diff --git a/src/librustc_cratesio_shim/Cargo.toml b/src/librustc_cratesio_shim/Cargo.toml
index b8e494e4040ec..6bdfbe09354b4 100644
--- a/src/librustc_cratesio_shim/Cargo.toml
+++ b/src/librustc_cratesio_shim/Cargo.toml
@@ -15,6 +15,7 @@
 authors = ["The Rust Project Developers"]
 name = "rustc_cratesio_shim"
 version = "0.0.0"
+edition = "2018"
 
 [lib]
 crate-type = ["dylib"]
diff --git a/src/librustc_cratesio_shim/src/lib.rs b/src/librustc_cratesio_shim/src/lib.rs
index 4024087f4d3ef..4c170f4f5f6f9 100644
--- a/src/librustc_cratesio_shim/src/lib.rs
+++ b/src/librustc_cratesio_shim/src/lib.rs
@@ -1,3 +1,5 @@
+#![deny(rust_2018_idioms)]
+
 // See Cargo.toml for a comment explaining this crate.
 #![allow(unused_extern_crates)]