pub use self::SubregionOrigin::*;
pub use self::ValuePairs::*;
+pub(crate) use self::undo_log::{InferCtxtUndoLogs, Snapshot, UndoLog};
+
use crate::traits::{self, ObligationCause, PredicateObligations, TraitEngine};
use rustc_ast::ast;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::sync::Lrc;
+use rustc_data_structures::undo_log::{Rollback, Snapshots};
use rustc_data_structures::unify as ut;
use rustc_errors::DiagnosticBuilder;
use rustc_hir as hir;
use rustc_middle::infer::canonical::{Canonical, CanonicalVarValues};
use rustc_middle::infer::unify_key::{ConstVarValue, ConstVariableValue};
use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind, ToType};
-use rustc_middle::middle::free_region::RegionRelations;
use rustc_middle::middle::region;
use rustc_middle::mir;
use rustc_middle::mir::interpret::ConstEvalResult;
use std::cell::{Cell, Ref, RefCell};
use std::collections::BTreeMap;
use std::fmt;
+use std::marker::PhantomData;
use self::combine::CombineFields;
+use self::free_regions::RegionRelations;
use self::lexical_region_resolve::LexicalRegionResolutions;
use self::outlives::env::OutlivesEnvironment;
use self::region_constraints::{GenericKind, RegionConstraintData, VarInfos, VerifyBound};
-use self::region_constraints::{RegionConstraintCollector, RegionSnapshot};
+use self::region_constraints::{
+ RegionConstraintCollector, RegionConstraintStorage, RegionSnapshot,
+};
use self::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
pub mod at;
mod combine;
mod equate;
pub mod error_reporting;
+pub mod free_regions;
mod freshen;
mod fudge;
mod glb;
pub mod resolve;
mod sub;
pub mod type_variable;
+mod undo_log;
use crate::infer::canonical::OriginalQueryValues;
pub use rustc_middle::infer::unify_key;
pub type UnitResult<'tcx> = RelateResult<'tcx, ()>; // "unify result"
pub type FixupResult<'tcx, T> = Result<T, FixupError<'tcx>>; // "fixup result"
+pub(crate) type UnificationTable<'a, 'tcx, T> = ut::UnificationTable<
+ ut::InPlace<T, &'a mut ut::UnificationStorage<T>, &'a mut InferCtxtUndoLogs<'tcx>>,
+>;
+
/// How we should handle region solving.
///
/// This is used so that the region values inferred by HIR region solving are
/// Cache for projections. This cache is snapshotted along with the infcx.
///
/// Public so that `traits::project` can use it.
- pub projection_cache: traits::ProjectionCache<'tcx>,
+ pub projection_cache: traits::ProjectionCacheStorage<'tcx>,
/// We instantiate `UnificationTable` with `bounds<Ty>` because the types
/// that might instantiate a general type variable have an order,
/// represented by its upper and lower bounds.
- type_variables: type_variable::TypeVariableTable<'tcx>,
+ type_variables: type_variable::TypeVariableStorage<'tcx>,
/// Map from const parameter variable to the kind of const it represents.
- const_unification_table: ut::UnificationTable<ut::InPlace<ty::ConstVid<'tcx>>>,
+ const_unification_table: ut::UnificationStorage<ty::ConstVid<'tcx>>,
/// Map from integral variable to the kind of integer it represents.
- int_unification_table: ut::UnificationTable<ut::InPlace<ty::IntVid>>,
+ int_unification_table: ut::UnificationStorage<ty::IntVid>,
/// Map from floating variable to the kind of float it represents.
- float_unification_table: ut::UnificationTable<ut::InPlace<ty::FloatVid>>,
+ float_unification_table: ut::UnificationStorage<ty::FloatVid>,
/// Tracks the set of region variables and the constraints between them.
/// This is initially `Some(_)` but when
/// `resolve_regions_and_report_errors` is invoked, this gets set to `None`
/// -- further attempts to perform unification, etc., may fail if new
/// region constraints would've been added.
- region_constraints: Option<RegionConstraintCollector<'tcx>>,
+ region_constraints: Option<RegionConstraintStorage<'tcx>>,
/// A set of constraints that regionck must validate. Each
/// constraint has the form `T:'a`, meaning "some type `T` must
/// 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.
- pub region_obligations: Vec<(hir::HirId, RegionObligation<'tcx>)>,
+ region_obligations: Vec<(hir::HirId, RegionObligation<'tcx>)>,
+
+ undo_log: InferCtxtUndoLogs<'tcx>,
}
impl<'tcx> InferCtxtInner<'tcx> {
fn new() -> InferCtxtInner<'tcx> {
InferCtxtInner {
projection_cache: Default::default(),
- type_variables: type_variable::TypeVariableTable::new(),
- const_unification_table: ut::UnificationTable::new(),
- int_unification_table: ut::UnificationTable::new(),
- float_unification_table: ut::UnificationTable::new(),
- region_constraints: Some(RegionConstraintCollector::new()),
+ type_variables: type_variable::TypeVariableStorage::new(),
+ undo_log: InferCtxtUndoLogs::default(),
+ const_unification_table: ut::UnificationStorage::new(),
+ int_unification_table: ut::UnificationStorage::new(),
+ float_unification_table: ut::UnificationStorage::new(),
+ region_constraints: Some(RegionConstraintStorage::new()),
region_obligations: vec![],
}
}
- pub fn unwrap_region_constraints(&mut self) -> &mut RegionConstraintCollector<'tcx> {
- self.region_constraints.as_mut().expect("region constraints already solved")
+ pub fn region_obligations(&self) -> &[(hir::HirId, RegionObligation<'tcx>)] {
+ &self.region_obligations
+ }
+
+ pub(crate) fn projection_cache(&mut self) -> traits::ProjectionCache<'tcx, '_> {
+ self.projection_cache.with_log(&mut self.undo_log)
+ }
+
+ fn type_variables(&mut self) -> type_variable::TypeVariableTable<'tcx, '_> {
+ self.type_variables.with_log(&mut self.undo_log)
+ }
+
+ fn int_unification_table(
+ &mut self,
+ ) -> ut::UnificationTable<
+ ut::InPlace<
+ ty::IntVid,
+ &mut ut::UnificationStorage<ty::IntVid>,
+ &mut InferCtxtUndoLogs<'tcx>,
+ >,
+ > {
+ ut::UnificationTable::with_log(&mut self.int_unification_table, &mut self.undo_log)
+ }
+
+ fn float_unification_table(
+ &mut self,
+ ) -> ut::UnificationTable<
+ ut::InPlace<
+ ty::FloatVid,
+ &mut ut::UnificationStorage<ty::FloatVid>,
+ &mut InferCtxtUndoLogs<'tcx>,
+ >,
+ > {
+ ut::UnificationTable::with_log(&mut self.float_unification_table, &mut self.undo_log)
+ }
+
+ fn const_unification_table(
+ &mut self,
+ ) -> ut::UnificationTable<
+ ut::InPlace<
+ ty::ConstVid<'tcx>,
+ &mut ut::UnificationStorage<ty::ConstVid<'tcx>>,
+ &mut InferCtxtUndoLogs<'tcx>,
+ >,
+ > {
+ ut::UnificationTable::with_log(&mut self.const_unification_table, &mut self.undo_log)
+ }
+
+ pub fn unwrap_region_constraints(&mut self) -> RegionConstraintCollector<'tcx, '_> {
+ self.region_constraints
+ .as_mut()
+ .expect("region constraints already solved")
+ .with_log(&mut self.undo_log)
}
}
/// from a `for<'a> T` binder). Meant to represent "any region".
Placeholder(ty::PlaceholderRegion),
+ /// The variable we create to represent `'empty(U0)`.
+ RootEmptyRegion,
+
Existential {
/// If this is true, then this variable was created to represent a lifetime
/// bound in a `for` binder. For example, it might have been created to
NLLRegionVariableOrigin::FreeRegion => true,
NLLRegionVariableOrigin::Placeholder(..) => true,
NLLRegionVariableOrigin::Existential { .. } => false,
+ NLLRegionVariableOrigin::RootEmptyRegion => false,
}
}
}
#[must_use = "once you start a snapshot, you should always consume it"]
-pub struct CombinedSnapshot<'a, 'tcx> {
- projection_cache_snapshot: traits::ProjectionCacheSnapshot,
- type_snapshot: type_variable::Snapshot<'tcx>,
- const_snapshot: ut::Snapshot<ut::InPlace<ty::ConstVid<'tcx>>>,
- int_snapshot: ut::Snapshot<ut::InPlace<ty::IntVid>>,
- float_snapshot: ut::Snapshot<ut::InPlace<ty::FloatVid>>,
+pub struct FullSnapshot<'a, 'tcx> {
+ snapshot: CombinedSnapshot<'a, 'tcx>,
region_constraints_snapshot: RegionSnapshot,
- region_obligations_snapshot: usize,
+ type_snapshot: type_variable::Snapshot<'tcx>,
+ const_snapshot: usize,
+ int_snapshot: usize,
+ float_snapshot: usize,
+}
+
+#[must_use = "once you start a snapshot, you should always consume it"]
+pub struct CombinedSnapshot<'a, 'tcx> {
+ undo_snapshot: Snapshot<'tcx>,
universe: ty::UniverseIndex,
was_in_snapshot: bool,
- was_skip_leak_check: bool,
_in_progress_tables: Option<Ref<'a, ty::TypeckTables<'tcx>>>,
}
pub fn type_var_diverges(&'a self, ty: Ty<'_>) -> bool {
match ty.kind {
- ty::Infer(ty::TyVar(vid)) => self.inner.borrow().type_variables.var_diverges(vid),
+ ty::Infer(ty::TyVar(vid)) => self.inner.borrow_mut().type_variables().var_diverges(vid),
_ => false,
}
}
use rustc_middle::ty::error::UnconstrainedNumeric::{UnconstrainedFloat, UnconstrainedInt};
match ty.kind {
ty::Infer(ty::IntVar(vid)) => {
- if self.inner.borrow_mut().int_unification_table.probe_value(vid).is_some() {
+ if self.inner.borrow_mut().int_unification_table().probe_value(vid).is_some() {
Neither
} else {
UnconstrainedInt
}
}
ty::Infer(ty::FloatVar(vid)) => {
- if self.inner.borrow_mut().float_unification_table.probe_value(vid).is_some() {
+ if self.inner.borrow_mut().float_unification_table().probe_value(vid).is_some() {
Neither
} else {
UnconstrainedFloat
// FIXME(const_generics): should there be an equivalent function for const variables?
let mut vars: Vec<Ty<'_>> = inner
- .type_variables
+ .type_variables()
.unsolved_variables()
.into_iter()
.map(|t| self.tcx.mk_ty_var(t))
.collect();
vars.extend(
- (0..inner.int_unification_table.len())
+ (0..inner.int_unification_table().len())
.map(|i| ty::IntVid { index: i as u32 })
- .filter(|&vid| inner.int_unification_table.probe_value(vid).is_none())
+ .filter(|&vid| inner.int_unification_table().probe_value(vid).is_none())
.map(|v| self.tcx.mk_int_var(v)),
);
vars.extend(
- (0..inner.float_unification_table.len())
+ (0..inner.float_unification_table().len())
.map(|i| ty::FloatVid { index: i as u32 })
- .filter(|&vid| inner.float_unification_table.probe_value(vid).is_none())
+ .filter(|&vid| inner.float_unification_table().probe_value(vid).is_none())
.map(|v| self.tcx.mk_float_var(v)),
);
vars
result
}
+ fn start_full_snapshot(&self) -> FullSnapshot<'a, 'tcx> {
+ let snapshot = self.start_snapshot();
+ let mut inner = self.inner.borrow_mut();
+ FullSnapshot {
+ snapshot,
+ type_snapshot: inner.type_variables().snapshot(),
+ const_snapshot: inner.const_unification_table().len(),
+ int_snapshot: inner.int_unification_table().len(),
+ float_snapshot: inner.float_unification_table().len(),
+ region_constraints_snapshot: inner.unwrap_region_constraints().start_snapshot(),
+ }
+ }
+
fn start_snapshot(&self) -> CombinedSnapshot<'a, 'tcx> {
debug!("start_snapshot()");
let in_snapshot = self.in_snapshot.replace(true);
let mut inner = self.inner.borrow_mut();
+
CombinedSnapshot {
- projection_cache_snapshot: inner.projection_cache.snapshot(),
- type_snapshot: inner.type_variables.snapshot(),
- const_snapshot: inner.const_unification_table.snapshot(),
- int_snapshot: inner.int_unification_table.snapshot(),
- float_snapshot: inner.float_unification_table.snapshot(),
- region_constraints_snapshot: inner.unwrap_region_constraints().start_snapshot(),
- region_obligations_snapshot: inner.region_obligations.len(),
+ undo_snapshot: inner.undo_log.start_snapshot(),
universe: self.universe(),
was_in_snapshot: in_snapshot,
- was_skip_leak_check: self.skip_leak_check.get(),
// Borrow tables "in progress" (i.e., during typeck)
// to ban writes from within a snapshot to them.
_in_progress_tables: self.in_progress_tables.map(|tables| tables.borrow()),
fn rollback_to(&self, cause: &str, snapshot: CombinedSnapshot<'a, 'tcx>) {
debug!("rollback_to(cause={})", cause);
- let CombinedSnapshot {
- projection_cache_snapshot,
- type_snapshot,
- const_snapshot,
- int_snapshot,
- float_snapshot,
- region_constraints_snapshot,
- region_obligations_snapshot,
- universe,
- was_in_snapshot,
- was_skip_leak_check,
- _in_progress_tables,
- } = snapshot;
+ let CombinedSnapshot { undo_snapshot, universe, was_in_snapshot, _in_progress_tables } =
+ snapshot;
self.in_snapshot.set(was_in_snapshot);
self.universe.set(universe);
- self.skip_leak_check.set(was_skip_leak_check);
- let mut inner = self.inner.borrow_mut();
- inner.projection_cache.rollback_to(projection_cache_snapshot);
- inner.type_variables.rollback_to(type_snapshot);
- inner.const_unification_table.rollback_to(const_snapshot);
- inner.int_unification_table.rollback_to(int_snapshot);
- inner.float_unification_table.rollback_to(float_snapshot);
- inner.unwrap_region_constraints().rollback_to(region_constraints_snapshot);
- inner.region_obligations.truncate(region_obligations_snapshot);
+ let InferCtxtInner {
+ type_variables,
+ const_unification_table,
+ int_unification_table,
+ float_unification_table,
+ region_constraints,
+ projection_cache,
+ region_obligations,
+ undo_log,
+ ..
+ } = &mut *self.inner.borrow_mut();
+ undo_log.rollback_to(
+ || undo_log::RollbackView {
+ type_variables,
+ const_unification_table,
+ int_unification_table,
+ float_unification_table,
+ region_constraints: region_constraints.as_mut().unwrap(),
+ projection_cache,
+ region_obligations,
+ },
+ undo_snapshot,
+ );
}
fn commit_from(&self, snapshot: CombinedSnapshot<'a, 'tcx>) {
debug!("commit_from()");
- let CombinedSnapshot {
- projection_cache_snapshot,
- type_snapshot,
- const_snapshot,
- int_snapshot,
- float_snapshot,
- region_constraints_snapshot,
- region_obligations_snapshot: _,
- universe: _,
- was_in_snapshot,
- was_skip_leak_check,
- _in_progress_tables,
- } = snapshot;
+ let CombinedSnapshot { undo_snapshot, universe: _, was_in_snapshot, _in_progress_tables } =
+ snapshot;
self.in_snapshot.set(was_in_snapshot);
- self.skip_leak_check.set(was_skip_leak_check);
let mut inner = self.inner.borrow_mut();
- inner.projection_cache.commit(projection_cache_snapshot);
- inner.type_variables.commit(type_snapshot);
- inner.const_unification_table.commit(const_snapshot);
- inner.int_unification_table.commit(int_snapshot);
- inner.float_unification_table.commit(float_snapshot);
- inner.unwrap_region_constraints().commit(region_constraints_snapshot);
+ inner.undo_log.commit(undo_snapshot);
}
/// Executes `f` and commit the bindings.
r
}
+ pub fn probe_full<R, F>(&self, f: F) -> R
+ where
+ F: FnOnce(&FullSnapshot<'a, 'tcx>) -> R,
+ {
+ debug!("probe()");
+ let snapshot = self.start_full_snapshot();
+ let r = f(&snapshot);
+ self.rollback_to("probe", snapshot.snapshot);
+ r
+ }
+
/// If `should_skip` is true, then execute `f` then unroll any bindings it creates.
pub fn probe_maybe_skip_leak_check<R, F>(&self, should_skip: bool, f: F) -> R
where
{
debug!("probe()");
let snapshot = self.start_snapshot();
- let skip_leak_check = should_skip || self.skip_leak_check.get();
- self.skip_leak_check.set(skip_leak_check);
+ let was_skip_leak_check = self.skip_leak_check.get();
+ if should_skip {
+ self.skip_leak_check.set(true);
+ }
let r = f(&snapshot);
self.rollback_to("probe", snapshot);
+ self.skip_leak_check.set(was_skip_leak_check);
r
}
self.inner
.borrow_mut()
.unwrap_region_constraints()
- .region_constraints_added_in_snapshot(&snapshot.region_constraints_snapshot)
+ .region_constraints_added_in_snapshot(&snapshot.undo_snapshot)
}
pub fn add_given(&self, sub: ty::Region<'tcx>, sup: ty::RegionVid) {
}
pub fn next_ty_var_id(&self, diverging: bool, origin: TypeVariableOrigin) -> TyVid {
- self.inner.borrow_mut().type_variables.new_var(self.universe(), diverging, origin)
+ self.inner.borrow_mut().type_variables().new_var(self.universe(), diverging, origin)
}
pub fn next_ty_var(&self, origin: TypeVariableOrigin) -> Ty<'tcx> {
origin: TypeVariableOrigin,
universe: ty::UniverseIndex,
) -> Ty<'tcx> {
- let vid = self.inner.borrow_mut().type_variables.new_var(universe, false, origin);
+ let vid = self.inner.borrow_mut().type_variables().new_var(universe, false, origin);
self.tcx.mk_ty_var(vid)
}
let vid = self
.inner
.borrow_mut()
- .const_unification_table
+ .const_unification_table()
.new_key(ConstVarValue { origin, val: ConstVariableValue::Unknown { universe } });
self.tcx.mk_const_var(vid, ty)
}
pub fn next_const_var_id(&self, origin: ConstVariableOrigin) -> ConstVid<'tcx> {
- self.inner.borrow_mut().const_unification_table.new_key(ConstVarValue {
+ self.inner.borrow_mut().const_unification_table().new_key(ConstVarValue {
origin,
val: ConstVariableValue::Unknown { universe: self.universe() },
})
}
fn next_int_var_id(&self) -> IntVid {
- self.inner.borrow_mut().int_unification_table.new_key(None)
+ self.inner.borrow_mut().int_unification_table().new_key(None)
}
pub fn next_int_var(&self) -> Ty<'tcx> {
}
fn next_float_var_id(&self) -> FloatVid {
- self.inner.borrow_mut().float_unification_table.new_key(None)
+ self.inner.borrow_mut().float_unification_table().new_key(None)
}
pub fn next_float_var(&self) -> Ty<'tcx> {
// used in a path such as `Foo::<T, U>::new()` will
// use an inference variable for `C` with `[T, U]`
// as the substitutions for the default, `(T, U)`.
- let ty_var_id = self.inner.borrow_mut().type_variables.new_var(
+ let ty_var_id = self.inner.borrow_mut().type_variables().new_var(
self.universe(),
false,
TypeVariableOrigin {
span,
};
let const_var_id =
- self.inner.borrow_mut().const_unification_table.new_key(ConstVarValue {
+ self.inner.borrow_mut().const_unification_table().new_key(ConstVarValue {
origin,
val: ConstVariableValue::Unknown { universe: self.universe() },
});
.region_constraints
.take()
.expect("regions already resolved")
+ .with_log(&mut inner.undo_log)
.into_infos_and_data();
let region_rels = &RegionRelations::new(
/// called. This is used only during NLL processing to "hand off" ownership
/// of the set of region variables into the NLL region context.
pub fn take_region_var_origins(&self) -> VarInfos {
- let (var_infos, data) = self
- .inner
- .borrow_mut()
+ let mut inner = self.inner.borrow_mut();
+ let (var_infos, data) = inner
.region_constraints
.take()
.expect("regions already resolved")
+ .with_log(&mut inner.undo_log)
.into_infos_and_data();
assert!(data.is_empty());
var_infos
pub fn probe_ty_var(&self, vid: TyVid) -> Result<Ty<'tcx>, ty::UniverseIndex> {
use self::type_variable::TypeVariableValue;
- match self.inner.borrow_mut().type_variables.probe(vid) {
+ match self.inner.borrow_mut().type_variables().probe(vid) {
TypeVariableValue::Known { value } => Ok(value),
TypeVariableValue::Unknown { universe } => Err(universe),
}
}
pub fn root_var(&self, var: ty::TyVid) -> ty::TyVid {
- self.inner.borrow_mut().type_variables.root_var(var)
+ self.inner.borrow_mut().type_variables().root_var(var)
}
/// Where possible, replaces type/const variables in
&self,
vid: ty::ConstVid<'tcx>,
) -> Result<&'tcx ty::Const<'tcx>, ty::UniverseIndex> {
- match self.inner.borrow_mut().const_unification_table.probe_value(vid).val {
+ match self.inner.borrow_mut().const_unification_table().probe_value(vid).val {
ConstVariableValue::Known { value } => Ok(value),
ConstVariableValue::Unknown { universe } => Err(universe),
}
self.tcx.replace_bound_vars(value, fld_r, fld_t, fld_c)
}
- /// See the [`region_constraints::verify_generic_bound`] method.
+ /// See the [`region_constraints::RegionConstraintCollector::verify_generic_bound`] method.
pub fn verify_generic_bound(
&self,
origin: SubregionOrigin<'tcx>,
pub fn clear_caches(&self) {
self.selection_cache.clear();
self.evaluation_cache.clear();
- self.inner.borrow_mut().projection_cache.clear();
+ self.inner.borrow_mut().projection_cache().clear();
}
fn universe(&self) -> ty::UniverseIndex {
//
// Note: if these two lines are combined into one we get
// dynamic borrow errors on `self.inner`.
- let known = self.inner.borrow_mut().type_variables.probe(v).known();
+ let known = self.inner.borrow_mut().type_variables().probe(v).known();
known.map(|t| self.shallow_resolve_ty(t)).unwrap_or(typ)
}
ty::Infer(ty::IntVar(v)) => self
.inner
.borrow_mut()
- .int_unification_table
+ .int_unification_table()
.probe_value(v)
.map(|v| v.to_type(self.tcx))
.unwrap_or(typ),
ty::Infer(ty::FloatVar(v)) => self
.inner
.borrow_mut()
- .float_unification_table
+ .float_unification_table()
.probe_value(v)
.map(|v| v.to_type(self.tcx))
.unwrap_or(typ),
// If `inlined_probe` returns a `Known` value, it never equals
// `ty::Infer(ty::TyVar(v))`.
- match self.inner.borrow_mut().type_variables.inlined_probe(v) {
+ match self.inner.borrow_mut().type_variables().inlined_probe(v) {
TypeVariableValue::Unknown { .. } => false,
TypeVariableValue::Known { .. } => true,
}
// If `inlined_probe_value` returns a value it's always a
// `ty::Int(_)` or `ty::UInt(_)`, which never matches a
// `ty::Infer(_)`.
- self.inner.borrow_mut().int_unification_table.inlined_probe_value(v).is_some()
+ self.inner.borrow_mut().int_unification_table().inlined_probe_value(v).is_some()
}
TyOrConstInferVar::TyFloat(v) => {
// `ty::Float(_)`, which never matches a `ty::Infer(_)`.
//
// Not `inlined_probe_value(v)` because this call site is colder.
- self.inner.borrow_mut().float_unification_table.probe_value(v).is_some()
+ self.inner.borrow_mut().float_unification_table().probe_value(v).is_some()
}
TyOrConstInferVar::Const(v) => {
self.infcx
.inner
.borrow_mut()
- .const_unification_table
+ .const_unification_table()
.probe_value(*vid)
.val
.known()
projects / rust.git / blobdiff