Enable deny-warnings feature everywhere in CI

ci/base-tests.sh

@@ -15,9 +15,9 @@ fi
 cargo build --features deny-warnings
 cargo test --features deny-warnings
 
-(cd clippy_lints && cargo test)
-(cd rustc_tools_util && cargo test)
-(cd clippy_dev && cargo test)
+(cd clippy_lints && cargo test --features deny-warnings)
+(cd rustc_tools_util && cargo test --features deny-warnings)
+(cd clippy_dev && cargo test --features deny-warnings)
 
 # make sure clippy can be called via ./path/to/cargo-clippy
 (

clippy_dev/Cargo.toml

@@ -11,3 +11,6 @@ regex = "1"
 lazy_static = "1.0"
 shell-escape = "0.1"
 walkdir = "2"
+
+[features]
+deny-warnings = []

clippy_dev/src/lib.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(feature = "deny-warnings", deny(warnings))]
+
 use itertools::Itertools;
 use lazy_static::lazy_static;
 use regex::Regex;

clippy_dev/src/main.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(feature = "deny-warnings", deny(warnings))]
+
 extern crate clap;
 extern crate clippy_dev;
 extern crate regex;

rustc_tools_util/Cargo.toml

@@ -9,4 +9,8 @@ license = "MIT OR Apache-2.0"
 keywords = ["rustc", "tool", "git", "version", "hash"]
 categories = ["development-tools"]
 edition = "2018"
+
 [dependencies]
+
+[features]
+deny-warnings = []

rustc_tools_util/src/lib.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(feature = "deny-warnings", deny(warnings))]
+
 use std::env;
 
 #[macro_export]