diff --git a/lib/filecheck/src/lib.rs b/lib/filecheck/src/lib.rs
index f6c53c5dcf..66fe6036ab 100644
--- a/lib/filecheck/src/lib.rs
+++ b/lib/filecheck/src/lib.rs
@@ -234,6 +234,8 @@
 //! This will match `"one, two"` , but not `"one,two"`. Without the `$()`, trailing whitespace
 //! would be trimmed from the pattern.
 
+#![deny(missing_docs)]
+
 pub use error::{Error, Result};
 pub use variable::{VariableMap, Value, NO_VARIABLES};
 pub use checker::{Checker, CheckerBuilder};
diff --git a/lib/filecheck/src/variable.rs b/lib/filecheck/src/variable.rs
index 51bc38fc07..1a43f1428a 100644
--- a/lib/filecheck/src/variable.rs
+++ b/lib/filecheck/src/variable.rs
@@ -19,7 +19,9 @@ pub fn varname_prefix(s: &str) -> usize {
 /// A variable can contain either a regular expression or plain text.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum Value<'a> {
+    /// Verbatim text.
     Text(Cow<'a, str>),
+    /// Regular expression.
     Regex(Cow<'a, str>),
 }