diff --git a/rust-version b/rust-version
index 685628ac99d..5a3074f09a4 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-18b53cefdf7456bf68937b08e377b7e622a115c2
+9a251644fa2adde5f46eea8d342b7e60e4716039
diff --git a/src/bin/miri.rs b/src/bin/miri.rs
index 0030c24b19e..3fac07a41a6 100644
--- a/src/bin/miri.rs
+++ b/src/bin/miri.rs
@@ -1,4 +1,4 @@
-#![feature(rustc_private, bool_to_option, stmt_expr_attributes)]
+#![feature(rustc_private, stmt_expr_attributes)]
 #![allow(clippy::manual_range_contains)]
 
 extern crate rustc_data_structures;
diff --git a/src/lib.rs b/src/lib.rs
index 3f1ba574ce0..ee7a3bcdc5c 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -4,7 +4,6 @@
 #![feature(never_type)]
 #![feature(try_blocks)]
 #![feature(let_else)]
-#![feature(bool_to_option)]
 #![feature(io_error_more)]
 #![warn(rust_2018_idioms)]
 #![allow(
diff --git a/tests/run-pass/stacked-borrows/2phase.rs b/tests/run-pass/stacked-borrows/2phase.rs
index 948da140477..065c76913a7 100644
--- a/tests/run-pass/stacked-borrows/2phase.rs
+++ b/tests/run-pass/stacked-borrows/2phase.rs
@@ -1,5 +1,4 @@
 // compile-flags: -Zmiri-tag-raw-pointers
-#![allow(mutable_borrow_reservation_conflict)]
 
 trait S: Sized {
     fn tpb(&mut self, _s: Self) {}