diff --git a/src/tools/cargotest/Cargo.toml b/src/tools/cargotest/Cargo.toml
index f4163a6f117..3811fee3936 100644
--- a/src/tools/cargotest/Cargo.toml
+++ b/src/tools/cargotest/Cargo.toml
@@ -2,6 +2,7 @@
 name = "cargotest2"
 version = "0.1.0"
 authors = ["Brian Anderson <banderson@mozilla.com>"]
+edition = "2018"
 
 [[bin]]
 name = "cargotest"
diff --git a/src/tools/cargotest/main.rs b/src/tools/cargotest/main.rs
index 120f238eb45..7f3c159075b 100644
--- a/src/tools/cargotest/main.rs
+++ b/src/tools/cargotest/main.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 use std::env;
 use std::process::Command;
 use std::path::{Path, PathBuf};