diff --git a/src/librustc/ich/impls_mir.rs b/src/librustc/ich/impls_mir.rs
index 337cc0fc627..b660187945c 100644
--- a/src/librustc/ich/impls_mir.rs
+++ b/src/librustc/ich/impls_mir.rs
@@ -587,3 +587,24 @@ impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for mir::ClosureOutlivesSubj
}
impl_stable_hash_for!(struct mir::interpret::GlobalId<'tcx> { instance, promoted });
+
+impl<'a, 'gcx> HashStable<StableHashingContext<'a>> for mir::UserTypeAnnotation<'gcx> {
+ fn hash_stable<W: StableHasherResult>(&self,
+ hcx: &mut StableHashingContext<'a>,
+ hasher: &mut StableHasher<W>) {
+ mem::discriminant(self).hash_stable(hcx, hasher);
+ match *self {
+ mir::UserTypeAnnotation::Ty(ref ty) => {
+ ty.hash_stable(hcx, hasher);
+ }
+ mir::UserTypeAnnotation::FnDef(ref def_id, ref substs) => {
+ def_id.hash_stable(hcx, hasher);
+ substs.hash_stable(hcx, hasher);
+ }
+ mir::UserTypeAnnotation::AdtDef(ref def_id, ref substs) => {
+ def_id.hash_stable(hcx, hasher);
+ substs.hash_stable(hcx, hasher);
+ }
+ }
+ }
+}
diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index dd2c41dda64..e54968c5274 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -1417,3 +1417,8 @@ impl_stable_hash_for!(enum traits::QuantifierKind {
Universal,
Existential
});
+
+impl_stable_hash_for!(struct ty::subst::UserSubsts<'tcx> { substs, user_self_ty });
+
+impl_stable_hash_for!(struct ty::subst::UserSelfTy<'tcx> { impl_def_id, self_ty });
+
diff --git a/src/librustc/infer/canonical/mod.rs b/src/librustc/infer/canonical/mod.rs
index a78b5b7d072..1863f08930f 100644
--- a/src/librustc/infer/canonical/mod.rs
+++ b/src/librustc/infer/canonical/mod.rs
@@ -241,7 +241,7 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
/// canonicalized) then represents the values that you computed
/// for each of the canonical inputs to your query.
- pub(in infer) fn instantiate_canonical_with_fresh_inference_vars<T>(
+ pub fn instantiate_canonical_with_fresh_inference_vars<T>(
&self,
span: Span,
canonical: &Canonical<'tcx, T>,
@@ -249,9 +249,6 @@ impl<'cx, 'gcx, 'tcx> InferCtxt<'cx, 'gcx, 'tcx> {
where
T: TypeFoldable<'tcx>,
{
- assert_eq!(self.universe(), ty::UniverseIndex::ROOT, "infcx not newly created");
- assert_eq!(self.type_variables.borrow().num_vars(), 0, "infcx not newly created");
-
let canonical_inference_vars =
self.fresh_inference_vars_for_canonical_vars(span, canonical.variables);
let result = canonical.substitute(self.tcx, &canonical_inference_vars);
diff --git a/src/librustc/infer/mod.rs b/src/librustc/infer/mod.rs
index ef9886e06d4..fbd38ebd78c 100644
--- a/src/librustc/infer/mod.rs
+++ b/src/librustc/infer/mod.rs
@@ -62,6 +62,7 @@ mod higher_ranked;
pub mod lattice;
mod lexical_region_resolve;
mod lub;
+pub mod nll_relate;
pub mod opaque_types;
pub mod outlives;
pub mod region_constraints;
diff --git a/src/librustc/infer/nll_relate/mod.rs b/src/librustc/infer/nll_relate/mod.rs
new file mode 100644
index 00000000000..e003c1989e0
--- /dev/null
+++ b/src/librustc/infer/nll_relate/mod.rs
@@ -0,0 +1,736 @@
+// Copyright 2017 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! This code is kind of an alternate way of doing subtyping,
+//! supertyping, and type equating, distinct from the `combine.rs`
+//! code but very similar in its effect and design. Eventually the two
+//! ought to be merged. This code is intended for use in NLL.
+//!
+//! Here are the key differences:
+//!
+//! - This code generally assumes that there are no unbound type
+//! inferences variables, because at NLL
+//! time types are fully inferred up-to regions.
+//! - Actually, to support user-given type annotations like
+//! `Vec<_>`, we do have some measure of support for type
+//! inference variables, but we impose some simplifying
+//! assumptions on them that would not be suitable for the infer
+//! code more generally. This could be fixed.
+//! - This code uses "universes" to handle higher-ranked regions and
+//! not the leak-check. This is "more correct" than what rustc does
+//! and we are generally migrating in this direction, but NLL had to
+//! get there first.
+
+use crate::infer::InferCtxt;
+use crate::ty::fold::{TypeFoldable, TypeVisitor};
+use crate::ty::relate::{self, Relate, RelateResult, TypeRelation};
+use crate::ty::subst::Kind;
+use crate::ty::{self, Ty, TyCtxt};
+use rustc_data_structures::fx::FxHashMap;
+
+pub struct TypeRelating<'me, 'gcx: 'tcx, 'tcx: 'me, D>
+where
+ D: TypeRelatingDelegate<'tcx>,
+{
+ infcx: &'me InferCtxt<'me, 'gcx, 'tcx>,
+
+ /// Callback to use when we deduce an outlives relationship
+ delegate: D,
+
+ /// How are we relating `a` and `b`?
+ ///
+ /// - covariant means `a <: b`
+ /// - contravariant means `b <: a`
+ /// - invariant means `a == b
+ /// - bivariant means that it doesn't matter
+ ambient_variance: ty::Variance,
+
+ /// When we pass through a set of binders (e.g., when looking into
+ /// a `fn` type), we push a new bound region scope onto here. This
+ /// will contain the instantiated region for each region in those
+ /// binders. When we then encounter a `ReLateBound(d, br)`, we can
+ /// use the debruijn index `d` to find the right scope, and then
+ /// bound region name `br` to find the specific instantiation from
+ /// within that scope. See `replace_bound_region`.
+ ///
+ /// This field stores the instantiations for late-bound regions in
+ /// the `a` type.
+ a_scopes: Vec<BoundRegionScope<'tcx>>,
+
+ /// Same as `a_scopes`, but for the `b` type.
+ b_scopes: Vec<BoundRegionScope<'tcx>>,
+}
+
+pub trait TypeRelatingDelegate<'tcx> {
+ /// Push a constraint `sup: sub` -- this constraint must be
+ /// satisfied for the two types to be related. `sub` and `sup` may
+ /// be regions from the type or new variables created through the
+ /// delegate.
+ fn push_outlives(&mut self, sup: ty::Region<'tcx>, sub: ty::Region<'tcx>);
+
+ /// Creates a new universe index. Used when instantiating placeholders.
+ fn create_next_universe(&mut self) -> ty::UniverseIndex;
+
+ /// Creates a new region variable representing a higher-ranked
+ /// region that is instantiated existentially. This creates an
+ /// inference variable, typically.
+ ///
+ /// So e.g. if you have `for<'a> fn(..) <: for<'b> fn(..)`, then
+ /// we will invoke this method to instantiate `'a` with an
+ /// inference variable (though `'b` would be instantiated first,
+ /// as a placeholder).
+ fn next_existential_region_var(&mut self) -> ty::Region<'tcx>;
+
+ /// Creates a new region variable representing a
+ /// higher-ranked region that is instantiated universally.
+ /// This creates a new region placeholder, typically.
+ ///
+ /// So e.g. if you have `for<'a> fn(..) <: for<'b> fn(..)`, then
+ /// we will invoke this method to instantiate `'b` with a
+ /// placeholder region.
+ fn next_placeholder_region(&mut self, placeholder: ty::Placeholder) -> ty::Region<'tcx>;
+
+ /// Creates a new existential region in the given universe. This
+ /// is used when handling subtyping and type variables -- if we
+ /// have that `?X <: Foo<'a>`, for example, we would instantiate
+ /// `?X` with a type like `Foo<'?0>` where `'?0` is a fresh
+ /// existential variable created by this function. We would then
+ /// relate `Foo<'?0>` with `Foo<'a>` (and probably add an outlives
+ /// relation stating that `'?0: 'a`).
+ fn generalize_existential(&mut self, universe: ty::UniverseIndex) -> ty::Region<'tcx>;
+}
+
+#[derive(Clone, Debug)]
+struct ScopesAndKind<'tcx> {
+ scopes: Vec<BoundRegionScope<'tcx>>,
+ kind: Kind<'tcx>,
+}
+
+#[derive(Clone, Debug, Default)]
+struct BoundRegionScope<'tcx> {
+ map: FxHashMap<ty::BoundRegion, ty::Region<'tcx>>,
+}
+
+#[derive(Copy, Clone)]
+struct UniversallyQuantified(bool);
+
+impl<'me, 'gcx, 'tcx, D> TypeRelating<'me, 'gcx, 'tcx, D>
+where
+ D: TypeRelatingDelegate<'tcx>,
+{
+ pub fn new(
+ infcx: &'me InferCtxt<'me, 'gcx, 'tcx>,
+ delegate: D,
+ ambient_variance: ty::Variance,
+ ) -> Self {
+ Self {
+ infcx,
+ delegate,
+ ambient_variance,
+ a_scopes: vec![],
+ b_scopes: vec![],
+ }
+ }
+
+ fn ambient_covariance(&self) -> bool {
+ match self.ambient_variance {
+ ty::Variance::Covariant | ty::Variance::Invariant => true,
+ ty::Variance::Contravariant | ty::Variance::Bivariant => false,
+ }
+ }
+
+ fn ambient_contravariance(&self) -> bool {
+ match self.ambient_variance {
+ ty::Variance::Contravariant | ty::Variance::Invariant => true,
+ ty::Variance::Covariant | ty::Variance::Bivariant => false,
+ }
+ }
+
+ fn create_scope(
+ &mut self,
+ value: &ty::Binder<impl TypeFoldable<'tcx>>,
+ universally_quantified: UniversallyQuantified,
+ ) -> BoundRegionScope<'tcx> {
+ let mut scope = BoundRegionScope::default();
+
+ // Create a callback that creates (via the delegate) either an
+ // existential or placeholder region as needed.
+ let mut next_region = {
+ let delegate = &mut self.delegate;
+ let mut lazy_universe = None;
+ move |br: ty::BoundRegion| {
+ if universally_quantified.0 {
+ // The first time this closure is called, create a
+ // new universe for the placeholders we will make
+ // from here out.
+ let universe = lazy_universe.unwrap_or_else(|| {
+ let universe = delegate.create_next_universe();
+ lazy_universe = Some(universe);
+ universe
+ });
+
+ let placeholder = ty::Placeholder { universe, name: br };
+ delegate.next_placeholder_region(placeholder)
+ } else {
+ delegate.next_existential_region_var()
+ }
+ }
+ };
+
+ value.skip_binder().visit_with(&mut ScopeInstantiator {
+ next_region: &mut next_region,
+ target_index: ty::INNERMOST,
+ bound_region_scope: &mut scope,
+ });
+
+ scope
+ }
+
+ /// When we encounter binders during the type traversal, we record
+ /// the value to substitute for each of the things contained in
+ /// that binder. (This will be either a universal placeholder or
+ /// an existential inference variable.) Given the debruijn index
+ /// `debruijn` (and name `br`) of some binder we have now
+ /// encountered, this routine finds the value that we instantiated
+ /// the region with; to do so, it indexes backwards into the list
+ /// of ambient scopes `scopes`.
+ fn lookup_bound_region(
+ debruijn: ty::DebruijnIndex,
+ br: &ty::BoundRegion,
+ first_free_index: ty::DebruijnIndex,
+ scopes: &[BoundRegionScope<'tcx>],
+ ) -> ty::Region<'tcx> {
+ // The debruijn index is a "reverse index" into the
+ // scopes listing. So when we have INNERMOST (0), we
+ // want the *last* scope pushed, and so forth.
+ let debruijn_index = debruijn.index() - first_free_index.index();
+ let scope = &scopes[scopes.len() - debruijn_index - 1];
+
+ // Find this bound region in that scope to map to a
+ // particular region.
+ scope.map[br]
+ }
+
+ /// If `r` is a bound region, find the scope in which it is bound
+ /// (from `scopes`) and return the value that we instantiated it
+ /// with. Otherwise just return `r`.
+ fn replace_bound_region(
+ &self,
+ r: ty::Region<'tcx>,
+ first_free_index: ty::DebruijnIndex,
+ scopes: &[BoundRegionScope<'tcx>],
+ ) -> ty::Region<'tcx> {
+ if let ty::ReLateBound(debruijn, br) = r {
+ Self::lookup_bound_region(*debruijn, br, first_free_index, scopes)
+ } else {
+ r
+ }
+ }
+
+ /// Push a new outlives requirement into our output set of
+ /// constraints.
+ fn push_outlives(&mut self, sup: ty::Region<'tcx>, sub: ty::Region<'tcx>) {
+ debug!("push_outlives({:?}: {:?})", sup, sub);
+
+ self.delegate.push_outlives(sup, sub);
+ }
+
+ /// When we encounter a canonical variable `var` in the output,
+ /// equate it with `kind`. If the variable has been previously
+ /// equated, then equate it again.
+ fn relate_var(&mut self, var_ty: Ty<'tcx>, value_ty: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
+ debug!("equate_var(var_ty={:?}, value_ty={:?})", var_ty, value_ty);
+
+ let generalized_ty = self.generalize_value(value_ty);
+ self.infcx
+ .force_instantiate_unchecked(var_ty, generalized_ty);
+
+ // The generalized values we extract from `canonical_var_values` have
+ // been fully instantiated and hence the set of scopes we have
+ // doesn't matter -- just to be sure, put an empty vector
+ // in there.
+ let old_a_scopes = ::std::mem::replace(&mut self.a_scopes, vec![]);
+
+ // Relate the generalized kind to the original one.
+ let result = self.relate(&generalized_ty, &value_ty);
+
+ // Restore the old scopes now.
+ self.a_scopes = old_a_scopes;
+
+ debug!("equate_var: complete, result = {:?}", result);
+ result
+ }
+
+ fn generalize_value<T: Relate<'tcx>>(&mut self, value: T) -> T {
+ TypeGeneralizer {
+ tcx: self.infcx.tcx,
+ delegate: &mut self.delegate,
+ first_free_index: ty::INNERMOST,
+ ambient_variance: self.ambient_variance,
+
+ // These always correspond to an `_` or `'_` written by
+ // user, and those are always in the root universe.
+ universe: ty::UniverseIndex::ROOT,
+ }.relate(&value, &value)
+ .unwrap()
+ }
+}
+
+impl<D> TypeRelation<'me, 'gcx, 'tcx> for TypeRelating<'me, 'gcx, 'tcx, D>
+where
+ D: TypeRelatingDelegate<'tcx>,
+{
+ fn tcx(&self) -> TyCtxt<'me, 'gcx, 'tcx> {
+ self.infcx.tcx
+ }
+
+ fn tag(&self) -> &'static str {
+ "nll::subtype"
+ }
+
+ fn a_is_expected(&self) -> bool {
+ true
+ }
+
+ fn relate_with_variance<T: Relate<'tcx>>(
+ &mut self,
+ variance: ty::Variance,
+ a: &T,
+ b: &T,
+ ) -> RelateResult<'tcx, T> {
+ debug!(
+ "relate_with_variance(variance={:?}, a={:?}, b={:?})",
+ variance, a, b
+ );
+
+ let old_ambient_variance = self.ambient_variance;
+ self.ambient_variance = self.ambient_variance.xform(variance);
+
+ debug!(
+ "relate_with_variance: ambient_variance = {:?}",
+ self.ambient_variance
+ );
+
+ let r = self.relate(a, b)?;
+
+ self.ambient_variance = old_ambient_variance;
+
+ debug!("relate_with_variance: r={:?}", r);
+
+ Ok(r)
+ }
+
+ fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
+ let a = self.infcx.shallow_resolve(a);
+ match a.sty {
+ ty::Infer(ty::TyVar(_)) | ty::Infer(ty::IntVar(_)) | ty::Infer(ty::FloatVar(_)) => {
+ self.relate_var(a.into(), b.into())
+ }
+
+ _ => {
+ debug!(
+ "tys(a={:?}, b={:?}, variance={:?})",
+ a, b, self.ambient_variance
+ );
+
+ relate::super_relate_tys(self, a, b)
+ }
+ }
+ }
+
+ fn regions(
+ &mut self,
+ a: ty::Region<'tcx>,
+ b: ty::Region<'tcx>,
+ ) -> RelateResult<'tcx, ty::Region<'tcx>> {
+ debug!(
+ "regions(a={:?}, b={:?}, variance={:?})",
+ a, b, self.ambient_variance
+ );
+
+ let v_a = self.replace_bound_region(a, ty::INNERMOST, &self.a_scopes);
+ let v_b = self.replace_bound_region(b, ty::INNERMOST, &self.b_scopes);
+
+ debug!("regions: v_a = {:?}", v_a);
+ debug!("regions: v_b = {:?}", v_b);
+
+ if self.ambient_covariance() {
+ // Covariance: a <= b. Hence, `b: a`.
+ self.push_outlives(v_b, v_a);
+ }
+
+ if self.ambient_contravariance() {
+ // Contravariant: b <= a. Hence, `a: b`.
+ self.push_outlives(v_a, v_b);
+ }
+
+ Ok(a)
+ }
+
+ fn binders<T>(
+ &mut self,
+ a: &ty::Binder<T>,
+ b: &ty::Binder<T>,
+ ) -> RelateResult<'tcx, ty::Binder<T>>
+ where
+ T: Relate<'tcx>,
+ {
+ // We want that
+ //
+ // ```
+ // for<'a> fn(&'a u32) -> &'a u32 <:
+ // fn(&'b u32) -> &'b u32
+ // ```
+ //
+ // but not
+ //
+ // ```
+ // fn(&'a u32) -> &'a u32 <:
+ // for<'b> fn(&'b u32) -> &'b u32
+ // ```
+ //
+ // We therefore proceed as follows:
+ //
+ // - Instantiate binders on `b` universally, yielding a universe U1.
+ // - Instantiate binders on `a` existentially in U1.
+
+ debug!(
+ "binders({:?}: {:?}, ambient_variance={:?})",
+ a, b, self.ambient_variance
+ );
+
+ if self.ambient_covariance() {
+ // Covariance, so we want `for<..> A <: for<..> B` --
+ // therefore we compare any instantiation of A (i.e., A
+ // instantiated with existentials) against every
+ // instantiation of B (i.e., B instantiated with
+ // universals).
+
+ let b_scope = self.create_scope(b, UniversallyQuantified(true));
+ let a_scope = self.create_scope(a, UniversallyQuantified(false));
+
+ debug!("binders: a_scope = {:?} (existential)", a_scope);
+ debug!("binders: b_scope = {:?} (universal)", b_scope);
+
+ self.b_scopes.push(b_scope);
+ self.a_scopes.push(a_scope);
+
+ // Reset the ambient variance to covariant. This is needed
+ // to correctly handle cases like
+ //
+ // for<'a> fn(&'a u32, &'a u3) == for<'b, 'c> fn(&'b u32, &'c u32)
+ //
+ // Somewhat surprisingly, these two types are actually
+ // **equal**, even though the one on the right looks more
+ // polymorphic. The reason is due to subtyping. To see it,
+ // consider that each function can call the other:
+ //
+ // - The left function can call the right with `'b` and
+ // `'c` both equal to `'a`
+ //
+ // - The right function can call the left with `'a` set to
+ // `{P}`, where P is the point in the CFG where the call
+ // itself occurs. Note that `'b` and `'c` must both
+ // include P. At the point, the call works because of
+ // subtyping (i.e., `&'b u32 <: &{P} u32`).
+ let variance = ::std::mem::replace(&mut self.ambient_variance, ty::Variance::Covariant);
+
+ self.relate(a.skip_binder(), b.skip_binder())?;
+
+ self.ambient_variance = variance;
+
+ self.b_scopes.pop().unwrap();
+ self.a_scopes.pop().unwrap();
+ }
+
+ if self.ambient_contravariance() {
+ // Contravariance, so we want `for<..> A :> for<..> B`
+ // -- therefore we compare every instantiation of A (i.e.,
+ // A instantiated with universals) against any
+ // instantiation of B (i.e., B instantiated with
+ // existentials). Opposite of above.
+
+ let a_scope = self.create_scope(a, UniversallyQuantified(true));
+ let b_scope = self.create_scope(b, UniversallyQuantified(false));
+
+ debug!("binders: a_scope = {:?} (universal)", a_scope);
+ debug!("binders: b_scope = {:?} (existential)", b_scope);
+
+ self.a_scopes.push(a_scope);
+ self.b_scopes.push(b_scope);
+
+ // Reset ambient variance to contravariance. See the
+ // covariant case above for an explanation.
+ let variance =
+ ::std::mem::replace(&mut self.ambient_variance, ty::Variance::Contravariant);
+
+ self.relate(a.skip_binder(), b.skip_binder())?;
+
+ self.ambient_variance = variance;
+
+ self.b_scopes.pop().unwrap();
+ self.a_scopes.pop().unwrap();
+ }
+
+ Ok(a.clone())
+ }
+}
+
+/// When we encounter a binder like `for<..> fn(..)`, we actually have
+/// to walk the `fn` value to find all the values bound by the `for`
+/// (these are not explicitly present in the ty representation right
+/// now). This visitor handles that: it descends the type, tracking
+/// binder depth, and finds late-bound regions targeting the
+/// `for<..`>. For each of those, it creates an entry in
+/// `bound_region_scope`.
+struct ScopeInstantiator<'me, 'tcx: 'me> {
+ next_region: &'me mut dyn FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
+ // The debruijn index of the scope we are instantiating.
+ target_index: ty::DebruijnIndex,
+ bound_region_scope: &'me mut BoundRegionScope<'tcx>,
+}
+
+impl<'me, 'tcx> TypeVisitor<'tcx> for ScopeInstantiator<'me, 'tcx> {
+ fn visit_binder<T: TypeFoldable<'tcx>>(&mut self, t: &ty::Binder<T>) -> bool {
+ self.target_index.shift_in(1);
+ t.super_visit_with(self);
+ self.target_index.shift_out(1);
+
+ false
+ }
+
+ fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool {
+ let ScopeInstantiator {
+ bound_region_scope,
+ next_region,
+ ..
+ } = self;
+
+ match r {
+ ty::ReLateBound(debruijn, br) if *debruijn == self.target_index => {
+ bound_region_scope
+ .map
+ .entry(*br)
+ .or_insert_with(|| next_region(*br));
+ }
+
+ _ => {}
+ }
+
+ false
+ }
+}
+
+/// The "type generalize" is used when handling inference variables.
+///
+/// The basic strategy for handling a constraint like `?A <: B` is to
+/// apply a "generalization strategy" to the type `B` -- this replaces
+/// all the lifetimes in the type `B` with fresh inference
+/// variables. (You can read more about the strategy in this [blog
+/// post].)
+///
+/// As an example, if we had `?A <: &'x u32`, we would generalize `&'x
+/// u32` to `&'0 u32` where `'0` is a fresh variable. This becomes the
+/// value of `A`. Finally, we relate `&'0 u32 <: &'x u32`, which
+/// establishes `'0: 'x` as a constraint.
+///
+/// As a side-effect of this generalization procedure, we also replace
+/// all the bound regions that we have traversed with concrete values,
+/// so that the resulting generalized type is independent from the
+/// scopes.
+///
+/// [blog post]: https://is.gd/0hKvIr
+struct TypeGeneralizer<'me, 'gcx: 'tcx, 'tcx: 'me, D>
+where
+ D: TypeRelatingDelegate<'tcx> + 'me,
+{
+ tcx: TyCtxt<'me, 'gcx, 'tcx>,
+
+ delegate: &'me mut D,
+
+ /// After we generalize this type, we are going to relative it to
+ /// some other type. What will be the variance at this point?
+ ambient_variance: ty::Variance,
+
+ first_free_index: ty::DebruijnIndex,
+
+ universe: ty::UniverseIndex,
+}
+
+impl<D> TypeRelation<'me, 'gcx, 'tcx> for TypeGeneralizer<'me, 'gcx, 'tcx, D>
+where
+ D: TypeRelatingDelegate<'tcx>,
+{
+ fn tcx(&self) -> TyCtxt<'me, 'gcx, 'tcx> {
+ self.tcx
+ }
+
+ fn tag(&self) -> &'static str {
+ "nll::generalizer"
+ }
+
+ fn a_is_expected(&self) -> bool {
+ true
+ }
+
+ fn relate_with_variance<T: Relate<'tcx>>(
+ &mut self,
+ variance: ty::Variance,
+ a: &T,
+ b: &T,
+ ) -> RelateResult<'tcx, T> {
+ debug!(
+ "TypeGeneralizer::relate_with_variance(variance={:?}, a={:?}, b={:?})",
+ variance, a, b
+ );
+
+ let old_ambient_variance = self.ambient_variance;
+ self.ambient_variance = self.ambient_variance.xform(variance);
+
+ debug!(
+ "TypeGeneralizer::relate_with_variance: ambient_variance = {:?}",
+ self.ambient_variance
+ );
+
+ let r = self.relate(a, b)?;
+
+ self.ambient_variance = old_ambient_variance;
+
+ debug!("TypeGeneralizer::relate_with_variance: r={:?}", r);
+
+ Ok(r)
+ }
+
+ fn tys(&mut self, a: Ty<'tcx>, _: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
+ debug!("TypeGeneralizer::tys(a={:?})", a,);
+
+ match a.sty {
+ ty::Infer(ty::TyVar(_)) | ty::Infer(ty::IntVar(_)) | ty::Infer(ty::FloatVar(_)) => {
+ bug!(
+ "unexpected inference variable encountered in NLL generalization: {:?}",
+ a
+ );
+ }
+
+ _ => relate::super_relate_tys(self, a, a),
+ }
+ }
+
+ fn regions(
+ &mut self,
+ a: ty::Region<'tcx>,
+ _: ty::Region<'tcx>,
+ ) -> RelateResult<'tcx, ty::Region<'tcx>> {
+ debug!("TypeGeneralizer::regions(a={:?})", a,);
+
+ if let ty::ReLateBound(debruijn, _) = a {
+ if *debruijn < self.first_free_index {
+ return Ok(a);
+ }
+ }
+
+ // For now, we just always create a fresh region variable to
+ // replace all the regions in the source type. In the main
+ // type checker, we special case the case where the ambient
+ // variance is `Invariant` and try to avoid creating a fresh
+ // region variable, but since this comes up so much less in
+ // NLL (only when users use `_` etc) it is much less
+ // important.
+ //
+ // As an aside, since these new variables are created in
+ // `self.universe` universe, this also serves to enforce the
+ // universe scoping rules.
+ //
+ // FIXME(#54105) -- if the ambient variance is bivariant,
+ // though, we may however need to check well-formedness or
+ // risk a problem like #41677 again.
+
+ let replacement_region_vid = self.delegate.generalize_existential(self.universe);
+
+ Ok(replacement_region_vid)
+ }
+
+ fn binders<T>(
+ &mut self,
+ a: &ty::Binder<T>,
+ _: &ty::Binder<T>,
+ ) -> RelateResult<'tcx, ty::Binder<T>>
+ where
+ T: Relate<'tcx>,
+ {
+ debug!("TypeGeneralizer::binders(a={:?})", a,);
+
+ self.first_free_index.shift_in(1);
+ let result = self.relate(a.skip_binder(), a.skip_binder())?;
+ self.first_free_index.shift_out(1);
+ Ok(ty::Binder::bind(result))
+ }
+}
+
+impl InferCtxt<'_, '_, 'tcx> {
+ /// A hacky sort of method used by the NLL type-relating code:
+ ///
+ /// - `var` must be some unbound type variable.
+ /// - `value` must be a suitable type to use as its value.
+ ///
+ /// `var` will then be equated with `value`. Note that this
+ /// sidesteps a number of important checks, such as the "occurs
+ /// check" that prevents cyclic types, so it is important not to
+ /// use this method during regular type-check.
+ fn force_instantiate_unchecked(&self, var: Ty<'tcx>, value: Ty<'tcx>) {
+ match (&var.sty, &value.sty) {
+ (&ty::Infer(ty::TyVar(vid)), _) => {
+ let mut type_variables = self.type_variables.borrow_mut();
+
+ // In NLL, we don't have type inference variables
+ // floating around, so we can do this rather imprecise
+ // variant of the occurs-check.
+ assert!(!value.has_infer_types());
+
+ type_variables.instantiate(vid, value);
+ }
+
+ (&ty::Infer(ty::IntVar(vid)), &ty::Int(value)) => {
+ let mut int_unification_table = self.int_unification_table.borrow_mut();
+ int_unification_table
+ .unify_var_value(vid, Some(ty::IntVarValue::IntType(value)))
+ .unwrap_or_else(|_| {
+ bug!("failed to unify int var `{:?}` with `{:?}`", vid, value);
+ });
+ }
+
+ (&ty::Infer(ty::IntVar(vid)), &ty::Uint(value)) => {
+ let mut int_unification_table = self.int_unification_table.borrow_mut();
+ int_unification_table
+ .unify_var_value(vid, Some(ty::IntVarValue::UintType(value)))
+ .unwrap_or_else(|_| {
+ bug!("failed to unify int var `{:?}` with `{:?}`", vid, value);
+ });
+ }
+
+ (&ty::Infer(ty::FloatVar(vid)), &ty::Float(value)) => {
+ let mut float_unification_table = self.float_unification_table.borrow_mut();
+ float_unification_table
+ .unify_var_value(vid, Some(ty::FloatVarValue(value)))
+ .unwrap_or_else(|_| {
+ bug!("failed to unify float var `{:?}` with `{:?}`", vid, value)
+ });
+ }
+
+ _ => {
+ bug!(
+ "force_instantiate_unchecked invoked with bad combination: var={:?} value={:?}",
+ var,
+ value,
+ );
+ }
+ }
+ }
+}
diff --git a/src/librustc/mir/mod.rs b/src/librustc/mir/mod.rs
index 2587e19b1cb..48b2ccbcf87 100644
--- a/src/librustc/mir/mod.rs
+++ b/src/librustc/mir/mod.rs
@@ -37,7 +37,7 @@ use syntax::ast::{self, Name};
use syntax::symbol::InternedString;
use syntax_pos::{Span, DUMMY_SP};
use ty::fold::{TypeFoldable, TypeFolder, TypeVisitor};
-use ty::subst::{Subst, Substs};
+use ty::subst::{CanonicalUserSubsts, Subst, Substs};
use ty::{self, AdtDef, CanonicalTy, ClosureSubsts, GeneratorSubsts, Region, Ty, TyCtxt};
use util::ppaux;
@@ -710,7 +710,7 @@ pub struct LocalDecl<'tcx> {
/// e.g. via `let x: T`, then we carry that type here. The MIR
/// borrow checker needs this information since it can affect
/// region inference.
- pub user_ty: Option<(CanonicalTy<'tcx>, Span)>,
+ pub user_ty: Option<(UserTypeAnnotation<'tcx>, Span)>,
/// Name of the local, used in debuginfo and pretty-printing.
///
@@ -1737,7 +1737,7 @@ pub enum StatementKind<'tcx> {
/// - `Contravariant` -- requires that `T_y :> T`
/// - `Invariant` -- requires that `T_y == T`
/// - `Bivariant` -- no effect
- AscribeUserType(Place<'tcx>, ty::Variance, CanonicalTy<'tcx>),
+ AscribeUserType(Place<'tcx>, ty::Variance, UserTypeAnnotation<'tcx>),
/// No-op. Useful for deleting instructions without affecting statement indices.
Nop,
@@ -2188,7 +2188,7 @@ pub enum AggregateKind<'tcx> {
&'tcx AdtDef,
usize,
&'tcx Substs<'tcx>,
- Option<CanonicalTy<'tcx>>,
+ Option<UserTypeAnnotation<'tcx>>,
Option<usize>,
),
@@ -2392,7 +2392,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
/// this does not necessarily mean that they are "==" in Rust -- in
/// particular one must be wary of `NaN`!
-#[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
+#[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
pub struct Constant<'tcx> {
pub span: Span,
pub ty: Ty<'tcx>,
@@ -2402,11 +2402,29 @@ pub struct Constant<'tcx> {
/// indicate that `Vec<_>` was explicitly specified.
///
/// Needed for NLL to impose user-given type constraints.
- pub user_ty: Option<CanonicalTy<'tcx>>,
+ pub user_ty: Option<UserTypeAnnotation<'tcx>>,
pub literal: &'tcx ty::Const<'tcx>,
}
+/// A user-given type annotation attached to a constant. These arise
+/// from constants that are named via paths, like `Foo::<A>::new` and
+/// so forth.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
+pub enum UserTypeAnnotation<'tcx> {
+ Ty(CanonicalTy<'tcx>),
+ FnDef(DefId, CanonicalUserSubsts<'tcx>),
+ AdtDef(&'tcx AdtDef, CanonicalUserSubsts<'tcx>),
+}
+
+EnumTypeFoldableImpl! {
+ impl<'tcx> TypeFoldable<'tcx> for UserTypeAnnotation<'tcx> {
+ (UserTypeAnnotation::Ty)(ty),
+ (UserTypeAnnotation::FnDef)(def, substs),
+ (UserTypeAnnotation::AdtDef)(def, substs),
+ }
+}
+
newtype_index! {
pub struct Promoted {
DEBUG_FORMAT = "promoted[{}]"
diff --git a/src/librustc/mir/visit.rs b/src/librustc/mir/visit.rs
index 920dc88d6a8..76c76404d2f 100644
--- a/src/librustc/mir/visit.rs
+++ b/src/librustc/mir/visit.rs
@@ -10,7 +10,7 @@
use hir::def_id::DefId;
use ty::subst::Substs;
-use ty::{CanonicalTy, ClosureSubsts, GeneratorSubsts, Region, Ty};
+use ty::{ClosureSubsts, GeneratorSubsts, Region, Ty};
use mir::*;
use syntax_pos::Span;
@@ -147,9 +147,9 @@ macro_rules! make_mir_visitor {
fn visit_ascribe_user_ty(&mut self,
place: & $($mutability)* Place<'tcx>,
variance: & $($mutability)* ty::Variance,
- c_ty: & $($mutability)* CanonicalTy<'tcx>,
+ user_ty: & $($mutability)* UserTypeAnnotation<'tcx>,
location: Location) {
- self.super_ascribe_user_ty(place, variance, c_ty, location);
+ self.super_ascribe_user_ty(place, variance, user_ty, location);
}
fn visit_place(&mut self,
@@ -214,8 +214,11 @@ macro_rules! make_mir_visitor {
self.super_ty(ty);
}
- fn visit_user_ty(&mut self, ty: & $($mutability)* CanonicalTy<'tcx>) {
- self.super_canonical_ty(ty);
+ fn visit_user_type_annotation(
+ &mut self,
+ ty: & $($mutability)* UserTypeAnnotation<'tcx>,
+ ) {
+ self.super_user_type_annotation(ty);
}
fn visit_region(&mut self,
@@ -390,9 +393,9 @@ macro_rules! make_mir_visitor {
StatementKind::AscribeUserType(
ref $($mutability)* place,
ref $($mutability)* variance,
- ref $($mutability)* c_ty,
+ ref $($mutability)* user_ty,
) => {
- self.visit_ascribe_user_ty(place, variance, c_ty, location);
+ self.visit_ascribe_user_ty(place, variance, user_ty, location);
}
StatementKind::Nop => {}
}
@@ -637,10 +640,10 @@ macro_rules! make_mir_visitor {
fn super_ascribe_user_ty(&mut self,
place: & $($mutability)* Place<'tcx>,
_variance: & $($mutability)* ty::Variance,
- c_ty: & $($mutability)* CanonicalTy<'tcx>,
+ user_ty: & $($mutability)* UserTypeAnnotation<'tcx>,
location: Location) {
self.visit_place(place, PlaceContext::Validate, location);
- self.visit_user_ty(c_ty);
+ self.visit_user_type_annotation(user_ty);
}
fn super_place(&mut self,
@@ -736,7 +739,7 @@ macro_rules! make_mir_visitor {
source_info: *source_info,
});
if let Some((user_ty, _)) = user_ty {
- self.visit_user_ty(user_ty);
+ self.visit_user_type_annotation(user_ty);
}
self.visit_source_info(source_info);
self.visit_source_scope(visibility_scope);
@@ -783,7 +786,10 @@ macro_rules! make_mir_visitor {
self.visit_source_scope(scope);
}
- fn super_canonical_ty(&mut self, _ty: & $($mutability)* CanonicalTy<'tcx>) {
+ fn super_user_type_annotation(
+ &mut self,
+ _ty: & $($mutability)* UserTypeAnnotation<'tcx>,
+ ) {
}
fn super_ty(&mut self, _ty: & $($mutability)* Ty<'tcx>) {
diff --git a/src/librustc/ty/context.rs b/src/librustc/ty/context.rs
index ab1df2d4c3b..6f0f258a217 100644
--- a/src/librustc/ty/context.rs
+++ b/src/librustc/ty/context.rs
@@ -33,7 +33,7 @@ use middle::resolve_lifetime::{self, ObjectLifetimeDefault};
use middle::stability;
use mir::{self, Mir, interpret};
use mir::interpret::Allocation;
-use ty::subst::{CanonicalSubsts, Kind, Substs, Subst};
+use ty::subst::{CanonicalUserSubsts, Kind, Substs, Subst};
use ty::ReprOptions;
use traits;
use traits::{Clause, Clauses, GoalKind, Goal, Goals};
@@ -383,7 +383,7 @@ pub struct TypeckTables<'tcx> {
/// If the user wrote `foo.collect::<Vec<_>>()`, then the
/// canonical substitutions would include only `for<X> { Vec<X>
/// }`.
- user_substs: ItemLocalMap<CanonicalSubsts<'tcx>>,
+ user_substs: ItemLocalMap<CanonicalUserSubsts<'tcx>>,
adjustments: ItemLocalMap<Vec<ty::adjustment::Adjustment<'tcx>>>,
@@ -573,14 +573,14 @@ impl<'tcx> TypeckTables<'tcx> {
self.node_substs.get(&id.local_id).cloned()
}
- pub fn user_substs_mut(&mut self) -> LocalTableInContextMut<'_, CanonicalSubsts<'tcx>> {
+ pub fn user_substs_mut(&mut self) -> LocalTableInContextMut<'_, CanonicalUserSubsts<'tcx>> {
LocalTableInContextMut {
local_id_root: self.local_id_root,
data: &mut self.user_substs
}
}
- pub fn user_substs(&self, id: hir::HirId) -> Option<CanonicalSubsts<'tcx>> {
+ pub fn user_substs(&self, id: hir::HirId) -> Option<CanonicalUserSubsts<'tcx>> {
validate_hir_id_for_typeck_tables(self.local_id_root, id, false);
self.user_substs.get(&id.local_id).cloned()
}
diff --git a/src/librustc/ty/subst.rs b/src/librustc/ty/subst.rs
index c0a42fd5854..64cfba7df6e 100644
--- a/src/librustc/ty/subst.rs
+++ b/src/librustc/ty/subst.rs
@@ -323,33 +323,6 @@ impl<'tcx> TypeFoldable<'tcx> for &'tcx Substs<'tcx> {
}
}
-pub type CanonicalSubsts<'gcx> = Canonical<'gcx, &'gcx Substs<'gcx>>;
-
-impl<'gcx> CanonicalSubsts<'gcx> {
- /// True if this represents a substitution like
- ///
- /// ```text
- /// [?0, ?1, ?2]
- /// ```
- ///
- /// i.e., each thing is mapped to a canonical variable with the same index.
- pub fn is_identity(&self) -> bool {
- self.value.iter().zip(CanonicalVar::new(0)..).all(|(kind, cvar)| {
- match kind.unpack() {
- UnpackedKind::Type(ty) => match ty.sty {
- ty::Infer(ty::CanonicalTy(cvar1)) => cvar == cvar1,
- _ => false,
- },
-
- UnpackedKind::Lifetime(r) => match r {
- ty::ReCanonical(cvar1) => cvar == *cvar1,
- _ => false,
- },
- }
- })
- }
-}
-
impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Substs<'tcx> {}
///////////////////////////////////////////////////////////////////////////
@@ -564,3 +537,98 @@ impl<'a, 'gcx, 'tcx> SubstFolder<'a, 'gcx, 'tcx> {
self.tcx().mk_region(ty::fold::shift_region(*region, self.region_binders_passed))
}
}
+
+pub type CanonicalUserSubsts<'tcx> = Canonical<'tcx, UserSubsts<'tcx>>;
+
+impl CanonicalUserSubsts<'tcx> {
+ /// True if this represents a substitution like
+ ///
+ /// ```text
+ /// [?0, ?1, ?2]
+ /// ```
+ ///
+ /// i.e., each thing is mapped to a canonical variable with the same index.
+ pub fn is_identity(&self) -> bool {
+ if self.value.user_self_ty.is_some() {
+ return false;
+ }
+
+ self.value.substs.iter().zip(CanonicalVar::new(0)..).all(|(kind, cvar)| {
+ match kind.unpack() {
+ UnpackedKind::Type(ty) => match ty.sty {
+ ty::Infer(ty::CanonicalTy(cvar1)) => cvar == cvar1,
+ _ => false,
+ },
+
+ UnpackedKind::Lifetime(r) => match r {
+ ty::ReCanonical(cvar1) => cvar == *cvar1,
+ _ => false,
+ },
+ }
+ })
+ }
+}
+
+/// Stores the user-given substs to reach some fully qualified path
+/// (e.g., `<T>::Item` or `<T as Trait>::Item`).
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
+pub struct UserSubsts<'tcx> {
+ /// The substitutions for the item as given by the user.
+ pub substs: &'tcx Substs<'tcx>,
+
+ /// The self-type, in the case of a `<T>::Item` path (when applied
+ /// to an inherent impl). See `UserSelfTy` below.
+ pub user_self_ty: Option<UserSelfTy<'tcx>>,
+}
+
+BraceStructTypeFoldableImpl! {
+ impl<'tcx> TypeFoldable<'tcx> for UserSubsts<'tcx> {
+ substs,
+ user_self_ty,
+ }
+}
+
+BraceStructLiftImpl! {
+ impl<'a, 'tcx> Lift<'tcx> for UserSubsts<'a> {
+ type Lifted = UserSubsts<'tcx>;
+ substs,
+ user_self_ty,
+ }
+}
+
+/// Specifies the user-given self-type. In the case of a path that
+/// refers to a member in an inherent impl, this self-type is
+/// sometimes needed to constrain the type parameters on the impl. For
+/// example, in this code:
+///
+/// ```
+/// struct Foo<T> { }
+/// impl<A> Foo<A> { fn method() { } }
+/// ```
+///
+/// when you then have a path like `<Foo<&'static u32>>::method`,
+/// this struct would carry the def-id of the impl along with the
+/// self-type `Foo<u32>`. Then we can instantiate the parameters of
+/// the impl (with the substs from `UserSubsts`) and apply those to
+/// the self-type, giving `Foo<?A>`. Finally, we unify that with
+/// the self-type here, which contains `?A` to be `&'static u32`
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
+pub struct UserSelfTy<'tcx> {
+ pub impl_def_id: DefId,
+ pub self_ty: Ty<'tcx>,
+}
+
+BraceStructTypeFoldableImpl! {
+ impl<'tcx> TypeFoldable<'tcx> for UserSelfTy<'tcx> {
+ impl_def_id,
+ self_ty,
+ }
+}
+
+BraceStructLiftImpl! {
+ impl<'a, 'tcx> Lift<'tcx> for UserSelfTy<'a> {
+ type Lifted = UserSelfTy<'tcx>;
+ impl_def_id,
+ self_ty,
+ }
+}
diff --git a/src/librustc_mir/borrow_check/nll/constraint_generation.rs b/src/librustc_mir/borrow_check/nll/constraint_generation.rs
index 7e8e1b32d4d..30b263a923a 100644
--- a/src/librustc_mir/borrow_check/nll/constraint_generation.rs
+++ b/src/librustc_mir/borrow_check/nll/constraint_generation.rs
@@ -18,9 +18,10 @@ use rustc::mir::visit::TyContext;
use rustc::mir::visit::Visitor;
use rustc::mir::{BasicBlock, BasicBlockData, Location, Mir, Place, Rvalue};
use rustc::mir::{Statement, Terminator};
+use rustc::mir::UserTypeAnnotation;
use rustc::ty::fold::TypeFoldable;
use rustc::ty::subst::Substs;
-use rustc::ty::{self, CanonicalTy, ClosureSubsts, GeneratorSubsts, RegionVid};
+use rustc::ty::{self, ClosureSubsts, GeneratorSubsts, RegionVid};
pub(super) fn generate_constraints<'cx, 'gcx, 'tcx>(
infcx: &InferCtxt<'cx, 'gcx, 'tcx>,
@@ -179,7 +180,7 @@ impl<'cg, 'cx, 'gcx, 'tcx> Visitor<'tcx> for ConstraintGeneration<'cg, 'cx, 'gcx
&mut self,
_place: &Place<'tcx>,
_variance: &ty::Variance,
- _c_ty: &CanonicalTy<'tcx>,
+ _user_ty: &UserTypeAnnotation<'tcx>,
_location: Location,
) {
}
diff --git a/src/librustc_mir/borrow_check/nll/renumber.rs b/src/librustc_mir/borrow_check/nll/renumber.rs
index 15a60badc93..363afb87ed9 100644
--- a/src/librustc_mir/borrow_check/nll/renumber.rs
+++ b/src/librustc_mir/borrow_check/nll/renumber.rs
@@ -9,8 +9,8 @@
// except according to those terms.
use rustc::ty::subst::Substs;
-use rustc::ty::{self, CanonicalTy, ClosureSubsts, GeneratorSubsts, Ty, TypeFoldable};
-use rustc::mir::{BasicBlock, Location, Mir, Statement, StatementKind};
+use rustc::ty::{self, ClosureSubsts, GeneratorSubsts, Ty, TypeFoldable};
+use rustc::mir::{BasicBlock, Location, Mir, Statement, StatementKind, UserTypeAnnotation};
use rustc::mir::visit::{MutVisitor, TyContext};
use rustc::infer::{InferCtxt, NLLRegionVariableOrigin};
@@ -65,12 +65,12 @@ impl<'a, 'gcx, 'tcx> MutVisitor<'tcx> for NLLVisitor<'a, 'gcx, 'tcx> {
debug!("visit_ty: ty={:?}", ty);
}
- fn visit_user_ty(&mut self, _ty: &mut CanonicalTy<'tcx>) {
- // `user_ty` annotations represent the types that the user
+ fn visit_user_type_annotation(&mut self, _ty: &mut UserTypeAnnotation<'tcx>) {
+ // User type annotations represent the types that the user
// wrote in the progarm. We don't want to erase the regions
// from these types: rather, we want to add them as
// constraints at type-check time.
- debug!("visit_user_ty: skipping renumber");
+ debug!("visit_user_type_annotation: skipping renumber");
}
fn visit_substs(&mut self, substs: &mut &'tcx Substs<'tcx>, location: Location) {
diff --git a/src/librustc_mir/borrow_check/nll/type_check/mod.rs b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
index e11f452e16b..1e79bc272e4 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -43,7 +43,7 @@ use rustc::traits::query::{Fallible, NoSolution};
use rustc::traits::{ObligationCause, PredicateObligations};
use rustc::ty::fold::TypeFoldable;
use rustc::ty::subst::{Subst, UnpackedKind};
-use rustc::ty::{self, CanonicalTy, RegionVid, ToPolyTraitRef, Ty, TyCtxt, TyKind};
+use rustc::ty::{self, RegionVid, ToPolyTraitRef, Ty, TyCtxt, TyKind};
use std::rc::Rc;
use std::{fmt, iter};
use syntax_pos::{Span, DUMMY_SP};
@@ -966,7 +966,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
&mut self,
a: Ty<'tcx>,
v: ty::Variance,
- b: CanonicalTy<'tcx>,
+ b: UserTypeAnnotation<'tcx>,
locations: Locations,
category: ConstraintCategory,
) -> Fallible<()> {
@@ -1837,7 +1837,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
/// If this rvalue supports a user-given type annotation, then
/// extract and return it. This represents the final type of the
/// rvalue and will be unified with the inferred type.
- fn rvalue_user_ty(&self, rvalue: &Rvalue<'tcx>) -> Option<CanonicalTy<'tcx>> {
+ fn rvalue_user_ty(&self, rvalue: &Rvalue<'tcx>) -> Option<UserTypeAnnotation<'tcx>> {
match rvalue {
Rvalue::Use(_)
| Rvalue::Repeat(..)
diff --git a/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs b/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs
index 96cc1c0afec..72120eb1841 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/relate_tys.rs
@@ -10,16 +10,14 @@
use borrow_check::nll::constraints::OutlivesConstraint;
use borrow_check::nll::type_check::{BorrowCheckContext, Locations};
-use rustc::infer::canonical::{Canonical, CanonicalVarInfos, CanonicalVarValues};
+use rustc::infer::nll_relate::{TypeRelating, TypeRelatingDelegate};
use rustc::infer::{InferCtxt, NLLRegionVariableOrigin};
-use rustc::mir::ConstraintCategory;
+use rustc::mir::{ConstraintCategory, UserTypeAnnotation};
use rustc::traits::query::Fallible;
-use rustc::ty::fold::{TypeFoldable, TypeVisitor};
-use rustc::ty::relate::{self, Relate, RelateResult, TypeRelation};
-use rustc::ty::subst::Kind;
-use rustc::ty::{self, CanonicalTy, CanonicalVar, Ty, TyCtxt};
-use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::indexed_vec::IndexVec;
+use rustc::ty::relate::TypeRelation;
+use rustc::ty::subst::{Subst, UserSelfTy, UserSubsts};
+use rustc::ty::{self, Ty, TypeFoldable};
+use syntax_pos::DUMMY_SP;
/// Adds sufficient constraints to ensure that `a <: b`.
pub(super) fn sub_types<'tcx>(
@@ -32,10 +30,9 @@ pub(super) fn sub_types<'tcx>(
) -> Fallible<()> {
debug!("sub_types(a={:?}, b={:?}, locations={:?})", a, b, locations);
TypeRelating::new(
- infcx.tcx,
+ infcx,
NllTypeRelatingDelegate::new(infcx, borrowck_context, locations, category),
ty::Variance::Covariant,
- ty::List::empty(),
).relate(&a, &b)?;
Ok(())
}
@@ -51,10 +48,9 @@ pub(super) fn eq_types<'tcx>(
) -> Fallible<()> {
debug!("eq_types(a={:?}, b={:?}, locations={:?})", a, b, locations);
TypeRelating::new(
- infcx.tcx,
+ infcx,
NllTypeRelatingDelegate::new(infcx, borrowck_context, locations, category),
ty::Variance::Invariant,
- ty::List::empty(),
).relate(&a, &b)?;
Ok(())
}
@@ -66,19 +62,15 @@ pub(super) fn relate_type_and_user_type<'tcx>(
infcx: &InferCtxt<'_, '_, 'tcx>,
a: Ty<'tcx>,
v: ty::Variance,
- b: CanonicalTy<'tcx>,
+ user_ty: UserTypeAnnotation<'tcx>,
locations: Locations,
category: ConstraintCategory,
borrowck_context: Option<&mut BorrowCheckContext<'_, 'tcx>>,
) -> Fallible<Ty<'tcx>> {
debug!(
- "sub_type_and_user_type(a={:?}, b={:?}, locations={:?})",
- a, b, locations
+ "relate_type_and_user_type(a={:?}, v={:?}, b={:?}, locations={:?})",
+ a, v, user_ty, locations
);
- let Canonical {
- variables: b_variables,
- value: b_value,
- } = b;
// The `TypeRelating` code assumes that the "canonical variables"
// appear in the "a" side, so flip `Contravariant` ambient
@@ -86,108 +78,75 @@ pub(super) fn relate_type_and_user_type<'tcx>(
let v1 = ty::Contravariant.xform(v);
let mut type_relating = TypeRelating::new(
- infcx.tcx,
+ infcx,
NllTypeRelatingDelegate::new(infcx, borrowck_context, locations, category),
v1,
- b_variables,
);
- type_relating.relate(&b_value, &a)?;
- Ok(b.substitute(
- infcx.tcx,
- &CanonicalVarValues {
- var_values: type_relating
- .canonical_var_values
- .into_iter()
- .map(|x| x.expect("unsubstituted canonical variable"))
- .collect(),
- },
- ))
-}
+ match user_ty {
+ UserTypeAnnotation::Ty(canonical_ty) => {
+ let (ty, _) =
+ infcx.instantiate_canonical_with_fresh_inference_vars(DUMMY_SP, &canonical_ty);
+ type_relating.relate(&ty, &a)?;
+ Ok(ty)
+ }
+ UserTypeAnnotation::FnDef(def_id, canonical_substs) => {
+ let (
+ UserSubsts {
+ substs,
+ user_self_ty,
+ },
+ _,
+ ) = infcx.instantiate_canonical_with_fresh_inference_vars(DUMMY_SP, &canonical_substs);
+ let ty = infcx.tcx.mk_fn_def(def_id, substs);
-struct TypeRelating<'me, 'gcx: 'tcx, 'tcx: 'me, D>
-where
- D: TypeRelatingDelegate<'tcx>,
-{
- tcx: TyCtxt<'me, 'gcx, 'tcx>,
+ type_relating.relate(&ty, &a)?;
- /// Callback to use when we deduce an outlives relationship
- delegate: D,
+ if let Some(UserSelfTy {
+ impl_def_id,
+ self_ty,
+ }) = user_self_ty
+ {
+ let impl_self_ty = infcx.tcx.type_of(impl_def_id);
+ let impl_self_ty = impl_self_ty.subst(infcx.tcx, &substs);
- /// How are we relating `a` and `b`?
- ///
- /// - covariant means `a <: b`
- /// - contravariant means `b <: a`
- /// - invariant means `a == b
- /// - bivariant means that it doesn't matter
- ambient_variance: ty::Variance,
+ // There may be type variables in `substs` and hence
+ // in `impl_self_ty`, but they should all have been
+ // resolved to some fixed value during the first call
+ // to `relate`, above. Therefore, if we use
+ // `resolve_type_vars_if_possible` we should get to
+ // something without type variables. This is important
+ // because the `b` type in `relate_with_variance`
+ // below is not permitted to have inference variables.
+ let impl_self_ty = infcx.resolve_type_vars_if_possible(&impl_self_ty);
+ assert!(!impl_self_ty.has_infer_types());
- /// When we pass through a set of binders (e.g., when looking into
- /// a `fn` type), we push a new bound region scope onto here. This
- /// will contain the instantiated region for each region in those
- /// binders. When we then encounter a `ReLateBound(d, br)`, we can
- /// use the debruijn index `d` to find the right scope, and then
- /// bound region name `br` to find the specific instantiation from
- /// within that scope. See `replace_bound_region`.
- ///
- /// This field stores the instantiations for late-bound regions in
- /// the `a` type.
- a_scopes: Vec<BoundRegionScope<'tcx>>,
+ type_relating.relate_with_variance(
+ ty::Variance::Invariant,
+ &self_ty,
+ &impl_self_ty,
+ )?;
+ }
- /// Same as `a_scopes`, but for the `b` type.
- b_scopes: Vec<BoundRegionScope<'tcx>>,
+ Ok(ty)
+ }
+ UserTypeAnnotation::AdtDef(adt_def, canonical_substs) => {
+ let (
+ UserSubsts {
+ substs,
+ user_self_ty,
+ },
+ _,
+ ) = infcx.instantiate_canonical_with_fresh_inference_vars(DUMMY_SP, &canonical_substs);
- /// As we execute, the type on the LHS *may* come from a canonical
- /// source. In that case, we will sometimes find a constraint like
- /// `?0 = B`, where `B` is a type from the RHS. The first time we
- /// find that, we simply record `B` (and the list of scopes that
- /// tells us how to *interpret* `B`). The next time we encounter
- /// `?0`, then, we can read this value out and use it.
- ///
- /// One problem: these variables may be in some other universe,
- /// how can we enforce that? I guess I could add some kind of
- /// "minimum universe constraint" that we can feed to the NLL checker.
- /// --> also, we know this doesn't happen
- canonical_var_values: IndexVec<CanonicalVar, Option<Kind<'tcx>>>,
-}
+ // We don't extract adt-defs with a self-type.
+ assert!(user_self_ty.is_none());
-trait TypeRelatingDelegate<'tcx> {
- /// Push a constraint `sup: sub` -- this constraint must be
- /// satisfied for the two types to be related. `sub` and `sup` may
- /// be regions from the type or new variables created through the
- /// delegate.
- fn push_outlives(&mut self, sup: ty::Region<'tcx>, sub: ty::Region<'tcx>);
-
- /// Creates a new universe index. Used when instantiating placeholders.
- fn create_next_universe(&mut self) -> ty::UniverseIndex;
-
- /// Creates a new region variable representing a higher-ranked
- /// region that is instantiated existentially. This creates an
- /// inference variable, typically.
- ///
- /// So e.g. if you have `for<'a> fn(..) <: for<'b> fn(..)`, then
- /// we will invoke this method to instantiate `'a` with an
- /// inference variable (though `'b` would be instantiated first,
- /// as a placeholder).
- fn next_existential_region_var(&mut self) -> ty::Region<'tcx>;
-
- /// Creates a new region variable representing a
- /// higher-ranked region that is instantiated universally.
- /// This creates a new region placeholder, typically.
- ///
- /// So e.g. if you have `for<'a> fn(..) <: for<'b> fn(..)`, then
- /// we will invoke this method to instantiate `'b` with a
- /// placeholder region.
- fn next_placeholder_region(&mut self, placeholder: ty::Placeholder) -> ty::Region<'tcx>;
-
- /// Creates a new existential region in the given universe. This
- /// is used when handling subtyping and type variables -- if we
- /// have that `?X <: Foo<'a>`, for example, we would instantiate
- /// `?X` with a type like `Foo<'?0>` where `'?0` is a fresh
- /// existential variable created by this function. We would then
- /// relate `Foo<'?0>` with `Foo<'a>` (and probably add an outlives
- /// relation stating that `'?0: 'a`).
- fn generalize_existential(&mut self, universe: ty::UniverseIndex) -> ty::Region<'tcx>;
+ let ty = infcx.tcx.mk_adt(adt_def, substs);
+ type_relating.relate(&ty, &a)?;
+ Ok(ty)
+ }
+ }
}
struct NllTypeRelatingDelegate<'me, 'bccx: 'me, 'gcx: 'tcx, 'tcx: 'bccx> {
@@ -256,585 +215,3 @@ impl TypeRelatingDelegate<'tcx> for NllTypeRelatingDelegate<'_, '_, '_, 'tcx> {
}
}
}
-
-#[derive(Clone, Debug)]
-struct ScopesAndKind<'tcx> {
- scopes: Vec<BoundRegionScope<'tcx>>,
- kind: Kind<'tcx>,
-}
-
-#[derive(Clone, Debug, Default)]
-struct BoundRegionScope<'tcx> {
- map: FxHashMap<ty::BoundRegion, ty::Region<'tcx>>,
-}
-
-#[derive(Copy, Clone)]
-struct UniversallyQuantified(bool);
-
-impl<'me, 'gcx, 'tcx, D> TypeRelating<'me, 'gcx, 'tcx, D>
-where
- D: TypeRelatingDelegate<'tcx>,
-{
- fn new(
- tcx: TyCtxt<'me, 'gcx, 'tcx>,
- delegate: D,
- ambient_variance: ty::Variance,
- canonical_var_infos: CanonicalVarInfos<'tcx>,
- ) -> Self {
- let canonical_var_values = IndexVec::from_elem_n(None, canonical_var_infos.len());
- Self {
- tcx,
- delegate,
- ambient_variance,
- canonical_var_values,
- a_scopes: vec![],
- b_scopes: vec![],
- }
- }
-
- fn ambient_covariance(&self) -> bool {
- match self.ambient_variance {
- ty::Variance::Covariant | ty::Variance::Invariant => true,
- ty::Variance::Contravariant | ty::Variance::Bivariant => false,
- }
- }
-
- fn ambient_contravariance(&self) -> bool {
- match self.ambient_variance {
- ty::Variance::Contravariant | ty::Variance::Invariant => true,
- ty::Variance::Covariant | ty::Variance::Bivariant => false,
- }
- }
-
- fn create_scope(
- &mut self,
- value: &ty::Binder<impl TypeFoldable<'tcx>>,
- universally_quantified: UniversallyQuantified,
- ) -> BoundRegionScope<'tcx> {
- let mut scope = BoundRegionScope::default();
-
- // Create a callback that creates (via the delegate) either an
- // existential or placeholder region as needed.
- let mut next_region = {
- let delegate = &mut self.delegate;
- let mut lazy_universe = None;
- move |br: ty::BoundRegion| {
- if universally_quantified.0 {
- // The first time this closure is called, create a
- // new universe for the placeholders we will make
- // from here out.
- let universe = lazy_universe.unwrap_or_else(|| {
- let universe = delegate.create_next_universe();
- lazy_universe = Some(universe);
- universe
- });
-
- let placeholder = ty::Placeholder { universe, name: br };
- delegate.next_placeholder_region(placeholder)
- } else {
- delegate.next_existential_region_var()
- }
- }
- };
-
- value.skip_binder().visit_with(&mut ScopeInstantiator {
- next_region: &mut next_region,
- target_index: ty::INNERMOST,
- bound_region_scope: &mut scope,
- });
-
- scope
- }
-
- /// When we encounter binders during the type traversal, we record
- /// the value to substitute for each of the things contained in
- /// that binder. (This will be either a universal placeholder or
- /// an existential inference variable.) Given the debruijn index
- /// `debruijn` (and name `br`) of some binder we have now
- /// encountered, this routine finds the value that we instantiated
- /// the region with; to do so, it indexes backwards into the list
- /// of ambient scopes `scopes`.
- fn lookup_bound_region(
- debruijn: ty::DebruijnIndex,
- br: &ty::BoundRegion,
- first_free_index: ty::DebruijnIndex,
- scopes: &[BoundRegionScope<'tcx>],
- ) -> ty::Region<'tcx> {
- // The debruijn index is a "reverse index" into the
- // scopes listing. So when we have INNERMOST (0), we
- // want the *last* scope pushed, and so forth.
- let debruijn_index = debruijn.index() - first_free_index.index();
- let scope = &scopes[scopes.len() - debruijn_index - 1];
-
- // Find this bound region in that scope to map to a
- // particular region.
- scope.map[br]
- }
-
- /// If `r` is a bound region, find the scope in which it is bound
- /// (from `scopes`) and return the value that we instantiated it
- /// with. Otherwise just return `r`.
- fn replace_bound_region(
- &self,
- r: ty::Region<'tcx>,
- first_free_index: ty::DebruijnIndex,
- scopes: &[BoundRegionScope<'tcx>],
- ) -> ty::Region<'tcx> {
- if let ty::ReLateBound(debruijn, br) = r {
- Self::lookup_bound_region(*debruijn, br, first_free_index, scopes)
- } else {
- r
- }
- }
-
- /// Push a new outlives requirement into our output set of
- /// constraints.
- fn push_outlives(&mut self, sup: ty::Region<'tcx>, sub: ty::Region<'tcx>) {
- debug!("push_outlives({:?}: {:?})", sup, sub);
-
- self.delegate.push_outlives(sup, sub);
- }
-
- /// When we encounter a canonical variable `var` in the output,
- /// equate it with `kind`. If the variable has been previously
- /// equated, then equate it again.
- fn relate_var(
- &mut self,
- var: CanonicalVar,
- b_kind: Kind<'tcx>,
- ) -> RelateResult<'tcx, Kind<'tcx>> {
- debug!("equate_var(var={:?}, b_kind={:?})", var, b_kind);
-
- let generalized_kind = match self.canonical_var_values[var] {
- Some(v) => v,
- None => {
- let generalized_kind = self.generalize_value(b_kind);
- self.canonical_var_values[var] = Some(generalized_kind);
- generalized_kind
- }
- };
-
- // The generalized values we extract from `canonical_var_values` have
- // been fully instantiated and hence the set of scopes we have
- // doesn't matter -- just to be sure, put an empty vector
- // in there.
- let old_a_scopes = ::std::mem::replace(&mut self.a_scopes, vec![]);
-
- // Relate the generalized kind to the original one.
- let result = self.relate(&generalized_kind, &b_kind);
-
- // Restore the old scopes now.
- self.a_scopes = old_a_scopes;
-
- debug!("equate_var: complete, result = {:?}", result);
- return result;
- }
-
- fn generalize_value(&mut self, kind: Kind<'tcx>) -> Kind<'tcx> {
- TypeGeneralizer {
- tcx: self.tcx,
- delegate: &mut self.delegate,
- first_free_index: ty::INNERMOST,
- ambient_variance: self.ambient_variance,
-
- // These always correspond to an `_` or `'_` written by
- // user, and those are always in the root universe.
- universe: ty::UniverseIndex::ROOT,
- }.relate(&kind, &kind)
- .unwrap()
- }
-}
-
-impl<D> TypeRelation<'me, 'gcx, 'tcx> for TypeRelating<'me, 'gcx, 'tcx, D>
-where
- D: TypeRelatingDelegate<'tcx>,
-{
- fn tcx(&self) -> TyCtxt<'me, 'gcx, 'tcx> {
- self.tcx
- }
-
- fn tag(&self) -> &'static str {
- "nll::subtype"
- }
-
- fn a_is_expected(&self) -> bool {
- true
- }
-
- fn relate_with_variance<T: Relate<'tcx>>(
- &mut self,
- variance: ty::Variance,
- a: &T,
- b: &T,
- ) -> RelateResult<'tcx, T> {
- debug!(
- "relate_with_variance(variance={:?}, a={:?}, b={:?})",
- variance, a, b
- );
-
- let old_ambient_variance = self.ambient_variance;
- self.ambient_variance = self.ambient_variance.xform(variance);
-
- debug!(
- "relate_with_variance: ambient_variance = {:?}",
- self.ambient_variance
- );
-
- let r = self.relate(a, b)?;
-
- self.ambient_variance = old_ambient_variance;
-
- debug!("relate_with_variance: r={:?}", r);
-
- Ok(r)
- }
-
- fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
- // Watch out for the case that we are matching a `?T` against the
- // right-hand side.
- if let ty::Infer(ty::CanonicalTy(var)) = a.sty {
- self.relate_var(var, b.into())?;
- Ok(a)
- } else {
- debug!(
- "tys(a={:?}, b={:?}, variance={:?})",
- a, b, self.ambient_variance
- );
-
- relate::super_relate_tys(self, a, b)
- }
- }
-
- fn regions(
- &mut self,
- a: ty::Region<'tcx>,
- b: ty::Region<'tcx>,
- ) -> RelateResult<'tcx, ty::Region<'tcx>> {
- if let ty::ReCanonical(var) = a {
- self.relate_var(*var, b.into())?;
- return Ok(a);
- }
-
- debug!(
- "regions(a={:?}, b={:?}, variance={:?})",
- a, b, self.ambient_variance
- );
-
- let v_a = self.replace_bound_region(a, ty::INNERMOST, &self.a_scopes);
- let v_b = self.replace_bound_region(b, ty::INNERMOST, &self.b_scopes);
-
- debug!("regions: v_a = {:?}", v_a);
- debug!("regions: v_b = {:?}", v_b);
-
- if self.ambient_covariance() {
- // Covariance: a <= b. Hence, `b: a`.
- self.push_outlives(v_b, v_a);
- }
-
- if self.ambient_contravariance() {
- // Contravariant: b <= a. Hence, `a: b`.
- self.push_outlives(v_a, v_b);
- }
-
- Ok(a)
- }
-
- fn binders<T>(
- &mut self,
- a: &ty::Binder<T>,
- b: &ty::Binder<T>,
- ) -> RelateResult<'tcx, ty::Binder<T>>
- where
- T: Relate<'tcx>,
- {
- // We want that
- //
- // ```
- // for<'a> fn(&'a u32) -> &'a u32 <:
- // fn(&'b u32) -> &'b u32
- // ```
- //
- // but not
- //
- // ```
- // fn(&'a u32) -> &'a u32 <:
- // for<'b> fn(&'b u32) -> &'b u32
- // ```
- //
- // We therefore proceed as follows:
- //
- // - Instantiate binders on `b` universally, yielding a universe U1.
- // - Instantiate binders on `a` existentially in U1.
-
- debug!(
- "binders({:?}: {:?}, ambient_variance={:?})",
- a, b, self.ambient_variance
- );
-
- if self.ambient_covariance() {
- // Covariance, so we want `for<..> A <: for<..> B` --
- // therefore we compare any instantiation of A (i.e., A
- // instantiated with existentials) against every
- // instantiation of B (i.e., B instantiated with
- // universals).
-
- let b_scope = self.create_scope(b, UniversallyQuantified(true));
- let a_scope = self.create_scope(a, UniversallyQuantified(false));
-
- debug!("binders: a_scope = {:?} (existential)", a_scope);
- debug!("binders: b_scope = {:?} (universal)", b_scope);
-
- self.b_scopes.push(b_scope);
- self.a_scopes.push(a_scope);
-
- // Reset the ambient variance to covariant. This is needed
- // to correctly handle cases like
- //
- // for<'a> fn(&'a u32, &'a u3) == for<'b, 'c> fn(&'b u32, &'c u32)
- //
- // Somewhat surprisingly, these two types are actually
- // **equal**, even though the one on the right looks more
- // polymorphic. The reason is due to subtyping. To see it,
- // consider that each function can call the other:
- //
- // - The left function can call the right with `'b` and
- // `'c` both equal to `'a`
- //
- // - The right function can call the left with `'a` set to
- // `{P}`, where P is the point in the CFG where the call
- // itself occurs. Note that `'b` and `'c` must both
- // include P. At the point, the call works because of
- // subtyping (i.e., `&'b u32 <: &{P} u32`).
- let variance = ::std::mem::replace(&mut self.ambient_variance, ty::Variance::Covariant);
-
- self.relate(a.skip_binder(), b.skip_binder())?;
-
- self.ambient_variance = variance;
-
- self.b_scopes.pop().unwrap();
- self.a_scopes.pop().unwrap();
- }
-
- if self.ambient_contravariance() {
- // Contravariance, so we want `for<..> A :> for<..> B`
- // -- therefore we compare every instantiation of A (i.e.,
- // A instantiated with universals) against any
- // instantiation of B (i.e., B instantiated with
- // existentials). Opposite of above.
-
- let a_scope = self.create_scope(a, UniversallyQuantified(true));
- let b_scope = self.create_scope(b, UniversallyQuantified(false));
-
- debug!("binders: a_scope = {:?} (universal)", a_scope);
- debug!("binders: b_scope = {:?} (existential)", b_scope);
-
- self.a_scopes.push(a_scope);
- self.b_scopes.push(b_scope);
-
- // Reset ambient variance to contravariance. See the
- // covariant case above for an explanation.
- let variance =
- ::std::mem::replace(&mut self.ambient_variance, ty::Variance::Contravariant);
-
- self.relate(a.skip_binder(), b.skip_binder())?;
-
- self.ambient_variance = variance;
-
- self.b_scopes.pop().unwrap();
- self.a_scopes.pop().unwrap();
- }
-
- Ok(a.clone())
- }
-}
-
-/// When we encounter a binder like `for<..> fn(..)`, we actually have
-/// to walk the `fn` value to find all the values bound by the `for`
-/// (these are not explicitly present in the ty representation right
-/// now). This visitor handles that: it descends the type, tracking
-/// binder depth, and finds late-bound regions targeting the
-/// `for<..`>. For each of those, it creates an entry in
-/// `bound_region_scope`.
-struct ScopeInstantiator<'me, 'tcx: 'me> {
- next_region: &'me mut dyn FnMut(ty::BoundRegion) -> ty::Region<'tcx>,
- // The debruijn index of the scope we are instantiating.
- target_index: ty::DebruijnIndex,
- bound_region_scope: &'me mut BoundRegionScope<'tcx>,
-}
-
-impl<'me, 'tcx> TypeVisitor<'tcx> for ScopeInstantiator<'me, 'tcx> {
- fn visit_binder<T: TypeFoldable<'tcx>>(&mut self, t: &ty::Binder<T>) -> bool {
- self.target_index.shift_in(1);
- t.super_visit_with(self);
- self.target_index.shift_out(1);
-
- false
- }
-
- fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool {
- let ScopeInstantiator {
- bound_region_scope,
- next_region,
- ..
- } = self;
-
- match r {
- ty::ReLateBound(debruijn, br) if *debruijn == self.target_index => {
- bound_region_scope
- .map
- .entry(*br)
- .or_insert_with(|| next_region(*br));
- }
-
- _ => {}
- }
-
- false
- }
-}
-
-/// The "type generalize" is used when handling inference variables.
-///
-/// The basic strategy for handling a constraint like `?A <: B` is to
-/// apply a "generalization strategy" to the type `B` -- this replaces
-/// all the lifetimes in the type `B` with fresh inference
-/// variables. (You can read more about the strategy in this [blog
-/// post].)
-///
-/// As an example, if we had `?A <: &'x u32`, we would generalize `&'x
-/// u32` to `&'0 u32` where `'0` is a fresh variable. This becomes the
-/// value of `A`. Finally, we relate `&'0 u32 <: &'x u32`, which
-/// establishes `'0: 'x` as a constraint.
-///
-/// As a side-effect of this generalization procedure, we also replace
-/// all the bound regions that we have traversed with concrete values,
-/// so that the resulting generalized type is independent from the
-/// scopes.
-///
-/// [blog post]: https://is.gd/0hKvIr
-struct TypeGeneralizer<'me, 'gcx: 'tcx, 'tcx: 'me, D>
-where
- D: TypeRelatingDelegate<'tcx> + 'me,
-{
- tcx: TyCtxt<'me, 'gcx, 'tcx>,
-
- delegate: &'me mut D,
-
- /// After we generalize this type, we are going to relative it to
- /// some other type. What will be the variance at this point?
- ambient_variance: ty::Variance,
-
- first_free_index: ty::DebruijnIndex,
-
- universe: ty::UniverseIndex,
-}
-
-impl<D> TypeRelation<'me, 'gcx, 'tcx> for TypeGeneralizer<'me, 'gcx, 'tcx, D>
-where
- D: TypeRelatingDelegate<'tcx>,
-{
- fn tcx(&self) -> TyCtxt<'me, 'gcx, 'tcx> {
- self.tcx
- }
-
- fn tag(&self) -> &'static str {
- "nll::generalizer"
- }
-
- fn a_is_expected(&self) -> bool {
- true
- }
-
- fn relate_with_variance<T: Relate<'tcx>>(
- &mut self,
- variance: ty::Variance,
- a: &T,
- b: &T,
- ) -> RelateResult<'tcx, T> {
- debug!(
- "TypeGeneralizer::relate_with_variance(variance={:?}, a={:?}, b={:?})",
- variance, a, b
- );
-
- let old_ambient_variance = self.ambient_variance;
- self.ambient_variance = self.ambient_variance.xform(variance);
-
- debug!(
- "TypeGeneralizer::relate_with_variance: ambient_variance = {:?}",
- self.ambient_variance
- );
-
- let r = self.relate(a, b)?;
-
- self.ambient_variance = old_ambient_variance;
-
- debug!("TypeGeneralizer::relate_with_variance: r={:?}", r);
-
- Ok(r)
- }
-
- fn tys(&mut self, a: Ty<'tcx>, _: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>> {
- debug!("TypeGeneralizer::tys(a={:?})", a,);
-
- match a.sty {
- ty::Infer(ty::TyVar(_)) | ty::Infer(ty::IntVar(_)) | ty::Infer(ty::FloatVar(_)) => {
- bug!(
- "unexpected inference variable encountered in NLL generalization: {:?}",
- a
- );
- }
-
- _ => relate::super_relate_tys(self, a, a),
- }
- }
-
- fn regions(
- &mut self,
- a: ty::Region<'tcx>,
- _: ty::Region<'tcx>,
- ) -> RelateResult<'tcx, ty::Region<'tcx>> {
- debug!("TypeGeneralizer::regions(a={:?})", a,);
-
- if let ty::ReLateBound(debruijn, _) = a {
- if *debruijn < self.first_free_index {
- return Ok(a);
- }
- }
-
- // For now, we just always create a fresh region variable to
- // replace all the regions in the source type. In the main
- // type checker, we special case the case where the ambient
- // variance is `Invariant` and try to avoid creating a fresh
- // region variable, but since this comes up so much less in
- // NLL (only when users use `_` etc) it is much less
- // important.
- //
- // As an aside, since these new variables are created in
- // `self.universe` universe, this also serves to enforce the
- // universe scoping rules.
- //
- // FIXME(#54105) -- if the ambient variance is bivariant,
- // though, we may however need to check well-formedness or
- // risk a problem like #41677 again.
-
- let replacement_region_vid = self.delegate.generalize_existential(self.universe);
-
- Ok(replacement_region_vid)
- }
-
- fn binders<T>(
- &mut self,
- a: &ty::Binder<T>,
- _: &ty::Binder<T>,
- ) -> RelateResult<'tcx, ty::Binder<T>>
- where
- T: Relate<'tcx>,
- {
- debug!("TypeGeneralizer::binders(a={:?})", a,);
-
- self.first_free_index.shift_in(1);
- let result = self.relate(a.skip_binder(), a.skip_binder())?;
- self.first_free_index.shift_out(1);
- Ok(ty::Binder::bind(result))
- }
-}
diff --git a/src/librustc_mir/build/matches/mod.rs b/src/librustc_mir/build/matches/mod.rs
index 394fa4e077c..99c0a52a8ee 100644
--- a/src/librustc_mir/build/matches/mod.rs
+++ b/src/librustc_mir/build/matches/mod.rs
@@ -20,7 +20,7 @@ use build::{GuardFrame, GuardFrameLocal, LocalsForNode};
use hair::*;
use rustc::hir;
use rustc::mir::*;
-use rustc::ty::{self, CanonicalTy, Ty};
+use rustc::ty::{self, Ty};
use rustc_data_structures::bit_set::BitSet;
use rustc_data_structures::fx::FxHashMap;
use syntax::ast::{Name, NodeId};
@@ -491,7 +491,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
pub fn visit_bindings(
&mut self,
pattern: &Pattern<'tcx>,
- mut pattern_user_ty: Option<(CanonicalTy<'tcx>, Span)>,
+ mut pattern_user_ty: Option<(UserTypeAnnotation<'tcx>, Span)>,
f: &mut impl FnMut(
&mut Self,
Mutability,
@@ -500,7 +500,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
NodeId,
Span,
Ty<'tcx>,
- Option<(CanonicalTy<'tcx>, Span)>,
+ Option<(UserTypeAnnotation<'tcx>, Span)>,
),
) {
match *pattern.kind {
@@ -626,7 +626,7 @@ struct Binding<'tcx> {
struct Ascription<'tcx> {
span: Span,
source: Place<'tcx>,
- user_ty: CanonicalTy<'tcx>,
+ user_ty: UserTypeAnnotation<'tcx>,
}
#[derive(Clone, Debug)]
@@ -1470,7 +1470,7 @@ impl<'a, 'gcx, 'tcx> Builder<'a, 'gcx, 'tcx> {
num_patterns: usize,
var_id: NodeId,
var_ty: Ty<'tcx>,
- user_var_ty: Option<(CanonicalTy<'tcx>, Span)>,
+ user_var_ty: Option<(UserTypeAnnotation<'tcx>, Span)>,
has_guard: ArmHasGuard,
opt_match_place: Option<(Option<Place<'tcx>>, Span)>,
pat_span: Span,
diff --git a/src/librustc_mir/hair/cx/block.rs b/src/librustc_mir/hair/cx/block.rs
index 022c606a0f8..9865867a196 100644
--- a/src/librustc_mir/hair/cx/block.rs
+++ b/src/librustc_mir/hair/cx/block.rs
@@ -86,12 +86,12 @@ fn mirror_stmts<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
let mut pattern = cx.pattern_from_hir(&local.pat);
if let Some(ty) = &local.ty {
- if let Some(user_ty) = cx.tables.user_provided_tys().get(ty.hir_id) {
+ if let Some(&user_ty) = cx.tables.user_provided_tys().get(ty.hir_id) {
pattern = Pattern {
ty: pattern.ty,
span: pattern.span,
kind: Box::new(PatternKind::AscribeUserType {
- user_ty: *user_ty,
+ user_ty: UserTypeAnnotation::Ty(user_ty),
user_ty_span: ty.span,
subpattern: pattern
})
diff --git a/src/librustc_mir/hair/cx/expr.rs b/src/librustc_mir/hair/cx/expr.rs
index c969a3ef348..56a29f29d68 100644
--- a/src/librustc_mir/hair/cx/expr.rs
+++ b/src/librustc_mir/hair/cx/expr.rs
@@ -295,13 +295,7 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
let substs = cx.tables().node_substs(fun.hir_id);
let user_ty = cx.tables().user_substs(fun.hir_id)
- .map(|user_substs| {
- user_substs.unchecked_map(|user_substs| {
- // Here, we just pair an `AdtDef` with the
- // `user_substs`, so no new types etc are introduced.
- cx.tcx().mk_adt(adt_def, user_substs)
- })
- });
+ .map(|user_substs| UserTypeAnnotation::AdtDef(adt_def, user_substs));
let field_refs = args.iter()
.enumerate()
@@ -725,9 +719,15 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
}
hir::ExprKind::Type(ref source, ref ty) => {
let user_provided_tys = cx.tables.user_provided_tys();
- let user_ty = *user_provided_tys
- .get(ty.hir_id)
- .expect(&format!("{:?} not found in user_provided_tys, source: {:?}", ty, source));
+ let user_ty = UserTypeAnnotation::Ty(
+ *user_provided_tys
+ .get(ty.hir_id)
+ .expect(&format!(
+ "{:?} not found in user_provided_tys, source: {:?}",
+ ty,
+ source,
+ ))
+ );
if source.is_place_expr() {
ExprKind::PlaceTypeAscription {
source: source.to_ref(),
@@ -759,11 +759,11 @@ fn make_mirror_unadjusted<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
}
}
-fn user_annotated_ty_for_def(
+fn user_substs_applied_to_def(
cx: &mut Cx<'a, 'gcx, 'tcx>,
hir_id: hir::HirId,
def: &Def,
-) -> Option<CanonicalTy<'tcx>> {
+) -> Option<UserTypeAnnotation<'tcx>> {
match def {
// A reference to something callable -- e.g., a fn, method, or
// a tuple-struct or tuple-variant. This has the type of a
@@ -772,11 +772,7 @@ fn user_annotated_ty_for_def(
Def::Method(_) |
Def::StructCtor(_, CtorKind::Fn) |
Def::VariantCtor(_, CtorKind::Fn) =>
- Some(cx.tables().user_substs(hir_id)?.unchecked_map(|user_substs| {
- // Here, we just pair a `DefId` with the
- // `user_substs`, so no new types etc are introduced.
- cx.tcx().mk_fn_def(def.def_id(), user_substs)
- })),
+ Some(UserTypeAnnotation::FnDef(def.def_id(), cx.tables().user_substs(hir_id)?)),
Def::Const(_def_id) |
Def::AssociatedConst(_def_id) =>
@@ -795,7 +791,7 @@ fn user_annotated_ty_for_def(
cx.user_substs_applied_to_ty_of_hir_id(hir_id),
_ =>
- bug!("user_annotated_ty_for_def: unexpected def {:?} at {:?}", def, hir_id)
+ bug!("user_substs_applied_to_def: unexpected def {:?} at {:?}", def, hir_id)
}
}
@@ -815,7 +811,7 @@ fn method_callee<'a, 'gcx, 'tcx>(
.unwrap_or_else(|| {
span_bug!(expr.span, "no type-dependent def for method callee")
});
- let user_ty = user_annotated_ty_for_def(cx, expr.hir_id, def);
+ let user_ty = user_substs_applied_to_def(cx, expr.hir_id, def);
(def.def_id(), cx.tables().node_substs(expr.hir_id), user_ty)
}
};
@@ -882,7 +878,7 @@ fn convert_path_expr<'a, 'gcx, 'tcx>(cx: &mut Cx<'a, 'gcx, 'tcx>,
Def::StructCtor(_, CtorKind::Fn) |
Def::VariantCtor(_, CtorKind::Fn) |
Def::SelfCtor(..) => {
- let user_ty = user_annotated_ty_for_def(cx, expr.hir_id, &def);
+ let user_ty = user_substs_applied_to_def(cx, expr.hir_id, &def);
ExprKind::Literal {
literal: ty::Const::zero_sized(
cx.tcx,
diff --git a/src/librustc_mir/hair/mod.rs b/src/librustc_mir/hair/mod.rs
index e4f88e4fcc3..781b6c92aa1 100644
--- a/src/librustc_mir/hair/mod.rs
+++ b/src/librustc_mir/hair/mod.rs
@@ -14,11 +14,11 @@
//! unit-tested and separated from the Rust source and compiler data
//! structures.
-use rustc::mir::{BinOp, BorrowKind, Field, UnOp};
+use rustc::mir::{BinOp, BorrowKind, UserTypeAnnotation, Field, UnOp};
use rustc::hir::def_id::DefId;
use rustc::middle::region;
use rustc::ty::subst::Substs;
-use rustc::ty::{AdtDef, CanonicalTy, UpvarSubsts, Region, Ty, Const};
+use rustc::ty::{AdtDef, UpvarSubsts, Region, Ty, Const};
use rustc::hir;
use syntax::ast;
use syntax_pos::Span;
@@ -268,7 +268,7 @@ pub enum ExprKind<'tcx> {
/// Optional user-given substs: for something like `let x =
/// Bar::<T> { ... }`.
- user_ty: Option<CanonicalTy<'tcx>>,
+ user_ty: Option<UserTypeAnnotation<'tcx>>,
fields: Vec<FieldExprRef<'tcx>>,
base: Option<FruInfo<'tcx>>
@@ -276,12 +276,12 @@ pub enum ExprKind<'tcx> {
PlaceTypeAscription {
source: ExprRef<'tcx>,
/// Type that the user gave to this expression
- user_ty: CanonicalTy<'tcx>,
+ user_ty: UserTypeAnnotation<'tcx>,
},
ValueTypeAscription {
source: ExprRef<'tcx>,
/// Type that the user gave to this expression
- user_ty: CanonicalTy<'tcx>,
+ user_ty: UserTypeAnnotation<'tcx>,
},
Closure {
closure_id: DefId,
@@ -291,13 +291,7 @@ pub enum ExprKind<'tcx> {
},
Literal {
literal: &'tcx Const<'tcx>,
-
- /// Optional user-given type: for something like
- /// `collect::<Vec<_>>`, this would be present and would
- /// indicate that `Vec<_>` was explicitly specified.
- ///
- /// Needed for NLL to impose user-given type constraints.
- user_ty: Option<CanonicalTy<'tcx>>,
+ user_ty: Option<UserTypeAnnotation<'tcx>>,
},
InlineAsm {
asm: &'tcx hir::InlineAsm,
diff --git a/src/librustc_mir/hair/pattern/mod.rs b/src/librustc_mir/hair/pattern/mod.rs
index 0238a23895e..cb974366a30 100644
--- a/src/librustc_mir/hair/pattern/mod.rs
+++ b/src/librustc_mir/hair/pattern/mod.rs
@@ -20,9 +20,9 @@ use const_eval::{const_field, const_variant_index};
use hair::util::UserAnnotatedTyHelpers;
-use rustc::mir::{fmt_const_val, Field, BorrowKind, Mutability};
+use rustc::mir::{fmt_const_val, Field, BorrowKind, Mutability, UserTypeAnnotation};
use rustc::mir::interpret::{Scalar, GlobalId, ConstValue, sign_extend};
-use rustc::ty::{self, CanonicalTy, TyCtxt, AdtDef, Ty, Region};
+use rustc::ty::{self, Region, TyCtxt, AdtDef, Ty};
use rustc::ty::subst::{Substs, Kind};
use rustc::hir::{self, PatKind, RangeEnd};
use rustc::hir::def::{Def, CtorKind};
@@ -69,7 +69,7 @@ pub enum PatternKind<'tcx> {
Wild,
AscribeUserType {
- user_ty: CanonicalTy<'tcx>,
+ user_ty: UserTypeAnnotation<'tcx>,
subpattern: Pattern<'tcx>,
user_ty_span: Span,
},
@@ -980,7 +980,7 @@ macro_rules! CloneImpls {
CloneImpls!{ <'tcx>
Span, Field, Mutability, ast::Name, ast::NodeId, usize, &'tcx ty::Const<'tcx>,
Region<'tcx>, Ty<'tcx>, BindingMode<'tcx>, &'tcx AdtDef,
- &'tcx Substs<'tcx>, &'tcx Kind<'tcx>, CanonicalTy<'tcx>
+ &'tcx Substs<'tcx>, &'tcx Kind<'tcx>, UserTypeAnnotation<'tcx>
}
impl<'tcx> PatternFoldable<'tcx> for FieldPattern<'tcx> {
diff --git a/src/librustc_mir/hair/util.rs b/src/librustc_mir/hair/util.rs
index 48a2e67a3dc..71cbac6b7c8 100644
--- a/src/librustc_mir/hair/util.rs
+++ b/src/librustc_mir/hair/util.rs
@@ -9,7 +9,8 @@
// except according to those terms.
use rustc::hir;
-use rustc::ty::{self, AdtDef, CanonicalTy, TyCtxt};
+use rustc::mir::UserTypeAnnotation;
+use rustc::ty::{self, AdtDef, TyCtxt};
crate trait UserAnnotatedTyHelpers<'gcx: 'tcx, 'tcx> {
fn tcx(&self) -> TyCtxt<'_, 'gcx, 'tcx>;
@@ -20,32 +21,22 @@ crate trait UserAnnotatedTyHelpers<'gcx: 'tcx, 'tcx> {
&self,
hir_id: hir::HirId,
adt_def: &'tcx AdtDef,
- ) -> Option<CanonicalTy<'tcx>> {
+ ) -> Option<UserTypeAnnotation<'tcx>> {
let user_substs = self.tables().user_substs(hir_id)?;
- Some(user_substs.unchecked_map(|user_substs| {
- // Here, we just pair an `AdtDef` with the
- // `user_substs`, so no new types etc are introduced.
- self.tcx().mk_adt(adt_def, user_substs)
- }))
+ Some(UserTypeAnnotation::AdtDef(adt_def, user_substs))
}
/// Looks up the type associated with this hir-id and applies the
/// user-given substitutions; the hir-id must map to a suitable
/// type.
- fn user_substs_applied_to_ty_of_hir_id(&self, hir_id: hir::HirId) -> Option<CanonicalTy<'tcx>> {
+ fn user_substs_applied_to_ty_of_hir_id(
+ &self,
+ hir_id: hir::HirId,
+ ) -> Option<UserTypeAnnotation<'tcx>> {
let user_substs = self.tables().user_substs(hir_id)?;
match &self.tables().node_id_to_type(hir_id).sty {
- ty::Adt(adt_def, _) => Some(user_substs.unchecked_map(|user_substs| {
- // Ok to call `unchecked_map` because we just pair an
- // `AdtDef` with the `user_substs`, so no new types
- // etc are introduced.
- self.tcx().mk_adt(adt_def, user_substs)
- })),
- ty::FnDef(def_id, _) => Some(user_substs.unchecked_map(|user_substs| {
- // Here, we just pair a `DefId` with the
- // `user_substs`, so no new types etc are introduced.
- self.tcx().mk_fn_def(*def_id, user_substs)
- })),
+ ty::Adt(adt_def, _) => Some(UserTypeAnnotation::AdtDef(adt_def, user_substs)),
+ ty::FnDef(def_id, _) => Some(UserTypeAnnotation::FnDef(*def_id, user_substs)),
sty => bug!(
"sty: {:?} should not have user-substs {:?} recorded ",
sty,
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index d840c587464..14ce1bb4ccd 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -95,7 +95,8 @@ use rustc::infer::opaque_types::OpaqueTypeDecl;
use rustc::infer::type_variable::{TypeVariableOrigin};
use rustc::middle::region;
use rustc::mir::interpret::{ConstValue, GlobalId};
-use rustc::ty::subst::{CanonicalSubsts, UnpackedKind, Subst, Substs};
+use rustc::ty::subst::{CanonicalUserSubsts, UnpackedKind, Subst, Substs,
+ UserSelfTy, UserSubsts};
use rustc::traits::{self, ObligationCause, ObligationCauseCode, TraitEngine};
use rustc::ty::{self, Ty, TyCtxt, GenericParamDefKind, Visibility, ToPredicate, RegionKind};
use rustc::ty::adjustment::{Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability};
@@ -2136,7 +2137,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
method.substs[i]
}
});
- self.infcx.canonicalize_response(&just_method_substs)
+ self.infcx.canonicalize_response(&UserSubsts {
+ substs: just_method_substs,
+ user_self_ty: None, // not relevant here
+ })
});
debug!("write_method_call: user_substs = {:?}", user_substs);
@@ -2163,7 +2167,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
/// This should be invoked **before any unifications have
/// occurred**, so that annotations like `Vec<_>` are preserved
/// properly.
- pub fn write_user_substs_from_substs(&self, hir_id: hir::HirId, substs: &'tcx Substs<'tcx>) {
+ pub fn write_user_substs_from_substs(
+ &self,
+ hir_id: hir::HirId,
+ substs: &'tcx Substs<'tcx>,
+ user_self_ty: Option<UserSelfTy<'tcx>>,
+ ) {
debug!(
"write_user_substs_from_substs({:?}, {:?}) in fcx {}",
hir_id,
@@ -2172,13 +2181,16 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
);
if !substs.is_noop() {
- let user_substs = self.infcx.canonicalize_response(&substs);
+ let user_substs = self.infcx.canonicalize_response(&UserSubsts {
+ substs,
+ user_self_ty,
+ });
debug!("instantiate_value_path: user_substs = {:?}", user_substs);
self.write_user_substs(hir_id, user_substs);
}
}
- pub fn write_user_substs(&self, hir_id: hir::HirId, substs: CanonicalSubsts<'tcx>) {
+ pub fn write_user_substs(&self, hir_id: hir::HirId, substs: CanonicalUserSubsts<'tcx>) {
debug!(
"write_user_substs({:?}, {:?}) in fcx {}",
hir_id,
@@ -3617,7 +3629,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
if let Some((variant, did, substs)) = variant {
debug!("check_struct_path: did={:?} substs={:?}", did, substs);
let hir_id = self.tcx.hir.node_to_hir_id(node_id);
- self.write_user_substs_from_substs(hir_id, substs);
+ self.write_user_substs_from_substs(hir_id, substs, None);
// Check bounds on type arguments used in the path.
let bounds = self.instantiate_bounds(path_span, did, substs);
@@ -5005,7 +5017,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
let path_segs = self.def_ids_for_path_segments(segments, def);
- let mut ufcs_associated = None;
+ let mut user_self_ty = None;
match def {
Def::Method(def_id) |
Def::AssociatedConst(def_id) => {
@@ -5014,12 +5026,20 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
ty::TraitContainer(trait_did) => {
callee::check_legal_trait_for_method_call(self.tcx, span, trait_did)
}
- ty::ImplContainer(_) => {}
- }
- if segments.len() == 1 {
- // `<T>::assoc` will end up here, and so can `T::assoc`.
- let self_ty = self_ty.expect("UFCS sugared assoc missing Self");
- ufcs_associated = Some((container, self_ty));
+ ty::ImplContainer(impl_def_id) => {
+ if segments.len() == 1 {
+ // `<T>::assoc` will end up here, and so
+ // can `T::assoc`. It this came from an
+ // inherent impl, we need to record the
+ // `T` for posterity (see `UserSelfTy` for
+ // details).
+ let self_ty = self_ty.expect("UFCS sugared assoc missing Self");
+ user_self_ty = Some(UserSelfTy {
+ impl_def_id,
+ self_ty,
+ });
+ }
+ }
}
}
_ => {}
@@ -5173,6 +5193,10 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
assert!(!substs.has_escaping_regions());
assert!(!ty.has_escaping_regions());
+ // Write the "user substs" down first thing for later.
+ let hir_id = self.tcx.hir.node_to_hir_id(node_id);
+ self.write_user_substs_from_substs(hir_id, substs, user_self_ty);
+
// Add all the obligations that are required, substituting and
// normalized appropriately.
let bounds = self.instantiate_bounds(span, def_id, &substs);
@@ -5184,7 +5208,7 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// the referenced item.
let ty_substituted = self.instantiate_type_scheme(span, &substs, &ty);
- if let Some((ty::ImplContainer(impl_def_id), self_ty)) = ufcs_associated {
+ if let Some(UserSelfTy { impl_def_id, self_ty }) = user_self_ty {
// In the case of `Foo<T>::method` and `<Foo<T>>::method`, if `method`
// is inherent, there is no `Self` parameter, instead, the impl needs
// type parameters, which we can infer by unifying the provided `Self`
@@ -5208,16 +5232,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
debug!("instantiate_value_path: type of {:?} is {:?}",
node_id,
ty_substituted);
- let hir_id = self.tcx.hir.node_to_hir_id(node_id);
self.write_substs(hir_id, substs);
- debug!(
- "instantiate_value_path: id={:?} substs={:?}",
- node_id,
- substs,
- );
- self.write_user_substs_from_substs(hir_id, substs);
-
(ty_substituted, new_def)
}
diff --git a/src/test/mir-opt/basic_assignment.rs b/src/test/mir-opt/basic_assignment.rs
index 1abe63afa80..64e574fa8ae 100644
--- a/src/test/mir-opt/basic_assignment.rs
+++ b/src/test/mir-opt/basic_assignment.rs
@@ -56,7 +56,7 @@ fn main() {
// StorageLive(_4);
// _4 = std::option::Option<std::boxed::Box<u32>>::None;
// FakeRead(ForLet, _4);
-// AscribeUserType(_4, o, Canonical { variables: [], value: std::option::Option<std::boxed::Box<u32>> });
+// AscribeUserType(_4, o, Ty(Canonical { variables: [], value: std::option::Option<std::boxed::Box<u32>> }));
// StorageLive(_5);
// StorageLive(_6);
// _6 = move _4;
diff --git a/src/test/ui/nll/user-annotations/dump-adt-brace-struct.stderr b/src/test/ui/nll/user-annotations/dump-adt-brace-struct.stderr
index 2b0e5039d8d..901ace59d33 100644
--- a/src/test/ui/nll/user-annotations/dump-adt-brace-struct.stderr
+++ b/src/test/ui/nll/user-annotations/dump-adt-brace-struct.stderr
@@ -1,4 +1,4 @@
-error: user substs: Canonical { variables: [], value: [u32] }
+error: user substs: Canonical { variables: [], value: UserSubsts { substs: [u32], user_self_ty: None } }
--> $DIR/dump-adt-brace-struct.rs:28:5
|
LL | SomeStruct::<u32> { t: 22 }; //~ ERROR [u32]
diff --git a/src/test/ui/nll/user-annotations/dump-fn-method.stderr b/src/test/ui/nll/user-annotations/dump-fn-method.stderr
index 6531f87dd98..a26be359fc4 100644
--- a/src/test/ui/nll/user-annotations/dump-fn-method.stderr
+++ b/src/test/ui/nll/user-annotations/dump-fn-method.stderr
@@ -1,22 +1,22 @@
-error: user substs: Canonical { variables: [], value: [u32] }
+error: user substs: Canonical { variables: [], value: UserSubsts { substs: [u32], user_self_ty: None } }
--> $DIR/dump-fn-method.rs:36:13
|
LL | let x = foo::<u32>; //~ ERROR [u32]
| ^^^^^^^^^^
-error: user substs: Canonical { variables: [CanonicalVarInfo { kind: Ty(General) }, CanonicalVarInfo { kind: Ty(General) }], value: [?0, u32, ?1] }
+error: user substs: Canonical { variables: [CanonicalVarInfo { kind: Ty(General) }, CanonicalVarInfo { kind: Ty(General) }], value: UserSubsts { substs: [?0, u32, ?1], user_self_ty: None } }
--> $DIR/dump-fn-method.rs:42:13
|
LL | let x = <_ as Bazoom<u32>>::method::<_>; //~ ERROR [?0, u32, ?1]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-error: user substs: Canonical { variables: [], value: [u8, u16, u32] }
+error: user substs: Canonical { variables: [], value: UserSubsts { substs: [u8, u16, u32], user_self_ty: None } }
--> $DIR/dump-fn-method.rs:46:13
|
LL | let x = <u8 as Bazoom<u16>>::method::<u32>; //~ ERROR [u8, u16, u32]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-error: user substs: Canonical { variables: [CanonicalVarInfo { kind: Ty(General) }, CanonicalVarInfo { kind: Ty(General) }], value: [?0, ?1, u32] }
+error: user substs: Canonical { variables: [CanonicalVarInfo { kind: Ty(General) }, CanonicalVarInfo { kind: Ty(General) }], value: UserSubsts { substs: [?0, ?1, u32], user_self_ty: None } }
--> $DIR/dump-fn-method.rs:54:5
|
LL | y.method::<u32>(44, 66); //~ ERROR [?0, ?1, u32]
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-inherent-1.rs b/src/test/ui/nll/user-annotations/method-ufcs-inherent-1.rs
new file mode 100644
index 00000000000..b7292c0acbe
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/method-ufcs-inherent-1.rs
@@ -0,0 +1,20 @@
+#![feature(nll)]
+
+// Check that substitutions given on the self type (here, `A`) carry
+// through to NLL.
+
+struct A<'a> { x: &'a u32 }
+
+impl<'a> A<'a> {
+ fn new<'b, T>(x: &'a u32, y: T) -> Self {
+ Self { x }
+ }
+}
+
+fn foo<'a>() {
+ let v = 22;
+ let x = A::<'a>::new(&v, 22);
+ //~^ ERROR
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-inherent-1.stderr b/src/test/ui/nll/user-annotations/method-ufcs-inherent-1.stderr
new file mode 100644
index 00000000000..aa133ce286d
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/method-ufcs-inherent-1.stderr
@@ -0,0 +1,18 @@
+error[E0597]: `v` does not live long enough
+ --> $DIR/method-ufcs-inherent-1.rs:16:26
+ |
+LL | let x = A::<'a>::new(&v, 22);
+ | ^^ borrowed value does not live long enough
+LL | //~^ ERROR
+LL | }
+ | - `v` dropped here while still borrowed
+ |
+note: borrowed value must be valid for the lifetime 'a as defined on the function body at 14:8...
+ --> $DIR/method-ufcs-inherent-1.rs:14:8
+ |
+LL | fn foo<'a>() {
+ | ^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0597`.
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-inherent-2.rs b/src/test/ui/nll/user-annotations/method-ufcs-inherent-2.rs
new file mode 100644
index 00000000000..a77d6af5323
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/method-ufcs-inherent-2.rs
@@ -0,0 +1,21 @@
+#![feature(nll)]
+
+// Check that substitutions given on the self type (here, `A`) can be
+// used in combination with annotations given for method arguments.
+
+struct A<'a> { x: &'a u32 }
+
+impl<'a> A<'a> {
+ fn new<'b, T>(x: &'a u32, y: T) -> Self {
+ Self { x }
+ }
+}
+
+fn foo<'a>() {
+ let v = 22;
+ let x = A::<'a>::new::<&'a u32>(&v, &v);
+ //~^ ERROR
+ //~| ERROR
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-inherent-2.stderr b/src/test/ui/nll/user-annotations/method-ufcs-inherent-2.stderr
new file mode 100644
index 00000000000..f1f4787d058
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/method-ufcs-inherent-2.stderr
@@ -0,0 +1,33 @@
+error[E0597]: `v` does not live long enough
+ --> $DIR/method-ufcs-inherent-2.rs:16:37
+ |
+LL | let x = A::<'a>::new::<&'a u32>(&v, &v);
+ | ^^ borrowed value does not live long enough
+...
+LL | }
+ | - `v` dropped here while still borrowed
+ |
+note: borrowed value must be valid for the lifetime 'a as defined on the function body at 14:8...
+ --> $DIR/method-ufcs-inherent-2.rs:14:8
+ |
+LL | fn foo<'a>() {
+ | ^^
+
+error[E0597]: `v` does not live long enough
+ --> $DIR/method-ufcs-inherent-2.rs:16:41
+ |
+LL | let x = A::<'a>::new::<&'a u32>(&v, &v);
+ | ^^ borrowed value does not live long enough
+...
+LL | }
+ | - `v` dropped here while still borrowed
+ |
+note: borrowed value must be valid for the lifetime 'a as defined on the function body at 14:8...
+ --> $DIR/method-ufcs-inherent-2.rs:14:8
+ |
+LL | fn foo<'a>() {
+ | ^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0597`.
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-inherent-3.rs b/src/test/ui/nll/user-annotations/method-ufcs-inherent-3.rs
new file mode 100644
index 00000000000..24d83c468f4
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/method-ufcs-inherent-3.rs
@@ -0,0 +1,20 @@
+#![feature(nll)]
+
+// Check that inherent methods invoked with `<T>::new` style
+// carry their annotations through to NLL.
+
+struct A<'a> { x: &'a u32 }
+
+impl<'a> A<'a> {
+ fn new<'b, T>(x: &'a u32, y: T) -> Self {
+ Self { x }
+ }
+}
+
+fn foo<'a>() {
+ let v = 22;
+ let x = <A<'a>>::new(&v, 22);
+ //~^ ERROR
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-inherent-3.stderr b/src/test/ui/nll/user-annotations/method-ufcs-inherent-3.stderr
new file mode 100644
index 00000000000..f3766a8c8e5
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/method-ufcs-inherent-3.stderr
@@ -0,0 +1,18 @@
+error[E0597]: `v` does not live long enough
+ --> $DIR/method-ufcs-inherent-3.rs:16:26
+ |
+LL | let x = <A<'a>>::new(&v, 22);
+ | ^^ borrowed value does not live long enough
+LL | //~^ ERROR
+LL | }
+ | - `v` dropped here while still borrowed
+ |
+note: borrowed value must be valid for the lifetime 'a as defined on the function body at 14:8...
+ --> $DIR/method-ufcs-inherent-3.rs:14:8
+ |
+LL | fn foo<'a>() {
+ | ^^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0597`.
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-inherent-4.rs b/src/test/ui/nll/user-annotations/method-ufcs-inherent-4.rs
new file mode 100644
index 00000000000..3f88c3df48e
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/method-ufcs-inherent-4.rs
@@ -0,0 +1,22 @@
+#![feature(nll)]
+
+// Check that inherent methods invoked with `<T>::new` style
+// carry their annotations through to NLL in connection with
+// method type parameters.
+
+struct A<'a> { x: &'a u32 }
+
+impl<'a> A<'a> {
+ fn new<'b, T>(x: &'a u32, y: T) -> Self {
+ Self { x }
+ }
+}
+
+fn foo<'a>() {
+ let v = 22;
+ let x = <A<'a>>::new::<&'a u32>(&v, &v);
+ //~^ ERROR
+ //~| ERROR
+}
+
+fn main() {}
diff --git a/src/test/ui/nll/user-annotations/method-ufcs-inherent-4.stderr b/src/test/ui/nll/user-annotations/method-ufcs-inherent-4.stderr
new file mode 100644
index 00000000000..c9bce5077d6
--- /dev/null
+++ b/src/test/ui/nll/user-annotations/method-ufcs-inherent-4.stderr
@@ -0,0 +1,33 @@
+error[E0597]: `v` does not live long enough
+ --> $DIR/method-ufcs-inherent-4.rs:17:37
+ |
+LL | let x = <A<'a>>::new::<&'a u32>(&v, &v);
+ | ^^ borrowed value does not live long enough
+...
+LL | }
+ | - `v` dropped here while still borrowed
+ |
+note: borrowed value must be valid for the lifetime 'a as defined on the function body at 15:8...
+ --> $DIR/method-ufcs-inherent-4.rs:15:8
+ |
+LL | fn foo<'a>() {
+ | ^^
+
+error[E0597]: `v` does not live long enough
+ --> $DIR/method-ufcs-inherent-4.rs:17:41
+ |
+LL | let x = <A<'a>>::new::<&'a u32>(&v, &v);
+ | ^^ borrowed value does not live long enough
+...
+LL | }
+ | - `v` dropped here while still borrowed
+ |
+note: borrowed value must be valid for the lifetime 'a as defined on the function body at 15:8...
+ --> $DIR/method-ufcs-inherent-4.rs:15:8
+ |
+LL | fn foo<'a>() {
+ | ^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0597`.