diff --git a/Cargo.toml b/Cargo.toml
index 019c08ec..bfd79f23 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -137,3 +137,7 @@ required-features = ["std"]
 [[example]]
 name = "io"
 required-features = ["std"]
+
+[[example]]
+name = "foo"
+required-features = ["std"]
diff --git a/examples/foo.rs b/examples/foo.rs
index cb628d1b..ae58e43a 100644
--- a/examples/foo.rs
+++ b/examples/foo.rs
@@ -180,7 +180,8 @@ fn eval<'a>(
 }
 
 fn main() {
-    let src = std::fs::read_to_string(std::env::args().nth(1).unwrap()).unwrap();
+    let usage = "Run `cargo run --example foo -- examples/sample.foo`";
+    let src = std::fs::read_to_string(std::env::args().nth(1).expect(usage)).expect(usage);
 
     match parser().parse(&src).into_result() {
         Ok(ast) => match eval(&ast, &mut Vec::new(), &mut Vec::new()) {