Auto merge of #2103 - RalfJung:rustup, r=RalfJung

rustup

rust-version

@@ -1 +1 @@
-18b53cefdf7456bf68937b08e377b7e622a115c2
+9a251644fa2adde5f46eea8d342b7e60e4716039

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;

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(

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) {}