diff --git a/src/doc/src/reference/unstable.md b/src/doc/src/reference/unstable.md
index b9bead0eed9..e0769db917a 100644
--- a/src/doc/src/reference/unstable.md
+++ b/src/doc/src/reference/unstable.md
@@ -1141,7 +1141,7 @@ You can use the flag like this:
 cargo check -Z unstable-options -Z check-cfg
 ```
 
-### `cargo::rustc-check-cfg=CHECK_CFG`
+### `cargo:rustc-check-cfg=CHECK_CFG`
 
 The `rustc-check-cfg` instruction tells Cargo to pass the given value to the
 `--check-cfg` flag to the compiler. This may be used for compile-time
@@ -1157,7 +1157,8 @@ You can use the instruction like this:
 
 ```rust,no_run
 // build.rs
-println!("cargo::rustc-check-cfg=cfg(foo, bar)");
+println!("cargo:rustc-check-cfg=cfg(foo)");
+println!("cargo:rustc-check-cfg=cfg(bar, values(\"first\", \"second\"))");
 ```
 
 ```