refactor and cleanup region errors for NLL

src/librustc/ich/impls_mir.rs

@@ -30,7 +30,7 @@ impl_stable_hash_for!(struct mir::LocalDecl<'tcx> {
     internal,
     is_user_variable
 });
-impl_stable_hash_for!(struct mir::UpvarDecl { debug_name, by_ref, mutability });
+impl_stable_hash_for!(struct mir::UpvarDecl { debug_name, var_hir_id, by_ref, mutability });
 impl_stable_hash_for!(struct mir::BasicBlockData<'tcx> { statements, terminator, is_cleanup });
 impl_stable_hash_for!(struct mir::UnsafetyViolation { source_info, description, kind });
 impl_stable_hash_for!(struct mir::UnsafetyCheckResult { violations, unsafe_blocks });

src/librustc/mir/mod.rs

@@ -15,7 +15,7 @@
 use graphviz::IntoCow;
 use hir::def::CtorKind;
 use hir::def_id::DefId;
-use hir::{self, InlineAsm};
+use hir::{self, HirId, InlineAsm};
 use middle::region;
 use mir::interpret::{EvalErrorKind, Scalar, Value};
 use mir::visit::MirVisitable;
@@ -380,6 +380,15 @@ pub enum ClearCrossCrate<T> {
     Set(T),
 }
 
+impl<T> ClearCrossCrate<T> {
+    pub fn assert_crate_local(self) -> T {
+        match self {
+            ClearCrossCrate::Clear => bug!("unwrapping cross-crate data"),
+            ClearCrossCrate::Set(v) => v,
+        }
+    }
+}
+
 impl<T: serialize::Encodable> serialize::UseSpecializedEncodable for ClearCrossCrate<T> {}
 impl<T: serialize::Decodable> serialize::UseSpecializedDecodable for ClearCrossCrate<T> {}
 
@@ -785,6 +794,9 @@ impl<'tcx> LocalDecl<'tcx> {
 pub struct UpvarDecl {
     pub debug_name: Name,
 
+    /// `HirId` of the captured variable
+    pub var_hir_id: ClearCrossCrate<HirId>,
+
     /// If true, the capture is behind a reference.
     pub by_ref: bool,
 

src/librustc/ty/fold.rs

@@ -253,13 +253,34 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         value.fold_with(&mut RegionFolder::new(self, skipped_regions, &mut f))
     }
 
-    pub fn for_each_free_region<T,F>(self,
-                                     value: &T,
-                                     callback: F)
-        where F: FnMut(ty::Region<'tcx>),
-              T: TypeFoldable<'tcx>,
-    {
-        value.visit_with(&mut RegionVisitor {
+    /// Invoke `callback` on every region appearing free in `value`.
+    pub fn for_each_free_region(
+        self,
+        value: &impl TypeFoldable<'tcx>,
+        mut callback: impl FnMut(ty::Region<'tcx>),
+    ) {
+        self.any_free_region_meets(value, |r| {
+            callback(r);
+            false
+        });
+    }
+
+    /// True if `callback` returns true for every region appearing free in `value`.
+    pub fn all_free_regions_meet(
+        self,
+        value: &impl TypeFoldable<'tcx>,
+        mut callback: impl FnMut(ty::Region<'tcx>) -> bool,
+    ) -> bool {
+        !self.any_free_region_meets(value, |r| !callback(r))
+    }
+
+    /// True if `callback` returns true for some region appearing free in `value`.
+    pub fn any_free_region_meets(
+        self,
+        value: &impl TypeFoldable<'tcx>,
+        callback: impl FnMut(ty::Region<'tcx>) -> bool,
+    ) -> bool {
+        return value.visit_with(&mut RegionVisitor {
             outer_index: ty::INNERMOST,
             callback
         });
@@ -287,25 +308,22 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
         }
 
         impl<'tcx, F> TypeVisitor<'tcx> for RegionVisitor<F>
-            where F : FnMut(ty::Region<'tcx>)
+            where F: FnMut(ty::Region<'tcx>) -> bool
         {
             fn visit_binder<T: TypeFoldable<'tcx>>(&mut self, t: &Binder<T>) -> bool {
                 self.outer_index.shift_in(1);
-                t.skip_binder().visit_with(self);
+                let result = t.skip_binder().visit_with(self);
                 self.outer_index.shift_out(1);
-
-                false // keep visiting
+                result
             }
 
             fn visit_region(&mut self, r: ty::Region<'tcx>) -> bool {
                 match *r {
                     ty::ReLateBound(debruijn, _) if debruijn < self.outer_index => {
-                        /* ignore bound regions */
+                        false // ignore bound regions, keep visiting
                     }
                     _ => (self.callback)(r),
                 }
-
-                false // keep visiting
             }
         }
     }

src/librustc_mir/borrow_check/mod.rs

@@ -128,6 +128,8 @@ fn do_mir_borrowck<'a, 'gcx, 'tcx>(
     input_mir: &Mir<'gcx>,
     def_id: DefId,
 ) -> BorrowCheckResult<'gcx> {
+    debug!("do_mir_borrowck(def_id = {:?})", def_id);
+
     let tcx = infcx.tcx;
     let attributes = tcx.get_attrs(def_id);
     let param_env = tcx.param_env(def_id);
@@ -319,10 +321,14 @@ fn do_mir_borrowck<'a, 'gcx, 'tcx>(
         }
     }
 
-    BorrowCheckResult {
+    let result = BorrowCheckResult {
         closure_requirements: opt_closure_req,
         used_mut_upvars: mbcx.used_mut_upvars,
-    }
+    };
+
+    debug!("do_mir_borrowck: result = {:#?}", result);
+
+    result
 }
 
 #[allow(dead_code)]