diff --git a/src/Cargo.lock b/src/Cargo.lock
index c4314b41e3966..a0db98f95b0c3 100644
--- a/src/Cargo.lock
+++ b/src/Cargo.lock
@@ -536,6 +536,14 @@ name = "either"
version = "1.3.0"
source = "registry+https://github.com/rust-lang/crates.io-index"
+[[package]]
+name = "ena"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
[[package]]
name = "enum_primitive"
version = "0.1.1"
@@ -1649,6 +1657,7 @@ dependencies = [
name = "rustc_data_structures"
version = "0.0.0"
dependencies = [
+ "ena 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
"log 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
"serialize 0.0.0",
]
@@ -2633,6 +2642,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
"checksum dtoa 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "09c3753c3db574d215cba4ea76018483895d7bff25a31b49ba45db21c48e50ab"
"checksum duct 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "e45aa15fe0a8a8f511e6d834626afd55e49b62e5c8802e18328a87e8a8f6065c"
"checksum either 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "e311a7479512fbdf858fb54d91ec59f3b9f85bc0113659f46bba12b199d273ce"
+"checksum ena 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "58fb80e4764284ff0ec7054cb05c557f5ba01ccf65ff0c265e981c0b303d0ffc"
"checksum enum_primitive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "be4551092f4d519593039259a9ed8daedf0da12e5109c5280338073eaeb81180"
"checksum env_logger 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "15abd780e45b3ea4f76b4e9a26ff4843258dd8a3eed2775a0e7368c2e7936c2f"
"checksum env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3ddf21e73e016298f5cb37d6ef8e8da8e39f91f9ec8b0df44b7deb16a9f8cd5b"
diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index e7627b110fae4..c8000968e61e4 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -801,6 +801,7 @@ for ty::steal::Steal<T>
impl_stable_hash_for!(struct ty::ParamEnv<'tcx> {
caller_bounds,
+ universe,
reveal
});
@@ -970,3 +971,12 @@ for traits::VtableGeneratorData<'gcx, N> where N: HashStable<StableHashingContex
nested.hash_stable(hcx, hasher);
}
}
+
+impl<'gcx> HashStable<StableHashingContext<'gcx>>
+for ty::UniverseIndex {
+ fn hash_stable<W: StableHasherResult>(&self,
+ hcx: &mut StableHashingContext<'gcx>,
+ hasher: &mut StableHasher<W>) {
+ self.depth().hash_stable(hcx, hasher);
+ }
+}
diff --git a/src/librustc/infer/combine.rs b/src/librustc/infer/combine.rs
index 40e933b26a257..c0ca157997bf4 100644
--- a/src/librustc/infer/combine.rs
+++ b/src/librustc/infer/combine.rs
@@ -34,10 +34,10 @@
use super::equate::Equate;
use super::glb::Glb;
+use super::{InferCtxt, MiscVariable, TypeTrace};
use super::lub::Lub;
use super::sub::Sub;
-use super::InferCtxt;
-use super::{MiscVariable, TypeTrace};
+use super::type_variable::TypeVariableValue;
use hir::def_id::DefId;
use ty::{IntType, UintType};
@@ -132,7 +132,7 @@ impl<'infcx, 'gcx, 'tcx> InferCtxt<'infcx, 'gcx, 'tcx> {
{
self.int_unification_table
.borrow_mut()
- .unify_var_value(vid, val)
+ .unify_var_value(vid, Some(val))
.map_err(|e| int_unification_error(vid_is_expected, e))?;
match val {
IntType(v) => Ok(self.tcx.mk_mach_int(v)),
@@ -148,7 +148,7 @@ impl<'infcx, 'gcx, 'tcx> InferCtxt<'infcx, 'gcx, 'tcx> {
{
self.float_unification_table
.borrow_mut()
- .unify_var_value(vid, val)
+ .unify_var_value(vid, Some(ty::FloatVarValue(val)))
.map_err(|e| float_unification_error(vid_is_expected, e))?;
Ok(self.tcx.mk_mach_float(val))
}
@@ -194,7 +194,7 @@ impl<'infcx, 'gcx, 'tcx> CombineFields<'infcx, 'gcx, 'tcx> {
use self::RelationDir::*;
// Get the actual variable that b_vid has been inferred to
- debug_assert!(self.infcx.type_variables.borrow_mut().probe(b_vid).is_none());
+ debug_assert!(self.infcx.type_variables.borrow_mut().probe(b_vid).is_unknown());
debug!("instantiate(a_ty={:?} dir={:?} b_vid={:?})", a_ty, dir, b_vid);
@@ -388,12 +388,12 @@ impl<'cx, 'gcx, 'tcx> TypeRelation<'cx, 'gcx, 'tcx> for Generalizer<'cx, 'gcx, '
// `vid` are related via subtyping.
return Err(TypeError::CyclicTy);
} else {
- match variables.probe_root(vid) {
- Some(u) => {
+ match variables.probe(vid) {
+ TypeVariableValue::Known { value: u } => {
drop(variables);
self.relate(&u, &u)
}
- None => {
+ TypeVariableValue::Unknown { universe } => {
match self.ambient_variance {
// Invariant: no need to make a fresh type variable.
ty::Invariant => return Ok(t),
@@ -409,8 +409,8 @@ impl<'cx, 'gcx, 'tcx> TypeRelation<'cx, 'gcx, 'tcx> for Generalizer<'cx, 'gcx, '
ty::Covariant | ty::Contravariant => (),
}
- let origin = variables.origin(vid);
- let new_var_id = variables.new_var(false, origin, None);
+ let origin = *variables.var_origin(vid);
+ let new_var_id = variables.new_var(universe, false, origin);
let u = self.tcx().mk_var(new_var_id);
debug!("generalize: replacing original vid={:?} with new={:?}",
vid, u);
@@ -496,9 +496,9 @@ fn int_unification_error<'tcx>(a_is_expected: bool, v: (ty::IntVarValue, ty::Int
}
fn float_unification_error<'tcx>(a_is_expected: bool,
- v: (ast::FloatTy, ast::FloatTy))
+ v: (ty::FloatVarValue, ty::FloatVarValue))
-> TypeError<'tcx>
{
- let (a, b) = v;
+ let (ty::FloatVarValue(a), ty::FloatVarValue(b)) = v;
TypeError::FloatMismatch(ty::relate::expected_found_bool(a_is_expected, &a, &b))
}
diff --git a/src/librustc/infer/freshen.rs b/src/librustc/infer/freshen.rs
index 41e7dffe54dc1..468bfb514262a 100644
--- a/src/librustc/infer/freshen.rs
+++ b/src/librustc/infer/freshen.rs
@@ -212,7 +212,7 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for TypeFreshener<'a, 'gcx, 'tcx> {
match t.sty {
ty::TyInfer(ty::TyVar(v)) => {
- let opt_ty = self.infcx.type_variables.borrow_mut().probe(v);
+ let opt_ty = self.infcx.type_variables.borrow_mut().probe(v).known();
self.freshen(
opt_ty,
ty::TyVar(v),
@@ -222,7 +222,7 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for TypeFreshener<'a, 'gcx, 'tcx> {
ty::TyInfer(ty::IntVar(v)) => {
self.freshen(
self.infcx.int_unification_table.borrow_mut()
- .probe(v)
+ .probe_value(v)
.map(|v| v.to_type(tcx)),
ty::IntVar(v),
ty::FreshIntTy)
@@ -231,7 +231,7 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for TypeFreshener<'a, 'gcx, 'tcx> {
ty::TyInfer(ty::FloatVar(v)) => {
self.freshen(
self.infcx.float_unification_table.borrow_mut()
- .probe(v)
+ .probe_value(v)
.map(|v| v.to_type(tcx)),
ty::FloatVar(v),
ty::FreshFloatTy)
diff --git a/src/librustc/infer/fudge.rs b/src/librustc/infer/fudge.rs
index 9cad6ce6f9fad..72f22856304fa 100644
--- a/src/librustc/infer/fudge.rs
+++ b/src/librustc/infer/fudge.rs
@@ -131,7 +131,9 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for RegionFudger<'a, 'gcx, 'tcx> {
// variables to their binding anyhow, we know
// that it is unbound, so we can just return
// it.
- debug_assert!(self.infcx.type_variables.borrow_mut().probe(vid).is_none());
+ debug_assert!(self.infcx.type_variables.borrow_mut()
+ .probe(vid)
+ .is_unknown());
ty
}
@@ -139,7 +141,11 @@ impl<'a, 'gcx, 'tcx> TypeFolder<'gcx, 'tcx> for RegionFudger<'a, 'gcx, 'tcx> {
// This variable was created during the
// fudging. Recreate it with a fresh variable
// here.
- self.infcx.next_ty_var(origin)
+ //
+ // The ROOT universe is fine because we only
+ // ever invoke this routine at the
+ // "item-level" of inference.
+ self.infcx.next_ty_var(ty::UniverseIndex::ROOT, origin)
}
}
}
diff --git a/src/librustc/infer/higher_ranked/mod.rs b/src/librustc/infer/higher_ranked/mod.rs
index 6736751a5a2c2..ba6dde3ba6f50 100644
--- a/src/librustc/infer/higher_ranked/mod.rs
+++ b/src/librustc/infer/higher_ranked/mod.rs
@@ -242,7 +242,7 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
fn generalize_region<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
span: Span,
- snapshot: &CombinedSnapshot,
+ snapshot: &CombinedSnapshot<'a, 'tcx>,
debruijn: ty::DebruijnIndex,
new_vars: &[ty::RegionVid],
a_map: &FxHashMap<ty::BoundRegion, ty::Region<'tcx>>,
@@ -338,7 +338,7 @@ impl<'a, 'gcx, 'tcx> CombineFields<'a, 'gcx, 'tcx> {
fn generalize_region<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
span: Span,
- snapshot: &CombinedSnapshot,
+ snapshot: &CombinedSnapshot<'a, 'tcx>,
debruijn: ty::DebruijnIndex,
new_vars: &[ty::RegionVid],
a_map: &FxHashMap<ty::BoundRegion, ty::Region<'tcx>>,
@@ -477,7 +477,7 @@ fn fold_regions_in<'a, 'gcx, 'tcx, T, F>(tcx: TyCtxt<'a, 'gcx, 'tcx>,
impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
fn tainted_regions(&self,
- snapshot: &CombinedSnapshot,
+ snapshot: &CombinedSnapshot<'a, 'tcx>,
r: ty::Region<'tcx>,
directions: TaintDirections)
-> FxHashSet<ty::Region<'tcx>> {
@@ -485,7 +485,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}
fn region_vars_confined_to_snapshot(&self,
- snapshot: &CombinedSnapshot)
+ snapshot: &CombinedSnapshot<'a, 'tcx>)
-> Vec<ty::RegionVid>
{
/*!
@@ -576,7 +576,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
/// See `README.md` for more details.
pub fn skolemize_late_bound_regions<T>(&self,
binder: &ty::Binder<T>,
- snapshot: &CombinedSnapshot)
+ snapshot: &CombinedSnapshot<'a, 'tcx>)
-> (T, SkolemizationMap<'tcx>)
where T : TypeFoldable<'tcx>
{
@@ -601,7 +601,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
overly_polymorphic: bool,
_span: Span,
skol_map: &SkolemizationMap<'tcx>,
- snapshot: &CombinedSnapshot)
+ snapshot: &CombinedSnapshot<'a, 'tcx>)
-> RelateResult<'tcx, ()>
{
debug!("leak_check: skol_map={:?}",
@@ -676,7 +676,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
/// predicate is `for<'a> &'a int : Clone`.
pub fn plug_leaks<T>(&self,
skol_map: SkolemizationMap<'tcx>,
- snapshot: &CombinedSnapshot,
+ snapshot: &CombinedSnapshot<'a, 'tcx>,
value: T) -> T
where T : TypeFoldable<'tcx>
{
@@ -762,8 +762,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
/// Note: popping also occurs implicitly as part of `leak_check`.
pub fn pop_skolemized(&self,
skol_map: SkolemizationMap<'tcx>,
- snapshot: &CombinedSnapshot)
- {
+ snapshot: &CombinedSnapshot<'a, 'tcx>) {
debug!("pop_skolemized({:?})", skol_map);
let skol_regions: FxHashSet<_> = skol_map.values().cloned().collect();
self.region_vars.pop_skolemized(&skol_regions, &snapshot.region_vars_snapshot);
diff --git a/src/librustc/infer/lattice.rs b/src/librustc/infer/lattice.rs
index d5c1163cfc1b1..c4722f9a7f96c 100644
--- a/src/librustc/infer/lattice.rs
+++ b/src/librustc/infer/lattice.rs
@@ -70,14 +70,6 @@ pub fn super_lattice_tys<'a, 'gcx, 'tcx, L>(this: &mut L,
let a = infcx.type_variables.borrow_mut().replace_if_possible(a);
let b = infcx.type_variables.borrow_mut().replace_if_possible(b);
match (&a.sty, &b.sty) {
- (&ty::TyInfer(TyVar(..)), &ty::TyInfer(TyVar(..)))
- if infcx.type_var_diverges(a) && infcx.type_var_diverges(b) => {
- let v = infcx.next_diverging_ty_var(
- TypeVariableOrigin::LatticeVariable(this.cause().span));
- this.relate_bound(v, a, b)?;
- Ok(v)
- }
-
// If one side is known to be a variable and one is not,
// create a variable (`v`) to represent the LUB. Make sure to
// relate `v` to the non-type-variable first (by passing it
@@ -96,13 +88,17 @@ pub fn super_lattice_tys<'a, 'gcx, 'tcx, L>(this: &mut L,
// is (e.g.) `Box<i32>`. A more obvious solution might be to
// iterate on the subtype obligations that are returned, but I
// think this suffices. -nmatsakis
- (&ty::TyInfer(TyVar(..)), _) => {
- let v = infcx.next_ty_var(TypeVariableOrigin::LatticeVariable(this.cause().span));
+ (&ty::TyInfer(TyVar(a_vid)), _) => {
+ let universe = infcx.type_variables.borrow_mut().probe(a_vid).universe().unwrap();
+ let v = infcx.next_ty_var(universe,
+ TypeVariableOrigin::LatticeVariable(this.cause().span));
this.relate_bound(v, b, a)?;
Ok(v)
}
- (_, &ty::TyInfer(TyVar(..))) => {
- let v = infcx.next_ty_var(TypeVariableOrigin::LatticeVariable(this.cause().span));
+ (_, &ty::TyInfer(TyVar(b_vid))) => {
+ let universe = infcx.type_variables.borrow_mut().probe(b_vid).universe().unwrap();
+ let v = infcx.next_ty_var(universe,
+ TypeVariableOrigin::LatticeVariable(this.cause().span));
this.relate_bound(v, a, b)?;
Ok(v)
}
diff --git a/src/librustc/infer/mod.rs b/src/librustc/infer/mod.rs
index 79eeebfb25031..f411ad5b29602 100644
--- a/src/librustc/infer/mod.rs
+++ b/src/librustc/infer/mod.rs
@@ -23,14 +23,14 @@ use middle::free_region::{FreeRegionMap, RegionRelations};
use middle::region;
use middle::lang_items;
use mir::tcx::LvalueTy;
-use ty::subst::{Kind, Subst, Substs};
+use ty::subst::{Substs};
use ty::{TyVid, IntVid, FloatVid};
use ty::{self, Ty, TyCtxt};
use ty::error::{ExpectedFound, TypeError, UnconstrainedNumeric};
use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
use ty::relate::RelateResult;
use traits::{self, ObligationCause, PredicateObligations, Reveal};
-use rustc_data_structures::unify::{self, UnificationTable};
+use rustc_data_structures::unify as ut;
use std::cell::{Cell, RefCell, Ref};
use std::fmt;
use syntax::ast;
@@ -93,10 +93,10 @@ pub struct InferCtxt<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
pub type_variables: RefCell<type_variable::TypeVariableTable<'tcx>>,
// Map from integral variable to the kind of integer it represents
- int_unification_table: RefCell<UnificationTable<ty::IntVid>>,
+ int_unification_table: RefCell<ut::UnificationTable<ut::InPlace<ty::IntVid>>>,
// Map from floating variable to the kind of float it represents
- float_unification_table: RefCell<UnificationTable<ty::FloatVid>>,
+ float_unification_table: RefCell<ut::UnificationTable<ut::InPlace<ty::FloatVid>>>,
// For region variables.
region_vars: RegionVarBindings<'a, 'gcx, 'tcx>,
@@ -377,8 +377,8 @@ impl<'a, 'gcx, 'tcx> InferCtxtBuilder<'a, 'gcx, 'tcx> {
in_progress_tables,
projection_cache: RefCell::new(traits::ProjectionCache::new()),
type_variables: RefCell::new(type_variable::TypeVariableTable::new()),
- int_unification_table: RefCell::new(UnificationTable::new()),
- float_unification_table: RefCell::new(UnificationTable::new()),
+ int_unification_table: RefCell::new(ut::UnificationTable::new()),
+ float_unification_table: RefCell::new(ut::UnificationTable::new()),
region_vars: RegionVarBindings::new(tcx),
selection_cache: traits::SelectionCache::new(),
evaluation_cache: traits::EvaluationCache::new(),
@@ -409,9 +409,9 @@ impl<'tcx, T> InferOk<'tcx, T> {
#[must_use = "once you start a snapshot, you should always consume it"]
pub struct CombinedSnapshot<'a, 'tcx:'a> {
projection_cache_snapshot: traits::ProjectionCacheSnapshot,
- type_snapshot: type_variable::Snapshot,
- int_snapshot: unify::Snapshot<ty::IntVid>,
- float_snapshot: unify::Snapshot<ty::FloatVid>,
+ type_snapshot: type_variable::Snapshot<'tcx>,
+ int_snapshot: ut::Snapshot<ut::InPlace<ty::IntVid>>,
+ float_snapshot: ut::Snapshot<ut::InPlace<ty::FloatVid>>,
region_vars_snapshot: RegionSnapshot,
was_in_snapshot: bool,
_in_progress_tables: Option<Ref<'a, ty::TypeckTables<'tcx>>>,
@@ -611,14 +611,14 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
use ty::error::UnconstrainedNumeric::{UnconstrainedInt, UnconstrainedFloat};
match ty.sty {
ty::TyInfer(ty::IntVar(vid)) => {
- if self.int_unification_table.borrow_mut().has_value(vid) {
+ if self.int_unification_table.borrow_mut().probe_value(vid).is_some() {
Neither
} else {
UnconstrainedInt
}
},
ty::TyInfer(ty::FloatVar(vid)) => {
- if self.float_unification_table.borrow_mut().has_value(vid) {
+ if self.float_unification_table.borrow_mut().probe_value(vid).is_some() {
Neither
} else {
UnconstrainedFloat
@@ -628,46 +628,35 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}
}
- /// Returns a type variable's default fallback if any exists. A default
- /// must be attached to the variable when created, if it is created
- /// without a default, this will return None.
- ///
- /// This code does not apply to integral or floating point variables,
- /// only to use declared defaults.
- ///
- /// See `new_ty_var_with_default` to create a type variable with a default.
- /// See `type_variable::Default` for details about what a default entails.
- pub fn default(&self, ty: Ty<'tcx>) -> Option<type_variable::Default<'tcx>> {
- match ty.sty {
- ty::TyInfer(ty::TyVar(vid)) => self.type_variables.borrow().default(vid),
- _ => None
- }
- }
-
pub fn unsolved_variables(&self) -> Vec<Ty<'tcx>> {
let mut variables = Vec::new();
- let unbound_ty_vars = self.type_variables
- .borrow_mut()
- .unsolved_variables()
- .into_iter()
- .map(|t| self.tcx.mk_var(t));
-
- let unbound_int_vars = self.int_unification_table
- .borrow_mut()
- .unsolved_variables()
- .into_iter()
- .map(|v| self.tcx.mk_int_var(v));
+ {
+ let mut type_variables = self.type_variables.borrow_mut();
+ variables.extend(
+ type_variables
+ .unsolved_variables()
+ .into_iter()
+ .map(|t| self.tcx.mk_var(t)));
+ }
- let unbound_float_vars = self.float_unification_table
- .borrow_mut()
- .unsolved_variables()
- .into_iter()
- .map(|v| self.tcx.mk_float_var(v));
+ {
+ let mut int_unification_table = self.int_unification_table.borrow_mut();
+ variables.extend(
+ (0..int_unification_table.len())
+ .map(|i| ty::IntVid { index: i as u32 })
+ .filter(|&vid| int_unification_table.probe_value(vid).is_none())
+ .map(|v| self.tcx.mk_int_var(v)));
+ }
- variables.extend(unbound_ty_vars);
- variables.extend(unbound_int_vars);
- variables.extend(unbound_float_vars);
+ {
+ let mut float_unification_table = self.float_unification_table.borrow_mut();
+ variables.extend(
+ (0..float_unification_table.len())
+ .map(|i| ty::FloatVid { index: i as u32 })
+ .filter(|&vid| float_unification_table.probe_value(vid).is_none())
+ .map(|v| self.tcx.mk_float_var(v)));
+ }
return variables;
}
@@ -709,7 +698,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
result
}
- fn start_snapshot<'b>(&'b self) -> CombinedSnapshot<'b, 'tcx> {
+ fn start_snapshot(&self) -> CombinedSnapshot<'a, 'tcx> {
debug!("start_snapshot()");
let in_snapshot = self.in_snapshot.get();
@@ -730,7 +719,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
}
}
- fn rollback_to(&self, cause: &str, snapshot: CombinedSnapshot) {
+ fn rollback_to(&self, cause: &str, snapshot: CombinedSnapshot<'a, 'tcx>) {
debug!("rollback_to(cause={})", cause);
let CombinedSnapshot { projection_cache_snapshot,
type_snapshot,
@@ -758,7 +747,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
.rollback_to(region_vars_snapshot);
}
- fn commit_from(&self, snapshot: CombinedSnapshot) {
+ fn commit_from(&self, snapshot: CombinedSnapshot<'a, 'tcx>) {
debug!("commit_from()");
let CombinedSnapshot { projection_cache_snapshot,
type_snapshot,
@@ -799,7 +788,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
/// Execute `f` and commit the bindings if closure `f` returns `Ok(_)`
pub fn commit_if_ok<T, E, F>(&self, f: F) -> Result<T, E> where
- F: FnOnce(&CombinedSnapshot) -> Result<T, E>
+ F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> Result<T, E>
{
debug!("commit_if_ok()");
let snapshot = self.start_snapshot();
@@ -814,7 +803,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
// Execute `f` in a snapshot, and commit the bindings it creates
pub fn in_snapshot<T, F>(&self, f: F) -> T where
- F: FnOnce(&CombinedSnapshot) -> T
+ F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> T
{
debug!("in_snapshot()");
let snapshot = self.start_snapshot();
@@ -825,7 +814,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
/// Execute `f` then unroll any bindings it creates
pub fn probe<R, F>(&self, f: F) -> R where
- F: FnOnce(&CombinedSnapshot) -> R,
+ F: FnOnce(&CombinedSnapshot<'a, 'tcx>) -> R,
{
debug!("probe()");
let snapshot = self.start_snapshot();
@@ -953,18 +942,25 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
})
}
- pub fn next_ty_var_id(&self, diverging: bool, origin: TypeVariableOrigin) -> TyVid {
+ pub fn next_ty_var_id(&self,
+ universe: ty::UniverseIndex,
+ diverging: bool,
+ origin: TypeVariableOrigin)
+ -> TyVid {
self.type_variables
.borrow_mut()
- .new_var(diverging, origin, None)
+ .new_var(universe, diverging, origin)
}
- pub fn next_ty_var(&self, origin: TypeVariableOrigin) -> Ty<'tcx> {
- self.tcx.mk_var(self.next_ty_var_id(false, origin))
+ pub fn next_ty_var(&self, universe: ty::UniverseIndex, origin: TypeVariableOrigin) -> Ty<'tcx> {
+ self.tcx.mk_var(self.next_ty_var_id(universe, false, origin))
}
- pub fn next_diverging_ty_var(&self, origin: TypeVariableOrigin) -> Ty<'tcx> {
- self.tcx.mk_var(self.next_ty_var_id(true, origin))
+ pub fn next_diverging_ty_var(&self,
+ universe: ty::UniverseIndex,
+ origin: TypeVariableOrigin)
+ -> Ty<'tcx> {
+ self.tcx.mk_var(self.next_ty_var_id(universe, true, origin))
}
pub fn next_int_var_id(&self) -> IntVid {
@@ -1002,27 +998,15 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
/// use an inference variable for `C` with `[T, U]`
/// as the substitutions for the default, `(T, U)`.
pub fn type_var_for_def(&self,
+ universe: ty::UniverseIndex,
span: Span,
- def: &ty::TypeParameterDef,
- substs: &[Kind<'tcx>])
+ def: &ty::TypeParameterDef)
-> Ty<'tcx> {
- let default = if def.has_default {
- let default = self.tcx.type_of(def.def_id);
- Some(type_variable::Default {
- ty: default.subst_spanned(self.tcx, substs, Some(span)),
- origin_span: span,
- def_id: def.def_id
- })
- } else {
- None
- };
-
-
let ty_var_id = self.type_variables
.borrow_mut()
- .new_var(false,
- TypeVariableOrigin::TypeParameterDefinition(span, def.name),
- default);
+ .new_var(universe,
+ false,
+ TypeVariableOrigin::TypeParameterDefinition(span, def.name));
self.tcx.mk_var(ty_var_id)
}
@@ -1030,13 +1014,14 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
/// Given a set of generics defined on a type or impl, returns a substitution mapping each
/// type/region parameter to a fresh inference variable.
pub fn fresh_substs_for_item(&self,
+ universe: ty::UniverseIndex,
span: Span,
def_id: DefId)
-> &'tcx Substs<'tcx> {
Substs::for_item(self.tcx, def_id, |def, _| {
self.region_var_for_def(span, def)
- }, |def, substs| {
- self.type_var_for_def(span, def, substs)
+ }, |def, _| {
+ self.type_var_for_def(universe, span, def)
})
}
@@ -1115,15 +1100,16 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
// so this recursion should always be of very limited
// depth.
self.type_variables.borrow_mut()
- .probe(v)
- .map(|t| self.shallow_resolve(t))
- .unwrap_or(typ)
+ .probe(v)
+ .known()
+ .map(|t| self.shallow_resolve(t))
+ .unwrap_or(typ)
}
ty::TyInfer(ty::IntVar(v)) => {
self.int_unification_table
.borrow_mut()
- .probe(v)
+ .probe_value(v)
.map(|v| v.to_type(self.tcx))
.unwrap_or(typ)
}
@@ -1131,7 +1117,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
ty::TyInfer(ty::FloatVar(v)) => {
self.float_unification_table
.borrow_mut()
- .probe(v)
+ .probe_value(v)
.map(|v| v.to_type(self.tcx))
.unwrap_or(typ)
}
@@ -1233,28 +1219,6 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
self.report_and_explain_type_error(trace, &err)
}
- pub fn report_conflicting_default_types(&self,
- span: Span,
- body_id: ast::NodeId,
- expected: type_variable::Default<'tcx>,
- actual: type_variable::Default<'tcx>) {
- let trace = TypeTrace {
- cause: ObligationCause::misc(span, body_id),
- values: Types(ExpectedFound {
- expected: expected.ty,
- found: actual.ty
- })
- };
-
- self.report_and_explain_type_error(
- trace,
- &TypeError::TyParamDefaultMismatch(ExpectedFound {
- expected,
- found: actual
- }))
- .emit();
- }
-
pub fn replace_late_bound_regions_with_fresh_var<T>(
&self,
span: Span,
diff --git a/src/librustc/infer/region_inference/mod.rs b/src/librustc/infer/region_inference/mod.rs
index 8351be490767a..b197344bda914 100644
--- a/src/librustc/infer/region_inference/mod.rs
+++ b/src/librustc/infer/region_inference/mod.rs
@@ -21,7 +21,7 @@ use super::unify_key;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::graph::{self, Direction, NodeIndex, OUTGOING};
-use rustc_data_structures::unify::{self, UnificationTable};
+use rustc_data_structures::unify as ut;
use middle::free_region::RegionRelations;
use ty::{self, Ty, TyCtxt};
use ty::{Region, RegionVid};
@@ -216,7 +216,7 @@ pub struct RegionVarBindings<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
lubs: RefCell<CombineMap<'tcx>>,
glbs: RefCell<CombineMap<'tcx>>,
- skolemization_count: Cell<u32>,
+ skolemization_count: Cell<ty::UniverseIndex>,
bound_count: Cell<u32>,
/// The undo log records actions that might later be undone.
@@ -230,7 +230,7 @@ pub struct RegionVarBindings<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
/// back.
undo_log: RefCell<Vec<UndoLogEntry<'tcx>>>,
- unification_table: RefCell<UnificationTable<ty::RegionVid>>,
+ unification_table: RefCell<ut::UnificationTable<ut::InPlace<ty::RegionVid>>>,
/// This contains the results of inference. It begins as an empty
/// option and only acquires a value after inference is complete.
@@ -239,8 +239,8 @@ pub struct RegionVarBindings<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
pub struct RegionSnapshot {
length: usize,
- region_snapshot: unify::Snapshot<ty::RegionVid>,
- skolemization_count: u32,
+ region_snapshot: ut::Snapshot<ut::InPlace<ty::RegionVid>>,
+ skolemization_count: ty::UniverseIndex,
}
/// When working with skolemized regions, we often wish to find all of
@@ -362,10 +362,10 @@ impl<'a, 'gcx, 'tcx> RegionVarBindings<'a, 'gcx, 'tcx> {
givens: RefCell::new(FxHashSet()),
lubs: RefCell::new(FxHashMap()),
glbs: RefCell::new(FxHashMap()),
- skolemization_count: Cell::new(0),
+ skolemization_count: Cell::new(ty::UniverseIndex::ROOT),
bound_count: Cell::new(0),
undo_log: RefCell::new(Vec::new()),
- unification_table: RefCell::new(UnificationTable::new()),
+ unification_table: RefCell::new(ut::UnificationTable::new()),
}
}
@@ -389,7 +389,7 @@ impl<'a, 'gcx, 'tcx> RegionVarBindings<'a, 'gcx, 'tcx> {
assert!(self.undo_log.borrow().len() > snapshot.length);
assert!((*self.undo_log.borrow())[snapshot.length] == OpenSnapshot);
assert!(self.skolemization_count.get() == snapshot.skolemization_count,
- "failed to pop skolemized regions: {} now vs {} at start",
+ "failed to pop skolemized regions: {:?} now vs {:?} at start",
self.skolemization_count.get(),
snapshot.skolemization_count);
@@ -501,9 +501,9 @@ impl<'a, 'gcx, 'tcx> RegionVarBindings<'a, 'gcx, 'tcx> {
assert!(self.in_snapshot());
assert!(self.undo_log.borrow()[snapshot.length] == OpenSnapshot);
- let sc = self.skolemization_count.get();
- self.skolemization_count.set(sc + 1);
- self.tcx.mk_region(ReSkolemized(ty::SkolemizedRegionVid { index: sc }, br))
+ let universe = self.skolemization_count.get().subuniverse();
+ self.skolemization_count.set(universe);
+ self.tcx.mk_region(ReSkolemized(universe, br))
}
/// Removes all the edges to/from the skolemized regions that are
@@ -517,31 +517,31 @@ impl<'a, 'gcx, 'tcx> RegionVarBindings<'a, 'gcx, 'tcx> {
assert!(self.in_snapshot());
assert!(self.undo_log.borrow()[snapshot.length] == OpenSnapshot);
- assert!(self.skolemization_count.get() as usize >= skols.len(),
+ assert!(self.skolemization_count.get().as_usize() >= skols.len(),
"popping more skolemized variables than actually exist, \
sc now = {}, skols.len = {}",
- self.skolemization_count.get(),
+ self.skolemization_count.get().as_usize(),
skols.len());
- let last_to_pop = self.skolemization_count.get();
- let first_to_pop = last_to_pop - (skols.len() as u32);
+ let last_to_pop = self.skolemization_count.get().subuniverse();
+ let first_to_pop = ty::UniverseIndex::from(last_to_pop.as_u32() - (skols.len() as u32));
assert!(first_to_pop >= snapshot.skolemization_count,
"popping more regions than snapshot contains, \
- sc now = {}, sc then = {}, skols.len = {}",
+ sc now = {:?}, sc then = {:?}, skols.len = {}",
self.skolemization_count.get(),
snapshot.skolemization_count,
skols.len());
debug_assert! {
skols.iter()
.all(|&k| match *k {
- ty::ReSkolemized(index, _) =>
- index.index >= first_to_pop &&
- index.index < last_to_pop,
+ ty::ReSkolemized(universe, _) =>
+ universe >= first_to_pop &&
+ universe < last_to_pop,
_ =>
false
}),
- "invalid skolemization keys or keys out of range ({}..{}): {:?}",
+ "invalid skolemization keys or keys out of range ({:?}..{:?}): {:?}",
snapshot.skolemization_count,
self.skolemization_count.get(),
skols
@@ -808,7 +808,7 @@ impl<'a, 'gcx, 'tcx> RegionVarBindings<'a, 'gcx, 'tcx> {
}
pub fn opportunistic_resolve_var(&self, rid: RegionVid) -> ty::Region<'tcx> {
- let vid = self.unification_table.borrow_mut().find_value(rid).min_vid;
+ let vid = self.unification_table.borrow_mut().probe_value(rid).min_vid;
self.tcx.mk_region(ty::ReVar(vid))
}
@@ -1523,7 +1523,7 @@ impl<'tcx> fmt::Debug for RegionAndOrigin<'tcx> {
impl fmt::Debug for RegionSnapshot {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
- write!(f, "RegionSnapshot(length={},skolemization={})",
+ write!(f, "RegionSnapshot(length={},skolemization={:?})",
self.length, self.skolemization_count)
}
}
diff --git a/src/librustc/infer/type_variable.rs b/src/librustc/infer/type_variable.rs
index cc91a637b8931..4ee23d2647fa2 100644
--- a/src/librustc/infer/type_variable.rs
+++ b/src/librustc/infer/type_variable.rs
@@ -8,26 +8,28 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use self::TypeVariableValue::*;
-use hir::def_id::{DefId};
use syntax::ast;
use syntax_pos::Span;
use ty::{self, Ty};
-use std::cmp::min;
+use std::cmp;
use std::marker::PhantomData;
-use std::mem;
use std::u32;
use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::snapshot_vec as sv;
use rustc_data_structures::unify as ut;
pub struct TypeVariableTable<'tcx> {
- values: sv::SnapshotVec<Delegate<'tcx>>,
+ /// Extra data for each type variable, such as the origin. This is
+ /// not stored in the unification table since, when we inquire
+ /// after the origin of a variable X, we want the origin of **that
+ /// variable X**, not the origin of some other variable Y with
+ /// which X has been unified.
+ var_data: Vec<TypeVariableData>,
/// Two variables are unified in `eq_relations` when we have a
- /// constraint `?X == ?Y`.
- eq_relations: ut::UnificationTable<ty::TyVid>,
+ /// constraint `?X == ?Y`. This table also stores, for each key,
+ /// the known value.
+ eq_relations: ut::UnificationTable<ut::InPlace<TyVidEqKey<'tcx>>>,
/// Two variables are unified in `eq_relations` when we have a
/// constraint `?X <: ?Y` *or* a constraint `?Y <: ?X`. This second
@@ -46,7 +48,7 @@ pub struct TypeVariableTable<'tcx> {
/// This is reasonable because, in Rust, subtypes have the same
/// "skeleton" and hence there is no possible type such that
/// (e.g.) `Box<?3> <: ?3` for any `?3`.
- sub_relations: ut::UnificationTable<ty::TyVid>,
+ sub_relations: ut::UnificationTable<ut::InPlace<ty::TyVid>>,
}
/// Reasons to create a type inference variable
@@ -69,73 +71,91 @@ pub enum TypeVariableOrigin {
pub type TypeVariableMap = FxHashMap<ty::TyVid, TypeVariableOrigin>;
-struct TypeVariableData<'tcx> {
- value: TypeVariableValue<'tcx>,
+struct TypeVariableData {
origin: TypeVariableOrigin,
diverging: bool
}
-enum TypeVariableValue<'tcx> {
- Known(Ty<'tcx>),
- Bounded {
- default: Option<Default<'tcx>>
- }
+#[derive(Copy, Clone, Debug)]
+pub enum TypeVariableValue<'tcx> {
+ Known { value: Ty<'tcx> },
+ Unknown { universe: ty::UniverseIndex },
}
-// We will use this to store the required information to recapitulate what happened when
-// an error occurs.
-#[derive(Clone, Debug, PartialEq, Eq, Hash)]
-pub struct Default<'tcx> {
- pub ty: Ty<'tcx>,
- /// The span where the default was incurred
- pub origin_span: Span,
- /// The definition that the default originates from
- pub def_id: DefId
+#[derive(Copy, Clone, Debug)]
+pub enum ProbeTyValue<'tcx> {
+ Ty(Ty<'tcx>),
+ Vid(ty::TyVid),
}
-pub struct Snapshot {
- snapshot: sv::Snapshot,
- eq_snapshot: ut::Snapshot<ty::TyVid>,
- sub_snapshot: ut::Snapshot<ty::TyVid>,
-}
+impl<'tcx> TypeVariableValue<'tcx> {
+ /// If this value is known, returns the type it is known to be.
+ /// Otherwise, `None`.
+ pub fn known(&self) -> Option<Ty<'tcx>> {
+ match *self {
+ TypeVariableValue::Unknown { .. } => None,
+ TypeVariableValue::Known { value } => Some(value),
+ }
+ }
-struct Instantiate<'tcx> {
- vid: ty::TyVid,
- default: Option<Default<'tcx>>,
+ /// If this value is unknown, returns the universe, otherwise `None`.
+ pub fn universe(&self) -> Option<ty::UniverseIndex> {
+ match *self {
+ TypeVariableValue::Unknown { universe } => Some(universe),
+ TypeVariableValue::Known { .. } => None,
+ }
+ }
+
+ pub fn is_unknown(&self) -> bool {
+ match *self {
+ TypeVariableValue::Unknown { .. } => true,
+ TypeVariableValue::Known { .. } => false,
+ }
+ }
}
-struct Delegate<'tcx>(PhantomData<&'tcx ()>);
+pub struct Snapshot<'tcx> {
+ /// number of variables at the time of the snapshot
+ num_vars: usize,
+
+ /// snapshot from the `eq_relations` table
+ eq_snapshot: ut::Snapshot<ut::InPlace<TyVidEqKey<'tcx>>>,
+
+ /// snapshot from the `sub_relations` table
+ sub_snapshot: ut::Snapshot<ut::InPlace<ty::TyVid>>,
+}
impl<'tcx> TypeVariableTable<'tcx> {
pub fn new() -> TypeVariableTable<'tcx> {
TypeVariableTable {
- values: sv::SnapshotVec::new(),
+ var_data: Vec::new(),
eq_relations: ut::UnificationTable::new(),
sub_relations: ut::UnificationTable::new(),
}
}
- pub fn default(&self, vid: ty::TyVid) -> Option<Default<'tcx>> {
- match &self.values.get(vid.index as usize).value {
- &Known(_) => None,
- &Bounded { ref default, .. } => default.clone()
- }
- }
-
+ /// Returns the diverges flag given when `vid` was created.
+ ///
+ /// Note that this function does not return care whether
+ /// `vid` has been unified with something else or not.
pub fn var_diverges<'a>(&'a self, vid: ty::TyVid) -> bool {
- self.values.get(vid.index as usize).diverging
+ self.var_data[vid.index as usize].diverging
}
+ /// Returns the origin that was given when `vid` was created.
+ ///
+ /// Note that this function does not return care whether
+ /// `vid` has been unified with something else or not.
pub fn var_origin(&self, vid: ty::TyVid) -> &TypeVariableOrigin {
- &self.values.get(vid.index as usize).origin
+ &self.var_data[vid.index as usize].origin
}
/// Records that `a == b`, depending on `dir`.
///
/// Precondition: neither `a` nor `b` are known.
pub fn equate(&mut self, a: ty::TyVid, b: ty::TyVid) {
- debug_assert!(self.probe(a).is_none());
- debug_assert!(self.probe(b).is_none());
+ debug_assert!(self.probe(a).is_unknown());
+ debug_assert!(self.probe(b).is_unknown());
self.eq_relations.union(a, b);
self.sub_relations.union(a, b);
}
@@ -144,8 +164,8 @@ impl<'tcx> TypeVariableTable<'tcx> {
///
/// Precondition: neither `a` nor `b` are known.
pub fn sub(&mut self, a: ty::TyVid, b: ty::TyVid) {
- debug_assert!(self.probe(a).is_none());
- debug_assert!(self.probe(b).is_none());
+ debug_assert!(self.probe(a).is_unknown());
+ debug_assert!(self.probe(b).is_unknown());
self.sub_relations.union(a, b);
}
@@ -154,43 +174,44 @@ impl<'tcx> TypeVariableTable<'tcx> {
/// Precondition: `vid` must not have been previously instantiated.
pub fn instantiate(&mut self, vid: ty::TyVid, ty: Ty<'tcx>) {
let vid = self.root_var(vid);
- debug_assert!(self.probe_root(vid).is_none());
-
- let old_value = {
- let vid_data = &mut self.values[vid.index as usize];
- mem::replace(&mut vid_data.value, TypeVariableValue::Known(ty))
- };
-
- match old_value {
- TypeVariableValue::Bounded { default } => {
- self.values.record(Instantiate { vid: vid, default: default });
- }
- TypeVariableValue::Known(old_ty) => {
- bug!("instantiating type variable `{:?}` twice: new-value = {:?}, old-value={:?}",
- vid, ty, old_ty)
- }
- }
+ debug_assert!(self.probe(vid).is_unknown());
+ debug_assert!(self.eq_relations.probe_value(vid).is_unknown(),
+ "instantiating type variable `{:?}` twice: new-value = {:?}, old-value={:?}",
+ vid, ty, self.eq_relations.probe_value(vid));
+ self.eq_relations.union_value(vid, TypeVariableValue::Known { value: ty });
}
+ /// Creates a new type variable.
+ ///
+ /// - `diverging`: indicates if this is a "diverging" type
+ /// variable, e.g. one created as the type of a `return`
+ /// expression. The code in this module doesn't care if a
+ /// variable is diverging, but the main Rust type-checker will
+ /// sometimes "unify" such variables with the `!` or `()` types.
+ /// - `origin`: indicates *why* the type variable was created.
+ /// The code in this module doesn't care, but it can be useful
+ /// for improving error messages.
pub fn new_var(&mut self,
+ universe: ty::UniverseIndex,
diverging: bool,
- origin: TypeVariableOrigin,
- default: Option<Default<'tcx>>,) -> ty::TyVid {
- debug!("new_var(diverging={:?}, origin={:?})", diverging, origin);
- self.eq_relations.new_key(());
- self.sub_relations.new_key(());
- let index = self.values.push(TypeVariableData {
- value: Bounded { default: default },
- origin,
- diverging,
- });
- let v = ty::TyVid { index: index as u32 };
- debug!("new_var: diverging={:?} index={:?}", diverging, v);
- v
+ origin: TypeVariableOrigin)
+ -> ty::TyVid {
+ let eq_key = self.eq_relations.new_key(TypeVariableValue::Unknown { universe });
+
+ let sub_key = self.sub_relations.new_key(());
+ assert_eq!(eq_key.vid, sub_key);
+
+ assert_eq!(self.var_data.len(), sub_key.index as usize);
+ self.var_data.push(TypeVariableData { origin, diverging });
+
+ debug!("new_var(index={:?}, diverging={:?}, origin={:?}", eq_key.vid, diverging, origin);
+
+ eq_key.vid
}
+ /// Returns the number of type variables created thus far.
pub fn num_vars(&self) -> usize {
- self.values.len()
+ self.var_data.len()
}
/// Returns the "root" variable of `vid` in the `eq_relations`
@@ -199,7 +220,7 @@ impl<'tcx> TypeVariableTable<'tcx> {
/// algorithm), so `root_var(a) == root_var(b)` implies that `a ==
/// b` (transitively).
pub fn root_var(&mut self, vid: ty::TyVid) -> ty::TyVid {
- self.eq_relations.find(vid)
+ self.eq_relations.find(vid).vid
}
/// Returns the "root" variable of `vid` in the `sub_relations`
@@ -219,65 +240,58 @@ impl<'tcx> TypeVariableTable<'tcx> {
self.sub_root_var(a) == self.sub_root_var(b)
}
- pub fn probe(&mut self, vid: ty::TyVid) -> Option<Ty<'tcx>> {
- let vid = self.root_var(vid);
- self.probe_root(vid)
- }
-
- pub fn origin(&self, vid: ty::TyVid) -> TypeVariableOrigin {
- self.values.get(vid.index as usize).origin.clone()
- }
-
- /// Retrieves the type of `vid` given that it is currently a root in the unification table
- pub fn probe_root(&mut self, vid: ty::TyVid) -> Option<Ty<'tcx>> {
- debug_assert!(self.root_var(vid) == vid);
- match self.values.get(vid.index as usize).value {
- Bounded { .. } => None,
- Known(t) => Some(t)
- }
+ /// Retrieves the type to which `vid` has been instantiated, if
+ /// any.
+ pub fn probe(&mut self, vid: ty::TyVid) -> TypeVariableValue<'tcx> {
+ self.eq_relations.probe_value(vid)
}
+ /// If `t` is a type-inference variable, and it has been
+ /// instantiated, then return the with which it was
+ /// instantiated. Otherwise, returns `t`.
pub fn replace_if_possible(&mut self, t: Ty<'tcx>) -> Ty<'tcx> {
match t.sty {
ty::TyInfer(ty::TyVar(v)) => {
match self.probe(v) {
- None => t,
- Some(u) => u
+ TypeVariableValue::Unknown { .. } => t,
+ TypeVariableValue::Known { value } => value,
}
}
_ => t,
}
}
- pub fn snapshot(&mut self) -> Snapshot {
+ /// Creates a snapshot of the type variable state. This snapshot
+ /// must later be committed (`commit()`) or rolled back
+ /// (`rollback_to()`). Nested snapshots are permitted, but must
+ /// be processed in a stack-like fashion.
+ pub fn snapshot(&mut self) -> Snapshot<'tcx> {
Snapshot {
- snapshot: self.values.start_snapshot(),
+ num_vars: self.var_data.len(),
eq_snapshot: self.eq_relations.snapshot(),
sub_snapshot: self.sub_relations.snapshot(),
}
}
- pub fn rollback_to(&mut self, s: Snapshot) {
- debug!("rollback_to{:?}", {
- for action in self.values.actions_since_snapshot(&s.snapshot) {
- match *action {
- sv::UndoLog::NewElem(index) => {
- debug!("inference variable _#{}t popped", index)
- }
- _ => { }
- }
- }
- });
-
- let Snapshot { snapshot, eq_snapshot, sub_snapshot } = s;
- self.values.rollback_to(snapshot);
+ /// Undoes all changes since the snapshot was created. Any
+ /// snapshots created since that point must already have been
+ /// committed or rolled back.
+ pub fn rollback_to(&mut self, s: Snapshot<'tcx>) {
+ let Snapshot { num_vars, eq_snapshot, sub_snapshot } = s;
+ debug!("type_variables::rollback_to(num_vars = {})", num_vars);
+ assert!(self.var_data.len() >= num_vars);
self.eq_relations.rollback_to(eq_snapshot);
self.sub_relations.rollback_to(sub_snapshot);
+ self.var_data.truncate(num_vars);
}
- pub fn commit(&mut self, s: Snapshot) {
- let Snapshot { snapshot, eq_snapshot, sub_snapshot } = s;
- self.values.commit(snapshot);
+ /// Commits all changes since the snapshot was created, making
+ /// them permanent (unless this snapshot was created within
+ /// another snapshot). Any snapshots created since that point
+ /// must already have been committed or rolled back.
+ pub fn commit(&mut self, s: Snapshot<'tcx>) {
+ let Snapshot { num_vars, eq_snapshot, sub_snapshot } = s;
+ debug!("type_variables::commit(num_vars = {})", num_vars);
self.eq_relations.commit(eq_snapshot);
self.sub_relations.commit(sub_snapshot);
}
@@ -286,90 +300,125 @@ impl<'tcx> TypeVariableTable<'tcx> {
/// ty-variables created during the snapshot, and the values
/// `{V2}` are the root variables that they were unified with,
/// along with their origin.
- pub fn types_created_since_snapshot(&mut self, s: &Snapshot) -> TypeVariableMap {
- let actions_since_snapshot = self.values.actions_since_snapshot(&s.snapshot);
-
- actions_since_snapshot
+ pub fn types_created_since_snapshot(&mut self, snapshot: &Snapshot<'tcx>) -> TypeVariableMap {
+ self.var_data
.iter()
- .filter_map(|action| match action {
- &sv::UndoLog::NewElem(index) => Some(ty::TyVid { index: index as u32 }),
- _ => None,
- })
- .map(|vid| {
- let origin = self.values.get(vid.index as usize).origin.clone();
- (vid, origin)
- })
+ .enumerate()
+ .skip(snapshot.num_vars) // skip those that existed when snapshot was taken
+ .map(|(index, data)| (ty::TyVid { index: index as u32 }, data.origin))
.collect()
}
- pub fn types_escaping_snapshot(&mut self, s: &Snapshot) -> Vec<Ty<'tcx>> {
- /*!
- * Find the set of type variables that existed *before* `s`
- * but which have only been unified since `s` started, and
- * return the types with which they were unified. So if we had
- * a type variable `V0`, then we started the snapshot, then we
- * created a type variable `V1`, unifed `V0` with `T0`, and
- * unified `V1` with `T1`, this function would return `{T0}`.
- */
-
- let mut new_elem_threshold = u32::MAX;
- let mut escaping_types = Vec::new();
- let actions_since_snapshot = self.values.actions_since_snapshot(&s.snapshot);
- debug!("actions_since_snapshot.len() = {}", actions_since_snapshot.len());
- for action in actions_since_snapshot {
- match *action {
- sv::UndoLog::NewElem(index) => {
- // if any new variables were created during the
- // snapshot, remember the lower index (which will
- // always be the first one we see). Note that this
- // action must precede those variables being
- // specified.
- new_elem_threshold = min(new_elem_threshold, index as u32);
- debug!("NewElem({}) new_elem_threshold={}", index, new_elem_threshold);
- }
-
- sv::UndoLog::Other(Instantiate { vid, .. }) => {
- if vid.index < new_elem_threshold {
- // quick check to see if this variable was
- // created since the snapshot started or not.
- let escaping_type = match self.values.get(vid.index as usize).value {
- Bounded { .. } => bug!(),
- Known(ty) => ty,
- };
- escaping_types.push(escaping_type);
- }
- debug!("SpecifyVar({:?}) new_elem_threshold={}", vid, new_elem_threshold);
- }
-
- _ => { }
- }
- }
-
+ /// Find the set of type variables that existed *before* `s`
+ /// but which have only been unified since `s` started, and
+ /// return the types with which they were unified. So if we had
+ /// a type variable `V0`, then we started the snapshot, then we
+ /// created a type variable `V1`, unifed `V0` with `T0`, and
+ /// unified `V1` with `T1`, this function would return `{T0}`.
+ pub fn types_escaping_snapshot(&mut self, snapshot: &Snapshot<'tcx>) -> Vec<Ty<'tcx>> {
+ // We want to select only those instantiations that have
+ // occurred since the snapshot *and* which affect some
+ // variable that existed prior to the snapshot. This code just
+ // affects all instantiatons that ever occurred which affect
+ // variables prior to the snapshot.
+ //
+ // It's hard to do better than this, though, without changing
+ // the unification table to prefer "lower" vids -- the problem
+ // is that we may have a variable X (from before the snapshot)
+ // and Y (from after the snapshot) which get unified, with Y
+ // chosen as the new root. Now we are "instantiating" Y with a
+ // value, but it escapes into X, but we wouldn't readily see
+ // that. (In fact, earlier revisions of this code had this
+ // bug; it was introduced when we added the `eq_relations`
+ // table, but it's hard to create rust code that triggers it.)
+ //
+ // We could tell the table to prefer lower vids, and then we would
+ // see the case above, but we would get less-well-balanced trees.
+ //
+ // Since I hope to kill the leak-check in this branch, and
+ // that's the code which uses this logic anyway, I'm going to
+ // use the less efficient algorithm for now.
+ let mut escaping_types = Vec::with_capacity(snapshot.num_vars);
+ escaping_types.extend(
+ (0..snapshot.num_vars) // for all variables that pre-exist the snapshot, collect..
+ .map(|i| ty::TyVid { index: i as u32 })
+ .filter_map(|vid| self.probe(vid).known())); // ..types they are instantiated with.
+ debug!("types_escaping_snapshot = {:?}", escaping_types);
escaping_types
}
+ /// Returns indices of all variables that are not yet
+ /// instantiated.
pub fn unsolved_variables(&mut self) -> Vec<ty::TyVid> {
- (0..self.values.len())
+ (0..self.var_data.len())
.filter_map(|i| {
let vid = ty::TyVid { index: i as u32 };
- if self.probe(vid).is_some() {
- None
- } else {
- Some(vid)
+ match self.probe(vid) {
+ TypeVariableValue::Unknown { .. } => Some(vid),
+ TypeVariableValue::Known { .. } => None,
}
})
.collect()
}
}
+///////////////////////////////////////////////////////////////////////////
-impl<'tcx> sv::SnapshotVecDelegate for Delegate<'tcx> {
- type Value = TypeVariableData<'tcx>;
- type Undo = Instantiate<'tcx>;
+/// These structs (a newtyped TyVid) are used as the unification key
+/// for the `eq_relations`; they carry a `TypeVariableValue` along
+/// with them.
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+struct TyVidEqKey<'tcx> {
+ vid: ty::TyVid,
- fn reverse(values: &mut Vec<TypeVariableData<'tcx>>, action: Instantiate<'tcx>) {
- let Instantiate { vid, default } = action;
- values[vid.index as usize].value = Bounded {
- default,
- };
+ // in the table, we map each ty-vid to one of these:
+ phantom: PhantomData<TypeVariableValue<'tcx>>,
+}
+
+impl<'tcx> From<ty::TyVid> for TyVidEqKey<'tcx> {
+ fn from(vid: ty::TyVid) -> Self {
+ TyVidEqKey { vid, phantom: PhantomData }
+ }
+}
+
+impl<'tcx> ut::UnifyKey for TyVidEqKey<'tcx> {
+ type Value = TypeVariableValue<'tcx>;
+ fn index(&self) -> u32 { self.vid.index }
+ fn from_index(i: u32) -> Self { TyVidEqKey::from(ty::TyVid { index: i }) }
+ fn tag() -> &'static str { "TyVidEqKey" }
+}
+
+impl<'tcx> ut::UnifyValue for TypeVariableValue<'tcx> {
+ type Error = ut::NoError;
+
+ fn unify_values(value1: &Self, value2: &Self) -> Result<Self, ut::NoError> {
+ match (value1, value2) {
+ // We never equate two type variables, both of which
+ // have known types. Instead, we recursively equate
+ // those types.
+ (&TypeVariableValue::Known { .. }, &TypeVariableValue::Known { .. }) => {
+ bug!("equating two type variables, both of which have known types")
+ }
+
+ // If one side is known, prefer that one.
+ (&TypeVariableValue::Known { .. }, &TypeVariableValue::Unknown { .. }) => Ok(*value1),
+ (&TypeVariableValue::Unknown { .. }, &TypeVariableValue::Known { .. }) => Ok(*value2),
+
+ // If both sides are unknown, we need to pick the most restrictive universe.
+ (&TypeVariableValue::Unknown { universe: universe1 },
+ &TypeVariableValue::Unknown { universe: universe2 }) => {
+ let universe = cmp::min(universe1, universe2);
+ Ok(TypeVariableValue::Unknown { universe })
+ }
+ }
}
}
+
+/// Raw `TyVid` are used as the unification key for `sub_relations`;
+/// they carry no values.
+impl ut::UnifyKey for ty::TyVid {
+ type Value = ();
+ fn index(&self) -> u32 { self.index }
+ fn from_index(i: u32) -> ty::TyVid { ty::TyVid { index: i } }
+ fn tag() -> &'static str { "TyVid" }
+}
+
diff --git a/src/librustc/infer/unify_key.rs b/src/librustc/infer/unify_key.rs
index d7e3a53ff25c9..24e3aa51e290a 100644
--- a/src/librustc/infer/unify_key.rs
+++ b/src/librustc/infer/unify_key.rs
@@ -8,9 +8,8 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use syntax::ast;
-use ty::{self, IntVarValue, Ty, TyCtxt};
-use rustc_data_structures::unify::{Combine, UnifyKey};
+use ty::{self, FloatVarValue, IntVarValue, Ty, TyCtxt};
+use rustc_data_structures::unify::{NoError, EqUnifyValue, UnifyKey, UnifyValue};
pub trait ToType {
fn to_type<'a, 'gcx, 'tcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx>;
@@ -20,7 +19,10 @@ impl UnifyKey for ty::IntVid {
type Value = Option<IntVarValue>;
fn index(&self) -> u32 { self.index }
fn from_index(i: u32) -> ty::IntVid { ty::IntVid { index: i } }
- fn tag(_: Option<ty::IntVid>) -> &'static str { "IntVid" }
+ fn tag() -> &'static str { "IntVid" }
+}
+
+impl EqUnifyValue for IntVarValue {
}
#[derive(PartialEq, Copy, Clone, Debug)]
@@ -31,15 +33,17 @@ pub struct RegionVidKey {
pub min_vid: ty::RegionVid
}
-impl Combine for RegionVidKey {
- fn combine(&self, other: &RegionVidKey) -> RegionVidKey {
- let min_vid = if self.min_vid.index < other.min_vid.index {
- self.min_vid
+impl UnifyValue for RegionVidKey {
+ type Error = NoError;
+
+ fn unify_values(value1: &Self, value2: &Self) -> Result<Self, NoError> {
+ let min_vid = if value1.min_vid.index < value2.min_vid.index {
+ value1.min_vid
} else {
- other.min_vid
+ value2.min_vid
};
- RegionVidKey { min_vid: min_vid }
+ Ok(RegionVidKey { min_vid: min_vid })
}
}
@@ -47,7 +51,7 @@ impl UnifyKey for ty::RegionVid {
type Value = RegionVidKey;
fn index(&self) -> u32 { self.index }
fn from_index(i: u32) -> ty::RegionVid { ty::RegionVid { index: i } }
- fn tag(_: Option<ty::RegionVid>) -> &'static str { "RegionVid" }
+ fn tag() -> &'static str { "RegionVid" }
}
impl ToType for IntVarValue {
@@ -62,21 +66,17 @@ impl ToType for IntVarValue {
// Floating point type keys
impl UnifyKey for ty::FloatVid {
- type Value = Option<ast::FloatTy>;
+ type Value = Option<FloatVarValue>;
fn index(&self) -> u32 { self.index }
fn from_index(i: u32) -> ty::FloatVid { ty::FloatVid { index: i } }
- fn tag(_: Option<ty::FloatVid>) -> &'static str { "FloatVid" }
+ fn tag() -> &'static str { "FloatVid" }
}
-impl ToType for ast::FloatTy {
- fn to_type<'a, 'gcx, 'tcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
- tcx.mk_mach_float(*self)
- }
+impl EqUnifyValue for FloatVarValue {
}
-impl UnifyKey for ty::TyVid {
- type Value = ();
- fn index(&self) -> u32 { self.index }
- fn from_index(i: u32) -> ty::TyVid { ty::TyVid { index: i } }
- fn tag(_: Option<ty::TyVid>) -> &'static str { "TyVid" }
+impl ToType for FloatVarValue {
+ fn to_type<'a, 'gcx, 'tcx>(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
+ tcx.mk_mach_float(self.0)
+ }
}
diff --git a/src/librustc/traits/coherence.rs b/src/librustc/traits/coherence.rs
index 10a32c26e741d..bc805e85f7baa 100644
--- a/src/librustc/traits/coherence.rs
+++ b/src/librustc/traits/coherence.rs
@@ -50,7 +50,9 @@ fn with_fresh_ty_vars<'cx, 'gcx, 'tcx>(selcx: &mut SelectionContext<'cx, 'gcx, '
-> ty::ImplHeader<'tcx>
{
let tcx = selcx.tcx();
- let impl_substs = selcx.infcx().fresh_substs_for_item(DUMMY_SP, impl_def_id);
+ let impl_substs = selcx.infcx().fresh_substs_for_item(param_env.universe,
+ DUMMY_SP,
+ impl_def_id);
let header = ty::ImplHeader {
impl_def_id,
diff --git a/src/librustc/traits/error_reporting.rs b/src/librustc/traits/error_reporting.rs
index e2b23c12cf1f3..e4e53a6692751 100644
--- a/src/librustc/traits/error_reporting.rs
+++ b/src/librustc/traits/error_reporting.rs
@@ -285,7 +285,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
self.tcx.for_each_relevant_impl(
trait_ref.def_id, trait_self_ty, |def_id| {
- let impl_substs = self.fresh_substs_for_item(obligation.cause.span, def_id);
+ let impl_substs = self.fresh_substs_for_item(param_env.universe,
+ obligation.cause.span,
+ def_id);
let impl_trait_ref = tcx
.impl_trait_ref(def_id)
.unwrap()
@@ -1134,6 +1136,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
-> bool {
struct ParamToVarFolder<'a, 'gcx: 'a+'tcx, 'tcx: 'a> {
infcx: &'a InferCtxt<'a, 'gcx, 'tcx>,
+ param_env: ty::ParamEnv<'tcx>,
var_map: FxHashMap<Ty<'tcx>, Ty<'tcx>>
}
@@ -1143,9 +1146,14 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
fn fold_ty(&mut self, ty: Ty<'tcx>) -> Ty<'tcx> {
if let ty::TyParam(ty::ParamTy {name, ..}) = ty.sty {
let infcx = self.infcx;
- self.var_map.entry(ty).or_insert_with(||
- infcx.next_ty_var(
- TypeVariableOrigin::TypeParameterDefinition(DUMMY_SP, name)))
+ let param_env = self.param_env;
+ self.var_map
+ .entry(ty)
+ .or_insert_with(|| {
+ let origin = TypeVariableOrigin::TypeParameterDefinition(DUMMY_SP,
+ name);
+ infcx.next_ty_var(param_env.universe, origin)
+ })
} else {
ty.super_fold_with(self)
}
@@ -1157,6 +1165,7 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
let cleaned_pred = pred.fold_with(&mut ParamToVarFolder {
infcx: self,
+ param_env,
var_map: FxHashMap()
});
diff --git a/src/librustc/traits/mod.rs b/src/librustc/traits/mod.rs
index c08fe187f99bf..09c7d7316baa2 100644
--- a/src/librustc/traits/mod.rs
+++ b/src/librustc/traits/mod.rs
@@ -68,10 +68,21 @@ mod util;
/// scope. The eventual result is usually a `Selection` (defined below).
#[derive(Clone, PartialEq, Eq)]
pub struct Obligation<'tcx, T> {
+ /// Why do we have to prove this thing?
pub cause: ObligationCause<'tcx>,
+
+ /// In which environment should we prove this thing?
pub param_env: ty::ParamEnv<'tcx>,
- pub recursion_depth: usize,
+
+ /// What are we trying to prove?
pub predicate: T,
+
+ /// If we started proving this as a result of trying to prove
+ /// something else, track the total depth to ensure termination.
+ /// If this goes over a certain threshold, we abort compilation --
+ /// in such cases, we can not say whether or not the predicate
+ /// holds for certain. Stupid halting problem. Such a drag.
+ pub recursion_depth: usize,
}
pub type PredicateObligation<'tcx> = Obligation<'tcx, ty::Predicate<'tcx>>;
@@ -509,7 +520,8 @@ pub fn normalize_param_env_or_error<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
predicates);
let elaborated_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
- unnormalized_env.reveal);
+ unnormalized_env.reveal,
+ unnormalized_env.universe);
tcx.infer_ctxt().enter(|infcx| {
let predicates = match fully_normalize(
@@ -562,7 +574,9 @@ pub fn normalize_param_env_or_error<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
debug!("normalize_param_env_or_error: resolved predicates={:?}",
predicates);
- ty::ParamEnv::new(tcx.intern_predicates(&predicates), unnormalized_env.reveal)
+ ty::ParamEnv::new(tcx.intern_predicates(&predicates),
+ unnormalized_env.reveal,
+ unnormalized_env.universe)
})
}
diff --git a/src/librustc/traits/project.rs b/src/librustc/traits/project.rs
index 9c56df058c3dd..6cb556cc99aa5 100644
--- a/src/librustc/traits/project.rs
+++ b/src/librustc/traits/project.rs
@@ -404,6 +404,7 @@ pub fn normalize_projection_type<'a, 'b, 'gcx, 'tcx>(
let tcx = selcx.infcx().tcx;
let def_id = projection_ty.item_def_id;
let ty_var = selcx.infcx().next_ty_var(
+ param_env.universe,
TypeVariableOrigin::NormalizeProjectionType(tcx.def_span(def_id)));
let projection = ty::Binder(ty::ProjectionPredicate {
projection_ty,
@@ -724,6 +725,7 @@ fn normalize_to_error<'a, 'gcx, 'tcx>(selcx: &mut SelectionContext<'a, 'gcx, 'tc
let tcx = selcx.infcx().tcx;
let def_id = projection_ty.item_def_id;
let new_value = selcx.infcx().next_ty_var(
+ param_env.universe,
TypeVariableOrigin::NormalizeProjectionType(tcx.def_span(def_id)));
Normalized {
value: new_value,
diff --git a/src/librustc/traits/select.rs b/src/librustc/traits/select.rs
index 7716770d318ba..ec911911a07ba 100644
--- a/src/librustc/traits/select.rs
+++ b/src/librustc/traits/select.rs
@@ -452,7 +452,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
/// Wraps the inference context's in_snapshot s.t. snapshot handling is only from the selection
/// context's self.
fn in_snapshot<R, F>(&mut self, f: F) -> R
- where F: FnOnce(&mut Self, &infer::CombinedSnapshot) -> R
+ where F: FnOnce(&mut Self, &infer::CombinedSnapshot<'cx, 'tcx>) -> R
{
// The irrefutable nature of the operation means we don't need to snapshot the
// inferred_obligations vector.
@@ -462,7 +462,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
/// Wraps a probe s.t. obligations collected during it are ignored and old obligations are
/// retained.
fn probe<R, F>(&mut self, f: F) -> R
- where F: FnOnce(&mut Self, &infer::CombinedSnapshot) -> R
+ where F: FnOnce(&mut Self, &infer::CombinedSnapshot<'cx, 'tcx>) -> R
{
let inferred_obligations_snapshot = self.inferred_obligations.start_snapshot();
let result = self.infcx.probe(|snapshot| f(self, snapshot));
@@ -1407,7 +1407,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
fn match_projection_obligation_against_definition_bounds(
&mut self,
obligation: &TraitObligation<'tcx>,
- snapshot: &infer::CombinedSnapshot)
+ snapshot: &infer::CombinedSnapshot<'cx, 'tcx>)
-> bool
{
let poly_trait_predicate =
@@ -1478,7 +1478,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
trait_bound: ty::PolyTraitRef<'tcx>,
skol_trait_ref: ty::TraitRef<'tcx>,
skol_map: &infer::SkolemizationMap<'tcx>,
- snapshot: &infer::CombinedSnapshot)
+ snapshot: &infer::CombinedSnapshot<'cx, 'tcx>)
-> bool
{
assert!(!skol_trait_ref.has_escaping_regions());
@@ -2507,7 +2507,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
recursion_depth: usize,
param_env: ty::ParamEnv<'tcx>,
skol_map: infer::SkolemizationMap<'tcx>,
- snapshot: &infer::CombinedSnapshot)
+ snapshot: &infer::CombinedSnapshot<'cx, 'tcx>)
-> VtableImplData<'tcx, PredicateObligation<'tcx>>
{
debug!("vtable_impl(impl_def_id={:?}, substs={:?}, recursion_depth={}, skol_map={:?})",
@@ -2996,7 +2996,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
fn rematch_impl(&mut self,
impl_def_id: DefId,
obligation: &TraitObligation<'tcx>,
- snapshot: &infer::CombinedSnapshot)
+ snapshot: &infer::CombinedSnapshot<'cx, 'tcx>)
-> (Normalized<'tcx, &'tcx Substs<'tcx>>,
infer::SkolemizationMap<'tcx>)
{
@@ -3013,7 +3013,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
fn match_impl(&mut self,
impl_def_id: DefId,
obligation: &TraitObligation<'tcx>,
- snapshot: &infer::CombinedSnapshot)
+ snapshot: &infer::CombinedSnapshot<'cx, 'tcx>)
-> Result<(Normalized<'tcx, &'tcx Substs<'tcx>>,
infer::SkolemizationMap<'tcx>), ()>
{
@@ -3031,7 +3031,8 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
snapshot);
let skol_obligation_trait_ref = skol_obligation.trait_ref;
- let impl_substs = self.infcx.fresh_substs_for_item(obligation.cause.span,
+ let impl_substs = self.infcx.fresh_substs_for_item(obligation.param_env.universe,
+ obligation.cause.span,
impl_def_id);
let impl_trait_ref = impl_trait_ref.subst(self.tcx(),
@@ -3210,7 +3211,7 @@ impl<'cx, 'gcx, 'tcx> SelectionContext<'cx, 'gcx, 'tcx> {
def_id: DefId, // of impl or trait
substs: &Substs<'tcx>, // for impl or trait
skol_map: infer::SkolemizationMap<'tcx>,
- snapshot: &infer::CombinedSnapshot)
+ snapshot: &infer::CombinedSnapshot<'cx, 'tcx>)
-> Vec<PredicateObligation<'tcx>>
{
debug!("impl_or_trait_obligations(def_id={:?})", def_id);
diff --git a/src/librustc/traits/specialize/mod.rs b/src/librustc/traits/specialize/mod.rs
index d8d0715ff3957..5f2136ef9c8cf 100644
--- a/src/librustc/traits/specialize/mod.rs
+++ b/src/librustc/traits/specialize/mod.rs
@@ -217,7 +217,7 @@ fn fulfill_implication<'a, 'gcx, 'tcx>(infcx: &InferCtxt<'a, 'gcx, 'tcx>,
target_impl: DefId)
-> Result<&'tcx Substs<'tcx>, ()> {
let selcx = &mut SelectionContext::new(&infcx);
- let target_substs = infcx.fresh_substs_for_item(DUMMY_SP, target_impl);
+ let target_substs = infcx.fresh_substs_for_item(param_env.universe, DUMMY_SP, target_impl);
let (target_trait_ref, mut obligations) = impl_trait_ref_and_oblig(selcx,
param_env,
target_impl,
diff --git a/src/librustc/ty/error.rs b/src/librustc/ty/error.rs
index 5cfa72c07126f..7b46525544bfd 100644
--- a/src/librustc/ty/error.rs
+++ b/src/librustc/ty/error.rs
@@ -9,9 +9,8 @@
// except according to those terms.
use hir::def_id::DefId;
-use infer::type_variable;
use middle::const_val::ConstVal;
-use ty::{self, BoundRegion, DefIdTree, Region, Ty, TyCtxt};
+use ty::{self, BoundRegion, Region, Ty, TyCtxt};
use std::fmt;
use syntax::abi;
@@ -52,7 +51,6 @@ pub enum TypeError<'tcx> {
CyclicTy,
ProjectionMismatched(ExpectedFound<DefId>),
ProjectionBoundsLength(ExpectedFound<usize>),
- TyParamDefaultMismatch(ExpectedFound<type_variable::Default<'tcx>>),
ExistentialMismatch(ExpectedFound<&'tcx ty::Slice<ty::ExistentialPredicate<'tcx>>>),
}
@@ -161,11 +159,6 @@ impl<'tcx> fmt::Display for TypeError<'tcx> {
values.expected,
values.found)
},
- TyParamDefaultMismatch(ref values) => {
- write!(f, "conflicting type parameter defaults `{}` and `{}`",
- values.expected.ty,
- values.found.ty)
- }
ExistentialMismatch(ref values) => {
report_maybe_different(f, format!("trait `{}`", values.expected),
format!("trait `{}`", values.found))
@@ -257,42 +250,6 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
"consider boxing your closure and/or using it as a trait object");
}
},
- TyParamDefaultMismatch(values) => {
- let expected = values.expected;
- let found = values.found;
- db.span_note(sp, &format!("conflicting type parameter defaults `{}` and `{}`",
- expected.ty,
- found.ty));
-
- match self.hir.span_if_local(expected.def_id) {
- Some(span) => {
- db.span_note(span, "a default was defined here...");
- }
- None => {
- let item_def_id = self.parent(expected.def_id).unwrap();
- db.note(&format!("a default is defined on `{}`",
- self.item_path_str(item_def_id)));
- }
- }
-
- db.span_note(
- expected.origin_span,
- "...that was applied to an unconstrained type variable here");
-
- match self.hir.span_if_local(found.def_id) {
- Some(span) => {
- db.span_note(span, "a second default was defined here...");
- }
- None => {
- let item_def_id = self.parent(found.def_id).unwrap();
- db.note(&format!("a second default is defined on `{}`",
- self.item_path_str(item_def_id)));
- }
- }
-
- db.span_note(found.origin_span,
- "...that also applies to the same type variable here");
- }
_ => {}
}
}
diff --git a/src/librustc/ty/mod.rs b/src/librustc/ty/mod.rs
index 0deababd21829..af2bb1b1e7fab 100644
--- a/src/librustc/ty/mod.rs
+++ b/src/librustc/ty/mod.rs
@@ -68,7 +68,7 @@ pub use self::sty::{ExistentialTraitRef, PolyExistentialTraitRef};
pub use self::sty::{ExistentialProjection, PolyExistentialProjection, Const};
pub use self::sty::{BoundRegion, EarlyBoundRegion, FreeRegion, Region};
pub use self::sty::RegionKind;
-pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid, SkolemizedRegionVid};
+pub use self::sty::{TyVid, IntVid, FloatVid, RegionVid};
pub use self::sty::BoundRegion::*;
pub use self::sty::InferTy::*;
pub use self::sty::RegionKind::*;
@@ -655,12 +655,15 @@ pub struct ClosureUpvar<'tcx> {
pub ty: Ty<'tcx>,
}
-#[derive(Clone, Copy, PartialEq)]
+#[derive(Clone, Copy, PartialEq, Eq)]
pub enum IntVarValue {
IntType(ast::IntTy),
UintType(ast::UintTy),
}
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct FloatVarValue(pub ast::FloatTy);
+
#[derive(Copy, Clone, RustcEncodable, RustcDecodable)]
pub struct TypeParameterDef {
pub name: Name,
@@ -1236,6 +1239,85 @@ impl<'tcx> InstantiatedPredicates<'tcx> {
}
}
+/// "Universes" are used during type- and trait-checking in the
+/// presence of `for<..>` binders to control what sets of names are
+/// visible. Universes are arranged into a tree: the root universe
+/// contains names that are always visible. But when you enter into
+/// some subuniverse, then it may add names that are only visible
+/// within that subtree (but it can still name the names of its
+/// ancestor universes).
+///
+/// To make this more concrete, consider this program:
+///
+/// ```
+/// struct Foo { }
+/// fn bar<T>(x: T) {
+/// let y: for<'a> fn(&'a u8, Foo) = ...;
+/// }
+/// ```
+///
+/// The struct name `Foo` is in the root universe U0. But the type
+/// parameter `T`, introduced on `bar`, is in a subuniverse U1 --
+/// i.e., within `bar`, we can name both `T` and `Foo`, but outside of
+/// `bar`, we cannot name `T`. Then, within the type of `y`, the
+/// region `'a` is in a subuniverse U2 of U1, because we can name it
+/// inside the fn type but not outside.
+///
+/// Universes are related to **skolemization** -- which is a way of
+/// doing type- and trait-checking around these "forall" binders (also
+/// called **universal quantification**). The idea is that when, in
+/// the body of `bar`, we refer to `T` as a type, we aren't referring
+/// to any type in particular, but rather a kind of "fresh" type that
+/// is distinct from all other types we have actually declared. This
+/// is called a **skolemized** type, and we use universes to talk
+/// about this. In other words, a type name in universe 0 always
+/// corresponds to some "ground" type that the user declared, but a
+/// type name in a non-zero universe is a skolemized type -- an
+/// idealized representative of "types in general" that we use for
+/// checking generic functions.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
+pub struct UniverseIndex(u32);
+
+impl UniverseIndex {
+ /// The root universe, where things that the user defined are
+ /// visible.
+ pub const ROOT: UniverseIndex = UniverseIndex(0);
+
+ /// A "subuniverse" corresponds to being inside a `forall` quantifier.
+ /// So, for example, suppose we have this type in universe `U`:
+ ///
+ /// ```
+ /// for<'a> fn(&'a u32)
+ /// ```
+ ///
+ /// Once we "enter" into this `for<'a>` quantifier, we are in a
+ /// subuniverse of `U` -- in this new universe, we can name the
+ /// region `'a`, but that region was not nameable from `U` because
+ /// it was not in scope there.
+ pub fn subuniverse(self) -> UniverseIndex {
+ UniverseIndex(self.0.checked_add(1).unwrap())
+ }
+
+ pub fn from(v: u32) -> UniverseIndex {
+ UniverseIndex(v)
+ }
+
+ pub fn as_u32(&self) -> u32 {
+ self.0
+ }
+
+ pub fn as_usize(&self) -> usize {
+ self.0 as usize
+ }
+
+ /// Gets the "depth" of this universe in the universe tree. This
+ /// is not really useful except for e.g. the `HashStable`
+ /// implementation
+ pub fn depth(&self) -> u32 {
+ self.0
+ }
+}
+
/// When type checking, we use the `ParamEnv` to track
/// details about the set of where-clauses that are in scope at this
/// particular point.
@@ -1250,6 +1332,17 @@ pub struct ParamEnv<'tcx> {
/// want `Reveal::All` -- note that this is always paired with an
/// empty environment. To get that, use `ParamEnv::reveal()`.
pub reveal: traits::Reveal,
+
+ /// What is the innermost universe we have created? Starts out as
+ /// `UniverseIndex::root()` but grows from there as we enter
+ /// universal quantifiers.
+ ///
+ /// NB: At present, we exclude the universal quantifiers on the
+ /// item we are type-checking, and just consider those names as
+ /// part of the root universe. So this would only get incremented
+ /// when we enter into a higher-ranked (`for<..>`) type or trait
+ /// bound.
+ pub universe: UniverseIndex,
}
impl<'tcx> ParamEnv<'tcx> {
@@ -2565,7 +2658,8 @@ fn param_env<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
// sure that this will succeed without errors anyway.
let unnormalized_env = ty::ParamEnv::new(tcx.intern_predicates(&predicates),
- traits::Reveal::UserFacing);
+ traits::Reveal::UserFacing,
+ ty::UniverseIndex::ROOT);
let body_id = tcx.hir.as_local_node_id(def_id).map_or(DUMMY_NODE_ID, |id| {
tcx.hir.maybe_body_owned_by(id).map_or(id, |body| body.node_id)
diff --git a/src/librustc/ty/structural_impls.rs b/src/librustc/ty/structural_impls.rs
index 5f1448cd1f18e..15257fc5a277e 100644
--- a/src/librustc/ty/structural_impls.rs
+++ b/src/librustc/ty/structural_impls.rs
@@ -8,7 +8,6 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use infer::type_variable;
use middle::const_val::{self, ConstVal, ConstAggregate, ConstEvalErr};
use ty::{self, Lift, Ty, TyCtxt};
use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
@@ -239,6 +238,7 @@ impl<'a, 'tcx> Lift<'tcx> for ty::ParamEnv<'a> {
tcx.lift(&self.caller_bounds).map(|caller_bounds| {
ty::ParamEnv {
reveal: self.reveal,
+ universe: self.universe,
caller_bounds,
}
})
@@ -381,19 +381,6 @@ impl<'tcx, T: Lift<'tcx>> Lift<'tcx> for ty::error::ExpectedFound<T> {
}
}
-impl<'a, 'tcx> Lift<'tcx> for type_variable::Default<'a> {
- type Lifted = type_variable::Default<'tcx>;
- fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
- tcx.lift(&self.ty).map(|ty| {
- type_variable::Default {
- ty,
- origin_span: self.origin_span,
- def_id: self.def_id
- }
- })
- }
-}
-
impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
type Lifted = ty::error::TypeError<'tcx>;
fn lift_to_tcx<'b, 'gcx>(&self, tcx: TyCtxt<'b, 'gcx, 'tcx>) -> Option<Self::Lifted> {
@@ -425,9 +412,6 @@ impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
ProjectionBoundsLength(x) => ProjectionBoundsLength(x),
Sorts(ref x) => return tcx.lift(x).map(Sorts),
- TyParamDefaultMismatch(ref x) => {
- return tcx.lift(x).map(TyParamDefaultMismatch)
- }
ExistentialMismatch(ref x) => return tcx.lift(x).map(ExistentialMismatch)
})
}
@@ -601,12 +585,23 @@ impl<'tcx> TypeFoldable<'tcx> for ty::ParamEnv<'tcx> {
ty::ParamEnv {
reveal: self.reveal,
caller_bounds: self.caller_bounds.fold_with(folder),
+ universe: self.universe.fold_with(folder),
}
}
fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
- let &ty::ParamEnv { reveal: _, ref caller_bounds } = self;
- caller_bounds.super_visit_with(visitor)
+ let &ty::ParamEnv { reveal: _, ref universe, ref caller_bounds } = self;
+ universe.super_visit_with(visitor) || caller_bounds.super_visit_with(visitor)
+ }
+}
+
+impl<'tcx> TypeFoldable<'tcx> for ty::UniverseIndex {
+ fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, _folder: &mut F) -> Self {
+ *self
+ }
+
+ fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> bool {
+ false
}
}
@@ -1119,20 +1114,6 @@ impl<'tcx, T: TypeFoldable<'tcx>> TypeFoldable<'tcx> for ty::error::ExpectedFoun
}
}
-impl<'tcx> TypeFoldable<'tcx> for type_variable::Default<'tcx> {
- fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
- type_variable::Default {
- ty: self.ty.fold_with(folder),
- origin_span: self.origin_span,
- def_id: self.def_id
- }
- }
-
- fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> bool {
- self.ty.visit_with(visitor)
- }
-}
-
impl<'tcx, T: TypeFoldable<'tcx>, I: Idx> TypeFoldable<'tcx> for IndexVec<I, T> {
fn super_fold_with<'gcx: 'tcx, F: TypeFolder<'gcx, 'tcx>>(&self, folder: &mut F) -> Self {
self.iter().map(|x| x.fold_with(folder)).collect()
@@ -1172,7 +1153,6 @@ impl<'tcx> TypeFoldable<'tcx> for ty::error::TypeError<'tcx> {
ProjectionMismatched(x) => ProjectionMismatched(x),
ProjectionBoundsLength(x) => ProjectionBoundsLength(x),
Sorts(x) => Sorts(x.fold_with(folder)),
- TyParamDefaultMismatch(ref x) => TyParamDefaultMismatch(x.fold_with(folder)),
ExistentialMismatch(x) => ExistentialMismatch(x.fold_with(folder)),
}
}
@@ -1191,7 +1171,6 @@ impl<'tcx> TypeFoldable<'tcx> for ty::error::TypeError<'tcx> {
b.visit_with(visitor)
},
Sorts(x) => x.visit_with(visitor),
- TyParamDefaultMismatch(ref x) => x.visit_with(visitor),
ExistentialMismatch(x) => x.visit_with(visitor),
Mismatch |
Mutability |
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs
index d0ac7d0183a58..c1328552ccb4e 100644
--- a/src/librustc/ty/sty.rs
+++ b/src/librustc/ty/sty.rs
@@ -854,7 +854,7 @@ pub enum RegionKind {
/// A skolemized region - basically the higher-ranked version of ReFree.
/// Should not exist after typeck.
- ReSkolemized(SkolemizedRegionVid, BoundRegion),
+ ReSkolemized(ty::UniverseIndex, BoundRegion),
/// Empty lifetime is for data that is never accessed.
/// Bottom in the region lattice. We treat ReEmpty somewhat
@@ -898,11 +898,6 @@ pub struct RegionVid {
pub index: u32,
}
-#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
-pub struct SkolemizedRegionVid {
- pub index: u32,
-}
-
#[derive(Clone, Copy, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
pub enum InferTy {
TyVar(TyVid),
diff --git a/src/librustc/ty/util.rs b/src/librustc/ty/util.rs
index 39842a543b54b..2a7b0fb20e9fa 100644
--- a/src/librustc/ty/util.rs
+++ b/src/librustc/ty/util.rs
@@ -153,14 +153,15 @@ impl<'tcx> ty::ParamEnv<'tcx> {
/// Construct a trait environment suitable for contexts where
/// there are no where clauses in scope.
pub fn empty(reveal: Reveal) -> Self {
- Self::new(ty::Slice::empty(), reveal)
+ Self::new(ty::Slice::empty(), reveal, ty::UniverseIndex::ROOT)
}
/// Construct a trait environment with the given set of predicates.
pub fn new(caller_bounds: &'tcx ty::Slice<ty::Predicate<'tcx>>,
- reveal: Reveal)
+ reveal: Reveal,
+ universe: ty::UniverseIndex)
-> Self {
- ty::ParamEnv { caller_bounds, reveal }
+ ty::ParamEnv { caller_bounds, reveal, universe }
}
/// Returns a new parameter environment with the same clauses, but
diff --git a/src/librustc/util/ppaux.rs b/src/librustc/util/ppaux.rs
index acb929981fbf2..ba147443a71dc 100644
--- a/src/librustc/util/ppaux.rs
+++ b/src/librustc/util/ppaux.rs
@@ -762,7 +762,7 @@ define_print! {
}
ty::ReSkolemized(id, ref bound_region) => {
- write!(f, "ReSkolemized({}, {:?})", id.index, bound_region)
+ write!(f, "ReSkolemized({:?}, {:?})", id, bound_region)
}
ty::ReEmpty => write!(f, "ReEmpty"),
@@ -888,6 +888,12 @@ impl fmt::Debug for ty::IntVarValue {
}
}
+impl fmt::Debug for ty::FloatVarValue {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ self.0.fmt(f)
+ }
+}
+
// The generic impl doesn't work yet because projections are not
// normalized under HRTB.
/*impl<T> fmt::Display for ty::Binder<T>
diff --git a/src/librustc_data_structures/Cargo.toml b/src/librustc_data_structures/Cargo.toml
index 343b1ed68b804..381b89a238fd6 100644
--- a/src/librustc_data_structures/Cargo.toml
+++ b/src/librustc_data_structures/Cargo.toml
@@ -9,5 +9,6 @@ path = "lib.rs"
crate-type = ["dylib"]
[dependencies]
+ena = "0.8.0"
log = "0.3"
serialize = { path = "../libserialize" }
diff --git a/src/librustc_data_structures/lib.rs b/src/librustc_data_structures/lib.rs
index 3a20343033c23..e32ab10de4824 100644
--- a/src/librustc_data_structures/lib.rs
+++ b/src/librustc_data_structures/lib.rs
@@ -36,6 +36,7 @@
#![cfg_attr(test, feature(test))]
extern crate core;
+extern crate ena;
#[macro_use]
extern crate log;
extern crate serialize as rustc_serialize; // used by deriving
@@ -57,10 +58,10 @@ pub mod indexed_vec;
pub mod obligation_forest;
pub mod sip128;
pub mod snapshot_map;
-pub mod snapshot_vec;
+pub use ena::snapshot_vec;
pub mod stable_hasher;
pub mod transitive_relation;
-pub mod unify;
+pub use ena::unify;
pub mod fx;
pub mod tuple_slice;
pub mod veccell;
diff --git a/src/librustc_driver/test.rs b/src/librustc_driver/test.rs
index 5ff75351b635b..201b6e40b0426 100644
--- a/src/librustc_driver/test.rs
+++ b/src/librustc_driver/test.rs
@@ -503,7 +503,8 @@ fn sub_free_bound_false_infer() {
//! does NOT hold for any instantiation of `_#1`.
test_env(EMPTY_SOURCE_STR, errors(&[]), |env| {
- let t_infer1 = env.infcx.next_ty_var(TypeVariableOrigin::MiscVariable(DUMMY_SP));
+ let t_infer1 = env.infcx.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(DUMMY_SP));
let t_rptr_bound1 = env.t_rptr_late_bound(1);
env.check_not_sub(env.t_fn(&[t_infer1], env.tcx().types.isize),
env.t_fn(&[t_rptr_bound1], env.tcx().types.isize));
@@ -522,7 +523,8 @@ fn lub_free_bound_infer() {
test_env(EMPTY_SOURCE_STR, errors(&[]), |mut env| {
env.create_simple_region_hierarchy();
- let t_infer1 = env.infcx.next_ty_var(TypeVariableOrigin::MiscVariable(DUMMY_SP));
+ let t_infer1 = env.infcx.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(DUMMY_SP));
let t_rptr_bound1 = env.t_rptr_late_bound(1);
let t_rptr_free1 = env.t_rptr_free(1);
env.check_lub(env.t_fn(&[t_infer1], env.tcx().types.isize),
@@ -642,7 +644,8 @@ fn glb_bound_free() {
fn glb_bound_free_infer() {
test_env(EMPTY_SOURCE_STR, errors(&[]), |env| {
let t_rptr_bound1 = env.t_rptr_late_bound(1);
- let t_infer1 = env.infcx.next_ty_var(TypeVariableOrigin::MiscVariable(DUMMY_SP));
+ let t_infer1 = env.infcx.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(DUMMY_SP));
// compute GLB(fn(_) -> isize, for<'b> fn(&'b isize) -> isize),
// which should yield for<'b> fn(&'b isize) -> isize
diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 1471e235156eb..bbde41a3f4d83 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -19,7 +19,7 @@ use hir::def::Def;
use hir::def_id::DefId;
use middle::resolve_lifetime as rl;
use namespace::Namespace;
-use rustc::ty::subst::{Kind, Subst, Substs};
+use rustc::ty::subst::{Subst, Substs};
use rustc::traits;
use rustc::ty::{self, Ty, TyCtxt, ToPredicate, TypeFoldable};
use rustc::ty::wf::object_region_bounds;
@@ -51,7 +51,6 @@ pub trait AstConv<'gcx, 'tcx> {
/// Same as ty_infer, but with a known type parameter definition.
fn ty_infer_for_def(&self,
_def: &ty::TypeParameterDef,
- _substs: &[Kind<'tcx>],
span: Span) -> Ty<'tcx> {
self.ty_infer(span)
}
@@ -250,7 +249,7 @@ impl<'o, 'gcx: 'tcx, 'tcx> AstConv<'gcx, 'tcx>+'o {
} else if infer_types {
// No type parameters were provided, we can infer all.
let ty_var = if !default_needs_object_self(def) {
- self.ty_infer_for_def(def, substs, span)
+ self.ty_infer_for_def(def, span)
} else {
self.ty_infer(span)
};
diff --git a/src/librustc_typeck/check/_match.rs b/src/librustc_typeck/check/_match.rs
index 272f13b28030e..2fbdc3c236ede 100644
--- a/src/librustc_typeck/check/_match.rs
+++ b/src/librustc_typeck/check/_match.rs
@@ -285,6 +285,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let element_tys_iter = (0..max_len).map(|_| self.next_ty_var(
// FIXME: MiscVariable for now, obtaining the span and name information
// from all tuple elements isn't trivial.
+ ty::UniverseIndex::ROOT,
TypeVariableOrigin::TypeInference(pat.span)));
let element_tys = tcx.mk_type_list(element_tys_iter);
let pat_ty = tcx.mk_ty(ty::TyTuple(element_tys, false));
@@ -295,7 +296,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
pat_ty
}
PatKind::Box(ref inner) => {
- let inner_ty = self.next_ty_var(TypeVariableOrigin::TypeInference(inner.span));
+ let inner_ty = self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TypeInference(inner.span));
let uniq_ty = tcx.mk_box(inner_ty);
if self.check_dereferencable(pat.span, expected, &inner) {
@@ -328,6 +330,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
_ => {
let inner_ty = self.next_ty_var(
+ ty::UniverseIndex::ROOT,
TypeVariableOrigin::TypeInference(inner.span));
let mt = ty::TypeAndMut { ty: inner_ty, mutbl: mutbl };
let region = self.next_region_var(infer::PatternRegion(pat.span));
@@ -571,7 +574,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// ...but otherwise we want to use any supertype of the
// discriminant. This is sort of a workaround, see note (*) in
// `check_pat` for some details.
- discrim_ty = self.next_ty_var(TypeVariableOrigin::TypeInference(discrim.span));
+ discrim_ty = self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TypeInference(discrim.span));
self.check_expr_has_type_or_error(discrim, discrim_ty);
};
@@ -632,7 +636,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// arm for inconsistent arms or to the whole match when a `()` type
// is required).
Expectation::ExpectHasType(ety) if ety != self.tcx.mk_nil() => ety,
- _ => self.next_ty_var(TypeVariableOrigin::MiscVariable(expr.span)),
+ _ => self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(expr.span)),
};
CoerceMany::with_coercion_sites(coerce_first, arms)
};
diff --git a/src/librustc_typeck/check/closure.rs b/src/librustc_typeck/check/closure.rs
index d475fb0cf1a14..f7a086c160b64 100644
--- a/src/librustc_typeck/check/closure.rs
+++ b/src/librustc_typeck/check/closure.rs
@@ -100,7 +100,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
|_, _| span_bug!(expr.span, "closure has region param"),
|_, _| {
self.infcx
- .next_ty_var(TypeVariableOrigin::TransformedUpvar(expr.span))
+ .next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TransformedUpvar(expr.span))
},
);
let closure_type = self.tcx.mk_closure(expr_def_id, substs);
diff --git a/src/librustc_typeck/check/coercion.rs b/src/librustc_typeck/check/coercion.rs
index 94422f93e5922..3941b3c8f1b5a 100644
--- a/src/librustc_typeck/check/coercion.rs
+++ b/src/librustc_typeck/check/coercion.rs
@@ -179,6 +179,7 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
// micro-optimization: no need for this if `b` is
// already resolved in some way.
let diverging_ty = self.next_diverging_ty_var(
+ ty::UniverseIndex::ROOT,
TypeVariableOrigin::AdjustmentType(self.cause.span));
self.unify_and(&b, &diverging_ty, simple(Adjust::NeverToAny))
} else {
@@ -497,7 +498,7 @@ impl<'f, 'gcx, 'tcx> Coerce<'f, 'gcx, 'tcx> {
// We only have the latter, so we use an inference variable
// for the former and let type inference do the rest.
let origin = TypeVariableOrigin::MiscVariable(self.cause.span);
- let coerce_target = self.next_ty_var(origin);
+ let coerce_target = self.next_ty_var(ty::UniverseIndex::ROOT, origin);
let mut coercion = self.unify_and(coerce_target, target, |target| {
let unsize = Adjustment {
kind: Adjust::Unsize,
diff --git a/src/librustc_typeck/check/compare_method.rs b/src/librustc_typeck/check/compare_method.rs
index 554a858bcc173..d6c0156cbfec2 100644
--- a/src/librustc_typeck/check/compare_method.rs
+++ b/src/librustc_typeck/check/compare_method.rs
@@ -213,7 +213,8 @@ fn compare_predicate_entailment<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>,
// the new hybrid bounds we computed.
let normalize_cause = traits::ObligationCause::misc(impl_m_span, impl_m_node_id);
let param_env = ty::ParamEnv::new(tcx.intern_predicates(&hybrid_preds.predicates),
- Reveal::UserFacing);
+ Reveal::UserFacing,
+ ty::UniverseIndex::ROOT);
let param_env = traits::normalize_param_env_or_error(tcx,
impl_m.def_id,
param_env,
diff --git a/src/librustc_typeck/check/dropck.rs b/src/librustc_typeck/check/dropck.rs
index 610d07efa359d..0a5f3c76aec98 100644
--- a/src/librustc_typeck/check/dropck.rs
+++ b/src/librustc_typeck/check/dropck.rs
@@ -88,7 +88,7 @@ fn ensure_drop_params_and_item_params_correspond<'a, 'tcx>(
let drop_impl_span = tcx.def_span(drop_impl_did);
let fresh_impl_substs =
- infcx.fresh_substs_for_item(drop_impl_span, drop_impl_did);
+ infcx.fresh_substs_for_item(ty::UniverseIndex::ROOT, drop_impl_span, drop_impl_did);
let fresh_impl_self_ty = drop_impl_ty.subst(tcx, fresh_impl_substs);
let cause = &ObligationCause::misc(drop_impl_span, drop_impl_node_id);
diff --git a/src/librustc_typeck/check/method/confirm.rs b/src/librustc_typeck/check/method/confirm.rs
index a9830dd5ddece..b6b39a807563a 100644
--- a/src/librustc_typeck/check/method/confirm.rs
+++ b/src/librustc_typeck/check/method/confirm.rs
@@ -240,7 +240,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
// the process we will unify the transformed-self-type
// of the method with the actual type in order to
// unify some of these variables.
- self.fresh_substs_for_item(self.span, trait_def_id)
+ self.fresh_substs_for_item(ty::UniverseIndex::ROOT, self.span, trait_def_id)
}
probe::WhereClausePick(ref poly_trait_ref) => {
@@ -305,7 +305,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
} else {
self.region_var_for_def(self.span, def)
}
- }, |def, cur_substs| {
+ }, |def, _cur_substs| {
let i = def.index as usize;
if i < parent_substs.len() {
parent_substs.type_at(i)
@@ -316,7 +316,7 @@ impl<'a, 'gcx, 'tcx> ConfirmContext<'a, 'gcx, 'tcx> {
{
self.to_ty(ast_ty)
} else {
- self.type_var_for_def(self.span, def, cur_substs)
+ self.type_var_for_def(ty::UniverseIndex::ROOT, self.span, def)
}
})
}
diff --git a/src/librustc_typeck/check/method/mod.rs b/src/librustc_typeck/check/method/mod.rs
index 58d72e37d51cf..af86570309dfd 100644
--- a/src/librustc_typeck/check/method/mod.rs
+++ b/src/librustc_typeck/check/method/mod.rs
@@ -249,13 +249,13 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let substs = Substs::for_item(self.tcx,
trait_def_id,
|def, _| self.region_var_for_def(span, def),
- |def, substs| {
+ |def, _substs| {
if def.index == 0 {
self_ty
} else if let Some(ref input_types) = opt_input_types {
input_types[def.index as usize - 1]
} else {
- self.type_var_for_def(span, def, substs)
+ self.type_var_for_def(ty::UniverseIndex::ROOT, span, def)
}
});
diff --git a/src/librustc_typeck/check/method/probe.rs b/src/librustc_typeck/check/method/probe.rs
index 81e5b2fe00a6a..646867283e23b 100644
--- a/src/librustc_typeck/check/method/probe.rs
+++ b/src/librustc_typeck/check/method/probe.rs
@@ -693,7 +693,9 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
Def::Method(def_id) => {
let fty = self.tcx.fn_sig(def_id);
self.probe(|_| {
- let substs = self.fresh_substs_for_item(self.span, method.def_id);
+ let substs = self.fresh_substs_for_item(ty::UniverseIndex::ROOT,
+ self.span,
+ method.def_id);
let fty = fty.subst(self.tcx, substs);
let (fty, _) = self.replace_late_bound_regions_with_fresh_var(
self.span, infer::FnCall, &fty);
@@ -1265,12 +1267,12 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
// `impl_self_ty()` for an explanation.
self.tcx.types.re_erased
}
- }, |def, cur_substs| {
+ }, |def, _cur_substs| {
let i = def.index as usize;
if i < substs.len() {
substs.type_at(i)
} else {
- self.type_var_for_def(self.span, def, cur_substs)
+ self.type_var_for_def(ty::UniverseIndex::ROOT, self.span, def)
}
});
xform_fn_sig.subst(self.tcx, substs)
@@ -1287,6 +1289,7 @@ impl<'a, 'gcx, 'tcx> ProbeContext<'a, 'gcx, 'tcx> {
def_id,
|_, _| self.tcx.types.re_erased,
|_, _| self.next_ty_var(
+ ty::UniverseIndex::ROOT,
TypeVariableOrigin::SubstitutionPlaceholder(
self.tcx.def_span(def_id))))
}
diff --git a/src/librustc_typeck/check/method/suggest.rs b/src/librustc_typeck/check/method/suggest.rs
index 8613ec86b4a73..bdb56b7da94e6 100644
--- a/src/librustc_typeck/check/method/suggest.rs
+++ b/src/librustc_typeck/check/method/suggest.rs
@@ -54,7 +54,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
self.autoderef(span, ty).any(|(ty, _)| {
self.probe(|_| {
let fn_once_substs = tcx.mk_substs_trait(ty,
- &[self.next_ty_var(TypeVariableOrigin::MiscVariable(span))]);
+ &[self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(span))]);
let trait_ref = ty::TraitRef::new(fn_once, fn_once_substs);
let poly_trait_ref = trait_ref.to_poly_trait_ref();
let obligation =
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index 82d59ecfc92cf..a1f2a0f3a5461 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -92,7 +92,7 @@ use namespace::Namespace;
use rustc::infer::{self, InferCtxt, InferOk, RegionVariableOrigin};
use rustc::infer::type_variable::{TypeVariableOrigin};
use rustc::middle::region;
-use rustc::ty::subst::{Kind, Subst, Substs};
+use rustc::ty::subst::{Subst, Substs};
use rustc::traits::{self, FulfillmentContext, ObligationCause, ObligationCauseCode};
use rustc::ty::{ParamTy, LvaluePreference, NoPreference, PreferMutLvalue};
use rustc::ty::{self, Ty, TyCtxt, Visibility};
@@ -360,7 +360,8 @@ impl<'a, 'gcx, 'tcx> Expectation<'tcx> {
/// hard constraint exists, creates a fresh type variable.
fn coercion_target_type(self, fcx: &FnCtxt<'a, 'gcx, 'tcx>, span: Span) -> Ty<'tcx> {
self.only_has_type(fcx)
- .unwrap_or_else(|| fcx.next_ty_var(TypeVariableOrigin::MiscVariable(span)))
+ .unwrap_or_else(|| fcx.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(span)))
}
}
@@ -945,7 +946,8 @@ impl<'a, 'gcx, 'tcx> GatherLocalsVisitor<'a, 'gcx, 'tcx> {
match ty_opt {
None => {
// infer the variable's type
- let var_ty = self.fcx.next_ty_var(TypeVariableOrigin::TypeInference(span));
+ let var_ty = self.fcx.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TypeInference(span));
self.fcx.locals.borrow_mut().insert(nid, var_ty);
var_ty
}
@@ -1038,7 +1040,8 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
let span = body.value.span;
if body.is_generator && can_be_generator {
- fcx.yield_ty = Some(fcx.next_ty_var(TypeVariableOrigin::TypeInference(span)));
+ fcx.yield_ty = Some(fcx.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TypeInference(span)));
}
GatherLocalsVisitor { fcx: &fcx, }.visit_body(body);
@@ -1068,7 +1071,8 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
};
inherited.tables.borrow_mut().generator_sigs_mut().insert(fn_hir_id, Some(gen_sig));
- let witness = fcx.next_ty_var(TypeVariableOrigin::MiscVariable(span));
+ let witness = fcx.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(span));
fcx.deferred_generator_interiors.borrow_mut().push((body.id(), witness));
let interior = ty::GeneratorInterior::new(witness);
@@ -1110,6 +1114,7 @@ fn check_fn<'a, 'gcx, 'tcx>(inherited: &'a Inherited<'a, 'gcx, 'tcx>,
let mut actual_return_ty = coercion.complete(&fcx);
if actual_return_ty.is_never() {
actual_return_ty = fcx.next_diverging_ty_var(
+ ty::UniverseIndex::ROOT,
TypeVariableOrigin::DivergingFn(span));
}
fcx.demand_suptype(span, ret_ty, actual_return_ty);
@@ -1647,14 +1652,14 @@ impl<'a, 'gcx, 'tcx> AstConv<'gcx, 'tcx> for FnCtxt<'a, 'gcx, 'tcx> {
}
fn ty_infer(&self, span: Span) -> Ty<'tcx> {
- self.next_ty_var(TypeVariableOrigin::TypeInference(span))
+ self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TypeInference(span))
}
fn ty_infer_for_def(&self,
ty_param_def: &ty::TypeParameterDef,
- substs: &[Kind<'tcx>],
span: Span) -> Ty<'tcx> {
- self.type_var_for_def(span, ty_param_def, substs)
+ self.type_var_for_def(ty::UniverseIndex::ROOT, span, ty_param_def)
}
fn projected_ty_from_poly_trait_ref(&self,
@@ -1945,7 +1950,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
return ty_var;
}
let span = self.tcx.def_span(def_id);
- let ty_var = self.next_ty_var(TypeVariableOrigin::TypeInference(span));
+ let ty_var = self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TypeInference(span));
self.anon_types.borrow_mut().insert(id, ty_var);
let predicates_of = self.tcx.predicates_of(def_id);
@@ -2279,7 +2285,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// If some lookup succeeds, write callee into table and extract index/element
// type from the method signature.
// If some lookup succeeded, install method in table
- let input_ty = self.next_ty_var(TypeVariableOrigin::AutoDeref(base_expr.span));
+ let input_ty = self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::AutoDeref(base_expr.span));
let method = self.try_overloaded_lvalue_op(
expr.span, self_ty, &[input_ty], lvalue_pref, LvalueOp::Index);
@@ -2723,6 +2730,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
assert!(!self.tables.borrow().adjustments().contains_key(expr.hir_id),
"expression with never type wound up being adjusted");
let adj_ty = self.next_diverging_ty_var(
+ ty::UniverseIndex::ROOT,
TypeVariableOrigin::AdjustmentType(expr.span));
self.apply_adjustments(expr, vec![Adjustment {
kind: Adjust::NeverToAny,
@@ -2801,7 +2809,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let ity = self.tcx.type_of(did);
debug!("impl_self_ty: ity={:?}", ity);
- let substs = self.fresh_substs_for_item(span, did);
+ let substs = self.fresh_substs_for_item(ty::UniverseIndex::ROOT, span, did);
let substd_ty = self.instantiate_type_scheme(span, &substs, &ity);
TypeAndSubsts { substs: substs, ty: substd_ty }
@@ -3932,7 +3940,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let element_ty = if !args.is_empty() {
let coerce_to = uty.unwrap_or_else(
- || self.next_ty_var(TypeVariableOrigin::TypeInference(expr.span)));
+ || self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TypeInference(expr.span)));
let mut coerce = CoerceMany::with_coercion_sites(coerce_to, args);
assert_eq!(self.diverges.get(), Diverges::Maybe);
for e in args {
@@ -3942,7 +3951,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
}
coerce.complete(self)
} else {
- self.next_ty_var(TypeVariableOrigin::TypeInference(expr.span))
+ self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::TypeInference(expr.span))
};
tcx.mk_array(element_ty, args.len() as u64)
}
@@ -3972,7 +3982,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
(uty, uty)
}
None => {
- let t: Ty = self.next_ty_var(TypeVariableOrigin::MiscVariable(element.span));
+ let t: Ty = self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(element.span));
let element_ty = self.check_expr_has_type_or_error(&element, t);
(element_ty, t)
}
@@ -4747,7 +4758,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// Handle Self first, so we can adjust the index to match the AST.
if has_self && i == 0 {
return opt_self_ty.unwrap_or_else(|| {
- self.type_var_for_def(span, def, substs)
+ self.type_var_for_def(ty::UniverseIndex::ROOT, span, def)
});
}
i -= has_self as usize;
@@ -4780,7 +4791,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// This can also be reached in some error cases:
// We prefer to use inference variables instead of
// TyError to let type inference recover somewhat.
- self.type_var_for_def(span, def, substs)
+ self.type_var_for_def(ty::UniverseIndex::ROOT, span, def)
}
});
diff --git a/src/librustc_typeck/check/op.rs b/src/librustc_typeck/check/op.rs
index 2d45f797ecb4d..987fead48c474 100644
--- a/src/librustc_typeck/check/op.rs
+++ b/src/librustc_typeck/check/op.rs
@@ -175,8 +175,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// trait matching creating lifetime constraints that are too strict.
// E.g. adding `&'a T` and `&'b T`, given `&'x T: Add<&'x T>`, will result
// in `&'a T <: &'x T` and `&'b T <: &'x T`, instead of `'a = 'b = 'x`.
- let lhs_ty = self.check_expr_coercable_to_type_with_lvalue_pref(lhs_expr,
- self.next_ty_var(TypeVariableOrigin::MiscVariable(lhs_expr.span)),
+ let lhs_ty = self.check_expr_coercable_to_type_with_lvalue_pref(
+ lhs_expr,
+ self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(lhs_expr.span)),
lhs_pref);
let lhs_ty = self.resolve_type_vars_with_obligations(lhs_ty);
@@ -186,7 +188,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// using this variable as the expected type, which sometimes lets
// us do better coercions than we would be able to do otherwise,
// particularly for things like `String + &String`.
- let rhs_ty_var = self.next_ty_var(TypeVariableOrigin::MiscVariable(rhs_expr.span));
+ let rhs_ty_var = self.next_ty_var(ty::UniverseIndex::ROOT,
+ TypeVariableOrigin::MiscVariable(rhs_expr.span));
let result = self.lookup_op_method(lhs_ty, &[rhs_ty_var], Op::Binary(op, is_assign));