Merge branch 'master' into 2phase-on-edition

Author: RalfJung

.appveyor.yml

@@ -21,7 +21,7 @@ install:
     - rustup-init.exe -y --default-host %TARGET% --default-toolchain stable
     - set PATH=%USERPROFILE%\.cargo\bin;%PATH%
     # Install "master" toolchain
-    - cargo install rustup-toolchain-install-master
+    - cargo install rustup-toolchain-install-master & exit 0
     - set /p RUSTC_HASH=<rust-version
     - rustup-toolchain-install-master -f -n master %RUSTC_HASH% -c cargo -c rust-src
     - rustup default master

README.md

@@ -53,6 +53,8 @@ Install Miri via `rustup`:
 rustup component add miri
 ```
 
+If `rustup` says the `miri` component is unavailable, that's because not all nightly releases come with all tools. Check out [this website](https://rust-lang.github.io/rustup-components-history) to determine a nightly version that comes with Miri and install that, e.g. using `rustup install nightly-2019-03-28`.
+
 Now you can run your project in Miri:
 
 1. Run `cargo clean` to eliminate any cached dependencies.  Miri needs your