Split librustc_infer.

Author: cjgillot

Cargo.lock

@@ -4129,11 +4129,13 @@ name = "rustc_trait_selection"
 version = "0.0.0"
 dependencies = [
  "fmt_macros",
+ "graphviz",
  "log",
  "rustc",
  "rustc_ast",
  "rustc_attr",
  "rustc_data_structures",
+ "rustc_error_codes",
  "rustc_errors",
  "rustc_hir",
  "rustc_index",

src/librustc_infer/infer/canonical/query_response.rs

@@ -14,7 +14,7 @@ use crate::infer::canonical::{
 };
 use crate::infer::nll_relate::{NormalizationStrategy, TypeRelating, TypeRelatingDelegate};
 use crate::infer::region_constraints::{Constraint, RegionConstraintData};
-use crate::infer::{InferCtxt, InferCtxtBuilder, InferOk, InferResult, NLLRegionVariableOrigin};
+use crate::infer::{InferCtxt, InferOk, InferResult, NLLRegionVariableOrigin};
 use crate::traits::query::{Fallible, NoSolution};
 use crate::traits::{DomainGoal, TraitEngine};
 use crate::traits::{Obligation, ObligationCause, PredicateObligation};
@@ -26,52 +26,8 @@ use rustc::ty::{self, BoundVar, Ty, TyCtxt};
 use rustc_data_structures::captures::Captures;
 use rustc_index::vec::Idx;
 use rustc_index::vec::IndexVec;
-use rustc_span::DUMMY_SP;
 use std::fmt::Debug;
 
-impl<'tcx> InferCtxtBuilder<'tcx> {
-    /// The "main method" for a canonicalized trait query. Given the
-    /// canonical key `canonical_key`, this method will create a new
-    /// inference context, instantiate the key, and run your operation
-    /// `op`. The operation should yield up a result (of type `R`) as
-    /// well as a set of trait obligations that must be fully
-    /// satisfied. These obligations will be processed and the
-    /// canonical result created.
-    ///
-    /// Returns `NoSolution` in the event of any error.
-    ///
-    /// (It might be mildly nicer to implement this on `TyCtxt`, and
-    /// not `InferCtxtBuilder`, but that is a bit tricky right now.
-    /// In part because we would need a `for<'tcx>` sort of
-    /// bound for the closure and in part because it is convenient to
-    /// have `'tcx` be free on this function so that we can talk about
-    /// `K: TypeFoldable<'tcx>`.)
-    pub fn enter_canonical_trait_query<K, R>(
-        &mut self,
-        canonical_key: &Canonical<'tcx, K>,
-        operation: impl FnOnce(&InferCtxt<'_, 'tcx>, &mut dyn TraitEngine<'tcx>, K) -> Fallible<R>,
-    ) -> Fallible<CanonicalizedQueryResponse<'tcx, R>>
-    where
-        K: TypeFoldable<'tcx>,
-        R: Debug + TypeFoldable<'tcx>,
-        Canonical<'tcx, QueryResponse<'tcx, R>>: ArenaAllocatable,
-    {
-        self.enter_with_canonical(
-            DUMMY_SP,
-            canonical_key,
-            |ref infcx, key, canonical_inference_vars| {
-                let mut fulfill_cx = TraitEngine::new(infcx.tcx);
-                let value = operation(infcx, &mut *fulfill_cx, key)?;
-                infcx.make_canonicalized_query_response(
-                    canonical_inference_vars,
-                    value,
-                    &mut *fulfill_cx,
-                )
-            },
-        )
-    }
-}
-
 impl<'cx, 'tcx> InferCtxt<'cx, 'tcx> {
     /// This method is meant to be invoked as the final step of a canonical query
     /// implementation. It is given:

src/librustc_infer/infer/error_reporting/mod.rs

@@ -2156,7 +2156,7 @@ impl<'tcx> ObligationCauseExt<'tcx> for ObligationCause<'tcx> {
 /// This is a bare signal of what kind of type we're dealing with. `ty::TyKind` tracks
 /// extra information about each type, but we only care about the category.
 #[derive(Clone, Copy, PartialEq, Eq, Hash)]
-crate enum TyCategory {
+pub enum TyCategory {
     Closure,
     Opaque,
     Generator,

src/librustc_infer/infer/mod.rs

@@ -13,11 +13,11 @@ use rustc::infer::canonical::{Canonical, CanonicalVarValues};
 use rustc::infer::unify_key::{ConstVarValue, ConstVariableValue};
 use rustc::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind, ToType};
 use rustc::middle::free_region::RegionRelations;
-use rustc::middle::lang_items;
 use rustc::middle::region;
 use rustc::mir;
 use rustc::mir::interpret::ConstEvalResult;
 use rustc::session::config::BorrowckMode;
+use rustc::traits::select;
 use rustc::ty::error::{ExpectedFound, TypeError, UnconstrainedNumeric};
 use rustc::ty::fold::{TypeFoldable, TypeFolder};
 use rustc::ty::relate::RelateResult;
@@ -58,7 +58,6 @@ pub mod lattice;
 mod lexical_region_resolve;
 mod lub;
 pub mod nll_relate;
-pub mod opaque_types;
 pub mod outlives;
 pub mod region_constraints;
 pub mod resolve;
@@ -215,10 +214,10 @@ pub struct InferCtxt<'a, 'tcx> {
 
     /// Caches the results of trait selection. This cache is used
     /// for things that have to do with the parameters in scope.
-    pub selection_cache: traits::SelectionCache<'tcx>,
+    pub selection_cache: select::SelectionCache<'tcx>,
 
     /// Caches the results of trait evaluation.
-    pub evaluation_cache: traits::EvaluationCache<'tcx>,
+    pub evaluation_cache: select::EvaluationCache<'tcx>,
 
     /// the set of predicates on which errors have been reported, to
     /// avoid reporting the same error twice.
@@ -1474,27 +1473,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
             .verify_generic_bound(origin, kind, a, bound);
     }
 
-    pub fn type_is_copy_modulo_regions(
-        &self,
-        param_env: ty::ParamEnv<'tcx>,
-        ty: Ty<'tcx>,
-        span: Span,
-    ) -> bool {
-        let ty = self.resolve_vars_if_possible(&ty);
-
-        if !(param_env, ty).has_local_value() {
-            return ty.is_copy_modulo_regions(self.tcx, param_env, span);
-        }
-
-        let copy_def_id = self.tcx.require_lang_item(lang_items::CopyTraitLangItem, None);
-
-        // This can get called from typeck (by euv), and `moves_by_default`
-        // rightly refuses to work with inference variables, but
-        // moves_by_default has a cache, which we want to use in other
-        // cases.
-        traits::type_known_to_meet_bound_modulo_regions(self, param_env, ty, copy_def_id, span)
-    }
-
     /// Obtains the latest type of the given closure; this may be a
     /// closure in the current function, in which case its
     /// `ClosureKind` may not yet be known.
@@ -1518,30 +1496,6 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         closure_sig_ty.fn_sig(self.tcx)
     }
 
-    /// Normalizes associated types in `value`, potentially returning
-    /// new obligations that must further be processed.
-    pub fn partially_normalize_associated_types_in<T>(
-        &self,
-        span: Span,
-        body_id: hir::HirId,
-        param_env: ty::ParamEnv<'tcx>,
-        value: &T,
-    ) -> InferOk<'tcx, T>
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        debug!("partially_normalize_associated_types_in(value={:?})", value);
-        let mut selcx = traits::SelectionContext::new(self);
-        let cause = ObligationCause::misc(span, body_id);
-        let traits::Normalized { value, obligations } =
-            traits::normalize(&mut selcx, param_env, cause, value);
-        debug!(
-            "partially_normalize_associated_types_in: result={:?} predicates={:?}",
-            value, obligations
-        );
-        InferOk { value, obligations }
-    }
-
     /// Clears the selection, evaluation, and projection caches. This is useful when
     /// repeatedly attempting to select an `Obligation` while changing only
     /// its `ParamEnv`, since `FulfillmentContext` doesn't use probing.

src/librustc_infer/infer/outlives/env.rs

@@ -1,10 +1,9 @@
 use crate::infer::{GenericKind, InferCtxt};
 use crate::traits::query::OutlivesBound;
+use rustc::ty;
 use rustc::ty::free_region_map::FreeRegionMap;
-use rustc::ty::{self, Ty};
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir as hir;
-use rustc_span::Span;
 
 use super::explicit_outlives_bounds;
 
@@ -144,39 +143,6 @@ impl<'a, 'tcx> OutlivesEnvironment<'tcx> {
         self.region_bound_pairs_accum.truncate(len);
     }
 
-    /// This method adds "implied bounds" into the outlives environment.
-    /// Implied bounds are outlives relationships that we can deduce
-    /// on the basis that certain types must be well-formed -- these are
-    /// either the types that appear in the function signature or else
-    /// the input types to an impl. For example, if you have a function
-    /// like
-    ///
-    /// ```
-    /// fn foo<'a, 'b, T>(x: &'a &'b [T]) { }
-    /// ```
-    ///
-    /// we can assume in the caller's body that `'b: 'a` and that `T:
-    /// 'b` (and hence, transitively, that `T: 'a`). This method would
-    /// add those assumptions into the outlives-environment.
-    ///
-    /// Tests: `src/test/compile-fail/regions-free-region-ordering-*.rs`
-    pub fn add_implied_bounds(
-        &mut self,
-        infcx: &InferCtxt<'a, 'tcx>,
-        fn_sig_tys: &[Ty<'tcx>],
-        body_id: hir::HirId,
-        span: Span,
-    ) {
-        debug!("add_implied_bounds()");
-
-        for &ty in fn_sig_tys {
-            let ty = infcx.resolve_vars_if_possible(&ty);
-            debug!("add_implied_bounds: ty = {}", ty);
-            let implied_bounds = infcx.implied_outlives_bounds(self.param_env, body_id, ty, span);
-            self.add_outlives_bounds(Some(infcx), implied_bounds)
-        }
-    }
-
     /// Save the current set of region-bound pairs under the given `body_id`.
     pub fn save_implied_bounds(&mut self, body_id: hir::HirId) {
         let old =
@@ -190,8 +156,11 @@ impl<'a, 'tcx> OutlivesEnvironment<'tcx> {
     /// contain inference variables, it must be supplied, in which
     /// case we will register "givens" on the inference context. (See
     /// `RegionConstraintData`.)
-    fn add_outlives_bounds<I>(&mut self, infcx: Option<&InferCtxt<'a, 'tcx>>, outlives_bounds: I)
-    where
+    pub fn add_outlives_bounds<I>(
+        &mut self,
+        infcx: Option<&InferCtxt<'a, 'tcx>>,
+        outlives_bounds: I,
+    ) where
         I: IntoIterator<Item = OutlivesBound<'tcx>>,
     {
         // Record relationships such as `T:'x` that don't go into the

src/librustc_infer/traits/engine.rs

@@ -0,0 +1,78 @@
+use crate::infer::InferCtxt;
+use crate::traits::Obligation;
+use rustc::ty::{self, ToPredicate, Ty, WithConstness};
+use rustc_hir::def_id::DefId;
+
+use super::FulfillmentError;
+use super::{ObligationCause, PredicateObligation};
+
+pub trait TraitEngine<'tcx>: 'tcx {
+    fn normalize_projection_type(
+        &mut self,
+        infcx: &InferCtxt<'_, 'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+        projection_ty: ty::ProjectionTy<'tcx>,
+        cause: ObligationCause<'tcx>,
+    ) -> Ty<'tcx>;
+
+    /// Requires that `ty` must implement the trait with `def_id` in
+    /// the given environment. This trait must not have any type
+    /// parameters (except for `Self`).
+    fn register_bound(
+        &mut self,
+        infcx: &InferCtxt<'_, 'tcx>,
+        param_env: ty::ParamEnv<'tcx>,
+        ty: Ty<'tcx>,
+        def_id: DefId,
+        cause: ObligationCause<'tcx>,
+    ) {
+        let trait_ref = ty::TraitRef { def_id, substs: infcx.tcx.mk_substs_trait(ty, &[]) };
+        self.register_predicate_obligation(
+            infcx,
+            Obligation {
+                cause,
+                recursion_depth: 0,
+                param_env,
+                predicate: trait_ref.without_const().to_predicate(),
+            },
+        );
+    }
+
+    fn register_predicate_obligation(
+        &mut self,
+        infcx: &InferCtxt<'_, 'tcx>,
+        obligation: PredicateObligation<'tcx>,
+    );
+
+    fn select_all_or_error(
+        &mut self,
+        infcx: &InferCtxt<'_, 'tcx>,
+    ) -> Result<(), Vec<FulfillmentError<'tcx>>>;
+
+    fn select_where_possible(
+        &mut self,
+        infcx: &InferCtxt<'_, 'tcx>,
+    ) -> Result<(), Vec<FulfillmentError<'tcx>>>;
+
+    fn pending_obligations(&self) -> Vec<PredicateObligation<'tcx>>;
+}
+
+pub trait TraitEngineExt<'tcx> {
+    fn register_predicate_obligations(
+        &mut self,
+        infcx: &InferCtxt<'_, 'tcx>,
+        obligations: impl IntoIterator<Item = PredicateObligation<'tcx>>,
+    );
+}
+
+impl<T: ?Sized + TraitEngine<'tcx>> TraitEngineExt<'tcx> for T {
+    fn register_predicate_obligations(
+        &mut self,
+        infcx: &InferCtxt<'_, 'tcx>,
+        obligations: impl IntoIterator<Item = PredicateObligation<'tcx>>,
+    ) {
+        for obligation in obligations {
+            self.register_predicate_obligation(infcx, obligation);
+        }
+    }
+}