Allow renamed lints and enable clippy-preview on stable

Allow renamed_and_removed_lints because new warnings on nightly
recommend the new clippy::* attribute syntax, which is not yet
stable (and we turn all warnings into hard errors).

Additionally, clippy-preview is now installed and run on stable.
We were previously running clippy on an old nightly from late June and
no new warnings (except the one noted above) are raised on nightly so
switching to the -preview component on stable shouldn't introduce
churn.  Also, unlike with rustfmt, we can fix and merge any clippy
recommendations before they hit the stable channel, so we don't have to
sync with new releases.

Author: jtgeibel

.travis.yml

@@ -47,16 +47,14 @@ matrix:
   allow_failures:
     - rust: nightly
   include:
-    - rust: nightly-2018-06-26
-      script:
-        - cargo install --force clippy --vers 0.0.210
-        - cargo clippy
     - rust: stable
       before_install:
         - nvm install 10
         - rustup component add rustfmt-preview
+        - rustup component add clippy-preview
       script:
         - cargo fmt -- --check
+        - cargo clippy
         - cargo build
         - cargo test
         - npm install

src/lib.rs

@@ -7,6 +7,8 @@
 #![deny(missing_debug_implementations, missing_copy_implementations)]
 #![deny(bare_trait_objects)]
 #![recursion_limit = "256"]
+
+#![allow(renamed_and_removed_lints)] // This can be removed once the new clippy:: lint sytnax is stable
 #![allow(unknown_lints, proc_macro_derive_resolution_fallback)] // This can be removed after diesel-1.4
 
 extern crate ammonia;

src/tests/all.rs

@@ -1,4 +1,6 @@
 #![deny(warnings)]
+
+#![allow(renamed_and_removed_lints)] // This can be removed once the new clippy:: lint sytnax is stable
 #![allow(unknown_lints, proc_macro_derive_resolution_fallback)] // This can be removed after diesel-1.4
 
 extern crate cargo_registry;