Cache cargo binaries

.travis.yml

@@ -13,6 +13,13 @@ branches:
     - trying.tmp
     - staging.tmp
 
+cache:
+  directories:
+    - $HOME/.cargo
+before_cache:
+  - cargo install -Z install-upgrade cargo-cache --debug
+  - cargo cache --autoclean
+
 env:
  global:
    - RUST_BACKTRACE=1
@@ -23,8 +30,10 @@ before_install:
   - export PATH="$HOME/.cargo/bin:$PATH"
 install:
   - |
-    if [ -z ${INTEGRATION} ]; then
-      rustup component add rustfmt || cargo install --git https://github.com/rust-lang/rustfmt/ --force
+    if [[ -z ${INTEGRATION} ]]; then
+      if ! rustup component add rustfmt; then
+        cargo install -Z install-upgrade --git https://github.com/rust-lang/rustfmt --bin rustfmt
+      fi
       if [ "$TRAVIS_OS_NAME" == "linux" ]; then
         . $HOME/.nvm/nvm.sh
         nvm install stable

appveyor.yml

@@ -13,12 +13,18 @@ branches:
       - auto
       - try
 
+cache:
+    - '%USERPROFILE%\.cargo'
+on_finish:
+    - cargo install -Z install-upgrade cargo-cache --debug
+    - cargo cache --autoclean
+
 install:
     - curl -sSf -o rustup-init.exe https://win.rustup.rs/
     - rustup-init.exe -y --default-host %TARGET% --default-toolchain nightly --profile=minimal
     - set PATH=%PATH%;C:\Users\appveyor\.cargo\bin
     - del rust-toolchain
-    - cargo install rustup-toolchain-install-master --debug || echo "rustup-toolchain-install-master already installed"
+    - cargo install -Z install-upgrade rustup-toolchain-install-master --debug || echo "rustup-toolchain-install-master already installed"
     - rustup-toolchain-install-master -f -n master
     - rustup component add rustfmt --toolchain nightly & exit 0 # Format test handles missing rustfmt
     - rustup default master

setup-toolchain.sh

@@ -7,6 +7,7 @@ cd "$(dirname "$0")" || exit
 
 if ! command -v rustup-toolchain-install-master > /dev/null; then
   cargo install \
+    -Z install-upgrade \
     rustup-toolchain-install-master \
     --bin rustup-toolchain-install-master \
     --debug