTERNALS
-
-pub struct RegionCtxt<'a, 'tcx> {
- pub fcx: &'a FnCtxt<'a, 'tcx>,
-
- outlives_environment: OutlivesEnvironment<'tcx>,
-
- // id of innermost fn body id
- body_id: hir::HirId,
- body_owner: LocalDefId,
-
- // id of AST node being analyzed (the subject of the analysis).
- subject_def_id: LocalDefId,
-}
-
-impl<'a, 'tcx> Deref for RegionCtxt<'a, 'tcx> {
- type Target = FnCtxt<'a, 'tcx>;
- fn deref(&self) -> &Self::Target {
- self.fcx
- }
-}
-
-pub struct Subject(LocalDefId);
-
-impl<'a, 'tcx> RegionCtxt<'a, 'tcx> {
- pub fn new(
- fcx: &'a FnCtxt<'a, 'tcx>,
- initial_body_id: hir::HirId,
- Subject(subject): Subject,
- param_env: ty::ParamEnv<'tcx>,
- ) -> RegionCtxt<'a, 'tcx> {
- let outlives_environment = OutlivesEnvironment::new(param_env);
- RegionCtxt {
- fcx,
- body_id: initial_body_id,
- body_owner: subject,
- subject_def_id: subject,
- outlives_environment,
- }
- }
-
- /// Try to resolve the type for the given node, returning `t_err` if an error results. Note that
- /// we never care about the details of the error, the same error will be detected and reported
- /// in the writeback phase.
- ///
- /// Note one important point: we do not attempt to resolve *region variables* here. This is
- /// because regionck is essentially adding constraints to those region variables and so may yet
- /// influence how they are resolved.
- ///
- /// Consider this silly example:
- ///
- /// ```ignore UNSOLVED (does replacing @i32 with Box<i32> preserve the desired semantics for the example?)
- /// fn borrow(x: &i32) -> &i32 {x}
- /// fn foo(x: @i32) -> i32 { // block: B
- /// let b = borrow(x); // region: <R0>
- /// *b
- /// }
- /// ```
- ///
- /// Here, the region of `b` will be `<R0>`. `<R0>` is constrained to be some subregion of the
- /// block B and some superregion of the call. If we forced it now, we'd choose the smaller
- /// region (the call). But that would make the *b illegal. Since we don't resolve, the type
- /// of b will be `&<R0>.i32` and then `*b` will require that `<R0>` be bigger than the let and
- /// the `*b` expression, so we will effectively resolve `<R0>` to be the block B.
- pub fn resolve_type(&self, unresolved_ty: Ty<'tcx>) -> Ty<'tcx> {
- self.resolve_vars_if_possible(unresolved_ty)
- }
-
- /// Try to resolve the type for the given node.
- fn resolve_node_type(&self, id: hir::HirId) -> Ty<'tcx> {
- let t = self.node_ty(id);
- self.resolve_type(t)
- }
-
- /// This is the "main" function when region-checking a function item or a
- /// closure within a function item. It begins by updating various fields
- /// (e.g., `outlives_environment`) to be appropriate to the function and
- /// then adds constraints derived from the function body.
- ///
- /// Note that it does **not** restore the state of the fields that
- /// it updates! This is intentional, since -- for the main
- /// function -- we wish to be able to read the final
- /// `outlives_environment` and other fields from the caller. For
- /// closures, however, we save and restore any "scoped state"
- /// before we invoke this function. (See `visit_fn` in the
- /// `intravisit::Visitor` impl below.)
- fn visit_fn_body(
- &mut self,
- id: hir::HirId, // the id of the fn itself
- body: &'tcx hir::Body<'tcx>,
- span: Span,
- ) {
- // When we enter a function, we can derive
- debug!("visit_fn_body(id={:?})", id);
-
- let body_id = body.id();
- self.body_id = body_id.hir_id;
- self.body_owner = self.tcx.hir().body_owner_def_id(body_id);
-
- let Some(fn_sig) = self.typeck_results.borrow().liberated_fn_sigs().get(id) else {
- bug!("No fn-sig entry for id={:?}", id);
- };
-
- // Collect the types from which we create inferred bounds.
- // For the return type, if diverging, substitute `bool` just
- // because it will have no effect.
- //
- // FIXME(#27579) return types should not be implied bounds
- let fn_sig_tys: FxHashSet<_> =
- fn_sig.inputs().iter().cloned().chain(Some(fn_sig.output())).collect();
-
- self.outlives_environment.add_implied_bounds(self.fcx, fn_sig_tys, body_id.hir_id, span);
- self.outlives_environment.save_implied_bounds(body_id.hir_id);
- self.link_fn_params(body.params);
- self.visit_body(body);
- self.visit_region_obligations(body_id.hir_id);
- }
-
- fn visit_inline_const(&mut self, id: hir::HirId, body: &'tcx hir::Body<'tcx>) {
- debug!("visit_inline_const(id={:?})", id);
-
- // Save state of current function. We will restore afterwards.
- let old_body_id = self.body_id;
- let old_body_owner = self.body_owner;
- let env_snapshot = self.outlives_environment.push_snapshot_pre_typeck_child();
-
- let body_id = body.id();
- self.body_id = body_id.hir_id;
- self.body_owner = self.tcx.hir().body_owner_def_id(body_id);
-
- self.outlives_environment.save_implied_bounds(body_id.hir_id);
-
- self.visit_body(body);
- self.visit_region_obligations(body_id.hir_id);
-
- // Restore state from previous function.
- self.outlives_environment.pop_snapshot_post_typeck_child(env_snapshot);
- self.body_id = old_body_id;
- self.body_owner = old_body_owner;
- }
-
- fn visit_region_obligations(&mut self, hir_id: hir::HirId) {
- debug!("visit_region_obligations: hir_id={:?}", hir_id);
-
- // region checking can introduce new pending obligations
- // which, when processed, might generate new region
- // obligations. So make sure we process those.
- self.select_all_obligations_or_error();
- }
-
- fn resolve_regions_and_report_errors(&self) {
- self.infcx.process_registered_region_obligations(
- self.outlives_environment.region_bound_pairs_map(),
- self.param_env,
- );
-
- self.fcx.resolve_regions_and_report_errors(
- self.subject_def_id.to_def_id(),
- &self.outlives_environment,
- );
- }
-
- fn constrain_bindings_in_pat(&mut self, pat: &hir::Pat<'_>) {
- debug!("regionck::visit_pat(pat={:?})", pat);
- pat.each_binding(|_, hir_id, span, _| {
- let typ = self.resolve_node_type(hir_id);
- let body_id = self.body_id;
- dropck::check_drop_obligations(self, typ, span, body_id);
- })
- }
-}
-
-impl<'a, 'tcx> Visitor<'tcx> for RegionCtxt<'a, 'tcx> {
- // (..) FIXME(#3238) should use visit_pat, not visit_arm/visit_local,
- // However, right now we run into an issue whereby some free
- // regions are not properly related if they appear within the
- // types of arguments that must be inferred. This could be
- // addressed by deferring the construction of the region
- // hierarchy, and in particular the relationships between free
- // regions, until regionck, as described in #3238.
-
- fn visit_fn(
- &mut self,
- fk: intravisit::FnKind<'tcx>,
- _: &'tcx hir::FnDecl<'tcx>,
- body_id: hir::BodyId,
- span: Span,
- hir_id: hir::HirId,
- ) {
- assert!(
- matches!(fk, intravisit::FnKind::Closure),
- "visit_fn invoked for something other than a closure"
- );
-
- // Save state of current function before invoking
- // `visit_fn_body`. We will restore afterwards.
- let old_body_id = self.body_id;
- let old_body_owner = self.body_owner;
- let env_snapshot = self.outlives_environment.push_snapshot_pre_typeck_child();
-
- let body = self.tcx.hir().body(body_id);
- self.visit_fn_body(hir_id, body, span);
-
- // Restore state from previous function.
- self.outlives_environment.pop_snapshot_post_typeck_child(env_snapshot);
- self.body_id = old_body_id;
- self.body_owner = old_body_owner;
- }
-
- //visit_pat: visit_pat, // (..) see above
-
- fn visit_arm(&mut self, arm: &'tcx hir::Arm<'tcx>) {
- // see above
- self.constrain_bindings_in_pat(arm.pat);
- intravisit::walk_arm(self, arm);
- }
-
- fn visit_local(&mut self, l: &'tcx hir::Local<'tcx>) {
- // see above
- self.constrain_bindings_in_pat(l.pat);
- self.link_local(l);
- intravisit::walk_local(self, l);
- }
-
- fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
- // Check any autoderefs or autorefs that appear.
- let cmt_result = self.constrain_adjustments(expr);
-
- // If necessary, constrain destructors in this expression. This will be
- // the adjusted form if there is an adjustment.
- match cmt_result {
- Ok(head_cmt) => {
- self.check_safety_of_rvalue_destructor_if_necessary(&head_cmt, expr.span);
- }
- Err(..) => {
- self.tcx.sess.delay_span_bug(expr.span, "cat_expr Errd");
- }
- }
-
- match expr.kind {
- hir::ExprKind::AddrOf(hir::BorrowKind::Ref, m, ref base) => {
- self.link_addr_of(expr, m, base);
-
- intravisit::walk_expr(self, expr);
- }
-
- hir::ExprKind::Match(ref discr, arms, _) => {
- self.link_match(discr, arms);
-
- intravisit::walk_expr(self, expr);
- }
-
- hir::ExprKind::ConstBlock(anon_const) => {
- let body = self.tcx.hir().body(anon_const.body);
- self.visit_inline_const(anon_const.hir_id, body);
- }
-
- _ => intravisit::walk_expr(self, expr),
- }
- }
-}
-
-impl<'a, 'tcx> RegionCtxt<'a, 'tcx> {
- /// Creates a temporary `MemCategorizationContext` and pass it to the closure.
- fn with_mc<F, R>(&self, f: F) -> R
- where
- F: for<'b> FnOnce(mc::MemCategorizationContext<'b, 'tcx>) -> R,
- {
- f(mc::MemCategorizationContext::new(
- &self.infcx,
- self.outlives_environment.param_env,
- self.body_owner,
- &self.typeck_results.borrow(),
- ))
- }
-
- /// Invoked on any adjustments that occur. Checks that if this is a region pointer being
- /// dereferenced, the lifetime of the pointer includes the deref expr.
- fn constrain_adjustments(
- &mut self,
- expr: &hir::Expr<'_>,
- ) -> mc::McResult<PlaceWithHirId<'tcx>> {
- debug!("constrain_adjustments(expr={:?})", expr);
-
- let mut place = self.with_mc(|mc| mc.cat_expr_unadjusted(expr))?;
-
- let typeck_results = self.typeck_results.borrow();
- let adjustments = typeck_results.expr_adjustments(expr);
- if adjustments.is_empty() {
- return Ok(place);
- }
-
- debug!("constrain_adjustments: adjustments={:?}", adjustments);
-
- // If necessary, constrain destructors in the unadjusted form of this
- // expression.
- self.check_safety_of_rvalue_destructor_if_necessary(&place, expr.span);
-
- for adjustment in adjustments {
- debug!("constrain_adjustments: adjustment={:?}, place={:?}", adjustment, place);
-
- if let adjustment::Adjust::Deref(Some(deref)) = adjustment.kind {
- self.link_region(
- expr.span,
- deref.region,
- ty::BorrowKind::from_mutbl(deref.mutbl),
- &place,
- );
- }
-
- if let adjustment::Adjust::Borrow(ref autoref) = adjustment.kind {
- self.link_autoref(expr, &place, autoref);
- }
-
- place = self.with_mc(|mc| mc.cat_expr_adjusted(expr, place, adjustment))?;
- }
-
- Ok(place)
- }
-
- fn check_safety_of_rvalue_destructor_if_necessary(
- &mut self,
- place_with_id: &PlaceWithHirId<'tcx>,
- span: Span,
- ) {
- if let PlaceBase::Rvalue = place_with_id.place.base {
- if place_with_id.place.projections.is_empty() {
- let typ = self.resolve_type(place_with_id.place.ty());
- let body_id = self.body_id;
- dropck::check_drop_obligations(self, typ, span, body_id);
- }
- }
- }
- /// Adds constraints to inference such that `T: 'a` holds (or
- /// reports an error if it cannot).
- ///
- /// # Parameters
- ///
- /// - `origin`, the reason we need this constraint
- /// - `ty`, the type `T`
- /// - `region`, the region `'a`
- pub fn type_must_outlive(
- &self,
- origin: infer::SubregionOrigin<'tcx>,
- ty: Ty<'tcx>,
- region: ty::Region<'tcx>,
- ) {
- self.infcx.register_region_obligation(
- self.body_id,
- RegionObligation { sub_region: region, sup_type: ty, origin },
- );
- }
-
- /// Computes the guarantor for an expression `&base` and then ensures that the lifetime of the
- /// resulting pointer is linked to the lifetime of its guarantor (if any).
- fn link_addr_of(
- &mut self,
- expr: &hir::Expr<'_>,
- mutability: hir::Mutability,
- base: &hir::Expr<'_>,
- ) {
- debug!("link_addr_of(expr={:?}, base={:?})", expr, base);
-
- let cmt = ignore_err!(self.with_mc(|mc| mc.cat_expr(base)));
-
- debug!("link_addr_of: cmt={:?}", cmt);
-
- self.link_region_from_node_type(expr.span, expr.hir_id, mutability, &cmt);
- }
-
- /// Computes the guarantors for any ref bindings in a `let` and
- /// then ensures that the lifetime of the resulting pointer is
- /// linked to the lifetime of the initialization expression.
- fn link_local(&self, local: &hir::Local<'_>) {
- debug!("regionck::for_local()");
- let init_expr = match local.init {
- None => {
- return;
- }
- Some(expr) => &*expr,
- };
- let discr_cmt = ignore_err!(self.with_mc(|mc| mc.cat_expr(init_expr)));
- self.link_pattern(discr_cmt, local.pat);
- }
-
- /// Computes the guarantors for any ref bindings in a match and
- /// then ensures that the lifetime of the resulting pointer is
- /// linked to the lifetime of its guarantor (if any).
- fn link_match(&self, discr: &hir::Expr<'_>, arms: &[hir::Arm<'_>]) {
- debug!("regionck::for_match()");
- let discr_cmt = ignore_err!(self.with_mc(|mc| mc.cat_expr(discr)));
- debug!("discr_cmt={:?}", discr_cmt);
- for arm in arms {
- self.link_pattern(discr_cmt.clone(), arm.pat);
- }
- }
-
- /// Computes the guarantors for any ref bindings in a match and
- /// then ensures that the lifetime of the resulting pointer is
- /// linked to the lifetime of its guarantor (if any).
- fn link_fn_params(&self, params: &[hir::Param<'_>]) {
- for param in params {
- let param_ty = self.node_ty(param.hir_id);
- let param_cmt =
- self.with_mc(|mc| mc.cat_rvalue(param.hir_id, param.pat.span, param_ty));
- debug!("param_ty={:?} param_cmt={:?} param={:?}", param_ty, param_cmt, param);
- self.link_pattern(param_cmt, param.pat);
- }
- }
-
- /// Link lifetimes of any ref bindings in `root_pat` to the pointers found
- /// in the discriminant, if needed.
- fn link_pattern(&self, discr_cmt: PlaceWithHirId<'tcx>, root_pat: &hir::Pat<'_>) {
- debug!("link_pattern(discr_cmt={:?}, root_pat={:?})", discr_cmt, root_pat);
- ignore_err!(self.with_mc(|mc| {
- mc.cat_pattern(discr_cmt, root_pat, |sub_cmt, hir::Pat { kind, span, hir_id, .. }| {
- // `ref x` pattern
- if let PatKind::Binding(..) = kind
- && let Some(ty::BindByReference(mutbl)) = mc.typeck_results.extract_binding_mode(self.tcx.sess, *hir_id, *span) {
- self.link_region_from_node_type(*span, *hir_id, mutbl, sub_cmt);
- }
- })
- }));
- }
-
- /// Link lifetime of borrowed pointer resulting from autoref to lifetimes in the value being
- /// autoref'd.
- fn link_autoref(
- &self,
- expr: &hir::Expr<'_>,
- expr_cmt: &PlaceWithHirId<'tcx>,
- autoref: &adjustment::AutoBorrow<'tcx>,
- ) {
- debug!("link_autoref(autoref={:?}, expr_cmt={:?})", autoref, expr_cmt);
-
- match *autoref {
- adjustment::AutoBorrow::Ref(r, m) => {
- self.link_region(expr.span, r, ty::BorrowKind::from_mutbl(m.into()), expr_cmt);
- }
-
- adjustment::AutoBorrow::RawPtr(_) => {}
- }
- }
-
- /// Like `link_region()`, except that the region is extracted from the type of `id`,
- /// which must be some reference (`&T`, `&str`, etc).
- fn link_region_from_node_type(
- &self,
- span: Span,
- id: hir::HirId,
- mutbl: hir::Mutability,
- cmt_borrowed: &PlaceWithHirId<'tcx>,
- ) {
- debug!(
- "link_region_from_node_type(id={:?}, mutbl={:?}, cmt_borrowed={:?})",
- id, mutbl, cmt_borrowed
- );
-
- let rptr_ty = self.resolve_node_type(id);
- if let ty::Ref(r, _, _) = rptr_ty.kind() {
- debug!("rptr_ty={}", rptr_ty);
- self.link_region(span, *r, ty::BorrowKind::from_mutbl(mutbl), cmt_borrowed);
- }
- }
-
- /// Informs the inference engine that `borrow_cmt` is being borrowed with
- /// kind `borrow_kind` and lifetime `borrow_region`.
- /// In order to ensure borrowck is satisfied, this may create constraints
- /// between regions, as explained in `link_reborrowed_region()`.
- fn link_region(
- &self,
- span: Span,
- borrow_region: ty::Region<'tcx>,
- borrow_kind: ty::BorrowKind,
- borrow_place: &PlaceWithHirId<'tcx>,
- ) {
- let origin = infer::DataBorrowed(borrow_place.place.ty(), span);
- self.type_must_outlive(origin, borrow_place.place.ty(), borrow_region);
-
- for pointer_ty in borrow_place.place.deref_tys() {
- debug!(
- "link_region(borrow_region={:?}, borrow_kind={:?}, pointer_ty={:?})",
- borrow_region, borrow_kind, borrow_place
- );
- match *pointer_ty.kind() {
- ty::RawPtr(_) => return,
- ty::Ref(ref_region, _, ref_mutability) => {
- if self.link_reborrowed_region(span, borrow_region, ref_region, ref_mutability)
- {
- return;
- }
- }
- _ => assert!(pointer_ty.is_box(), "unexpected built-in deref type {}", pointer_ty),
- }
- }
- if let PlaceBase::Upvar(upvar_id) = borrow_place.place.base {
- self.link_upvar_region(span, borrow_region, upvar_id);
- }
- }
-
- /// This is the most complicated case: the path being borrowed is
- /// itself the referent of a borrowed pointer. Let me give an
- /// example fragment of code to make clear(er) the situation:
- ///
- /// ```ignore (incomplete Rust code)
- /// let r: &'a mut T = ...; // the original reference "r" has lifetime 'a
- /// ...
- /// &'z *r // the reborrow has lifetime 'z
- /// ```
- ///
- /// Now, in this case, our primary job is to add the inference
- /// constraint that `'z <= 'a`. Given this setup, let's clarify the
- /// parameters in (roughly) terms of the example:
- ///
- /// ```plain,ignore (pseudo-Rust)
- /// A borrow of: `& 'z bk * r` where `r` has type `& 'a bk T`
- /// borrow_region ^~ ref_region ^~
- /// borrow_kind ^~ ref_kind ^~
- /// ref_cmt ^
- /// ```
- ///
- /// Here `bk` stands for some borrow-kind (e.g., `mut`, `uniq`, etc).
- ///
- /// There is a complication beyond the simple scenario I just painted: there
- /// may in fact be more levels of reborrowing. In the example, I said the
- /// borrow was like `&'z *r`, but it might in fact be a borrow like
- /// `&'z **q` where `q` has type `&'a &'b mut T`. In that case, we want to
- /// ensure that `'z <= 'a` and `'z <= 'b`.
- ///
- /// The return value of this function indicates whether we *don't* need to
- /// the recurse to the next reference up.
- ///
- /// This is explained more below.
- fn link_reborrowed_region(
- &self,
- span: Span,
- borrow_region: ty::Region<'tcx>,
- ref_region: ty::Region<'tcx>,
- ref_mutability: hir::Mutability,
- ) -> bool {
- debug!("link_reborrowed_region: {:?} <= {:?}", borrow_region, ref_region);
- self.sub_regions(infer::Reborrow(span), borrow_region, ref_region);
-
- // Decide whether we need to recurse and link any regions within
- // the `ref_cmt`. This is concerned for the case where the value
- // being reborrowed is in fact a borrowed pointer found within
- // another borrowed pointer. For example:
- //
- // let p: &'b &'a mut T = ...;
- // ...
- // &'z **p
- //
- // What makes this case particularly tricky is that, if the data
- // being borrowed is a `&mut` or `&uniq` borrow, borrowck requires
- // not only that `'z <= 'a`, (as before) but also `'z <= 'b`
- // (otherwise the user might mutate through the `&mut T` reference
- // after `'b` expires and invalidate the borrow we are looking at
- // now).
- //
- // So let's re-examine our parameters in light of this more
- // complicated (possible) scenario:
- //
- // A borrow of: `& 'z bk * * p` where `p` has type `&'b bk & 'a bk T`
- // borrow_region ^~ ref_region ^~
- // borrow_kind ^~ ref_kind ^~
- // ref_cmt ^~~
- //
- // (Note that since we have not examined `ref_cmt.cat`, we don't
- // know whether this scenario has occurred; but I wanted to show
- // how all the types get adjusted.)
- match ref_mutability {
- hir::Mutability::Not => {
- // The reference being reborrowed is a shareable ref of
- // type `&'a T`. In this case, it doesn't matter where we
- // *found* the `&T` pointer, the memory it references will
- // be valid and immutable for `'a`. So we can stop here.
- true
- }
-
- hir::Mutability::Mut => {
- // The reference being reborrowed is either an `&mut T`. This is
- // the case where recursion is needed.
- false
- }
- }
- }
-
- /// An upvar may be behind up to 2 references:
- ///
- /// * One can come from the reference to a "by-reference" upvar.
- /// * Another one can come from the reference to the closure itself if it's
- /// a `FnMut` or `Fn` closure.
- ///
- /// This function links the lifetimes of those references to the lifetime
- /// of the borrow that's provided. See [RegionCtxt::link_reborrowed_region] for some
- /// more explanation of this in the general case.
- ///
- /// We also supply a *cause*, and in this case we set the cause to
- /// indicate that the reference being "reborrowed" is itself an upvar. This
- /// provides a nicer error message should something go wrong.
- fn link_upvar_region(
- &self,
- span: Span,
- borrow_region: ty::Region<'tcx>,
- upvar_id: ty::UpvarId,
- ) {
- debug!("link_upvar_region(borrorw_region={:?}, upvar_id={:?}", borrow_region, upvar_id);
- // A by-reference upvar can't be borrowed for longer than the
- // upvar is borrowed from the environment.
- let closure_local_def_id = upvar_id.closure_expr_id;
- let mut all_captures_are_imm_borrow = true;
- for captured_place in self
- .typeck_results
- .borrow()
- .closure_min_captures
- .get(&closure_local_def_id.to_def_id())
- .and_then(|root_var_min_cap| root_var_min_cap.get(&upvar_id.var_path.hir_id))
- .into_iter()
- .flatten()
- {
- match captured_place.info.capture_kind {
- ty::UpvarCapture::ByRef(upvar_borrow) => {
- self.sub_regions(
- infer::ReborrowUpvar(span, upvar_id),
- borrow_region,
- captured_place.region.unwrap(),
- );
- if let ty::ImmBorrow = upvar_borrow {
- debug!("link_upvar_region: capture by shared ref");
- } else {
- all_captures_are_imm_borrow = false;
- }
- }
- ty::UpvarCapture::ByValue => {
- all_captures_are_imm_borrow = false;
- }
- }
- }
- if all_captures_are_imm_borrow {
- return;
- }
- let fn_hir_id = self.tcx.hir().local_def_id_to_hir_id(closure_local_def_id);
- let ty = self.resolve_node_type(fn_hir_id);
- debug!("link_upvar_region: ty={:?}", ty);
-
- // A closure capture can't be borrowed for longer than the
- // reference to the closure.
- if let ty::Closure(_, substs) = ty.kind() {
- match self.infcx.closure_kind(substs) {
- Some(ty::ClosureKind::Fn | ty::ClosureKind::FnMut) => {
- // Region of environment pointer
- let env_region = self.tcx.mk_region(ty::ReFree(ty::FreeRegion {
- scope: upvar_id.closure_expr_id.to_def_id(),
- bound_region: ty::BrEnv,
- }));
- self.sub_regions(
- infer::ReborrowUpvar(span, upvar_id),
- borrow_region,
- env_region,
- );
- }
- Some(ty::ClosureKind::FnOnce) => {}
- None => {
- span_bug!(span, "Have not inferred closure kind before regionck");
- }
- }
- }
- }
-}
diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_typeck/src/check/wfcheck.rs
index 7fe36781cf494..c76c3a4c7baee 100644
--- a/compiler/rustc_typeck/src/check/wfcheck.rs
+++ b/compiler/rustc_typeck/src/check/wfcheck.rs
@@ -62,7 +62,10 @@ impl<'tcx> CheckWfFcxBuilder<'tcx> {
}
let wf_tys = f(&fcx);
fcx.select_all_obligations_or_error();
- fcx.regionck_item(id, span, wf_tys);
+
+ let mut outlives_environment = OutlivesEnvironment::new(param_env);
+ outlives_environment.add_implied_bounds(&fcx.infcx, wf_tys, id);
+ fcx.infcx.check_region_obligations_and_report_errors(&outlives_environment);
});
}
}
@@ -655,13 +658,12 @@ fn resolve_regions_with_wf_tys<'tcx>(
// call individually.
tcx.infer_ctxt().enter(|infcx| {
let mut outlives_environment = OutlivesEnvironment::new(param_env);
- outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id, DUMMY_SP);
- outlives_environment.save_implied_bounds(id);
- let region_bound_pairs = outlives_environment.region_bound_pairs_map().get(&id).unwrap();
+ outlives_environment.add_implied_bounds(&infcx, wf_tys.clone(), id);
+ let region_bound_pairs = outlives_environment.region_bound_pairs();
add_constraints(&infcx, region_bound_pairs);
- let errors = infcx.resolve_regions(id.expect_owner().to_def_id(), &outlives_environment);
+ let errors = infcx.resolve_regions(&outlives_environment);
debug!(?errors, "errors");
diff --git a/compiler/rustc_typeck/src/coherence/builtin.rs b/compiler/rustc_typeck/src/coherence/builtin.rs
index c647c2a4c1baa..ec4fe3c420323 100644
--- a/compiler/rustc_typeck/src/coherence/builtin.rs
+++ b/compiler/rustc_typeck/src/coherence/builtin.rs
@@ -349,7 +349,7 @@ fn visit_implementation_of_dispatch_from_dyn<'tcx>(tcx: TyCtxt<'tcx>, impl_did:
// Finally, resolve all regions.
let outlives_env = OutlivesEnvironment::new(param_env);
- infcx.resolve_regions_and_report_errors(impl_did.to_def_id(), &outlives_env);
+ infcx.resolve_regions_and_report_errors(&outlives_env);
}
}
_ => {
@@ -606,7 +606,7 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn
// Finally, resolve all regions.
let outlives_env = OutlivesEnvironment::new(param_env);
- infcx.resolve_regions_and_report_errors(impl_did.to_def_id(), &outlives_env);
+ infcx.resolve_regions_and_report_errors(&outlives_env);
CoerceUnsizedInfo { custom_kind: kind }
})
diff --git a/compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs b/compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs
index f07396ce74ffb..24ad0ccbaaab8 100644
--- a/compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs
+++ b/compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs
@@ -150,7 +150,7 @@ fn get_impl_substs<'tcx>(
// Conservatively use an empty `ParamEnv`.
let outlives_env = OutlivesEnvironment::new(ty::ParamEnv::empty());
- infcx.resolve_regions_and_report_errors(impl1_def_id.to_def_id(), &outlives_env);
+ infcx.resolve_regions_and_report_errors(&outlives_env);
let Ok(impl2_substs) = infcx.fully_resolve(impl2_substs) else {
let span = tcx.def_span(impl1_def_id);
tcx.sess.emit_err(SubstsOnOverriddenImpl { span });
diff --git a/compiler/rustc_typeck/src/outlives/outlives_bounds.rs b/compiler/rustc_typeck/src/outlives/outlives_bounds.rs
index 3bf697e768269..70b8bcd02208d 100644
--- a/compiler/rustc_typeck/src/outlives/outlives_bounds.rs
+++ b/compiler/rustc_typeck/src/outlives/outlives_bounds.rs
@@ -1,6 +1,5 @@
use rustc_hir as hir;
use rustc_middle::ty::{self, Ty};
-use rustc_span::source_map::Span;
use rustc_trait_selection::infer::InferCtxt;
use rustc_trait_selection::traits::query::type_op::{self, TypeOp, TypeOpOutput};
use rustc_trait_selection::traits::query::NoSolution;
@@ -14,7 +13,6 @@ pub trait InferCtxtExt<'tcx> {
param_env: ty::ParamEnv<'tcx>,
body_id: hir::HirId,
ty: Ty<'tcx>,
- span: Span,
) -> Vec<OutlivesBound<'tcx>>;
}
@@ -38,16 +36,14 @@ impl<'cx, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'cx, 'tcx> {
/// Note that this may cause outlives obligations to be injected
/// into the inference context with this body-id.
/// - `ty`, the type that we are supposed to assume is WF.
- /// - `span`, a span to use when normalizing, hopefully not important,
- /// might be useful if a `bug!` occurs.
- #[instrument(level = "debug", skip(self, param_env, body_id, span))]
+ #[instrument(level = "debug", skip(self, param_env, body_id))]
fn implied_outlives_bounds(
&self,
param_env: ty::ParamEnv<'tcx>,
body_id: hir::HirId,
ty: Ty<'tcx>,
- span: Span,
) -> Vec<OutlivesBound<'tcx>> {
+ let span = self.tcx.hir().span(body_id);
let result = param_env
.and(type_op::implied_outlives_bounds::ImpliedOutlivesBounds { ty })
.fully_perform(self);