Auto merge of rust-lang#4273 - mikerite:deny-warnings, r=flip1995

Deny warnings in CI

changelog: none

Cargo.toml

@@ -61,4 +61,5 @@ rustc-workspace-hack = "1.0.0"
 rustc_tools_util = { version = "0.2.0", path = "rustc_tools_util"}
 
 [features]
+deny-warnings = []
 debugging = []

ci/base-tests.sh

@@ -7,8 +7,8 @@ if [ "$TRAVIS_OS_NAME" == "linux" ]; then
   remark -f *.md -f doc/*.md > /dev/null
 fi
 # build clippy in debug mode and run tests
-cargo build --features debugging
-cargo test --features debugging
+cargo build --features "debugging deny-warnings"
+cargo test --features "debugging deny-warnings"
 # for faster build, share target dir between subcrates
 export CARGO_TARGET_DIR=`pwd`/target/
 (cd clippy_lints && cargo test)

clippy_lints/src/lib.rs

@@ -9,6 +9,7 @@
 #![recursion_limit = "512"]
 #![warn(rust_2018_idioms, trivial_casts, trivial_numeric_casts)]
 #![deny(rustc::internal)]
+#![cfg_attr(feature = "deny-warnings", deny(warnings))]
 #![feature(crate_visibility_modifier)]
 #![feature(concat_idents)]
 

src/driver.rs

@@ -1,3 +1,4 @@
+#![cfg_attr(feature = "deny-warnings", deny(warnings))]
 #![feature(rustc_private)]
 
 // FIXME: switch to something more ergonomic here, once available.

src/main.rs

@@ -1,3 +1,5 @@
+#![cfg_attr(feature = "deny-warnings", deny(warnings))]
+
 use rustc_tools_util::*;
 
 const CARGO_CLIPPY_HELP: &str = r#"Checks a package to catch common mistakes and improve your Rust code.