diff --git a/src/librustc_typeck/astconv.rs b/src/librustc_typeck/astconv.rs
index 7cc8e067132f878257772434afd4ab46d0f30412..1471e235156eb8ade6a050fe0668ceb92e75565a 100644
--- a/src/librustc_typeck/astconv.rs
+++ b/src/librustc_typeck/astconv.rs
@@ -1206,65 +1206,6 @@ pub fn ty_of_fn(&self,
         bare_fn_ty
     }
 
-    pub fn ty_of_closure(&self,
-        unsafety: hir::Unsafety,
-        decl: &hir::FnDecl,
-        abi: abi::Abi,
-        expected_sig: Option<ty::FnSig<'tcx>>)
-        -> ty::PolyFnSig<'tcx>
-    {
-        debug!("ty_of_closure(expected_sig={:?})",
-               expected_sig);
-
-        let input_tys = decl.inputs.iter().enumerate().map(|(i, a)| {
-            let expected_arg_ty = expected_sig.as_ref().and_then(|e| {
-                // no guarantee that the correct number of expected args
-                // were supplied
-                if i < e.inputs().len() {
-                    Some(e.inputs()[i])
-                } else {
-                    None
-                }
-            });
-
-            let input_ty = self.ty_of_arg(a, expected_arg_ty);
-            debug!("ty_of_closure: i={} input_ty={:?} expected_arg_ty={:?}",
-                   i, input_ty, expected_arg_ty);
-
-            input_ty
-        });
-
-        let expected_ret_ty = expected_sig.as_ref().map(|e| e.output());
-
-        let output_ty = match decl.output {
-            hir::Return(ref output) => {
-                if let (&hir::TyInfer, Some(expected_ret_ty)) = (&output.node, expected_ret_ty) {
-                    self.record_ty(output.hir_id, expected_ret_ty, output.span);
-                    expected_ret_ty
-                } else {
-                    self.ast_ty_to_ty(&output)
-                }
-            }
-            hir::DefaultReturn(span) => {
-                if let Some(expected_ret_ty) = expected_ret_ty {
-                    expected_ret_ty
-                } else {
-                    self.ty_infer(span)
-                }
-            }
-        };
-
-        debug!("ty_of_closure: output_ty={:?}", output_ty);
-
-        ty::Binder(self.tcx().mk_fn_sig(
-            input_tys,
-            output_ty,
-            decl.variadic,
-            unsafety,
-            abi
-        ))
-    }
-
     /// Given the bounds on an object, determines what single region bound (if any) we can
     /// use to summarize this type. The basic idea is that we will use the bound the user
     /// provided, if they provided one, and otherwise search the supertypes of trait bounds
diff --git a/src/librustc_typeck/check/closure.rs b/src/librustc_typeck/check/closure.rs
index 077050167db287bda9a2caa0da23686d2d8683a8..fac2119cb44d6357f3417d34f14ecf42dda589b6 100644
--- a/src/librustc_typeck/check/closure.rs
+++ b/src/librustc_typeck/check/closure.rs
@@ -56,11 +56,7 @@ fn check_closure(&self,
                expected_sig);
 
         let expr_def_id = self.tcx.hir.local_def_id(expr.id);
-        let sig = AstConv::ty_of_closure(self,
-                                         hir::Unsafety::Normal,
-                                         decl,
-                                         Abi::RustCall,
-                                         expected_sig);
+        let sig = self.ty_of_closure(decl, expected_sig);
 
         debug!("check_closure: ty_of_closure returns {:?}", sig);
 
@@ -274,4 +270,72 @@ fn self_type_matches_expected_vid(&self,
             _ => None,
         }
     }
+
+    /// Invoked to compute the signature of a closure expression. This
+    /// combines any user-provided type annotations (e.g., `|x: u32|
+    /// -> u32 { .. }`) with the expected signature.
+    ///
+    /// The arguments here are a bit odd-ball:
+    ///
+    /// - `decl`: the HIR declaration of the closure
+    /// - `expected_sig`: the expected signature (if any). Note that
+    ///   this is missing a binder: that is, there may be late-bound
+    ///   regions with depth 1, which are bound then by the closure.
+    fn ty_of_closure(&self,
+                     decl: &hir::FnDecl,
+                     expected_sig: Option<ty::FnSig<'tcx>>)
+                     -> ty::PolyFnSig<'tcx>
+    {
+        let astconv: &AstConv = self;
+
+        debug!("ty_of_closure(expected_sig={:?})",
+               expected_sig);
+
+        let input_tys = decl.inputs.iter().enumerate().map(|(i, a)| {
+            let expected_arg_ty = expected_sig.as_ref().and_then(|e| {
+                // no guarantee that the correct number of expected args
+                // were supplied
+                if i < e.inputs().len() {
+                    Some(e.inputs()[i])
+                } else {
+                    None
+                }
+            });
+
+            let input_ty = astconv.ty_of_arg(a, expected_arg_ty);
+            debug!("ty_of_closure: i={} input_ty={:?} expected_arg_ty={:?}",
+                   i, input_ty, expected_arg_ty);
+
+            input_ty
+        });
+
+        let expected_ret_ty = expected_sig.as_ref().map(|e| e.output());
+
+        let output_ty = match decl.output {
+            hir::Return(ref output) => {
+                if let (&hir::TyInfer, Some(expected_ret_ty)) = (&output.node, expected_ret_ty) {
+                    astconv.record_ty(output.hir_id, expected_ret_ty, output.span);
+                    expected_ret_ty
+                } else {
+                    astconv.ast_ty_to_ty(&output)
+                }
+            }
+            hir::DefaultReturn(span) => {
+                if let Some(expected_ret_ty) = expected_ret_ty {
+                    expected_ret_ty
+                } else {
+                    astconv.ty_infer(span)
+                }
+            }
+        };
+
+        debug!("ty_of_closure: output_ty={:?}", output_ty);
+
+        ty::Binder(self.tcx.mk_fn_sig(
+            input_tys,
+            output_ty,
+            decl.variadic,
+            hir::Unsafety::Normal,
+            Abi::RustCall))
+    }
 }