diff --git a/Cargo.toml b/Cargo.toml
index c50ce8d1db..ee288f98a8 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -2,6 +2,7 @@
 name = "roc"
 version = "0.1.0"
 authors = ["Richard Feldman <oss@rtfeldman.com>"]
+edition = "2018"
 
 [dependencies]
 log = "0.4.8"