diff --git a/src/expression.rs b/src/expression.rs
index 0e4f386..a8f6a49 100644
--- a/src/expression.rs
+++ b/src/expression.rs
@@ -55,7 +55,7 @@ pub fn rust_name(input: &[u8]) -> PResult<&str> {
     map_res(
         recognize(pair(
             alt((tag("_"), alpha1)),
-            opt(is_a("_0123456789abcdefghijklmnopqrstuvwxyz")),
+            opt(is_a("_0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")),
         )),
         input_to_str,
     )(input)
diff --git a/src/template.rs b/src/template.rs
index 8c5d939..5b4aa2f 100644
--- a/src/template.rs
+++ b/src/template.rs
@@ -241,6 +241,11 @@ mod test {
         check_type_expr("SomeTypeWithRef<'_>");
     }
 
+    #[test]
+    fn multiword_constant() {
+        check_type_expr("ONE_TWO_THREE");
+    }
+
     fn check_type_expr(expr: &str) {
         assert_eq!(type_expression(expr.as_bytes()), Ok((&b""[..], ())));
     }