From e7a9e7aef2f90dd3e166be0c42570a70890d5dce Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Thu, 7 Jun 2018 05:14:32 -0400
Subject: [PATCH] extract a `enabled` helper to remove some ad-hoc conditionals

---
 src/librustc_mir/borrow_check/nll/facts.rs | 10 ++++++++++
 src/librustc_mir/borrow_check/nll/mod.rs   |  4 +---
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/src/librustc_mir/borrow_check/nll/facts.rs b/src/librustc_mir/borrow_check/nll/facts.rs
index 6cb8e64b9f5..fe2fc7e37b7 100644
--- a/src/librustc_mir/borrow_check/nll/facts.rs
+++ b/src/librustc_mir/borrow_check/nll/facts.rs
@@ -23,6 +23,10 @@ use std::path::Path;
 crate type AllFacts = PoloniusAllFacts<RegionVid, BorrowIndex, LocationIndex>;
 
 crate trait AllFactsExt {
+    /// Returns true if there is a need to gather `AllFacts` given the
+    /// current `-Z` flags.
+    fn enabled(tcx: TyCtxt<'_, '_, '_>) -> bool;
+
     fn write_to_dir(
         &self,
         dir: impl AsRef<Path>,
@@ -31,6 +35,12 @@ crate trait AllFactsExt {
 }
 
 impl AllFactsExt for AllFacts {
+    /// Return
+    fn enabled(tcx: TyCtxt<'_, '_, '_>) -> bool {
+        tcx.sess.opts.debugging_opts.nll_facts
+            || tcx.sess.opts.debugging_opts.polonius
+    }
+
     fn write_to_dir(
         &self,
         dir: impl AsRef<Path>,
diff --git a/src/librustc_mir/borrow_check/nll/mod.rs b/src/librustc_mir/borrow_check/nll/mod.rs
index dcb52a3b18a..e26665e8291 100644
--- a/src/librustc_mir/borrow_check/nll/mod.rs
+++ b/src/librustc_mir/borrow_check/nll/mod.rs
@@ -91,9 +91,7 @@ pub(in borrow_check) fn compute_regions<'cx, 'gcx, 'tcx>(
     Option<Rc<Output<RegionVid, BorrowIndex, LocationIndex>>>,
     Option<ClosureRegionRequirements<'gcx>>,
 ) {
-    let mut all_facts = if infcx.tcx.sess.opts.debugging_opts.nll_facts
-        || infcx.tcx.sess.opts.debugging_opts.polonius
-    {
+    let mut all_facts = if AllFacts::enabled(infcx.tcx) {
         Some(AllFacts::default())
     } else {
         None