introduce `type_op`

4 files changed, 65 insertions, 18 deletions

diff --git a/src/librustc_mir/borrow_check/nll/type_check/input_output.rs b/src/librustc_mir/borrow_check/nll/type_check/input_output.rs
index d44eed65201..be0a2494b04 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/input_output.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/input_output.rs
@@ -18,6 +18,7 @@
 //! contain revealed `impl Trait` values).
 
 use borrow_check::nll::renumber;
+use borrow_check::nll::type_check::type_op::CustomTypeOp;
 use borrow_check::nll::universal_regions::UniversalRegions;
 use rustc::hir::def_id::DefId;
 use rustc::infer::InferOk;
@@ -80,7 +81,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             self.fully_perform_op(
                 Locations::All,
                 || format!("input_output"),
-                |cx| {
+                CustomTypeOp::new(|cx| {
                     let mut obligations = ObligationAccumulator::default();
 
                     let dummy_body_id = ObligationCause::dummy().body_id;
@@ -135,7 +136,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                         value: Some(anon_type_map),
                         obligations: obligations.into_vec(),
                     })
-                },
+                }),
             ).unwrap_or_else(|terr| {
                 span_mirbug!(
                     self,
@@ -156,13 +157,13 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
             self.fully_perform_op(
                 Locations::All,
                 || format!("anon_type_map"),
-                |_cx| {
+                CustomTypeOp::new(|_cx| {
                     infcx.constrain_anon_types(&anon_type_map, universal_regions);
                     Ok(InferOk {
                         value: (),
                         obligations: vec![],
                     })
-                },
+                }),
             ).unwrap();
         }
     }
diff --git a/src/librustc_mir/borrow_check/nll/type_check/liveness.rs b/src/librustc_mir/borrow_check/nll/type_check/liveness.rs
index 80f5fe4184f..d58dc1a601a 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/liveness.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/liveness.rs
@@ -10,6 +10,7 @@
 
 use borrow_check::nll::region_infer::Cause;
 use borrow_check::nll::type_check::AtLocation;
+use borrow_check::nll::type_check::type_op::CustomTypeOp;
 use dataflow::move_paths::{HasMoveData, MoveData};
 use dataflow::MaybeInitializedPlaces;
 use dataflow::{FlowAtLocation, FlowsAtLocation};
@@ -220,12 +221,12 @@ impl<'gen, 'typeck, 'flow, 'gcx, 'tcx> TypeLivenessGenerator<'gen, 'typeck, 'flo
         let (dropped_kinds, region_constraint_data) =
             cx.fully_perform_op_and_get_region_constraint_data(
                 || format!("compute_drop_data(dropped_ty={:?})", dropped_ty),
-                |cx| {
+                CustomTypeOp::new(|cx| {
                     Ok(cx
                         .infcx
                         .at(&ObligationCause::dummy(), cx.param_env)
                         .dropck_outlives(dropped_ty))
-                },
+                }),
             ).unwrap();
 
         DropData {
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 d25cec79791..5d06513e2a8 100644
--- a/src/librustc_mir/borrow_check/nll/type_check/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/type_check/mod.rs
@@ -15,13 +15,14 @@ use borrow_check::location::LocationTable;
 use borrow_check::nll::facts::AllFacts;
 use borrow_check::nll::region_infer::Cause;
 use borrow_check::nll::region_infer::{ClosureRegionRequirementsExt, OutlivesConstraint, TypeTest};
+use borrow_check::nll::type_check::type_op::{CustomTypeOp, TypeOp};
 use borrow_check::nll::universal_regions::UniversalRegions;
 use dataflow::move_paths::MoveData;
 use dataflow::FlowAtLocation;
 use dataflow::MaybeInitializedPlaces;
 use rustc::hir::def_id::DefId;
 use rustc::infer::region_constraints::{GenericKind, RegionConstraintData};
-use rustc::infer::{InferCtxt, InferOk, InferResult, LateBoundRegionConversionTime, UnitResult};
+use rustc::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime, UnitResult};
 use rustc::mir::interpret::EvalErrorKind::BoundsCheck;
 use rustc::mir::tcx::PlaceTy;
 use rustc::mir::visit::{PlaceContext, Visitor};
@@ -67,6 +68,7 @@ macro_rules! span_mirbug_and_err {
 mod constraint_conversion;
 mod input_output;
 mod liveness;
+mod type_op;
 
 /// Type checks the given `mir` in the context of the inference
 /// context `infcx`. Returns any region constraints that have yet to
@@ -732,7 +734,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         &mut self,
         locations: Locations,
         describe_op: impl Fn() -> String,
-        op: impl FnOnce(&mut Self) -> InferResult<'tcx, R>,
+        op: impl TypeOp<'gcx, 'tcx, Output = R>,
     ) -> Result<R, TypeError<'tcx>> {
         let (r, opt_data) = self.fully_perform_op_and_get_region_constraint_data(
             || format!("{} at {:?}", describe_op(), locations),
@@ -777,7 +779,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
     fn fully_perform_op_and_get_region_constraint_data<R>(
         &mut self,
         describe_op: impl Fn() -> String,
-        op: impl FnOnce(&mut Self) -> InferResult<'tcx, R>,
+        op: impl TypeOp<'gcx, 'tcx, Output = R>,
     ) -> Result<(R, Option<Rc<RegionConstraintData<'tcx>>>), TypeError<'tcx>> {
         if cfg!(debug_assertions) {
             info!(
@@ -788,7 +790,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
 
         let mut fulfill_cx = TraitEngine::new(self.infcx.tcx);
         let dummy_body_id = ObligationCause::dummy().body_id;
-        let InferOk { value, obligations } = self.infcx.commit_if_ok(|_| op(self))?;
+        let InferOk { value, obligations } = self.infcx.commit_if_ok(|_| op.perform(self))?;
         debug_assert!(obligations.iter().all(|o| o.cause.body_id == dummy_body_id));
         fulfill_cx.register_predicate_obligations(self.infcx, obligations);
         if let Err(e) = fulfill_cx.select_all_or_error(self.infcx) {
@@ -824,11 +826,11 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         self.fully_perform_op(
             locations,
             || format!("sub_types({:?} <: {:?})", sub, sup),
-            |this| {
+            CustomTypeOp::new(|this| {
                 this.infcx
                     .at(&ObligationCause::dummy(), this.param_env)
                     .sup(sup, sub)
-            },
+            }),
         )
     }
 
@@ -841,11 +843,11 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         self.fully_perform_op(
             locations,
             || format!("eq_types({:?} = {:?})", a, b),
-            |this| {
+            CustomTypeOp::new(|this| {
                 this.infcx
                     .at(&ObligationCause::dummy(), this.param_env)
                     .eq(b, a)
-            },
+            }),
         )
     }
 
@@ -1635,12 +1637,12 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         self.fully_perform_op(
             location.at_self(),
             || format!("prove_predicates({:?})", predicates_vec),
-            |_this| {
+            CustomTypeOp::new(|_this| {
                 Ok(InferOk {
                     value: (),
                     obligations,
                 })
-            },
+            }),
         ).unwrap()
     }
 
@@ -1683,7 +1685,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
         self.fully_perform_op(
             location.to_locations(),
             || format!("normalize(value={:?})", value),
-            |this| {
+            CustomTypeOp::new(|this| {
                 let Normalized { value, obligations } = this
                     .infcx
                     .at(&ObligationCause::dummy(), this.param_env)
@@ -1697,7 +1699,7 @@ impl<'a, 'gcx, 'tcx> TypeChecker<'a, 'gcx, 'tcx> {
                         );
                     });
                 Ok(InferOk { value, obligations })
-            },
+            }),
         ).unwrap()
     }
 }
diff --git a/src/librustc_mir/borrow_check/nll/type_check/type_op.rs b/src/librustc_mir/borrow_check/nll/type_check/type_op.rs
new file mode 100644
index 00000000000..b4c71344cfc
--- /dev/null
+++ b/src/librustc_mir/borrow_check/nll/type_check/type_op.rs
@@ -0,0 +1,43 @@
+// Copyright 2016 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.
+
+use borrow_check::nll::type_check::TypeChecker;
+use rustc::infer::InferResult;
+
+pub(super) trait TypeOp<'gcx, 'tcx> {
+    type Output;
+
+    fn perform(self, type_checker: &mut TypeChecker<'_, 'gcx, 'tcx>) -> InferResult<'tcx, Self::Output>;
+}
+
+pub(super) struct CustomTypeOp<F> {
+    closure: F
+}
+
+impl<F> CustomTypeOp<F>
+{
+    pub(super) fn new<'gcx, 'tcx, R>(closure: F) -> Self
+    where
+        F: FnOnce(&mut TypeChecker<'_, 'gcx, 'tcx>) -> InferResult<'tcx, R>,
+    {
+        CustomTypeOp { closure }
+    }
+}
+
+impl<'gcx, 'tcx, F, R> TypeOp<'gcx, 'tcx> for CustomTypeOp<F>
+where
+    F: FnOnce(&mut TypeChecker<'_, 'gcx, 'tcx>) -> InferResult<'tcx, R>,
+{
+    type Output = R;
+
+    fn perform(self, type_checker: &mut TypeChecker<'_, 'gcx, 'tcx>) -> InferResult<'tcx, R> {
+        (self.closure)(type_checker)
+    }
+}