From 46e247bcec13f3e1e850c3baffc23e64a8023ae4 Mon Sep 17 00:00:00 2001
From: Matthew Jasper <mjjasper1@gmail.com>
Date: Thu, 13 Sep 2018 21:36:15 +0100
Subject: [PATCH] Don't check for conflicting borrows of `ReadForMatch`es

---
 src/librustc_mir/borrow_check/mod.rs | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/librustc_mir/borrow_check/mod.rs b/src/librustc_mir/borrow_check/mod.rs
index 5d919e88cad..06394ee44cc 100644
--- a/src/librustc_mir/borrow_check/mod.rs
+++ b/src/librustc_mir/borrow_check/mod.rs
@@ -499,11 +499,20 @@ impl<'cx, 'gcx, 'tcx> DataflowResultsConsumer<'cx, 'tcx> for MirBorrowckCtxt<'cx
                 );
             }
             StatementKind::FakeRead(_, ref place) => {
-                self.access_place(
+                // Read for match doesn't access any memory and is used to
+                // assert that a place is safe and live. So we don't have to
+                // do any checks here.
+                //
+                // FIXME: Remove check that the place is initialized. This is
+                // needed for now because matches don't have never patterns yet.
+                // So this is the only place we prevent
+                //      let x: !;
+                //      match x {};
+                // from compiling.
+                self.check_if_path_or_subpath_is_moved(
                     ContextKind::FakeRead.new(location),
+                    InitializationRequiringAction::Use,
                     (place, span),
-                    (Deep, Read(ReadKind::Borrow(BorrowKind::Shared))),
-                    LocalMutationIsAllowed::No,
                     flow_state,
                 );
             }