Deny unused-crate-dependencies in ci workflow

Author: kezhuw

.github/workflows/ci.yml

@@ -23,6 +23,8 @@ jobs:
       run: cargo fmt --all -- --check
   build:
     runs-on: ubuntu-latest
+    env:
+      RUSTFLAGS: -Dunused-crate-dependencies
     steps:
     - uses: actions/checkout@v2
     - uses: Swatinem/rust-cache@v1

Makefile

@@ -12,7 +12,7 @@ lint:
 	cargo clippy --all-features --no-deps -- -D clippy::all
 
 build:
-	cargo build-all-features
+	RUSTFLAGS=-Dunused-crate-dependencies cargo build-all-features
 
 test:
 	cargo test --all-features